TI JOURNAL 18 2-3

ADJUSTABLE ABOVE-KNEE PROSTHETIC INTERFACE 177



Subject Bock Healthcare, Duderstadt, Germany). The subject
Subject inclusion was unilateral TFA, either gen- was physically capable of completing the functional
der, any ethnicity, between 18 and 65 years of age, testing protocol. The subject had normal cognitive
and <113.4 kg. Exclusion criteria included non-TFA ability and was able to provide informed consent and
level, <18 and >65 years of age, and >113.4 kg. The socket fitting feedback to investigators.
subject identified had the following characteristics: Interventions Tested
male, 24 years old, right unilateral TFA, 1.7 m, 70.3 kg, 1. IRC. This design is characterized by a high
and a BMI of 24 kg/m . The subject elected for limb (proximal) brim that medially contains the ischio-
2
amputation at age 19, secondary to osteosarcoma. pubic ramus and is the SOC. The socket consisted of
His activity level was K4 per his medical record. No a rigid thermoplastic material. This was suspended
other known injuries were present. Subject exhibited with a gel pin-locking liner. The subject was casted
upper and LE active range of motion within normal and fit into a custom SOC socket over the same liner
limits. His current prosthesis included a pin-lock gel he had been using to eliminate confounding and the
liner, Infinite Socket™ (LIM Innovations, San Fran- potential introduction of dermatologic issues.
cisco, CA, USA), Genium knee, and Triton foot (Otto


Figure 1. Interventions tested. Pictured left is the standard of care socket with the 5-ply sock and the pin system. Pictured right is the
Infinite adjustable socket.

178 KAHLE ET AL.



2. Adjustable TFA Interface. The Infinite Socket™ six study conditions across three repeated indepen-
is a custom-molded four-strut design combined with dent utilization periods, each followed by an outcome
a textile brim and tensioner to contain and control assessment. The study design controlled for all pros-
the pelvis and femur and soft tissues across a varying thetic variables (Table 1), as the subject utilized his
volume. Adjustments can be made by both clinicians usual prosthetic components with only the exception
and patients to manage long-term and daily fluctua- of the socket (independent variable) throughout the
tions. The pivoting and sliding connection between study. The order of testing was randomized using an
the struts and base provides additional flexibility in offsite computer randomized number generator to
adjustability as well as shock absorption and energy improve methodological quality and minimize bias
response. The dynamic frame of the Infinite socket™ risk. Further, raters and the study statistician were
has a textile interface that is reportedly low in friction, blinded to the independent variables. Data collec-
anti-microbial, durable, and washable. The Infinite tion was completed over three sequential days. Each
Socket™ achieves control and pressure distribution data collection period began at the same time of day.
through multiple custom components, which include The subject was instructed to maintain fluid, salt
an ischial seat, proximal brim, four struts, and a flex- intake, and diet over the study period. Weight was
ible inner distal cup. recorded each day, in addition to RL circumference
measurements, to help ensure volume consistency.
Study Design A ten-minute rest period between conditions was
To simulate the same volume fluctuations an ampu- provided between tests to mitigate confounding from
tee would experience, three conditions were tested. fatigue. Blood pressure and heart rate were moni-
First, to establish a baseline (BASE), the subject was tored before each test to ensure normalization prior
casted over his Otto Bock 6Y87 3D TF pin-locking to re-testing.
liner (Otto Bock Healthcare, Duderstadt, Germany)
and a five-ply sock. Both the SOC and Infinite™ sock- Outcome Measures
ets were fabricated from this cast. The sockets were Physical performance measures were selected to
then fit and adjusted to this configuration to ensure assess functional capability and safety differences
an equal baseline. Second, to simulate volume loss between the two socket conditions. For instance,
(VLOSS), the five-ply sock was removed from the speed of movement and walking are valuable clinical
RL and liner, and then the subject was tested in this tests of functionality and provide good identification
condition. This constituted a 2 cm circumferential of multiple-falls risk (15-17). Slower gait has also been
volume change (VLOSS) less than the BASE circum- shown to be an indication of fall risk (18). Thus, the
ference. Third, to simulate volume gain (VGAIN), the following tests were selected:
five-ply sock plus an eight-ply sock was added to the
RL and liner for a total of 13-ply. This constituted a 2 a. L-Test: a short walking test with transitional
cm circumferential volume change (VGAIN) more movements and multiple turns
than the BASE circumference. b. Four Square Step Test (4SST): a brief assess-
An experimental case study design was utilized for ment of multi-directional stepping (15)
this project. An independent researcher randomized c. Two-Minute Walk Test (2MWT): a test to pro-
Table 1. Table of Variables
Table 1. Table of Variables
Independent Dependent Controlled
 SOC- IRC TFA  Subjective Response (i.e.,  Accommodation
Interface Comfort, Pain)  Clinical Schedule
 LIM -Adjustable TFA  Mobility, i.e., 4SST  Environment
Interface  Function, i.e., AMP  Knee, Foot, Liner,
 Gait Speed, L-Test, 2MWT Suspension

ADJUSTABLE ABOVE-KNEE PROSTHETIC INTERFACE 179



vide insight into cardiorespiratory and func- approach. Repeated measures assessment was selected
tional capacity and determine walking speed to determine differences across assessment sessions
d. The Amputee Mobility Predictor (AMP): an and between conditions. Additionally, differences
instrument used to determine mobility and were assessed at individual volume points (i.e., depen-
ambulatory status for amputees dent, between-group comparison tests) as well as
e. Socket Comfort Score (SCS): a valid, reliable, cumulatively across conditions. Parametric tests were
and sensitive assessment between practitioner used when possible (i.e., normal distribution); other-
and patient that indicates comfort and the need wise, non-parametric equivalent tests were selected.
for interface adjustments (19) Statistical significance was set a priori at p ≤ 0.05. It
f. Pain Scale: a valid and reliable tool for deter- must be noted that the use of statistical analysis with
mining the severity of specific types of pain case studies is not novel, but it is also not a commonly
accepted practice. However, at times, data generation
Data Analyses from case studies may be mathematically conducive
Data were entered into a database and analyzed to analyses that may provide insight into a magni-
for normality and completeness. Central tendency, tutde of effect that could be useful for power and
variance, and percent differences were calculated sample estimates for future expanded research with
where possible. The analysis included a two-part the intervention (20).



Figure 2. Results for: Socket Comfort Score (SCS), 2-Minute Walk Test (2MWT), 4 Square Step Test (4SST), and L Test.
*Statistical significance p ≤ 0.05, NT = not tested due to missing data.

180 KAHLE ET AL.



RESULTS had a total of 34 falls. Further, there were no revi-
In the BASE condition, SCS in the Infinite socket sions in the IPOP group, but eight patients in the
improved 37% over SOC, L-Test improved 21%, non-IPOP group required 10 revisions to a higher
FSST improved 19%, whereas 2MWT demonstrated amputation level, four of which were related to falls
equivalence. In the VLOSS condition, SCS improved (24). Others have noted that interventions that could
93%, L-Test improved 22%, FSST improved 25%, prevent secondary effects of falling in amputee reha-
and 2MWT improved 26% with the Infinite socket bilitation would be beneficial, including prosthetic
compared with the SOC. The VGAIN condition could devices that better accommodate the acute phase
not be analyzed across all three data collections, as when volume fluctuation is most prevalent (25-27).
the patient was unable to don the prosthesis on the Evidence is not available comparing the efficacy of
second and third collection due to pain and the inabil- interventions addressing issues related to poor socket
ity to don the SOC prosthesis. All aggregated data fit during the intermediate stage of rehabilitation in
(BASE, VLOSS, VGAIN), SCS improved 50%, L-Test TFA patients. An adjustable TFA socket interface that
improved 18%, 2MWT improved 21%, and 4SST better addresses the known problems of the SOC IRC
improved 16% using the Infinite socket compared socket interface could improve functional outcomes.
with SOC (Figure 2). Additional research is required to develop appropriate
intervention strategies to ameliorate the risk of falling
DISCUSSION during amputee rehabilitation (28-31).
In this study, we simulated minimum volume fluc- This case study compared the efficacy of an alter-
tuations that have been reported to occur commonly native TFA intervention for volume fluctuation. The
among amputees during the acute and intermediate socket is the most important element of the prosthe-
stage of rehabilitation. Generally, improvements with sis. However, prosthetic fit in the TFA during volume
the Infinite socket were shown in the outcomes of fluctuations is problematic using the current SOC
SCS, mobility, and gait speed. These functional out- prosthetic socket interface. As the socket loses its fit
comes are predictive of falling. SCS, mobility, and quality, the user loses control and comfort, which
gait speed should be a focus of interventions used in eventually leads to pain, compromised function,
rehabilitation of the amputee. Preventing falls during reduction in use, and potentially prosthetic aban-
the acute and intermediate stages of amputation reha- donment. The current SOC clinical procedure for
bilitation should be a priority in minimizing adverse volume management is the addition and subtrac-
effects. Curtze et al. reported the annual fall incidence tion of prosthetic socks of various ply to fill the void
in lower limb amputees as approximately 50% (21,22). between RL and socket. Although common, this
Injuries are sustained in 61% of falls, necessitating method is sub-optimal. An adjustable prosthetic
fall prevention strategies, such as improved socket socket is advantageous in assisting prosthetic users
interfaces, for the LE amputee (23). Falls in ampu- in managing common volume fluctuations. A socket
tees can be mitigated with strength and gait training with instant adjustability could be a valuable alterna-
programs. However, to begin a strength and walk- tive to common volume management strategies and
ing program, the use of an effective well-fit socket may help reduce adverse effects of prosthetic use due
interface is imperative. A prosthetic socket interface to poor volume management and socket fit (7,32-36).
that accommodates an amputee’s volume fluctuation,
known to occur in the acute and intermediate stage Limitations
of rehabilitation, could improve clinical outcomes Case studies could provide insight into important
and function. For instance, Schon et al. reported variables that should be considered in a larger clinical
on the use of an ambulatory immediate post-op- trial, and their conclusions merit consideration in the
erative prosthesis (IPOP) and found that none of development of future clinical trials. The outcome
the 19 patients had falls while wearing the IPOP. measures selected in this case showed a difference
However, in the non-IPOP group, 12 of 23 patients between the socket conditions. However, the strategy

ADJUSTABLE ABOVE-KNEE PROSTHETIC INTERFACE 181



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Technology and Innovation, Vol. 18, pp. 185-191, 2016 ISSN 1949-8241 • E-ISSN 1949-825X
Printed in the USA. All rights reserved. http://dx.doi.org/10.21300/18.2-3.2016.185
Copyright © 2016 National Academy of Inventors. www.technologyandinnovation.org

CONCURRENT VALIDITY OF THE CONTINUOUS SCALE-PHYSICAL

FUNCTIONAL PEFORMANCE-10 (CS-PFP-10) TEST
IN TRANSFEMORAL AMPUTEES

M. Jason Highsmith , Jason T. Kahle , Rebecca M. Miro , M. Elaine Cress ,
1-3
1
4,5
6
William S. Quillen , Stephanie L. Carey , Rajiv V. Dubey , and Larry J. Mengelkoch 8
7
7
1
1 School of Physical Therapy & Rehabilitation Sciences, University of South Florida, Tampa, FL, USA
2 Extremity Trauma & Amputation Center of Excellence (EACE), U.S. Department of Veterans Affairs, Tampa, FL, USA
3 319 Minimal Care Detachment, U.S. Army Reserves, Pinellas Park, FL, USA
th
4 OP Solutions, Tampa, FL, USA
5 Prosthetic Design + Research, Tampa, FL, USA
6 Department of Kinesiology, University of Georgia, Athens, GA, USA
7 Department of Mechanical Engineering, University of South Florida, Tampa, FL, USA
8 Doctor of Physical Therapy Program, University of St. Augustine for Health Sciences, St. Augustine, FL, USA
The Continuous Scale-Physical Functional Performance-10 (CS-PFP-10) test consists of 10
standardized daily living tasks that evaluate overall physical functional performance and
performance in five individual functional domains: upper body strength (UBS), upper body
flexibility (UBF), lower body strength (LBS), balance and coordination (BAL), and endurance
(END). This study sought to determine the concurrent validity of the CS-PFP-10 test and its
functional domains that involve the lower extremities (LBS, BAL, or END) in comparison
to measures that have established validity for use in persons with transfemoral amputation
(TFA). Ten TFA patients functioning at K3 or higher (Medicare Functional Classification
Level) completed the study. Participants were assessed performing the CS-PFP-10, Amputee
Mobility Predictor (AMP), 75 m self-selected walking speed (75 m SSWS) test, timed down
stair walking (DN stair time), and the limits of stability (LOS) balance test. Concurrent validity
was assessed using correlation analysis. The AMP, 75 m SSWS, LOS, and the DN stair time
tests were strongly correlated (r = ± 0.76 to 0.86) with their paired CS-PFP-10 domain score
(LBS, BAL, or END) and CS-PFP-10 total score. These findings indicate that the lower limb
and balance domains of the CS-PFP-10 are valid measures to assess the physical functional
performance of TFA patients.
Key words: Activities of daily living; Lower extremity amputees; Outcome measures; Physical
therapy; Psychometric testing


INTRODUCTION
There are approximately two million persons consideration for using any outcome measure is to
presently living with limb loss in the U.S. Of these, have evidence that the measure has strong psycho-
approximately 350,000 have transfemoral amputa- metric properties for its target population. Psycho-
tion (TFA) (1). For clinicians, it is often challenging metric properties include the level of measurement
to select appropriate outcome measures to evaluate of the outcome data, the validity and reliability of the
physical functional performance for persons with test, and the test’s sensitivity to detect change among
lower extremity amputation (LEA). An important different interventions.
_____________________
Accepted July 1, 2016.
Address correspondence to M. Jason Highsmith, Extremity Trauma & Amputation Center of Excellence (EACE), 8900 Grand Oak Circle (151R), Tampa, FL
33637-1022, USA. Tel: +1 (813) 558-3936; Fax: +1 (813) 558-3990; E-mail: [email protected]



185

186 HIGHSMITH ET AL.



The Amputee Mobility Predictor (AMP) is a score and five individual domain scores. The contin-
21-item test of functional mobility used to predict uous scaling (ratio level data) allows the use of more
an LEA patient’s ability to ambulate. The AMP was precise parametric statistical analyses and provides
shown to have moderate to strong concurrent validity sensitivity to discriminate small differences with a
with the six-minute walk test (6MWT) (r = 0.69 to small number of participants. In a study with healthy
0.82) and the Amputee Activity Survey (r = 0.67 to elderly, the CS-PFP-10 demonstrated strong psy-
0.77) (2). It was also found to have strong test-retest chometric properties (ratio level data/parametric
and inter-rater reliability (intraclass correlation coeffi- statistical analyses, convergent validity, test-retest
cients (ICC) = 0.86 to 0.98) (2). Recently, Resnik and reliability, and sensitivity to change) (4). Thus, the
Borgia (3) reported a minimal detectable change of CS-PFP-10 meets requirements to recommend its
3.4 points for the AMP. This population-specific test is use in clinical and research applications. Furthermore,
designed to require minimal equipment and approxi- the CS-PFP-10 has been utilized in multiple diagnos-
mately 10 to 15 min to administer. While these are all tic groups, including frail elderly (4, 5); wheelchair
positive attributes, there are limitations to the AMP. users (6); persons with stroke (7), cardiac disorders
For instance, at the item level, the AMP is scored with (8, 9), and Parkinson’s disease (10); and others (11-
ordinal ranking. Arguably, this necessitates non-para- 15). Therefore, performance comparisons against
metric analysis. Additionally, some assessment items different populations are possible.
on the AMP may be inordinately difficult or easy for Recently, the CS-PFP-10 was utilized to deter-
different amputees. For example, maintaining single- mine significant change differences in functional
limb balance for persons with higher level amputation performance with TFA patients using two different
(i.e., hip disarticulation, transfemoral) may be quite microprocessor knee systems (Genium™ and C-Leg™)
difficult, while maintaining seated balance for ampu- (16). This study reported that Genium use signifi-
tees who function as community ambulators may be cantly improved UBF, BAL, and END domain scores
quite easy. The AMP is ultimately a test of mobility (change difference 7% to 8.4%; effect size 0.28 to 0.45)
that includes walking. However, walking distance is compared to C-Leg use (16). However, in order to
actually quite limited within the AMP test (24 to 48 generally recommend use of the CS-PFP-10 as the
feet). Furthermore, the AMP does not assess activities preferred outcome measure for testing functional
of daily living (ADL) function, and there is no way performance in TFA patients, additional testing of
to compare amputee values from the AMP test with psychometric properties in this specific population
other diagnostic groups or with non-amputees. is warranted. This study sought to determine the
The Continuous Scale-Physical Functional Perfor- concurrent validity of the CS-PFP-10 and its domains
mance-10 (CS-PFP-10) test measures physical func- that involved the lower extremities (LBS, BAL, or
tion across a wide range of functional abilities (4). The END) in comparison to measures of comparable ADL
CS-PFP-10 consists of 10 standardized ADL tasks that tasks or physiologic measures that have established
evaluate overall physical functional performance and validity for use in persons with TFA.
performance in five individual physiologic functional
domains: upper body strength (UBS), upper body METHODS
flexibility (UBF), lower body strength (LBS), balance
and coordination (BAL), and endurance (END). A Subjects
key difference in measuring physical performance in Adult individuals with unilateral TFA were consid-
this way is that the test’s activities are familiar to par- ered for enrollment if they met the following inclusion
ticipants in terms of their usual activities as opposed criteria: had used a microprocessor prosthetic knee
to isolated tests that may have seemingly little rele- (MPK) system for ≥1 year; had no skin impairments
vance to participants. Raw data (time, distance, mass) on lower extremities for the previous 90 d; performed
from each task are converted, via an algorithm within ADL tasks independently; and were able to ambulate
licensed scoring software, into a continuously scaled independently within the home and community at
score (0 to 100) for a singular overall performance K3 or higher (Medicare Functional Classification

CS-PFP-10 VALIDITY IN TRANSFEMORAL AMPUTEES 187


Table 1. Description of CS-PFP-10 Tasks
Table 1. Description of CS-PFP-10 Tasks
Functional Domains
Task
Difficulty Task UBS LBS UBF BAL END
1. Pot carry 1 m Mass Time
Low
Difficulty 2. Don/Doff jacket Time Time
3. Vertical reach Distance
4. Pick up scarves from floor Time Time
5. Floor sweep Time Time
Moderate
Difficulty 6. Laundry: a) transfer clothes
washer to dryer, b) dryer to Time Time Time
basket
7. Transfer from standing to
long-sit on floor and back to Time Time
High standing
Difficulty 8. Stair ascent/descent Time Time
9. Carry groceries 70 m Mass Mass Time
10. 6-minute walk test Distance

Balance and coordination (BAL), endurance (END), lower body strength (LBS), upper body flexibility (UBF), and upper body strength
(UBS).
Balance and coordination (BAL), endurance (END), lower body strength (LBS), upper body flexibility
Level) (17). TFA subjects used their preferred pros- judgement of safety and comfort. Tasks are performed
(UBF), and upper body strength (UBS).
theses with an MPK system and an energy storing serially from low to high difficulty. The CS-PFP-10


and return prosthetic foot. Each participant had their tasks use time, distance, and weight to evaluate overall
prosthesis evaluated for proper fit, alignment, and physical functional performance and performance in
function by the study’s licensed prosthetist. The study five physiologic functional domains: UBS, UBF, LBS,
protocol was approved by the University of South BAL, and END. Raw data (time, distance, mass) are
Florida’s Institutional Review Board, and each study converted, via an algorithm within licensed scoring
participant provided written informed consent. software, into a continuously scaled score (0 to 100)
Study Design for a singular overall total performance score and five
This was a cross-sectional study to determine con- individual domain scores. The CS-PFP-10 requires
approximately 30 to 40 min to complete. Table 1 pro-
current validity (the extent of statistical correlation) vides a description of CS-PFP-10 tasks.
of the CS-PFP-10 and its specific physiologic domains
that involved the lower extremities (LBS, BAL, or Amputee Mobility Predictor (AMP)
END) in comparison to measures of comparable ADL The AMP is a 21-item test of functional mobility
tasks or physiologic measures that have established used to predict an LEA patient’s ability to ambulate
validity for use in persons with TFA. Participants and was shown to have moderate to strong concurrent
were assessed performing the CS-PFP-10, AMP, 75 m validity with the 6MWT and the Amputee Activ-
self-selected walking speed test (75 m SSWS), down ity Survey (2). Specific details of each item and test
stair walking time (DN stair time), and the limits of administration of the AMP have been described pre-
stability (LOS) balance test.
viously (2). The following is a synopsis of the mobility
CS-PFP-10 functions assessed by the AMP (2). Items 1 and 2
The CS-PFP-10 was administered using stan- test the ability to maintain sitting balance. Items 3
dardized procedures (i.e., certified test site and test through 7 test the ability to maintain balance while
administrators, script dialogue; all reported else- performing tasks of transferring from chair to chair
where) (4,18). The CS-PFP-10 consists of 10 ADL and standing unchallenged. Items 8 through 13 test
tasks performed at maximal effort within the person’s more challenging standing balance activities. Items

188 HIGHSMITH ET AL.



14 through 20 evaluate quality of gait and the ability Limits of Stability (LOS)
to negotiate specific obstacles. Item 21 accounts for For individuals to safely engage in functional activ-
the use of particular assistive devices. Most AMP ities while standing, they need to effectively maintain
items offer three scoring choices: 0 indicates inabil- balance by positioning their center of mass (COM)
ity to perform the task, 1 indicates minimal level of within the limits of their base of support. The LOS
achievement or that some assistance was required balance test represents the maximal inclination from
in completing the task, and 2 indicates complete the vertical position that an individual can achieve
independence or mastery of the task. The AMP test without taking a step or falling (i.e., without changing
requires approximately 10 to 15 min to administer. their base of support) (22,23). The LOS test using
The AMP test was administered by the study’s licensed computer posturography has validated that LEA
physical therapist. The AMP score was used to test patients have decreased LOS compared to non-am-
for correlations with the CS-PFP-10 total score and putee controls (22).
the END score. The Biodex Balance SD system™ (Biodex Medical
75 m Self-Selected Walking Speed (75 m SSWS) Systems, Shirley, NY, USA) was used to measure
Test LOS. The Biodex Balance SD system™ incorporates
Walking tests, including the 75 m SSWS test, are a hemispherical suspended force platform that can
tilt any direction up to 20˚ from horizontal (23). The
accepted measures of ambulatory function for TFA platform includes gridlines for test-retest position-
patients using both mechanical and microprocessor ing reliability and a screen to provide COM data in
knee systems (19). In this study, timed performance real time to the patient visually. LOS were assessed
data were collected using a manual stopwatch for a in eight directions: forward, backward, right, left,
distance-based walking test of 75 m on even terrain. forward-right, forward-left, backward-right, and
The test included a turnaround at 37.5 m. Participants backward-left. Poor directional control is scored by
were instructed to walk at their preferred self-selected large variance (unitless). Subjects had to maintain
walking speed (SSWS). The average of three trials the COM in the middle of a concentric circle that
was the participant’s representative time. The 75 m appeared on a screen positioned in front of them at a
SSWS test was used to test for correlations with the comfortable height. The LOS assessment consisted of
CS-PFP-10 total score and the END score. three trials of 20 s duration each with 25 s rest periods

Down Stair Walking (DN Stair Time) between trials. The Biodex SD tests LOS by displaying
Stair descent is recognized as an important mea- an onscreen target placed in front of the subject. The
sure of functional independence for LEA patients (19- target appears randomly in eight different directions
21). Participants walked down stairs from a bilaterally only once, indicated when the respective target blinks
railed, four-step stair platform. Subjects were asked in an alternating color (yellow to red) onscreen. Sub-
to walk down the stairs in the manner and speed that jects are instructed to move their COM toward the
represents their usual technique if they were in their target without changing foot position. The system
homes or out in public. Subjects were asked to begin permits three difficulty levels for this task (100%, 50%,
at the platform, facing down the stairs. They were and 25%) depending on the degree of ankle motion
asked to walk down following the command, “ready, required to reach the target. Pilot testing with two
set, go.” A handheld stopwatch was used to record TFA patients (not study subjects) was used to select
the time between the “go” command and the instant the appropriate level at which the targets could be
when both feet were in contact with the floor. The reached safely without loss of balance. For safety
average of three trials was the subject’s representative reasons following pilot data assessment, we selected
time. DN stair time was used to test for correlation the 25% difficulty level, which required platform tilt
with the LBS score. of 2° anteriorly, 1° posteriorly, 2° towards right, and
2° towards left. Sway required to reach each target
from the center by the perfect shortest vertical or
horizontal path is recorded by the instrument and

CS-PFP-10 VALIDITY IN TRANSFEMORAL AMPUTEES 189



scored. A score of 100 is the maximal achievable DISCUSSION
score in any direction. In each LOS test, the system To recommend the general use of an outcome
computes the eight directional LOS scores and an measure, evidence is necessary that the measure has
overall LOS score as a percentage of the maximal strong psychometric properties for the target pop-
score, which is 100. A lower score indicates greater ulation. Psychometric properties include the level
sway. The system also calculates the time it takes for of measurement of the outcome data, validity and
the subject to reach all eight directional targets, thus reliability, and the test’s sensitivity to detect change
completing the assessment. The overall LOS score following intervention. Since the CS-PFP-10 provides
was used to test for correlation with the BAL score. ratio level outcome data, it allows for more precise
Statistical Analysis parametric statistical analyses. Previous work by
The extent of statistical correlation was examined Highsmith et al. (16) has shown that the CS-PFP-10
to determine concurrent validity. Data were entered was able to determine significant change differences
into a database and examined for normality. For nor- in functional performance with TFA patients using
mally distributed data, Pearson product moment two different interventions (i.e., microprocessor knee
correlation coefficients (r) were calculated for each systems).
test pair (i.e., respective PFP total or domain score The primary findings of this study were that the
compared to a test with established validity for use CS-PFP-10 and its specific physiologic functional
with TFA). If data were abnormally distributed, Spear- domains that involve the lower extremities (LBS,
man rank correlation coefficients (rs) were calculated. BAL, or END) demonstrated high concurrent validity
Strength of correlation values were categorized as 0 (i.e., statistically significant, strong correlations) with
to ± 0.29 very weak, ± 0.30 to 0.49 weak, ± 0.50 to measures of comparable ADL tasks or physiologic
0.69 moderate, and ± 0.70 to 1.00 strong (24). Sta-
Table 2. Physical Characteristics of Transfemoral Amputee
tistical significance for test pairs was also assessed Table 2. Physical Characteristics of Transfemoral Amputee (TFA) Participants
(TFA)
with a critical α of p < 0.05. Statistical analyses were

performed using IBM SPSS (v21, Armonk, NY, USA). Gender Male n = 8
Female n = 2
Etiology of Amputation
RESULTS Cancer n = 3
Ten persons (eight males, two females) aged 24 Peripheral Vascular Disease n = 1
Trauma
n = 6
to 75 years with unilateral TFA were recruited. See Age (y) 41.3 ± 15.5
Table 2 for TFA participants’ physical characteristics. Time since Amputation (y) 9.6 ± 10.8

Residual Limb Ratio
(Residual limb length ÷ Intact limb length * 100%) 76% ± 19 %
Correlations for Concurrent Validity Height (cm) 176.5 ± 5.2
Weight (kg)
78.8 ± 16.5
All four selected comparison tests, representing
mobility, walking speed, balance, and stair walking Table 3. Correlations for Concurrent Validity
Table 3. Correlations for Concurrent Validity

capacity (i.e., the AMP test, 75 m SSWS test, LOS test, CS-PFP-10 Comparative Pearson
Correlation
and the DN stair time test), strongly correlated (i.e., Total Score or Specific Test Coefficient (r)
Domain Score
r = ± 0.76 to 0.86) with their matched CS-PFP-10 Total Score AMP 0.80
Total Score
domain score or total score. For example, the BAL Domain 75m SSWS -0.86
LOS
0.76
CS-PFP-10 domain score for LBS strongly correlated END Domain AMP 0.76
75m SSWS
(r = -0 .79) with stair descent time (DN stair time) END Domain DN stair time -0.81
-0.79
LBS Domain
as a concurrent measure of strength. Furthermore, Balance and coordination (BAL), endurance (END), lower body
all of the paired tests’ correlations were statistically strength (LBS). Amputee Mobility Predictor (AMP), 75m self-se-
lected walking speed (75m SSWS), down stair walking time (DN
significant at p ≤ 0.01 (Table 3). Balance and coordination (BAL), endurance (END), lower body strength (LBS). Amputee Mobility
Predictor (AMP), 75m self-selected walking speed (75m SSWS), down stair walking time (DN stair time),
stair time), limits of stability (LOS). All paired tests’ correlations
limits of stability (LOS). All paired tests’ correlations were statistically significant at p ≤ 0.01.
were statistically significant at p ≤ 0.01.

190 HIGHSMITH ET AL.



measures that have established validity for use with the prevalence of limb loss in the United States:
TFA patients. 2005 to 2050. Arch Phys Med Rehabil.
Our findings of the correlation between the END 2008;89(3):422-9.
domain (i.e., 6MWT) and AMP (r = 0.76) agree well 2. Gailey RS, Roach KE, Applegate EB, Cho B,
with the correlation between the AMP and 6MWT Cunniffe B, Licht S, Maguire M, Nash MS. The
reported by Gailey et al. (r = 0.69 to 0.82) (2). Addi- amputee mobility predictor: an instrument to
tionally, the CS-PFP-10 total score correlates strongly assess determinants of the lower-limb ampu-
with the AMP (r = 0.80). We suggest that it may be tee’s ability to ambulate. Arch Phys Med Rehabil.
more advantageous to use the CS-PFP-10 rather than 2002;83(5):613-27.
the AMP with TFA patients as a measure of general 3. Resnik L, Borgia M. Reliability of outcome mea-
physical functional performance, as the CS-PFP-10 sures for people with lower-limb amputations:
involves usual ADL tasks, including more functional distinguishing true change from statistical error.
walking tasks (i.e., carrying groceries 70 m, 6MWT, Phys Ther. 2011;91(4):555-65.
and manipulating clothing and cookware). Further- 4. Cress ME, Petrella JK, Moore TL, Schenkman
more, use of the CS-PFP-10 allows for performance ML. Continuous-scale physical functional
comparisons to other populations. performance test: validity, reliability, and sen-
sitivity of data for the short version. Phys Ther.
CONCLUSION 2005;85(4):323-35.
These findings, combined with the results reported 5. Cress ME, Meyer M. Maximal voluntary and
by Highsmith et al. (16), indicate that the CS-PFP-10 functional performance levels needed for inde-
pendence in adults aged 65 to 97 years. Phys
has strong psychometric properties. These include the Ther. 2003;83(1):37-48.
ability to detect change in a small sample clinical trial 6. Cress ME, Kinne S, Patrick DL, Maher E. Phys-
and concurrent validity in high functioning persons ical functional performance in persons using a
with TFA. To further increase confidence with use of manual wheelchair. J Orthop Sports Phys Ther.
the CS-PFP-10 in TFA cases, additional psychometric 2002;32(3):104-13.
properties should be determined, such as test-retest 7. Manns PJ, Tomczak CR, Jelani A, Cress ME,
reliability. Haennel R. Use of the continuous scale physical
functional performance test in stroke survivors.
ACKNOWLEDGMENTS Arch Phys Med Rehabil. 2009;90(3):488-93.
This project was funded by: 8. Brochu M, Savage P, Lee M, Dee J, Cress ME,
1. The Center for Prosthetic Orthotic Learning. Poehlman ET, Tischler M, Ades PA. Effects of
(USF Grant #6140103000) resistance training on physical function in older
2. National Institutes of Health Scholars in Patient disabled women with coronary heart disease. J
Oriented Research (SPOR) grant (1K30RR22270) Appl Physiol (1985). 2002;92(2):672-8.
Contents of this manuscript represent the opinions 9. Ades PA, Savage P, Cress ME, Brochu M,
Lee NM, Poehlman ET. Resistance training
of the authors and not necessarily those of the U.S. on physical performance in disabled older
Department of Defense, U.S. Department of the Army, female cardiac patients. Med Sci Sports Exerc.
U.S. Department of Veterans Affairs, or any academic 2003;35(8):1265-70.
or health care institution. The authors declare no 10. Hearty TM, Schenkman ML, Kohrt WM, Cress
conflicts of interest. ME. Continuous scale physical functional per-
formance test: appropriateness for middle-aged
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Technology and Innovation, Vol. 18, pp. 193-201, 2016 ISSN 1949-8241 • E-ISSN 1949-825X
Printed in the USA. All rights reserved. http://dx.doi.org/10.21300/18.2-3.2016.193
Copyright © 2016 National Academy of Inventors. www.technologyandinnovation.org





PSYCHOMETRIC EVALUATION OF THE HILL ASSESSMENT INDEX
(HAI) AND STAIR ASSESSMENT INDEX (SAI) IN
HIGH-FUNCTIONING TRANSFEMORAL AMPUTEES



M. Jason Highsmith , Jason T. Kahle , Brian Kaluf , Rebecca M. Miro ,
6
1
1-3
4,5
7
Larry J. Mengelkoch , and Tyler D. Klenow 8
1 School of Physical Therapy & Rehabilitation Sciences, University of South Florida, Tampa, FL, USA
2 Extremity Trauma & Amputation Center of Excellence (EACE), U.S. Department of Veterans Affairs, Tampa, FL, USA
3 319 Minimal Care Detachment, U.S. Army Reserves, Pinellas Park, FL, USA
th
4 OP Solutions, Tampa, FL, USA
5 Prosthetic Design + Research, Tampa, FL, USA
6 Ability Prosthetics and Orthotics, Greenville, SC, USA
7 Doctor of Physical Therapy Program, University of St. Augustine for Health Sciences, St. Augustine, FL, USA
8 Prosthetics and Sensory Aids Service, James A. Haley Veterans’ Hospital, Tampa, FL, USA

The hill assessment index (HAI) and stair assessment index (SAI) were developed to objectively
evaluate ramp and stair gait. This study’s purpose was to determine the validity and reliability
of these tests in a sample of persons with unilateral transfemoral amputation (TFA) using
microprocessor prosthetic knee systems. All subjects were fit with a microprocessor knee
system. After accommodation, subjects performed three trials ascending and descending a
5° ramp and a flight of stairs while being recorded on video. Sensitivity and specificity for the
HAI was calculated against degree of asymmetry in step length using Dartfish video analysis
software. Reliability was assessed using intraclass correlational coefficients calculated using
Spearman’s Rho (r s). A priori significance level was set at p ≤ 0.05. Twenty (n = 20) individuals
with TFA completed the study protocol. Sensitivity and specificity of the HAI were calculated
at 88.0% and 75.0% during ascending conditions and 94.0% and 67.0% during descending
conditions, respectively. Significant correlations for the HAI included r s = 0.87 and r s = 0.73
within raters uphill and downhill, respectively. Corresponding coefficients of r s = 0.80 and r s
= 0.67 were calculated between raters. For the SAI, significant correlations included r s = 1.00
for both comparisons within raters and in the comparison between raters in the ascending
condition. A correlation of r s = 0.89 was calculated for the between-rater comparison in the
descending condition. The HAI showed moderate to excellent sensitivity and specificity but
good to adequate reliability. The SAI showed excellent to good reliability.

Key words: Gait evaluation; Observational gait assessment; Outcome measures; Physical
therapy; Ramps; Rehabilitation; Step




_____________________
Accepted July 1, 2016.
Address correspondence to M. Jason Highsmith, Extremity Trauma & Amputation Center of Excellence (EACE), 8900 Grand Oak Circle (151R), Tampa, FL
33637-1022, USA. Tel: +1 (813) 558-3936; Fax: +1 (813) 558-3990; E-mail: [email protected]



193

194 HIGHSMITH ET AL.



INTRODUCTION • Ability to ascend and descend a ramp without
Observational gait analysis (OGA) serves an human support
integral role in many rehabilitation fields and is a • Ability to ascend and descend stairs without
current clinical assessment standard for prosthet- human support
ics. However, while OGA has been found to have Subjects who met the inclusion criteria were
approximately 60% to 85% reliability (1), it has been enrolled in the study and evaluated by the study
infrequently investigated on ramps and stairs (2). prosthetist to assure proper fit and function. The
Further, few clinically useful outcome measures to study prosthetist was state-licensed and certified by
objectively evaluate gait on ramps and stairs have the American Board for Certification in Orthotics,
been introduced. The hill assessment index (HAI) Prosthetics, and Pedorthics. Subjects’ prosthetic sock-
and stair assessment index (SAI) were developed for ets and suspension systems were not changed for the
this reason (3,4). These assessments utilize an 11- duration of the experiment to reduce confounding
and 13-point ordinal scale, respectively, to describe from fit and acclimation issues. All subjects were fit
gross motor pattern implementation, degree of step with the same model energy-storing prosthetic foot
length symmetry, and use of assistive devices. The for use over the study duration. Manufacturer spec-
inter-rater and intra-rater reliability of the HAI was ifications were used to set componentry alignment
found to be excellent in hill descent tasks for a sample and were verified using the LASAR alignment system
of unilateral transfemoral amputation (TFA) patients (Ottobock Healthcare, Duderstadt, Germany). Each
using mechanical and C-Leg microprocessor knee subject received training from the study physical
(MPK) systems (2). However, no further evidence of therapist on the functions of the MPK and study foot
psychometric properties for either outcome measure for transitional movements, obstacle crossing, ramps,
is available. stairs, speed variation, and variable surfaces. Train-
Video motion analysis has been used to determine ing techniques were used from prior publications
criterion validity for other observational and func- (8,9). Subjects then accommodated with the new foot
tional outcome measures in the past and may allow components until they reported and demonstrated
for establishing evidence of the validity of the HAI confidence in walking unassisted on level ground,
and SAI (5-7). Therefore, the purpose of this study inclines, declines, and up and down stairs. Following
was to determine the criterion validity and inter- this accommodation, subjects were scheduled for
rater and intra-rater reliability of the HAI and SAI testing.
in a sample of persons with unilateral TFA using a Subjects were asked to ascend and descend an
prosthetic MPK system. Americans with Disabilities Act-compliant cement

METHODS Figure 1. Hill Assessment Index (HAI).
All procedures were reviewed and approved by
the University of South Florida’s Institutional Review
Board, and subjects gave informed consent prior to
study participation.
Subjects were considered for study inclusion if
they met the following criteria:
• Unilateral transfemoral or knee disarticulation
amputation
• Use of a prosthesis with MPK for at least one
year
• Independent level of community ambulation
without use of an assistive device

HILL & STAIR ASSESSMENT IN ABOVE-KNEE AMPUTEES 195



ramp, which was 0.9 m in width, 4.9 m in length, Figure 2. Stair Assessment Index (SAI).
and sloped at an angle of 5°. Each subject completed
three trials up and three trials down at a self-selected
walking speed using handrails as they deemed neces-
sary. These trials were timed using a stopwatch and
recorded (sagitally) on video. The recordings were
scored by two independent raters who reviewed the
video recordings to determine the appropriate HAI
value based on the criteria outlined in Figure 1 (3,4).
The recordings were then assessed using Dartfish™
2D (v7, Dartfish USA, Inc. Alpharetta, GA,USA) gait
analysis software to determine prosthetic and sound
side step length. Step length was measured relative
to a 1.0 m reference object captured in the video
background and measured using reflective mark-
ers placed on subjects’ heels and toes. A previous
investigation found inconsequential differences in rater. Asymmetrical movements in function and gait
marker movement tracked by 3D motion capture between 5% and 10% have previously been described
and Dartfish software on the order of ≤5 mm (10). as typical (13,14). A perfect DoA score of 0, providing
Further, this program was previously found to be allowances for normal asymmetrical movement, can
a valid (PCC ≥ 0.95; p < 0.05) and reliable (ICC ≥ then be assumed to equate to a perfect HAI score.
0.93; p < 0.05) motion analysis tool (11). Degree of Therefore, absolute DoA values of ≤±0.1 were deter-
asymmetry (DoA) was then calculated for step length mined to be representative of a symmetric step length
using the following equation: and thus eligible for an HAI rating of 11/11. This was
used to establish the reference standard and those
Sound Step Length – Prostethetic Step Length
Degree of Asymmetry = participants with absolute DoA values >±0.1 from
Sound Step Length + Prostethetic Step Length
the video motion analysis were determined to have
Subjects then repeated the protocol on a flight of an asymmetric step length and scored 10/11 on the
Americans with Disabilities Act-compliant stairs (12). HAI in this dichotomous set.
The three trials ascending and three trials descending Sensitivity and specificity are statistical measures
at a self-selected speed were timed using a handheld of the validity of an outcome measure (15). Sensitivity
stopwatch and sagittaly recorded on video. These is the proportion of subjects who test positive for a
recordings were again scored by two independent condition to all those who truly have the condition.
raters, this time using the criteria outlined in Figure 2 Specificity is the proportion of subjects who test nega-
to determine the appropriate SAI score (3,4). Subjects tive for a condition to all those who truly do not have
repeated the study protocol on the ramp and stairs 90 the condition. In this case, sensitivity and specificity
d after initial testing to assess intra-rater reliability. of the HAI in identifying subjects who do and do not
The HAI is scored on an ordinal scale from 0 to exhibit step length symmetry during ramp gait was
11. In this sample, however, all subjects received a assessed. These variables were calculated using a two-
score of 10 or 11, resulting in a dichotomous data by-two configuration of HAI score and step length
set. This allowed for step length, specifically DoA of symmetry determined by the Dartfish software and
step length (13), to become the reference standard the calculation of DoA in step length. Sensitivity and
for an assessment of sensitivity and specificity of the specificity were calculated as:
instrument at its higher scoring levels. The HAI indi- n n
cates that a perfect score of 11 is an even step length Sensitivity = ( HAI score 10/ |DoA|>0.1) * 100
n
n
without an assistive device determined visually by the Specificity = ( HAI score 11/ |DoA|≤0.1) * 100

196 HIGHSMITH ET AL.



In the above equation for sensitivity, n HAI score 10 of each instrument, respectively. Data were compared
represents the number of subjects who scored 10 for both tests for ascending and descending condi-
on the HAI because the rater found them to have an tions. Intraclass correlation coefficients (ICC) were
n
asymmetrical step length, and |DoA|>0.1 represents the determined using Spearman’s Rho. Definitions for
number of subjects who truly exhibited asymmetri- correlation strength also vary (15,18-20). We inter-
cal steps as assessed with video motion analysis and preted 0.9 to 1.0 as an excellent correlation, 0.75 to
the DoA equation for step length symmetry. In the 0.89 a good correlation, 0.5 to 0.74 an adequate cor-
n
above equation for specificity, HAI score 11 represents relation, and below 0.5 a poor correlation. The level
the number of subjects who scored 11 on the HAI for statistical significance was determined a priori to
because the rater found them to have symmetrical be p ≤ 0.05.
n
step length, and |DoA|≤0.1 represents the number of
subjects who truly did exhibit symmetrical steps as RESULTS
assessed with video motion analysis and the DoA Twenty (n = 20) individuals with TFA completed
equation for step length symmetry. Higher levels of the study. The sample was 80% male with etiology
sensitivity and specificity provide evidence to support of trauma (70%), tumor (20%), or vascular disease
the validity of the HAI to assess step length symmetry (10%). Mean (SD) age was 46.5 years of age (±14.2).
walking on ramps. To evaluate levels of sensitivity All subjects were unlimited community ambulators.
and specificity, we interpreted scores from 90% to Sensitivity of the HAI was calculated at 88.0% for
100% as excellent, 75% to 89% as good, 50% to 74% uphill and 94.0% for downhill conditions. These
as adequate, and below 50% as poor sensitivity and results correspond to positive likelihood ratios of
specificity for the HAI uphill and downhill. 3.5 and 2.8, respectively. Specificity for the instrument
Positive and negative likelihood ratios can be cal- was determined to be 75.0% for uphill and 67.0%
culated from the sensitivity and specificity values. A for downhill. These results correspond to negative
positive likelihood ratio indicates how many times
more likely a positive test will be seen in those with likelihood ratios of 0.17 and 0.10, respectively. These
more symmetric step lengths than in those with less results are summarized in Table 1.
symmetric step lengths (15). Interpretation of like- For the HAI, Spearman Rho ICCs of r s = 0.80 (p
lihood ratios vary (16,17). We interpreted a positive < 0.001) for uphill and 0.67 (p = 0.001) for downhill
likelihood ratio of 10 or more as large, 5 to 9.94 as conditions between rater one and rater two were
moderate, 2 to 4.94 as small, and 1 to 1.94 as very found. ICCs of r s = 0.87 (p < 0.001) and 0.73 (p <
small positive likelihood. These positive likelihood 0.001) were calculated between initial and repeat
ratios were used to determine if the HAI was a very testing scores for uphill and downhill conditions,
useful, often useful, sometimes useful, or rarely useful respectively (Table 2). Mean (SD) uphill times (Table
test, respectively. A negative likelihood ratio, then, 3), in seconds, for trials one, two, and three were
indicated how many times more likely a negative test 4.71 (0.86), 4.71 (0.99), and 4.72 (1.03), respectively,
will be seen in those with more step length symmetry resulting in a mean percent difference of 0.11% among
compared to those with less step length symmetry trials. Mean and median scores were 10.8 and 11 for
(15). A negative likelihood ratio of less than 0.1 was all trials. Mean downhill times, in seconds, for trials
interpreted as large, 0.11 to 0.2 as moderate, 0.21 to one, two, and three were 4.80 (1.14), 4.74 (1.19), and
0.5 as small, and 0.51 to 1.0 as very small negative 4.78 (1.40), respectively, resulting in a mean percent
likelihood. These negative likelihood ratios were used difference of 1.1% among trials. Mean and median
to determine if the HAI was a very useful, often useful, downhill scores were 10.9 and 11 for all trials.
sometimes useful, or rarely useful test, respectively. For the SAI, ICCs of rs = 1.00 (p < 0.001) and 0.89
Comparisons between rater one and rater two at (p < 0.001) were found between raters one and two for
initial testing and rater one at the repeat evaluation ascending and descending conditions, respectively.
were made to assess inter- and intra-rater reliability ICCs of rs = 1.00(p < 0.001) were calculated for both

HILL & STAIR ASSESSMENT IN ABOVE-KNEE AMPUTEES 197

Table 1. Sensitivity, Specificity, and Likelihood Ratios
Table 1. Sensitivity, Specificity, Likelihood Ratios 12.0, 11.7, and 11.8, with a constant median of 11.
Times and scores for the HAI and SAI are shown in
Condition Uphill Downhill Table 3.


Sensitivity 88.0% 94.0% DISCUSSION
The results of this study provide evidence of the
Specificity 75.0% 67.0%
validity and reliability of the HAI and SAI in a sample
of persons with unilateral TFA using an MPK system
+ Likelihood Ratio' 3.50 2.80
and ambulating at an unlimited-community level.
The sensitivity of the HAI was determined to be
- Likelihood Ratio' 0.17 0.10
good for uphill and excellent for downhill evaluations
in this sample of community ambulating transfemoral
amputees. The good sensitivity for uphill and excellent
ascending and descending conditions between ini- sensitivity for downhill evaluations resulted because
tial and repeat testing (Table 2). Mean (SD) ascent the raters on the HAI correctly identified those who


times (Table 3), in seconds, for trials one, two, and walked with step length DoA above the 0.1 reference
three were 4.95 (1.01), 5.15 (1.62), and 4.68 (1.33), standard. Especially on hill descent, the excellent
respectively, resulting in a mean percent difference of sensitivity shows that the HAI will have a low rate of
6.7% among trials. Corresponding mean trial scores false negatives, meaning that if a subject is identified
were 9.7, 9.9, and 10.1, with a constant median of 11. by the rater as having asymmetrical step length, it is
Mean descent times, in seconds, for trials one, two, highly likely that they actually do have asymmetrical
and three were 3.82 (0.97), 3.72 (0.80), and 3.61 (0.80), step length. Both positive likelihood ratios indicate
respectively, resulting in a mean percent difference of the HAI is a “sometimes useful” test for uphill and
2.76%. Corresponding mean descending scores were downhill assessments of hill gait in higher functioning
Table 2. HAI/SAI Inter/Intra-Rater Correlations TFA subjects.
Table 2. HAI/SAI Inter/Intra-Rater Correlations
Hill Assessment Index Inter-rater Intra-rater

Variable Uphill Downhill Uphill Downhill

Spearman's Rho (rs) 0.80 0.67 0.87 0.73

ICC significance p < 0.001 p = 0.001 p < 0.001 p < 0.001


Stair Assessment
Index Inter-rater Intra-rater


Variable Ascent Descent Ascent Descent
Spearman's Rho (rs) 1.00 0.89 1.00 1.00


ICC significance p < 0.001 p < 0.001 p < 0.001 p < 0.001

198 HIGHSMITH ET AL.


Table 3. Mean/Median Stair Performance
Table 3. Mean/Median Stair Performance
Instrument HAI SAI

Condition Uphill Downhill Ascent Descent
Time (sec) mean SD mean SD mean SD mean SD

Trial 1 4.71 0.86 4.80 1.14 4.95 1.01 3.82 0.97
Trial 2 4.71 0.99 4.74 1.19 5.15 1.62 3.72 0.80

Trial 3 4.72 1.03 4.78 1.40 4.68 1.33 3.61 0.80
% diff 0.11% -- 1.07% -- 6.72% -- 2.76% --

Score mean median mean median mean median mean median
Trial 1 10.8 11.0 10.9 11.0 9.7 11.0 12.0 11.0

Trial 2 10.8 11.0 10.9 11.0 9.9 11.0 11.7 11.0
Trial 3 10.8 11.0 10.9 11.0 10.1 11.0 11.8 11.0


The specificity of the HAI was determined to be Assessment of intra-rater reliability for the HAI

good for uphill and adequate for downhill assessment. was found to be good for uphill but adequate for
The lower specificity on ramp descent was a result of downhill gait in this sample based on the strength

some subjects being scored by the raters as having of correlation (Spearman’s Rho). These results were
asymmetrical step length although they actually had identical to the inter-rater reliability in this sample,
symmetrical step lengths based on having step length with uphill being found as good and downhill being
DoA below 0.1. This could mean that identifying step found as adequate. The downhill inter-rater reliability
length symmetry during ramp descent may be more assessment was adequate. These results differ slightly
difficult and there is the potential for an increased from the results of previous work, which found excel-
rate of false positives (i.e., giving a lower HAI score lent inter-rater reliability in a more heterogeneous
for step symmetry). The negative likelihood ratios sample of TFA subjects utilizing C-Leg MPKs (2).
confirm that the HAI is a “sometimes useful” test for The modest differences could be multi-factorial and
both uphill and downhill assessments of hill gait. In potentially include sample heterogeneity, rater expe-
summary, the HAI was found to be an adequate to rience and background, a lack of scoring instructions
excellent assessment tool of step length symmetry for the instrument, slight performance interpretation
during uphill and downhill gait of subjects in this differences, and other factors.
sample. The assessment was found to be more sen- The consistency of HAI times, with a percent
sitive for downhill assessment and more specific for change in time of 0.1% and 1.1% for ascent and
uphill in high-functioning persons with unilateral descent, respectively, and the reliability of uphill HAI
TFA. Due to the lower specificity in ramp descent, scores among trials provide some evidence of the
low scores may be vulnerable to false results in this instrument’s stability on repeat testing within a single
population. However, due to the good and excellent visit. Based on the negligible differences in time to
sensitivity of the HAI, lower scores should truly iden- ambulate on the ramp and HAI scores, no learning or
tify those with less symmetrical step length during fatigue effects were noted in this sample. This internal
ramp gait. consistency commonly suggests no benefit between

HILL & STAIR ASSESSMENT IN ABOVE-KNEE AMPUTEES 199



a single or repeated testing protocol. Thus, in the Limitations
interest of valuable clinical time, it seems feasible that This study utilized a group of high-functioning
a single administration of the test may be sufficient subjects with unilateral TFA who ambulated with
to determine the patient’s ability to ambulate ramps. MPKs. Therefore, results may not be applicable to
Repeated testing of high-functioning TFA patients individuals of differing amputation level(s), those
within a single clinic visit seems unlikely to yield dif- with bilateral or upper extremity involvement, ampu-
ferent scores provided conditions (e.g., components, tees of lower functional levels, or individuals of other
physical status) are not changed. diagnostic groups. Further, the dichotomous results
The SAI was found to be a very reliable assessment of the HAI allowed for sensitivity and specificity
tool for high-functioning transfemoral prosthetic calculation but prevented evaluation of the entire
users. Inter-rater reliability was excellent for ascend- ordinal scale (i.e., at the lower end of the functional
ing and good for downhill conditions based on the spectrum). A lack of low scores was also observed
strength of correlation. Excellent intra-rater reliability in SAI scores, resulting in left skewed data. Also, the
was found for both ascending and descending assess- reference standard adopted for this study, DoA in
ments. The percent differences among trial times was step length, while a more objective measure of step
higher than the HAI, but the mean differences remain length symmetry than observational gait analysis,
adequately low to preliminarily declare the instru- has not been thoroughly evaluated. The DoA cut-off
ment as stable in comparable samples. No clear trend score of ±0.1 was chosen based on the assumption
in time or scoring for the SAI was found among trials, that 5% to 10% asymmetry in movement is typical in
further suggesting no learning or fatigue effect. The gait and other functional movement patterns (13,14).
results of this work also show no benefit or detriment For this reason, it is difficult to make definitive con-
to performing the test once or multiple times. For clusions of the reliability and validity of the entirety
clinical simplicity, the test may only require a single of the HAI and SAI. Further research is needed to
administration to determine a high-functioning TFA confirm the results of this work in other amputation
subject’s true stair ascent or descent capability. As populations, including lower-functioning patients
with the HAI, this is provided that the subject has
been trained and is confident in using the specific who would score lower in the range of the HAI and
functional features (e.g., stair ascent mode) of the SAI measures.
MPK. The SAI may provide more obvious differen-
tiation between scores relative to the HAI, as there is CONCLUSION
less opportunity for subjectivity in the construct. The The results of this work established validity and
HAI requires the rater to determine step length ratios, reliability of the upper end of the HAI and SAI in a
which may have large variability between subjects, population of high-functioning subjects with uni-
whereas the SAI requires identification of more dis- lateral TFA using microprocessor knee systems. The
cretely discernable stepping patterns. Future research HAI showed moderate sensitivity and specificity.
should attempt to establish validity for the SAI, as this Intra-rater reliability of the HAI was good for uphill
study demonstrated strong evidence of the inter-rater and adequate for downhill assessment. Inter-rater
and intra-rater reliability for the SAI as a measure reliability was found to be good for uphill and ade-
of stair ascent and descent. Replication research is quate for downhill assessment. Since other ramp gait
needed to confirm the recommendation for a single assessment tools are scarce, the HAI was shown to be
test in comparable samples but also in TFA patients a viable assessment tool. The SAI showed excellent
using mechanical knees or other types of knees and and good inter-rater reliability for ascending and
in those who ambulate at lower functional levels. descending conditions, respectively, and excellent
intra-rater reliability for both. Both HAI and SAI were
shown to be stable instruments for both ascending
and descending assessments, resulting in a recom-

200 HIGHSMITH ET AL.



mendation for one trial as a true assessment of hill DynaPort GaitMonitor for assessment of spatio-
and stair gait. More research is needed to determine temporal parameters in amputee gait. J Rehabil
validity of the SAI and to confirm all of these results Res Dev. 2008;45:1335-42.
in other amputation populations. 6. McDonough AL, Batavia M, Chen FC, Kwon S,
Ziai J. The validity and reliability of the GAITRite
ACKNOWLEDGMENTS system’s measurements: a preliminary evaluation.
The authors declare no conflicts of interest and Arch Phys Med Rehabil. 2001;2001:419-25.
are solely responsible for the content of this man- 7. van Loo MA, Moseley AM, Bosman JM, de Bie
uscript. Contents of this manuscript represent the RA, Hassett L. Inter-rater reliability and con-
opinions of the authors and not necessarily those of current validity of step length and step width
the U.S. Department of Defense, U.S. Department measurement after traumatic brain injury.
of the Army, U.S. Department of Veterans Affairs, Disabil Rehabil. 2003;25:1195-200.
or any academic or health care institution. 8. Highsmith MJ, Kahle JT, Lewandowski AL, Kim
SH, Mengelkoch LJ. A method for training step-
This project was funded by: over-step stair descent gait with stance yielding
1. The Florida High Tech Corridor/USF Connect. prosthetic knees. J Prosthet Orthot. 2012;24:10-5.
(Grant # FHT 10-26) 9. Highsmith MJ, Kahle JT, Lura DJ, Lewandowski
2. National Institutes of Health Scholars in Patient AL, Quillen WS, Kim SH. Stair ascent and ramp
Oriented Research (SPOR) grant (1K30RR22270) gait training with the Genium knee. Technol
Innov. 2014;15(4):349-58.
REFERENCES 10. Eltoukhy M, Asfour S, Thompson C, Latta L.
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1. Krebs DE, Edelstein JE, Fishman S. Reliability of analysis of human motion: Dartfish tracking
observational kinematic gait analysis. Phys Ther. system. Int J Sci Eng Res. 2012;3:1-6.
1985;65:1027-33. 11. Norris BS, Olson SL. Concurrent validity and
2. Highsmith MJ, Kahle JT, Miro RM, Mengelkoch reliability of two-dimensional video analysis of
LJ. Ramp descent performance with the C-Leg hip and knee joint motion during mechanical
and interrater reliability of the Hill Assessment lifting. Physiother Theory Pract. 2011;27:521-30.
Index. Prosthet Orthot Int. 2013;37(5):362-8. 12. US Department of Justice. ADA standards
3. Buell NC, Willingham LL, Allyn KJ, Hafner BJ, for accessible design. Washington (DC): US
Smith DG. Evaluation of gait style to ascend Department of Justice; 2010.
and descend stairs for lower limb amputees. 13. Highsmith MJ, Schulz BW, Hart-Hughes S, Latlief
In: Boone D, editor. Proceedings of the 11th GA, Phillips SL. Differences in the spatiotempo-
World Congress of the International Society of ral parameters of transtibial and transfemoral
Prosthetics and Orthotics; 2004 Aug 1-6, Hong amputee gait. J Prosthet Orthot. 2010;22:26-30.
Kong. Hong Kong: Hong Kong National Society 14. Highsmith MJ, Kahle JT, Carey SL, Lura DJ,
of the International Society for Prosthetics and Dubey RV, Csavina KR, Quillen WS. Kinetic
Orthotics; 2004. p 367. asymmetry in transfemoral amputees while per-
4. Hafner BJ, Willingham LL, Buell NC, Allyn KJ, forming sit to stand and stand to sit movements.
Smith DG. Evaluation of function, performance, Gait Posture. 2011;34:86-91.
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2007;88:207-17. 16. McGee S. Simplifying likelihood ratios. J Gen
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for radiologists. Radiographics. 2015;35:1789-
801.
18. Highsmith MJ, Lura DJ, Carey SL, Mengelkoch
LJ, Kim SH, Quillen WS, Kahle JT, Miro RM.
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joint moments during sitting and standing move-
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Technology and Innovation, Vol. 18, pp. 203-206, 2016 ISSN 1949-8241 • E-ISSN 1949-825X
Printed in the USA. All rights reserved. http://dx.doi.org/10.21300/18.2-3.2016.203
Copyright © 2016 National Academy of Inventors. www.technologyandinnovation.org







BIOPSY 1-2-3 IN DERMATOLOGIC SURGERY: IMPROVING
SMARTPHONE USE TO AVOID WRONG-SITE SURGERY



James T. Highsmith , David A. Weinstein , M. Jason Highsmith , Jeremy R. Etzkorn 7
1,2
4-6
3
1 Dermatology Service, James A. Haley Veterans’ Hospital, Tampa, FL, USA
2 Dermatology Surgery Institute, Lutz, FL, USA
3 Department of Internal Medicine, University of Central Florida College of Medicine, Orlando, FL, USA
4 School of Physical Therapy & Rehabilitation Sciences, University of South Florida, Tampa, FL, USA
5 Extremity Trauma & Amputation Center of Excellence (EACE), U.S. Department of Veterans Affairs, Tampa, FL, USA
th
6 319 Minimal Care Detachment, U.S. Army Reserves, Pinellas Park, FL, USA
7 Department of Dermatology, Hospital of the University of Pennsylvania, Philadelphia, PA, USA

The smartphone has become a ubiquitous tool in modern culture. Given the current high
quality of smartphone cameras, they should be considered a valuable tool for the dermatologic
surgeon in the pre-operative consultation. The purpose of this technical note is to describe a
methodology using smartphone camera technology to improve the process for capturing bi-
opsy site photographs and including those photos in decision making to maximize cutaneous
surgical outcomes. This technical note describes a three-step procedure (BIOPSY 1-2-3) to
simplify and standardize the protocol for capturing a biopsy site photograph using the patient’s
own smartphone. The steps are also intended to improve the resolution and value of the image.
A case example is provided. Using the steps of BIOPSY 1-2-3, the case example biopsy site
image is clearly identified compared to a less structured image. Using BIOPSY 1-2-3, biopsy
site images taken by patient-owned smartphone cameras can empower and involve patients
in their care, improve image quality, and reduce medical errors.

Key words: Cutaneous surgery; Digital photography; Mohs micrographic surgery; Skin cancer;
Surgical site; Wrong-site surgery



INTRODUCTION taken, calorie intake, and exercise. Healthcare pro-
The smartphone has become a ubiquitous tool in fessionals use smartphones to replace pagers, assist
modern culture. In 2011, 83% of Americans were in gait evaluation, and monitor medications (2).
estimated to have cellular phones (1). These devices Additionally, they may be used to monitor ulcers
have applications to entertain, assist in navigation, in amputees or reduce the incidence of wrong-site
and receive electronic messages; they can also mon- surgeries in dermatologic surgery (1,3,4). With the
itor health by logging sleep duration, heart rate, steps current high quality of smartphone cameras, they
_____________________
Accepted July 1, 2016.
Address correspondence to James T. Highsmith, James A. Haley Veterans’ Administration Hospital, Dermatology Service, 13000 Bruce B Downs Blvd,
Tampa, Florida 33612, USA. Tel +1 (813) 457-0153; Fax +1 (813) 631-3228; E-mail: [email protected]



203

204 HIGHSMITH ET AL.


















Figure 1. Patient presented for MMS for a biopsy-proven squamous cell carcinoma on
his “right temple” that healed well and is difficult to locate. He initially refused treatment
but eventually rescheduled, and the lesion was excised using MMS. Note the biopsy site is
difficult to confidently locate because of background solar damage, rhytids, and scarring.

should be considered a valuable tool for the derma- METHODS
tologic surgeon in the pre-operative consultation. Many of the problems encountered with a biopsy
Wrong-site surgery has been identified as one of site selfie (BSS) may be overcome by using a key strat-
the most common adverse events (13.1%) reported egy we have named BIOPSY 1-2-3. The three steps
by The Joint Commission (TJC) (4). To reduce these of the technique are as follows:
errors, TJC has implemented a “Universal Proto-
col,” thereby mandating pre-procedure verification, 1. First, it is optimal to have one other person
surgical site marking, and a “time out” to prevent take the photo.
surgical errors (5). Wrong-site surgeries are also a 2. Next, make sure there are two anatomical land
common cause of medical malpractice lawsuits affect- marks in the image.
ing fellowship-trained Mohs surgeons (14.3%) (6). 3. Finally, verify there are three photos of each
Identifying the correct biopsy site is complicated by site.
background sun damage, adjacent skin conditions, With each biopsy site, have one person who is not the
biopsy technique (e.g., deep scallop versus superficial patient take the photograph to avoid problems inher-
shave), and the amount of time between the biopsy ent with a BSS. This is recommended because often
and planned curative procedure (7). Biopsy sites often the secondary self-facing camera on the smartphone
heal very well and can be difficult to locate, leading device is typically inferior to the primary camera,
many patients to refuse an excision or at least question which results in lower quality photographs. Also,
the need for another procedure as in the case example BSSs tend to be excessively zoomed in and out of
in Figure 1. An estimated 25% of patients present- focus. Having someone else take the picture with the
ing for Mohs Micrographic Surgery (MMS) could patient’s device allows the picture to be taken with the
not correctly identify their biopsy sites (8). While a primary camera at an adequate distance. The pictures
pre-operative biopsy may result in complete tumor can be taken at home by the patient’s family member
removal in 15% to 42% of cases, identification of the or even at the office by the patient’s nurse at the time of
correct surgical site is imperative to ensure definitive their visit. Always mark the area that was, or is about
treatment of most cutaneous neoplasms (9,10). Given to be, biopsied, as in Figure 2 of the case example. Use
the previously identified value of patient involvement a dark pen, highlighter, or marker to circle the lesion
and the ease of access to smartphone technology and to distinguish between two nearby dyspigmented
digital photography, the purpose of this project was patches at a later date. Next, have two body parts
to describe a methodology to improve the process for (e.g., ear and nose) or two joints (e.g., elbow and
capturing biopsy site photographs and including those wrist) visualized in at least two of the pictures. Lastly,
photos in decision making to maximize cutaneous have at least three pictures of every site. It is best if
surgical outcomes. each photograph is taken from a different vantage

BIOPSY 1-2-3 IN DERMATOLOGIC SURGERY 205


















Figure 2. Smartphone photograph of the planned biopsy site taken prior to shave re-
moval. Note that the lesion is circled and at least two anatomic landmarks are present.



point to ensure the site can be isolated from nearby essary re-biopsies were avoided (8). However, the
lesions or background skin changes. Always zoom in BSS has several limitations. For example, a biopsy
to review each photograph. Delete the photo(s) and site on the scalp or back may be difficult to self-pho-
re-take them if they are out of focus or otherwise tograph, or the patient may have difficulty using a
unsatisfactory. Consider repeating the technique with smartphone due to arthritis or lack of hand dexterity.
each biopsy site on the day of biopsy or at any time There are also problems with the photos themselves.
within the first week after the biopsy, which will still For instance, photos may be out of focus or excessively
provide tremendous benefit at follow-up. zoomed in, resulting in too few anatomical landmarks
to facilitate location. Finally, patients may be resistant
RESULTS AND DISCUSSION to taking a BSS picture.
The outlined steps (Figure 3) are simple and
should improve biopsy site photography to facilitate Figure 3. BIOPSY 1-2-3 steps.
improved outcomes and reduce medical errors. The
case example highlights the value in a systematic BIOPSY 1-2-3
approach for this process. Photography has become
the gold standard in the pre-operative evaluation of
dermatologic surgery and has been shown to reduce Biopsy: mark every biopsy site with
wrong-site surgeries. Furthermore, pre-operative a pen, marker, or highlighter.
photography has been shown to facilitate patient
confidence in the treatment of the appropriate surgi-
cal site (7). Given the popular nature of smartphones 1. One other person take your biopsy
today, patients may be encouraged to participate in site pictures
their own care by using their own cell phone cameras
to document the biopsy site and assist in the identi-
fication of the appropriate surgical site. 2. Two joints or two body parts in at
Nijhawan et al. found the use of BSSs was cru- least two of the pictures
cial in correctly locating the surgical site in 21% of
referred cases. This study also noted that the use of 3. Three total pictures (different
BSSs empowered patients to be active participants in distances or angles)
their own care. Moreover, delaying surgery to confirm
the correct biopsy site was minimized, and unnec-

206 HIGHSMITH ET AL.



CONCLUSION Hausdorff JM, Mirelman A. Feasibility and
Although dedicated high-resolution cameras effects of home-based smartphone-delivered
would be ideal for biopsy site photography, many automated feedback training for gait in people
referring physicians do not send pictures with their with Parkinson’s disease: a pilot randomized con-
consultations. Some physicians may not integrate trolled trial. Parkinsonism Relat Disord. 2016;
photography into their practice, and others simply 22:28-34.
have the printed photographs on a paper chart and 3. Foltynski P, Ladyzynski P, Wojcicki JM. A new
have not converted to electronic medical record sys- smartphone-based method for wound area mea-
tems (EMRs). Whether the referring and consulting surement. Artif Organs. 2014;38(4):346-52.
physician has adopted EMRs or not, another obstacle 4. Ke M, Moul D, Camouse M, Avram M, Carranza
is that EMRs are not universal and do not link or D, Soriano T, Lask G. Where is it? The utility
synchronize data. Even if all EMRs were fully inte- of biopsy-site photography. Dermatol Surg.
grated, there would still be a potential to violate the 2010;36(2):198-202.
Health Insurance Portability and Accountability Act 5. The Joint Commission Universal Protocol
(HIPAA) if the photos were released. Therefore, the [poster]. [accessed 2016 Mar 2]. http://www.
only truly universal form of photography that would jointcommission.org/assets/1/18/up_poster1.
not violate HIPAA and could go to every patient pdf.
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device. Smartphones may one day provide a real-time, Dufresne RG Jr. Incidence of and risk factors
universal, and fully integrated EMR platform between for medical malpractice lawsuits among Mohs
clinicians and patients. However, until a more reliable surgeons. Dermatol Surg. 2006;32(1):79-83.
system is in place, BIOPSY 1-2-3 serves as a simple 7. Zhang J, Rosen A, Orenstein L, Van Voorhees
solution to a common problem in dermatologic sur- A, Miller CJ, Sobanko JF, Shin TM, Etzkorn JR.
gery today. Factors associated with biopsy site identification,
postponement of surgery, and patient confidence
ACKNOWLEDGMENTS in a dermatologic surgery practice. J Am Acad
This work was partially funded by the National Dermatol. 2016; Epub ahead of print.
Institutes of Health Scholars in Patient Oriented 8. Nijhawan RI, Lee EH, Nehal KS. Biopsy site
Research (SPOR) grant (1K30RR22270). Contents of selfies—a quality improvement pilot study to
this manuscript represent the opinions of the authors assist with correct surgical site identification.
and not necessarily those of the U.S. Department of Dermatol Surg. 2015;41(4):499–504.
Defense, U.S. Department of the Army, U.S. Depart- 9. Gurunluoglu R, Kubek E, Arton J, Olsen A,
ment of Veterans Affairs, or any academic or health Bronsert M. No residual basal cell carcinoma
care institution. after excision for biopsy-proven tumor: clinical
and medicolegal implications. Plast Reconstr
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Technology and Innovation, Vol. 18, pp. 207-210, 2016 ISSN 1949-8241 • E-ISSN 1949-825X
Printed in the USA. All rights reserved. http://dx.doi.org/10.21300/18.2-3.2016.207
Copyright © 2016 National Academy of Inventors. www.technologyandinnovation.org








PLAY HANDS PROTECTIVE GLOVES:
TECHNICAL NOTE ON DESIGN AND CONCEPT



Michele Houston-Hicks , Derek J. Lura , and M. Jason Highsmith 3-5
2
1
1 Physical Therapy Center, University of South Florida Morsani College of Medicine, Tampa, FL, USA
2 Department of Bioengineering and Software Engineering, Florida Gulf Coast University, Ft. Myers, FL, USA
3 School of Physical Therapy & Rehabilitation Sciences, University of South Florida, Tampa, FL, USA
4 Extremity Trauma & Amputation Center of Excellence (EACE), U.S. Department of Veterans Affairs, Tampa, FL, USA
5 319 Minimal Care Detachment, U.S. Army Reserves, Pinellas Park, FL, USA
th

Cerebral Palsy (CP) is the leading cause of childhood motor disability, with a global incidence of
1.6 to 2.5/1,000 live births. Approximately 23% of children with CP are dependent upon assistive
technologies. Some children with developmental disabilities have self-injurious behaviors such
as finger biting but also have therapeutic needs. The purpose of this technical note is to describe
design considerations for a protective glove and finger covering that maintains finger dexterity
for children who exhibit finger and hand chewing (dermatophagia) and require therapeutic
range of motion and may benefit from sensory stimulation resulting from constant contact
between glove and skin. Protecting Little and Adolescent Youth (PLAY) Hands are protective
gloves for children with developmental disorders such as CP who injure themselves by biting
their hands due to pain or sensory issues. PLAY Hands will be cosmetically appealing gloves
that provide therapeutic warmth, tactile sensory feedback, range of motion for donning/
doffing, and protection to maximize function and quality of life for families of children with
developmental disorders. The technology is either a per-finger protective orthosis or an entire
glove solution designed from durable 3D-printed biodegradable/bioabsorbable materials such
as thermoplastics. PLAY Hands represent a series of protective hand wear interventions in the
areas of self-mutilating behavior, kinematics, and sensation. They will be made available in a
range of protective iterations from single- or multi-digit finger orthoses to a basic glove design
to a more structurally robust and protective iteration. To improve the quality of life for patients
and caregivers, they are conceptualized to be cosmetically appealing, protective, and therapeutic.

Key words: Cerebral Palsy; Developmental delay; Finger biting; Physical therapy; Rehabili-
tation; Self-mutilation






_____________________
Accepted July 1, 2016.
Address correspondence to M. Jason Highsmith, Extremity Trauma & Amputation Center of Excellence (EACE), 8900 Grand Oak Circle (151R), Tampa, FL
33637-1022, USA. Tel: +1 (813) 558-3936; Fax: +1 (813) 558-3990; E-mail: [email protected]



207

208 HOUSTON-HICKS ET AL.



INTRODUCTION attempt to bite and traumatize the fingers, leading to
Annually in the U.S., approximately 10,000 infants pain, wounds, and difficulties with subsequent self-
are born with cerebral palsy (CP) (1). The worldwide care tasks and play. The reinforcing material will be
incidence of CP is 1.6 to 2.5/1,000 live births, placing non-toxic but durable to minimize the risk of ingest-
CP as the leading cause of childhood motor disabil- ing harmful materials. The gloves would ideally appeal
ity (1,2). Approximately 23% of children with CP to children by being adorned with popular cartoon
are dependent upon assistive technologies (3). Use characters, pending licensing agreements. The gloves
of these assistive technologies includes functional will facilitate higher quality of life for patients and
uses such as walking aids and orthoses but may also caregivers by mitigating complications associated
include protective roles. Protective roles may be aimed with finger biting. An additional benefit of PLAY
at limiting injury during function but may also be Hands is that many people affected by CP and other
necessary in the case of self-injury caused by behav- neurologic disorders may have contractures of the
iors such as finger biting. Currently, technologies to joints of the hands and fingers. The act of donning/
facilitate the dual role of therapeutics and protection doffing PLAY Hands will require a range of motion
of the hand and finger in populations such as these activity for the hands, offering a therapeutic effect in
are limited. The purpose of this technical note is to addition to protection. Finally, wearing a glove offers
describe potential needs and design considerations a sensory experience from both tactile and thermal
for a protective glove and/or finger covering that perspectives that may be beneficial for some users.
maintains dexterity of the finger for children with The wearable finger protection design is dependent
diagnoses such as cerebral palsy, Lesch-Nyhan syn- upon the desired device utilization. A solution is pre-
drome, and dermatophagia who exhibit finger/hand sented that is either an entire glove or independent for
chewing, require therapeutic range of motion, and each finger, allowing either targeted intervention on
may benefit from sensory stimulation from constant digits that are more prone to chewing or protection for
contact. the entire hand when used in combination. For this
construction, use of high molecular weight poly(lactic
acid) PLA or high to ultra-high molecular weight
CONCEPT polyethylene  (UHMWPE) should be considered in
Protecting Little and Adolescent Hands (PLAY) the design of a bite protection device. Both materials
Hands Gloves are protective gloves for children with are commonly used in food packaging materials, are
developmental disorders such as CP who injure them- non-toxic, and can be used in implantable devices
selves by biting their hands due to pain or sensory with proper processing.
issues. At times, these self-mutilating behaviors result “PLA is a thermoplastic, high-strength, high-mod-
in wounds, pain, loss of function, and increased ulus polymer that can be made from annually
dependence or self-care. PLAY Hands are conceived renewable resources to yield articles for use in …
to be cosmetically appealing gloves that provide biocompatible/bioabsorbable medical device market”
therapeutic warmth, tactile sensory feedback, range according to Garlotta (4). PLA is a thermoplastic
of motion for donning/doffing, and protection to material with a melting point of approximately 180
maximize function and quality of life for families of °C, a tensile strength typically in the range of 50
children with developmental disorders. MPa (depending upon processing and origin), and
an elastic modulus of 3500 MPa. PLA also has a glass
DESIGN transition temperature of 60 to 65 °C, which allows
PLAY Hands are gloves with protective finger pad for easy at-home thermofitting around the patient’s
material reinforcement to prevent young persons with finger to ensure a tight yet comfortable fit. Figure 1
CP, or other diagnoses contributing to self-mutilating presents a sample prototype showing fitting of a basic
behaviors, from biting and traumatizing their fingers. protective frame using 3D-printed PLA.
The gloves will be reinforced with protective materi- The second thermoplastic under consideration
als to cover the finger pads where these individuals for the proposed design is UHMWPE. Although it

PLAY HANDS PROTECTIVE GLOVES 209


































Figure 1. 3D-printed prototype showing a simple thermo-molded protective frame with compliant hinges. A)
Original 3D-printed device, B) device after molding to the user’s finger, C) device attached to the finger in an
extended position, and D) device attached to the finger in a flexed position. These images are a basic orthotic
framework for only the single digit and lack the cosmetic/protective outer covering. Further, the concept is envi-
sioned for use either as single- or multi-digit finger covering(s) or as a whole hand glove.

typically has a lower tensile strength than PLA (~25 and motocross gloves, to assure wear and failure com-
MPa), it is also considerably softer (elastic modulus mensurate with other established protective wear for
500 to 800 MPa) and has a longer elongation range hands.
prior to failure (5). These characteristics would make
the final product less prone to breakage but more CONCLUSION
likely to bend and thus less likely to damage teeth. This PLAY Hands represent a series of protective hand
product would not be formable to the user; therefore, wear interventions that offer solutions in the areas of
it would require more complex molds to produce the self-mutilating behavior, kinematics, and sensation.
finished product, and careful attention would have They will be made available in a range of protec-
to be used when selecting sizes. tive iterations, from a basic glove design to a more
Protective plates could also be added to textile structurally robust and protective iteration. They are
gloves for pressure distribution in patients where a conceptualized to be cosmetically appealing, protec-
rigid frame is not needed (low force chewing). Ulti- tive, and therapeutic and to ultimately improve the
mate selection of materials depends on a variety of quality of life for patients and caregivers.
desired specifications for the final product, including
weight, strength, and stiffness as well as cost and ACKNOWLEDGMENTS
production volume. Initial prototyping in PLA is Contents of this manuscript represent the opinions
advisable, as it can be 3D printed readily by fuse of the authors and not necessarily those of the U.S.
deposition modeling or fused filament fabrication. Department of Defense, U.S. Department of the Army,
Custom gloves and inserts should be tested along U.S. Department of Veterans Affairs, or any academic
with traditional protective hand wear, such as hockey or health care institution. Authors declare no conflicts

210 HOUSTON-HICKS ET AL.



of interest. This project was partially supported by Society. Neurology. 2004;62(6):851-863.
the National Institutes of Health Scholars in Patient 2. Odding E, Roebroeck ME, Stam HJ. The epidemi-
Oriented Research (SPOR) grant (1K30RR22270). ology of cerebral palsy: incidence, impairments
and risk factors. Disabil Rehabil. 2006;28(4):183-
REFERENCES 191.
1. Ashwal S, Russman BS, Blasco PA, Miller G, 3. Beckung E, Hagberg G, Uldall P, Cans C. Proba-
Sandler A, Shevell M, Stevenson R, Quality Stan- bility of walking in children with cerebral palsy
dards Subcommittee of the American Academy in Europe. Pediatrics. 2008;121(1):e187-192.
of Neurology, Practice Committee of the Child 4. Garlotta D. A literature review of poly(lactic
Neurology Society. Practice parameter: diagnos- acid). J. Polym. Environ. 2001;9(2):63-84.
tic assessment of the child with cerebral palsy: 5. Kurtz SM. UHMWPE biomaterials handbook:
report of the Quality Standards Subcommittee ultra high molecular weight polyethylene in total
nd
of the American Academy of Neurology and joint replacement and medical devices. 2 ed.
the Practice Committee of the Child Neurology Cambridge (MA): Academic Press; 2009.

Technology and Innovation, Vol. 18, pp. 211-216, 2016 ISSN 1949-8241 • E-ISSN 1949-825X
Printed in the USA. All rights reserved. http://dx.doi.org/10.21300/18.2-3.2016.211
Copyright © 2016 National Academy of Inventors. www.technologyandinnovation.org






RADIOGRAPHIC ASSESSMENT OF EXTREMITY
OSSEOINTEGRATION FOR THE AMPUTEE


Munjed Al Muderis , Belinda A. Bosley , Anthony V. Florschutz , Paul A. Lunseth ,
1-3
4
3
4
Tyler D. Klenow , M. Jason Highsmith , and Jason T. Kahle 9,10
5
6-8
1 The Australian School of Advanced Medicine, Macquarie University, Macquarie, Australia
2 School of Medicine, University of Notre Dame Australia, Auburn, Australia
3 Norwest Private Hospital, Bella Vista, Australia
4 BayCare Medical Group, Tampa, FL, USA
5 Prosthetics and Sensory Aids Service, James A. Haley Veterans’ Hospital, Tampa, FL, USA
6 School of Physical Therapy & Rehabilitation Sciences, University of South Florida, Tampa, FL, USA
7 Extremity Trauma & Amputation Center of Excellence (EACE), U.S. Department of Veterans Affairs, Tampa, FL, USA
8 319 Minimal Care Detachment, U.S. Army Reserves, Pinellas Park, FL, USA
th
9 OP Solutions, Tampa, FL, USA
10 Prosthetic Design + Research, Tampa, FL, USA

Osseointegration (OI) is a bone-anchoring procedure that allows the direct skeletal attachment
of a prosthesis through the use of an implant. Transcutaneous OI implants are similar to subcuta-
neous intramedullary joint implants with some exceptions. Particularly, OI implants are inserted
at the distal aspect of the femur, while intramedullary implants are inserted at the proximal
aspect of the femur. In this report, an additional adaptation of the radiographic zonal analysis
used for intramedullary implants, known as Gruen zones, is introduced to include OI implants
of extremity prosthetics. Radiographic zonal analyses and interpretations are proposed. Gruen
zones are used for intramedullary implants, which are generally inserted from the proximal aspect
of the bone. OI extremity implants are inserted from the distal end of the bone. Therefore, the
zonal analysis is inverted. A radiographic zonal analysis has been introduced by the Osseointe-
gration Group of Australia (OGA). This analysis is needed specifically for the clinical evaluation
of extremity OI, as significant changes to the bone and OI implant have been reported and
need to be clinically described. A classification technique is necessary for establishing treatment
guidelines for the extremity osseointegrated implant. The OGA Zonal analysis addresses this
need by adapting a common reference standard to osseointegration of the extremity amputee.
Key words: Amputation surgery; Implant; Interface; Socket; Prosthesis; Transfemoral amputation





_____________________
Accepted July 1, 2016.
Address correspondence to: Jason T. Kahle, OP Solutions, 12206 Bruce B. Downs Blvd., Tampa, FL 33612, USA. Tel: +1 (813) 971-1100; Fax: +1 (813)
971-9300; E-mail: [email protected]



1-207211

212 MUDERIS ET AL.



INTRODUCTION techniques do not perform equally. Additionally, there
The current standard of care for a person living are several types of failures that can occur. Because of
with limb loss who uses an artificial limb is a socket the popularity of joint replacement and the prevalence
attached to the prosthetic limb components. Examples of failure at the time, Gruen et al. reported on the
of prosthetic components for the lower extremity modes of failure and a technique to radiographically
amputee would be the knee, foot, and pylon, and, identify the area, or zone, of failure (10,12). The stabil-
for the upper extremity amputee, they would be the ity of the joint replacement is graded using this zonal
elbow and hand. The prosthetic socket interface is analysis, or Gruen zones. Gruen zones and modes of
the aspect of the prosthesis that attaches the compo- failure are the standard for evaluating the condition
nents to the residual limb, or the remaining part of of a subcutaneous intramedullary joint replacement
the amputated arm or leg. The socket interface has (Figure 1).
two primary functions: 1) to suspend the prosthesis Figure 1. Gruen zones compared to OGA Zones. The zones are
to the human body during periods of unweighting simply inverted to properly place the exit of the OI extremity im-
and 2) to support the body weight of user during plant from the bone distal.
periods of weight bearing (1). A socket interface is
designed to support the weight through the sidewalls,
as walking on the distal end would cause excessive
pain and discomfort. To achieve this and give the user
control, the socket interface must be tightly fit and
must enclose the majority of the residual limb. This
can be uncomfortable, evidenced by more than 30%
of lower extremity users noting problems with their
socket interfaces, including skin breakdown, excessive
heat and subsequent perspiration, limited range of
motion, interference with urogenital function, quality
of life, and function (2,3). Socket interface problems
lead to more than 30 percent of amputees reducing
their prosthetic use and having diminished quality
of life and some choosing not to wear a prosthesis at
all (4,5).
Osseointegration (OI) is a bone-anchoring pro-
cedure that allows direct skeletal attachment of a
prosthesis through the use of an implant (6-8).
Increasing in popularity, OI is now used routinely OI for the extremity amputee is only offered in
in maxillofacial prosthetics and dentistry and, more a limited number of countries. In those countries,
recently, is gaining support for use in attaching lower however, OI is beginning to gain popularity simi-
and upper extremity prosthetics. In an extremity OI, lar to the way subcutaneous joint replacement did
the implant is an intramedullary attachment similar to nearly 50 years ago, and a protocol for zonal analysis
a total hip arthrhroplasty (THA) or hip joint replace- must be similarly implemented. Recently, OI for the
ment. Extremity OI is transcutaneous, whereas other extremity amputee cleared Food and Drug Admin-
joint replacements are contained beneath the skin and istration (FDA) approval with an Investigational
underlying soft anatomy (subcutaneous) (6,7). Mod- Device Exemption for limited inclusion criteria in
ern intramedullary joints report high rates of success the U.S. Given the high incidence of amputees with
(9); however, when first introduced, failure rates were socket interface problems, it is likely that OI for the
near 20% (10,11). There are several techniques to sub- extremity amputee will garner a significant patient
cutaneous intramedullary joint replacement, and all population seeking solutions, similar to those with

RADIOGRAPHIC ASSESSMENT OF OSSEOINTEGRATION 213



pain associated with joints over 50 years ago. As with using Zones 1 and 7 to describe the coated area, where
joint replacement, there are many OI techniques. the implant exits the bone, the zones must be inverted.
Different modes and types of failures associated with
these techniques have been reported and can be antic- ZONES
ipated as these techniques are studied over time. A Gruen originally divided the femur into seven
system for radiographically analyzing transcutaneous zones using the coronal (A/P) radiograph view (Fig-
extremity OI, similar to a traditional intramedullary ure 2a). While Johnston et al. added the sagittal (ML)
implant, would be beneficial for future analysis of OI view zones, OGA Zones are divided into seven zones
extremity implants. Therefore, the purpose of this and radiographically measured on the coronal (A/P)
report is to introduce a radiological zonal analysis for view only. These include three equally divided zones
the use of the extremity OI transcutaneous implants. on each side of the radiograph and a zone (Zone 4) at
the proximal aspect of the implant (Figure 1). Zone
METHODS 1 is the most distolateral aspect of the bone implant
While Gruen et al. originally reported on using interface opposite to Zone 7, which is the most vital,
an analysis for intramedullary implants, there is on the medial aspect on the radiograph. Zone 2 is
precedence for modifying the protocol (10). In a mid-lateral portion opposite to zone 6 medially, and
later report, Gruen et al. changed the seven zones Zone 3 is at the lateral proximal aspect of the implant
to include uncemented stems with porous coatings. bone interface opposite to Zone 5 medially (Figure
Ten years after the original report, Johnston et al. 2).
described a more comprehensive approach to include
extensive clinical parameters, such as demographics, IMPLANT DESIGN CHANGES AND THE EFFECT
pain levels, and activities of daily living. Additionally, ON BONE
they expanded the radiographic approach to include The initial design of the Integral Leg Prosthesis
sagittal (M/L) zonal analysis, adding Zones 8 to 14. (ILP; Orthdynamic GmbH, Lübeck, Germany) was
Further, an algorithmic scoring system was added made from a Chrome cobalt alloy with a surface coat-
to provide an overall rating (12). Amstutz et al. also ing having a spongy metal macroporous structure of
added three zones to include the short metaphyseal 300 to 1500 um in pore diameter with titanium coat-
stem of a metal hip joint (13). Ultimately, Santori and ing (press fit cementless implant; Figure 3) . The area
Santori modified this approach to five zones for the of the implant that has this macroporous structure
proximal-loading short femoral stem (14). covers most of the implant with the exception of the
In this report, an additional adaptation of the distal 1.5 cm at Zones 1 and 7 and at the proximal
Gruen zones technique is introduced to include OI portion of the implant at Zone 4, where the surface is
implants of extremity prosthetics. Gruen zones are smooth. The observation first reported by OGA was
used for intramedullary implants, which are generally that the cortical bone remodels over time and fol-
inserted from the proximal aspect of the bone. OI low-up radiographs demonstrate bone resorption at
extremity implants are inserted from the distal end the area where the implant portion is smooth (Zones 1
of the bone. Therefore, the zonal analysis is inverted. and 7), with the resorption stopping at the beginning
This extremity OI zonal analysis technique, first of the spongy metal structure (Figures 2a and 2b).
reported by the Osseointegration Group of Austra- Conversely, the area of Zones 3 and 5 shows signifi-
lia (OGA) as the OGA Zones, would simply invert cant cortical bone thickening. These observations led
the zones to properly correspond with the aspects to fundamental changes in the implant design of the
to the uncemented portion of the implant (9,15). Osseointegrated Prosthetic Limb (OPL; Permedica
Adaptation is necessary to transpose the spatial terms s.p.a, Milan, Italy) (Figure 3). First, the material was
because extremity OI terminates proximal into the changed to titanium, which has a modulus of elasticity
bone, whereas the traditional implant terminates closer to bone of 110 GPa (bone modulus of elasticity
distal into the bone. Therefore, to stay consistent with is 17 GPa), while chrome cobalt alloy modulus of

214 MUDERIS ET AL.



























Figure 2. Two separate subjects with an ILP OI implant with distal bone resorption or the femur in Zones 1 and 7 (a and b);
Two separate subjects with an OPL OI implant with distal cortical bone thickening in Zones 1 and 7 (c and d).
elasticity is 190 GPa. Second, the implant shape was using the OGA Zonal analysis and has noted changes
changed, making a proximal 80 mm smooth surface particularly in the distal aspects of the implant, or
with multiple longitudinal sharp splines of 1 mm high Zones 1 and 7 (9,15). Implementation of the OGA
to cut through the cortical bone during implantation Zones allows determination of location of radio-
to provide initial rotational stability. Third, the distal graphic changes, such as resorption, overgrowth,
80 mm of the implant is fully coated with microp- extremity OI implant changes, description, and con-
orous plasma spray particles to provide potential sistency in clinical reporting. The OGA Zonal analysis
bony ingrowth and has a similar collar to the ILP will allow a practitioner to accurately track changes
to provide initial axial stability against subsidence. that occur over a timeframe to allow evidence-based
The design changes have led to recent observations decision making regarding OI extremity implants.
of distal stress shielding and proximal cortical bone
thickening over time (Figures 2c and 2d) (9,15). CONCLUSION
Radiographic zonal analysis is used in orthopedic
DISCUSSION intramedullary implant evaluation to clinically assess
Clinical trials of OI have not yet been extensively the location of changes as a result of the implant. OI
reported. OI for the extremity amputee is relatively using an intramedullary implant for the extremity
early in the cycle of product, procedure, and tech- amputee may yield similar changes. A classification
nique development. Currently it is only offered in a technique is necessary for establishing treatment
few countries and has only recently been introduced guidelines. The OGA Zonal analysis addresses this
in the U.S. There is an opportunity for amputees to need by adapting a common reference standard to
potentially benefit from this technology. However, OI of the extremity amputee.
potential side effects must also be understood. As the
health care community observes changes and results ACKNOWLEDGMENTS
of OI use, the evolution of OI implant design and Contents of this manuscript represent the opinions
technique can progress. Bone resorption, growth, and of the authors and not necessarily those of the U.S.
problems may be associated with the extremity OI Department of Defense, U.S. Department of the Army,
at different locations than traditional intramedullary U.S. Department of Veterans Affairs, or any academic
implants. Muderis et al. first reported these changes or health care institution. Authors declare no conflicts

RADIOGRAPHIC ASSESSMENT OF OSSEOINTEGRATION 215



























Figure 3. Design changes in the OPL implant (bottom) compared to the IPL (top): 1) Titanium material, 2) proximal
80 mm smooth surface with multiple longitudinal sharp splines of 1 mm high to cut through the cortical bone, and
3) distal 80 mm of the implant is fully coated with microporous plasma spray particles.
of interest. This project was partially supported by Acad Dermatol. 2000;42:501-7.
the National Institutes of Health Scholars in Patient 6. Branemark R, Berlin O, Hagberg K, Bergh P,
Oriented Research (SPOR) grant (1K30RR22270). Gunterberg B, Rydevik B. A novel osseointe-
grated percutaneous prosthetic system for the
REFERENCES treatment of patients with transfemoral ampu-

1. Smith DG, Bowker J, Michael J, editors. Atlas tation: a prospective study of 51 patients. Bone
of amputations and limb deficiencies: surgi- Joint J. 2014;96-B:106-13.
cal, prosthetic and rehabilitation principles. 7. Branemark R, Branemark PI, Rydevik B, Myers
3rd ed. Rosemont (IL): American Academy of RR. Osseointegration in skeletal reconstruction
Orthopaedic Surgeons; 2004. and rehabilitation: a review. J Rehabil Res Dev.
2. Kahle JT, Highsmith MJ. Transfemoral sockets 2001;38:175-81.
with vacuum-assisted suspension comparison 8. Hagberg K, Branemark R. One hundred patients
of hip kinematics, socket position, contact pres- treated with osseointegrated transfemoral ampu-
sure, and preference: ischial containment versus tation prostheses--rehabilitation perspective. J
brimless. J Rehabil Res Dev. 2013;50:1241-52. Rehabil Res Dev. 2009;46:331-44.
3. Kahle JT, Highsmith MJ. Transfemoral interfaces 9. Al Muderis M, Bosley B, Tungusova A. Post
with vacuum assisted suspension comparison limb reconstruction strategy for post traumatic
of gait, balance, and subjective analysis: ischial amputees (OGAAP-2). Paper presented at: First
containment versus brimless. Gait Posture. World Congress on Innovations in Amputation
2014;40:315-20. Surgery and Prosthetic Technologies; 2016 May
4. Dillingham TR, Pezzin LE, MacKenzie EJ, 12-13; Chicago, IL.
Burgess AR. Use and satisfaction with prosthetic 10. Gruen TA, McNeice GM, Amstutz HC. “Modes
devices among persons with trauma-related of failure” of cemented stem-type femoral com-
amputations: a long-term outcome study. Am ponents: a radiographic analysis of loosening.
J Phys MedRehabil. 2001;80:563-71. Clin Orthop Relat Res. 1979:17-27.
5. Lyon CC, Kulkarni J, Zimerson E, Van Ross E, 11. Banaszkiewicz PA, Kader DF, editors. Classic
Beck MH. Skin disorders in amputees. J Am papers in orthopaedics. London (UK): Springer-

216 MUDERIS ET AL.



Verlag; 2014. custom-made short proximal loading femoral
12. Johnston RC, Fitzgerald RH Jr, Harris WH, Poss component. J Bone Joint Surg. 2010;92:1231-7.
R, Muller ME, Sledge CB. Clinical and radio- 15. Tetsworth K, Al Muderis, M, Khemka, A,
graphic evaluation of total hip replacement. A Wilmot, S, Bosley, B, Lord, S, Glatt, V. The
standard system of terminology for reporting Osseointegration Group of Australia Accelerated
results. J Bone Joint Surg.1990;72:161-8. Protocol (OGAAP‐1) for Two‐stage osse-
13. Amstutz HC, Beaule PE, Dorey FJ, Le Duff MJ, ointegrated reconstruction of amputees.
Campbell PA, Gruen TA. Metal-on-metal hybrid Paper presented at: First World Congress
surface arthroplasty: two to six-year follow-up on Innovations in Amputation Surgery and
study. J Bone Joint Surg. 2004;86-A:28-39. Prosthetic Technologies; 2016 May 12-13;
14. Santori FS, Santori N. Mid-term results of a Chicago, IL.

Technology and Innovation, Vol. 18, pp. 217-218, 2016 ISSN 1949-8241 • E-ISSN 1949-825X
Printed in the USA. All rights reserved. http://dx.doi.org/10.21300/18.2-3.2016.217
Copyright © 2016 National Academy of Inventors. www.technologyandinnovation.org







TAKING AIM AT CANCER



James Higgins and Alex Camarota
Office of Innovation Development, United States Patent and Trademark Office, Alexandria, VA, USA


In his final State of the Union Address, President Obama announced the “Cancer Moonshot,”
an effort to greatly accelerate the rate of progress in cancer treatment development over the
next five years. To support this effort, the USPTO is launching several initiatives that leverage
the role patents play in catalyzing life-saving medical treatments.

Key words: Patents; Innovation; Immunotherapy; Cancer; Cancer moonshot; USPTO





Fostering American innovation has always been for this goal to be realized. The USPTO has a partic-
a central mission of the United States Patent and ular call to action in this “moonshot moment.” The
Trademark Office (USPTO), inseparable from our president’s plan leverages the USPTO’s mission as an
role in protecting it. Although the process for receiving important catalyst for research and development by
that protection in the form of a patent can be lengthy, freeing trapped data, resolving applications that are
the USPTO strives to ensure that it is thorough and without a final decision, and increasing patient access
fair. Patents must be issued while the technology is to treatment and clinical studies. The goal is to halve
still relevant in order to provide a benefit in the mar- the average examination time of patents pertaining to
ketplace. The patenting process has been especially certain medical technologies and thereby reduce the
critical in the medical field, as it protects and mone- time it takes for that technology to reach a patient. To
tizes the investment in research and development that meet the president’s expectations, we must also tap
is poured into life-saving technologies. Indeed, the into the resources of several different agencies. The
patent system has spurred life-changing technological USPTO will launch two new programs to accomplish
innovation around the world. these tasks.
In that same spirit of progress and improvement, First, the USPTO established a “Fast Track” review
President Obama used his final State of the Union pilot program for certain treatment-related patents
address to challenge the United States to make ten in order for medicines and technologies to reach
years’ worth of progress toward finding a cure for can- patients more quickly. This pilot program, “Patents 4
cer in just five. Federal and state agencies, nonprofits, Patients,” more formally known as the “Cancer Immu-
businesses, and citizens must collectively contribute notherapy Pilot Program,” will cut the time it takes to

_____________________
Accepted July 1, 2016.
Address correspondence to: Alex Camarota, Office of Innovation Development, U.S. Patent and Trademark Office, 600 Dulany Street, Alexandria, VA 22314,
USA. E-mail: [email protected]



217

218 HIGGINS & CAMAROTA



review patent applications for cancer immunotherapy tool will enable users to make more informed policy
in half (final decisions achieved in less than twelve and investment decisions. It has the potential to help
months). This “Fast Track” review will be open to inform Securities and Exchange Commission filings,
new application filings from any applicant, includ- FDA reporting, National Science Foundation grant
ing early-stage bio-tech companies, universities, and applications and approvals, and philanthropic and
large pharmaceutical firms alike. Entities who have venture capital investments, achieving maximum
products already in Food and Drug Administration impact across a spectrum of innovation incubators.
(FDA) clinical trials will also be able to opt in to Following the release of the IP Horizon Scanning
the acceleration program in applications already on Tool, the USPTO’s Office of the Chief Economist will
file. With approximately 900 cancer immunotherapy host public workshops that bring together cancer
applications received by the USPTO annually from experts, policymakers, and data scientists to discuss
around the world, this program aims to move innova- how combinations of data sets can improve cancer
tive new treatments from conception through patent research. The goal will be to find the most efficient
approval, helping to swiftly reach the patient’s bedside. way to connect various agencies’ data and grasp the
To be eligible for the “Patents 4 Patients” program, insights contained within them.
an application must contain one or more claims to The USPTO’s new programs will provide the same
a method of treating a cancer using immunotherapy. protection to inventors more quickly while also con-
There are several other requirements, which can be necting federal agencies and research teams with
found on the USPTO website. There is no additional each other. While it is true that the Cancer Moonshot
fee to participate in the program. comes in the twilight of the Obama Administration,
Second, the agency aims to stimulate innovation the goal is to cultivate a host of programs and efforts
and improve economic competitiveness by unlocking that can be seamlessly packaged and passed along to
the potential in expansive data sets. The USPTO’s new the next administration. The productive competition
“IP Horizon-Scanning Tool” will sift through data of businesses and inventors, aided by the resources of
products contained in the USPTO’s Developer Hub government and the research prowess of academia,
data and will use applied data science to unveil trend promises to accelerate our march towards curing a
lines based on successful and failed immunology and disease that has left virtually no American untouched.
cancer-related product development and treatments. For the health of the nation and the world, these
Users will be able to build rich visualizations of intel- collective efforts must come to fruition. They remind
lectual property data as a way to locate meaningful us that when the various components of America’s
research and development at an earlier stage. Com- innovation ecosystem work together, no challenge is
bined with economic, funding, and litigation data, the insurmountable.

Technology and Innovation, Vol. 18, pp. 219-225, 2016 ISSN 1949-8241 • E-ISSN 1949-825X
Printed in the USA. All rights reserved. http://dx.doi.org/10.21300/18.2-3.2016.219
Copyright © 2016 National Academy of Inventors. www.technologyandinnovation.org


THE NAI FELLOW PROFILE: AN INTERVIEW WITH
DR. ROBERT S. LANGER


Robert S. Langer and Kimberly A. Macuare 2
1
1 Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
2 National Academy of Inventors, Tampa, FL, USA

In a recent interview with T&I, inventor and professor Dr. Robert S. Langer discusses his most
recent work and weighs in on the symbiotic relationship between universities and companies
in the tech transfer arena, the importance of teaching students to ask good questions as well as
to give good answers, and the ongoing motivation that impels him to excellence.


INTRODUCTION
In our continuing series of profiles, which honor
academic invention and inventors, Technology and
Innovation (T&I) is pleased to present Dr. Robert
S. Langer—biotechnologist, chemical engineer, and
serial entrepreneur—as the subject of this issue’s NAI
Fellow Profile. Langer is one of thirteen Institute Pro-
fessors at MIT, the highest honor awarded to faculty,
and the head of Langer Lab at the Massachusetts
Institute of Technology (MIT), one of the largest
academic biomedical engineering labs in the world.
Langer holds a B.S. in chemical engineering from
Cornell University and a Sc.D. in chemical engineer-
ing from MIT. At a time when chemical engineers
rarely did crossover work in medicine, he took a
postdoctoral position with Dr. Judah Folkman, a
medical researcher who was working on tumor angio-
genesis. This allowed Langer to forgo the multiple
job offers he received in the petroleum industry, a
much more traditional chemical engineering arena,
to focus on his passion: helping others. From that
beginning sprung a career in biomedical engineering
that has spanned five decades and led to important
breakthroughs in drug delivery, tissue engineering, (photo courtesy of Robert Langer)
_____________________
Accepted July 1, 2016.
Address correspondence to:
Robert S. Langer, PhD, Langer Lab, 77 Massachusetts Avenue, Room 76-661, Cambridge, MA 02139-4307, USA.
®
Kimberly A. Macuare, PhD, Assistant Editor, Technology and Innovation, Journal of the National Academy of Inventors , USF Research Park, 3702 Spectrum
Boulevard, Suite 165, Tampa, FL 33612, USA. Tel +1 (813) 974-1347; E-mail: [email protected]


219

220 THE NAI PROFILE



and nanotechnology. As the author of over 1350 years between your first publication on angiogenesis
articles; the inventor on over 1,100 U.S. and foreign and the approval of the first cancer drug based on
patents; and the mastermind behind over 30 compa- your work?
nies, Langer’s innovation output calls for an adjective Langer: I would say that [the idea of grit as a key
beyond prolific. As if his own work weren’t impressive to success] is true. I think that’s exactly right what
enough, his accolades are legion. He is the recipient of she said. And, as to what kind of traits [allowed me
over 220 prestigious awards, including the National to persevere], I guess that would be stubbornness, a
Medal of Science, the National Medal of Technology strong belief in wanting to do good for the world, and
and Innovation, the Charles Stark Draper Prize, the perseverance, things like that. That’s a very good ques-
Millennium Prize, the Kyoto Prize, and the Queen tion; people have asked that before, and I don’t really
Elizabeth Prize for Engineering. He is also one of the know 100%. But, I think it’s those kinds of things.
select group who has been elected to the U.S. National
Academies of Science, Engineering, and Medicine and T&I: Where does that strong core of self-belief come
elected a fellow of the National Academy of Inventors, from?
the American Association for the Advancement of Langer: Well, I don’t know if it’s a strong core of
Science, and the American Academy of Arts and self-belief. I mean there are lots of times that I’ve
Sciences. had a lot of doubts. You know, I think most things
Langer’s work is inveterately transdisciplinary, come from your family. I mean my mom and dad.
leveraging the fundamentals of materials science My mom was the type of person who was very nice
to create advanced biotechnological products and and helped people, and my dad got me interested
applications. A large part of that work has centered in more intellectual stuff, like he’d play math games
on drug delivery systems, where Langer has engi- with me. They got me these Gilbert chemistry sets
neered polymers that allow drugs to be delivered at and gifts like that.
controlled rates for specific and often prolonged time
spans. These advances offer the potential for better T&I: When you consider that time gap from your and
treatment of disease, advances in gene therapy, and Judah Folkman’s discovery of the first angiogenesis
improved vaccines among other areas. In addition, inhibitor (1976) to the first angiogenesis inhibitor
Langer’s lab has been active in the field of artificial being approved by the FDA (2004), 28 years is a long
tissue and organs, investigating the use of polymers time.
for improved tissue engineering. Langer: Well, it is, but medicine takes a long time.
Dr. Langer graciously agreed to an interview with There have been longer times for people to go from
T&I, discussing his most recent work and weighing discovery to FDA approval, but that’s a long time, I
in on various topics, including the symbiotic relation- agree.
ship between universities and companies in the tech T&I: You read Outliers, a book analyzing exceptional
transfer arena, the importance of teaching students to
ask good questions as well as give good answers, and performers by Malcolm Gladwell. Do you see yourself
as an outlier?
the ongoing motivation that impels him to excellence.
Langer: Probably I am in different ways. I think that’s
INTERVIEW probably right. All of these people you are talking to
T&I: In her recent book Grit, Angela Duckworth, a [NAI Fellows] are outliers in different ways.
psychology professor at U Penn, suggests that “grit”—a T&I: You have been and remain a leader in invention
combination of resilience to failure and sustained and translational technology and a champion for
passion for your core interests—is key to success. companies and the role they play in getting technol-
To what extent do you think this is true in your case, ogy to consumers. As someone who was involved in
especially given the early years of your career when academic start-ups before they were in vogue, what
your scientific work was not well received? What do you see as being the ideal relationship between
kind of traits allowed you to persevere during the 28 universities and start-up companies? What roles do

THE NAI PROFILE 221



they play in making sure that research has a real and to help others. What motivates that? Did you have
measurable impact? any early experiences or role models that ignited your
Langer: I think that what MIT does and Stanford does passion for service?
is close to ideal. In other words, I think that research Langer: I don’t know if I’m on a mission, but I’ve
goes on in the universities, but when research gets past always gotten a lot of satisfaction out of teaching,
a certain point, when it gets to be more development, out of helping people get educated. It’s just who I
when a lot of the things involve manufacturing issues, am. Why I am that way? I don’t know. I think again
clinical trial issues in our case, I think then it does those things probably come down to your parents.
make sense to have a company, and I think it’s also You asked about people, and I’d say a couple of people
been a great career for the people in the lab who have made a big impact on me. My mom and dad were
spent a lot of their graduate student or postdoctoral probably the biggest influences, but there was also
lives working on these things. So, it’s kind of like a Judah Folkman, who was my postdoctoral mentor.
hand-off. And yet, I don’t think the things that the He was a terrific scientist, he was a surgeon, and he
company does are what you’d want to see done in the definitely wanted to do a lot of good for the world
university or vice versa. I think that what happens in and did do a lot of good. Also, he was the kind of
Kendall Square and what happens in Silicon Valley person who had all kinds of far-reaching ideas and
is terrific. was criticized for them. And yet, he persevered, and
T&I: How is that hand-off connected to the mission he certainly was a great role model in a lot of ways.
of each type of entity? That is, why isn’t the university And the other person I would say is George Scheele.
the ideal place to develop businesses? I was his teaching assistant at Cornell when I was a
senior, and I loved that. That was a great experience
Langer: Well, I think that the university can do it, but for me to teach young students. In that case, it was
the problem is that it is not really something that the heat and mass transfer. I really enjoyed the experience,
university is skilled at, and it’s not really something and I think that got me excited about teaching. So,
the professors are skilled at either, or the students. I those would be some of the people who made an
mean, we can help, but I think it’s a business kind of impact on me.
thing—it’s really production, development, clinical
trials, so I think that it is not a classical skill of the
university. Could it be some day? I suppose it could
be. I mean, I think that would be a big change, but
that’s not impossible. But I think people would be also
concerned about conflicts of interest and things like
that if that were to happen. I think people already are
concerned about some conflicts of interest. My feel-
ing is that what we and Stanford are doing gives you
the best of both worlds. It gives you the opportunity
to do research and yet not just the opportunity to
do research but the opportunity to see that research
benefit mankind and even benefit the economy too.
So I think that’s good.
T&I: Moving beyond your research, you have a clear
dedication to service. From your early work writing a
math and science curriculum for inner city students
to your current projects with the Bill & Melinda Gates
Foundation to your daily meetings, phone calls, and
emails to offer advice and help to students, colleagues,
and business associates, you are a man on a mission (photo courtesy of Robert Langer)

222 THE NAI PROFILE



T&I: You are a dedicated teacher and mentor as well T&I: How would you assess your success as a teacher?
as researcher. Do you still love teaching? Langer: I think it’s pretty good. I don’t know if it’s
Langer: I do. I still love giving lectures. I don’t teach just me; I’ve been very lucky to have had really good
a formal class right now. I have at different points in people in my lab. There’s different metrics you could
time. When you are an Institute Professor, which is the use. One metric you could use is to ask how many are
title I have at MIT, you can pretty much do what you in the National Academy of Inventors. I think there
feel like, but I do like teaching. I enjoy it very much. are 21. I know there are 14 who are in the National
And I like teaching in different ways, and this gets to Academy of Engineering, 9 in the National Academy
part of the next question. I like teaching classes, but of Medicine, 36 in the Technology Review, and there
I also like being a part of my students’ and postdocs’ are nearly 300 or so who are professors. A whole
lives and teaching them research and seeing them do bunch who have started companies. I don’t want to
well in the lab and later on. I like all of that. brag. If I look back at what I’ve done, I’m very proud
T&I: One intriguing comment you made about your of the research, but the thing I’m always proudest
teaching was that instead of teaching students to give of is how well my students have done. This year, we
good answers, you want to teach them to ask good will have people become professors at places like
questions. How would you describe the pedagogical Stanford, Harvard, and MIT, and that’s great. I’m
process by which you achieve this? delighted about that.
Langer: I think it’s individualized, and it’s not some- T&I: I’ve read that your work has impacted two bil-
thing that you can really do in a class very well. But it lion lives. What does that mean to you?
is something that you can do for postdoctoral fellows Langer: I guess that was my dream. Not two billion
and for graduate students. It’s trying to be a bit of a but the fact that our research could do good for the
guide but not too much of a guide. In other words, if world. When I was a young person, I didn’t have a
somebody is doing a research project, you want to try very clear idea of what I wanted to do, but I definitely
to get them to think. You want to give them a bit of wanted to help people, and I’m thrilled that what I’ve
guidance but not tell them what to do. Let me use an done as a scientist and an educator has hopefully
airplane view analogy: Maybe I would give students helped people. That was my dream, so I feel very
a 50,000- to 100,000-foot view of what I want them happy about that.
to do to get started, but, ultimately, they are going to T&I: How does it relate to your perception of your
figure out the 30,000-foot view, the 10,000-foot view. own success? It seems like a lot of your perception
They are going to ultimately figure it all out. But I try
to help them if they run into problems. I don’t think of your success is connected to your ability to help
it is that structured, but it’s really with the intent that people.
you want to see what they’re interested in, you put Langer: Helping people is what I wanted to do, so
them on the course to do something that you and they success ultimately relates back to that. Not that I had
feel is important, but how they get there is going to a very clear sense of goals, but if you set some goals
be mostly up to them. And, of course, you help them and you are able to get there, then you feel like you’ve
if they get lost a bit. done ok. It’s nice to see that a lot of the therapies
T&I: Do you model that process for them? have gotten out to the world. That’s one of the things
I wanted to see happen. I think the companies have
Langer: No, not really. I don’t think I model it. I think helped that, and I think the students have done that.
that it’s very individualized. Everybody is different, It’s a team effort.
and some people want more guidance than others,
and so I adjust what I do for each student. I never T&I: How do you sustain such a high level of engage-
want to give too much, or too little, guidance. You ment and commitment?
want people to stretch a little bit, but you don’t want Langer: It’s the students and the postdocs and the
them to have to stretch too much. things that we’re doing. I think the projects we’re

THE NAI PROFILE 223



working on will do even more good, so I want them using materials and cells to create new tissues and
—both in terms of the research itself and the train- organs, and that’s already led to artificial skin for
ing—to be successful. And I have just a fantastic group burn victims. We’re in clinical trials helping people
of people in the lab, and I just love that, so I think it who are paralyzed with spinal cord repair. Some of
kind of [sustains itself] automatically. It’s the people the newer things we’re doing are new treatments for
and the mission of being an educator and trying to do diabetes. We published a couple of papers in Nature
research that I really enjoy and that can do more good. Journals earlier this year on new methods and new
T&I: Thinking about the people and the research, materials for encapsulating islet cells that could create
tell us about some of the current projects your lab an artificial pancreas that you could put in the body
is working on. and hopefully someday even be a cure for diabetes.
There are a lot of different things along those lines,
Langer: One of the things we are doing a lot with is like more basic work on understanding how materi-
the Gates Foundation. This is great because they want als could affect drug behavior and different disease
to help developing countries, and I do too. One big treatments. Those are a few things that we’re doing.
area we’re involved in is drug delivery systems, so I’ll There are a lot of areas where we could potentially do
give you a few examples of some of the new things a lot of good. The Gates Foundation has been great
we’re doing there. One is the idea that you could make to work with. They have been big supporters of a
a pill that can last anywhere from—not just a day, number of different things that we’ve done. We’re also
which is the longest they last now— a week to a month doing stuff with NIH and with different foundations.
to a year. The reason for that is that patient compliance Some of the work with the nanoparticles is aimed at
in developing countries is very poor. They’ve done cancer, so we’re working on a lot of different things
calculations at the Gates Foundation that if someone that I hope will help people in the long run.
could keep a blood level of a certain drug—say over
six nanograms per ml for two weeks—it could treat T&I: This last question is a little off the wall, but let’s
malaria, but people don’t keep taking their drugs. talk about your work with Living Proof, the hair care
So we are working on a pill that could literally last company. Given your work in the medical field, it
any length of time, and it’s looking quite promising. might seem like a departure in some way from your
Similarly with vaccines, people don’t come back other ventures. However, it’s often the fact that two
for second or third injections. Some years ago, there things which seem to be contrary are actually fun-
were statistics from the World Health Organization damentally similar. How is your work with Living
indicating that around half a million babies die of Proof connected to your other work?
tetanus every year because their mothers don’t come Langer: This is really a two-part question. The first
back for a second tetanus shot. So we’re creating a part is: why do we do it? The reason I did it is because
vaccine that allows you to give a single injection of the investors, some of whom are my former students,
any vaccine that is actually many injections in one. had been nice enough to invest in the companies that
Basically, we have little microspheres that release have spun out of our lab. One day, they said they
their compounds not only at time zero but also at one wanted to do a hair company and asked if I would
month, six months, and one year. We are also working help them, and they have been so good to me in terms
on nanotechnology, ways of delivering new drugs like of putting money into the companies that we’ve done
siRNA (these are gene therapy agents), CRISPR, and in medicine that I felt it was the least that I could do
messenger RNA. One of the big challenges of many of to help them.
these genetic therapies is getting it to the right cells, Then, secondly, when I looked into it, it was exactly
so we have been doing a lot of work on nanoparticles what you just said. Basically, some of the major
that are specially designed to do that. products really came from looking at fundamentals
The other big area is tissue engineering. We’ve of materials. In the case of the anti-frizz product,
done a lot on trying to come up with new strategies what happened is the same thing I saw in medicine.

224 THE NAI PROFILE



People were taking off-the-shelf materials and apply- When reviewing Langer’s career and hearing the
ing them to every single hair care product and with sincerity of his sentiments when discussing his work,
very little scientific fundamentals. Every single prod- you realize that his productiveness and intellectual
uct for anti-frizz has silicone as the main ingredient, generosity are quite simply products of who he is: a
and that doesn’t work that well. It doesn’t keep mois- genuinely nice person with a passion for service. His
ture out that well, and that’s the issue with frizz. We dream was always to help people, and he lives that
just took a more fundamental look and asked what dream every day.
would you really want from a material to keep mois-
ture out, and we examined the fundamentals and FURTHER READING
came up with one specific material, and that’s how 1. Langer R, Brem H, Falterman K, Klein M,
we solved that problem. Another example that relates Folkman J. Isolation of a cartilage factor that
to what you said is a product to give hair more body. inhibits tumor neovascularization. Science.
Dan Anderson, one of my former postdocs who is a 1976;193:70-72.
professor now at MIT, and I designed this library of 2. Langer R. Controlled release: a new approach to
polymers for gene therapy agents. There are literally drug delivery, Tech Rev. 1981;83:26-34.
thousands and thousands of polymers in that library, 3. Langer R. New methods of drug delivery. Science.
and we have composition of matter patents on them 1990;249:1527-1533.
so that you could fish one out for gene therapy, but 4. Langer R, Vacanti J. Tissue engineering. Science.
you could also fish others out for other things. We 1993;260:920-926.
picked one out that gave hair a lot more body, and so 5. Gref R, Minamitake Y, Peracchia M, Trubetskoy
this built off some of the other things we were already V, Torchillin V, Langer R. Biodegradable long-cir-
doing and had already done in the lab. culating polymeric nanospheres. Science.
1994;263:1600-1603.
CONCLUSION 6. Langer R, Vacanti J. Artificial organs. Sci Am.
As if to reaffirm his prodigious productive capac- 1995;273:100-103.
ities, in the brief interval between the interview and 7. Langer R. Drug delivery and targeting. Nature.
the write-up, Langer has been named as a finalist for 1998;392(Supp):5-10.
another major prize, the 2016 European Inventor 8. Langer R, Tirrell D. Designing materials for biol-
Award (he subsequently received that award); has ogy and medicine. Nature. 2004;428:487-492.
published a paper in Nature Materials on a “second 9. Khademhosseini A, Vacanti J, Borenstein J,
skin” technology that was picked up by every major Langer R. Microscale technologies for tissue
news outlet in the country; and has taken yet another engineering and biology. PNAS. 2006;103:2480-
company, Selecta Biosciences, public. Taken in the 2487.
context of his CV, which in the complete version 10. Peer D, Karp J, Hong S, Farokhzad O, Margalit R,
occupies some 70-odd pages, one understands that Langer R. Nanocarriers: emerging platforms for
this is par for the course for Langer. cancer therapy. , Nat Nanotechnol. 2007;2:751-
His level of output is all the more incredible when 760.
you consider that Langer is well-known for devoting a 11. Langer R. Biomaterials and biotechnology: from
large number of his waking hours to advising others— the discovery of the first angiogenesis inhibitors
from undergraduates to fellow researchers to biotech to the development of controlled drug delivery
entrepreneurs—both in person and by phone. It is systems and the foundation of tissue engineering,
not just an apocryphal tale that Langer will respond J Biomed Mater Res. 2013;101A:2449-2455.
to requests at lightning speed; it’s factual, with rarely 12. Langer R, Fuller J, Levin M. Entrepreneurship in
more than a few minutes elapsing between his receipt Biomaterials. In: Ratner D, Hoffman S, Schoen
rd
of a message and his response. F, editors. Biomaterials science. 3 ed. Oxford

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(UK): Academic Press; 2013. pp. 1459-1472.
13. Dang T, Thai A, Cohen J, Slosberg J, Siniakowicz
D, Doloff J, Ma M, Hollister-Lock J, Tang K, Gu
Z, Cheng H, Weir G, Langer R, Anderson D.
Enhanced function of immune-isolated islets
in diabetes therapy by co-encapsulation with
an anti-inflammatory drug, Biomaterials.
2013;34:5792-5801.
14. Dahlman J, Kauffman K, Langer R, Anderson
D. Nanotechnology for in vivo targeted siRNA
delivery. Adv Genet. 2014;88:37-69.
15. Yu B, Kang S, Akthakul A, Ramadurai N,
Pilkenton M, Sakamoto F, Gilchrest B, Anderson
R, Langer R. An elastic second skin. Nat Mater.
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nature.com/nmat/journal/vaop/ncurrent/full/
nmat4635.html.