Appendix I: Summary of Medical Device Adverse Event Reports

Appendix I: Summary of Medical Device Adverse Event Reports

 

A. The FDA Manufacturer and User Facility Device Experience (MAUDE) Database

The MAUDE database houses all Medical Device Reports (adverse event and product problem reports)
which are received by FDA for marketed medical devices. MAUDE is comprised of MDRs received from
various sources, including manufacturers, user facilities, distributors, and voluntary reporters. FDA
medical device adverse event reporting is a passive surveillance system with many benefits as well as
limitations. The strengths of MDRs are that they provide:

 A qualitative snapshot of adverse events for a specific device or device type
 A source for detection of new or emerging safety signals for

o device problems in “real users” in “real world” settings/environment
o rare serious adverse events
o unexpected adverse events
o long-term adverse events
o vulnerable populations
o off-label use
o use error

However, MDRs also have the typical limitations of a passive surveillance system including:
 under-reporting of events
 incomplete information
 lack of definite causality
 reporting bias, attributed to potential causes such as reporting practice, increased media attention,
and/or regulatory actions
 inability to estimate rate of adverse events (no “denominator” data)
 limited interpretation of “trends” in numbers

B. FDA MAUDE Search Methodology: Metal-on-Metal THR Systems

The following searches and steps were conducted to query the CDRH MAUDE database on February 7, 2012
for all MDRs associated with Metal-on-Metal THR systems.

 The first search was performed for all Metal-on-Metal THR system product codes
 Three additional searches were performed to extract all MDRs for all available total hip bearing

types using associated product codes for: Metal-on-Polyethylene, Ceramic-on-Ceramic, and
Ceramic-on-Polyethylene.
 A final search was conducted to identify MDRs specific to other known total hip systems submitted
under incorrect product codes.
 Duplicate and multiple reports were removed. (Note: MDRs submitted for the same event either by
different sources or for different components are defined as multiple reports).
 Text searches were performed on all resulting MDRs using 65 adverse event terms that were
grouped together into larger categories. (MDRs including more than one term in each category were
counted once per category)

C. FDA MAUDE Summary Results – THR Systems

A total of 16,818 MDRs were received by the FDA for Metal-on-Metal (MoM) THR system devices from
1992 – December 31, 2011. A total of 22,090 MDRs were received for all non-MoM THR systems (metal-
on-polyethylene, ceramic-on-ceramic, ceramic-on-polyethylene). The number of MDRs received for MoM

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and all non-MoM THR systems reflects the number of incidents that were reported to the FDA for these
devices. Due to previously mentioned limitations of a passive surveillance system, the numbers of adverse
events for these devices does not reflect the rate at which these incidents are occurring nor the actual number
of incidents that may have occurred during this time frame.

Medical Device Reports Received

Table 1 shows the number of MDRs received by the FDA by year for MoM THR systems compared to all
other available bearing type THR systems. Please note, the date of receipt of an MDR by FDA is not always
reflective of the date of the adverse event. (i.e., delayed reporting is common).

Table 1: Number of Medical Device Reports (MDRs) Received by Year

   
Recalls, negative media attention, litigation, and increased/decreased usage of a medical device may
substantially increase or decrease the number of MDRs received by the FDA. The recall for the DePuy ASR
(August 23, 2010) contributed to the sharp increase in MoM THR MDRs received in 2010 and 2011. For
example, of the 12,137 MoM THR reports received in 2011, DePuy ASR accounted for 9,006 of these
reports (74.2%).

“Local” Adverse Event Types

Table 2 shows the major types of adverse events received by the FDA for MoM THR systems compared to
all available non-MoM THR systems devices. Sixty-five terms were used to categorize the adverse events
occurring for total hip devices. These 65 terms were then combined to yield 22 adverse event types. It should
be noted that an adverse event report may have contained in more than one of the 22 adverse event types.

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 Tinnitus/hearing loss
 Vision impairment
 Seizures
 “Drop foot”
 Fibromyalgia

Seven reports noted renal or urinary issues although details beyond “renal failure” or “kidney damage”
were not provided in most. One report noted a “renal mass” but no further information was provided. One
report noted hematuria, but again, no additional details were given.

Five MDRs mentioned the diagnoses of a malignancy in the time period following MoM THR
implantation. One did not mention the specific location, and the other four cited the following

 Breast
 Myeloma
 Thyroid
 Metastatic cancer of unknown primary (metastatic to lung and liver)

Three of the reports specifically mentioned the thyroid gland. One noted a thyroid malignancy (as stated
above) and the other two noted hypothyroidism

Finally, CDRH has received one MDR which notes a patient with high serum cobalt levels and
cardiomyopathy. This report stated that the patient died from his/her cardiomyopathy.

D. FDA MAUDE Search Methodology: Metal-on-Metal Hip Resurfacing Systems

The following searches and steps were conducted to query the CDRH MAUDE database on May 11,
2012 for all MDRs associated with Metal-on-Metal Hip Resurfacing systems.

 The first search was performed for all Resurfacing Hip system product codes.
 A second search was performed to extract all MDRs for all available hemi hip devices in order to

obtain all hip resurfacing MDRs incorrectly categorized under hemi hip device product codes.
 Duplicate and multiple reports were removed. (Note: MDRs submitted for the same event either by

different sources or for different components are defined as multiple reports).
 Text searches were performed on all resulting MDRs using 65 adverse event terms that were

grouped together into larger categories. (MDRs including more than one term in each category were
counted once per category)

E. FDA MAUDE Summary Results – Resurfacing Systems

A total of 796 MDRs were received by the FDA for Metal-on-Metal (MoM) hip resurfacing systems from
1992 – December 31, 2011. There were no MDRs received for hip resurfacing systems of different bearing
types as none have been approved in the United States.

Medical Device Reports Received

Table 4 shows the number of MDRs received by the FDA by year for MoM hip resurfacing systems. Please
again note, the date of receipt of an MDR by FDA is not always reflective of the date of the adverse event.
Please also note that these devices were not approved for marketing within the United States prior to 2006.

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