Suomen Ortopedia ja traumatologia - 45. julkaisu 1/2022

Antibiotic impregnated bone graft to reduce infections after revision hip replacement; The ABOGRAFT trial
Daphne Wezenberg, Andreas Meunier, Lars Palm, Jörg Schilcher
Department of Orthopedic Surgery, and De- partment of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
Rationale
Aim
The aim is to investigate whether antibiotic im- pregnated bone graft decreases the risk of infection after revision hip arthroplasty compared to controls treated with placebo impregnated bone graft.
Outcome
The primary outcome is the number of reoperations due to infection with bacteria sensitive to vancomy- cin or tobramycin within 2 years after reoperation. Secondary outcomes are time and cause for reoper- ation or implant revision within 2- and 5-year, and for cases complicated with postoperative infection, type of microbe and antibiotic resistance pattern. In addition, patient-reported outcome measures (PROM) are collected using the pre- and post-op- eratively questionnaire as send out by the Swedish joint prosthetic register (Svenska Ledprothesregis- tret). See Figure 1 for an overview of the study.
Method
After screening, patients are randomized to treat- ment or placebo. The treatment group will receive 1 gram of vancomycin diluted with 6 ml of tobra- mycin (80mg/ml) and 2 ml of NaCl (0.9%) mixed with the morselized bone graft. The placebo group will receive 8 ml of NaCl blended with the bone graft. Treatment allocation will be double blinded. Patients will receive care as usual. Figure 2 shows the study related actions during surgery. Data on reop- erations are collected at 2- and 5-year post operation through register data from the Swedish joint pros- thetic register, which is complimented and validated using medical record review.
Approximately 8% of revision total hip arthroplas- ty (THA), will become infected and the incidence of prosthetic joint infection is rising. The intro- duction of antibiotics blended into bone cement has led to a 50% reduction in postoperative infec- tion in primary THA. However, bone cement can seldomly be used in relevant amounts in revision hip arthroplasty. As a result, the need for improved infection prophylaxis in revision THA is urgent.
One proven effective method to ensure local delivery of antibiotics is by using morselized bone allograft as a carrier instead of cement. Though promising, one potential side effect could be the development of antibiotic resistant organisms. In the ABOGRAFT trial, we aim to determine the risks and benefits of using antibiotic impregnated bone graft as a prophylaxis in revision THA.
Study design
This study is a phase II, randomized, double-blind, placebo-controlled, international, multicenter drug trial.
Patients
All patients scheduled for reoperation of a pre-ex- isting THA requiring bone grafting, for any reason other than infection, are eligible for participation. A total of 1200 patients will be recruited.
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ATTACHEMENT 1: Study flow chart
Figure 1: Flow chart. Schematic overview of the ABOGRAFT study PROM; Patient-reported outcome measures
Analysis
The primary outcome will be analyzed using propor- tional hazard models (Cox regression). Hazard rate ratios will be calculated for the two groups stratified for study site and sex.
Progress
Patient recruitment will start in March 2022. After an initial feasibility trial, performed at Linköping University Hospital (20 patients), patient recruit-
ment will be extended to high volume revision centers willing to participate.
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ATTACHEMENT 2: Study related action during surgery
Figure 2: Study related action during surgery. Drug preparation is done by an unblinded study nurse. Bone graft is prepared conform clinical care protocol at each center. The bone graft is impregnated with the drug, followed by an incubation period, after which the bone graft is used conform clinical practice.
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SOY XXV
ORTOPEDIAN JA TRAUMATOLOGIAN KURSSI
19.-24.3.2023 Levi, Kittilä