Non-Biological Modular Knee Arthrodesis for Prosthetic Infections With Large Defects at 5-year Follow-up: An Alternative to Amputation

Introduction: Treatment of recurrent periprosthetic knee infections is challenging. Arthrodesis may be inapplicable in prosthetic infections with large defects and amputation prosthetics do not restore adequate function. A novel implant was used for non-biological arthrodesis in infections with large defects for which amputation was otherwise considered necessary. Methods: Patients who had the Biomet Orthopedic Salvage System (OSS) for non-biological knee arthrodesis with a minimum 2 years of follow-up or early failure and patients who received it as a temporary spacer before the second stage revision were identified and their charts were reviewed. Results: Eighteen patients were included. Four patients had temporary spacers then, second stage revision. One patient had amputation for recurrent infection, and 3 were infection-free at the last follow-up. In 14 patients, non-biological arthrodesis was performed. There were 11 females and 3 males with a mean age of 65 years. Bone loss at the knee was 11 to 47 (average 26) centimeters. Seven patients had recurrent infection: 5 remained on antibiotic suppression and retained functional extremities whereas 2 patients required above-the-knee amputation. A third patient required amputation for early spacer dislocation. Eleven patients (79%) retained functional extremities, and revision-free implant survival was 50% at an average 59 months (range 24 to 126 mo). Conclusion: Results of non-biological arthrodesis in prosthetic knee infection with large defects were encouraging. Patients should be counseled that although the procedure may offer an alternative to amputation, the goal is containment rather than cure of infection.