A comparative analysis of three knee arthrodesis techniques to manage failed total knee arthroplasty due to infection: intramedullary nailing, LRS external fixator, and compression plating.

INTRODUCTION: This study compared external fixation (EF), intramedullary nailing (IMN), and compression plating (CP) for knee arthrodesis (KA) following failed total knee arthroplasty (TKA) due to periprosthetic joint infection, focusing on complications, radiological, and functional outcomes.

METHODS: Patients aged ≥ 18 who underwent knee arthrodesis following failed TKA due to infection from 2008 to 2023 were included. Four surgeons used three techniques: EF, IMN, and CP. Retrospective data on demographics, surgical techniques, complications, and outcomes were collected. Postoperative patient-reported outcome measures (PROMs), pain, and functional status were assessed. Radiographic data was reviewed for limb shortening and union status.

RESULTS: 46 patients (mean age 61.9 years, BMI 28.2), predominantly male (84.8%) were involved in this study. Twenty patients underwent EF, 16 underwent CP, and 10 underwent IMN, all for infected primary TKA. Pseudomonas was the most common infecting organism (15.2%). Average follow-up was 29.1 months. Bony fusion was achieved in 41 knees (89.1%), with five requiring additional surgery; four eventually required amputation due to non-fusion. EF group had the shortest time to union and no major complications or amputations. Time to union was significantly shorter in the CP group compared to the IMN group (p < 0.001), and EF group also had a significantly shorter time to union compared to IMN (p = 0.02). Infection eradication was 100% in the EF group, with significantly fewer additional surgeries and complications compared to the IMN group. Overall patient satisfaction was high (82.6%), with most patients reporting no pain and functional outcomes ranging from mild limitation to fully normal function.

CONCLUSION: KA has shown to be an effective method to control infection, achieve fusion and provide pain relief following failed infected TKA. EF emerged as the preferable method for knee arthrodesis, showing fewer complications, shorter union times, and no additional surgeries compared to IMN and CP.