Low complication rate and better results for intramedullary nail - arthrodesis for infected knee joints compared to external fixator-a series of one hundred fifty two patients.

PURPOSE: Arthrodesis of the knee joint is still a salvage procedure after recurrent prosthetic joint infections (PJI) of total knee arthroplasties (TKA) with substantial bone loss and seems to be a good solution to avoid amputation. Until now, intramedullary arthrodesis has increasingly been performed; no study has yet been published to compare these techniques after septic removal of TKA in terms of functional assessment and quality of daily life.

METHODS: In a single-centre retrospective setting, clinical and radiographic evaluation of consecutive patients after knee arthrodesis using intramedullary and external fixation for infected knee joints was performed. All patients were evaluated clinically, with x-ray and questionnaire including analysis regarding any complications at latest follow-up of a minimum 12 months postoperatively.

RESULTS: We included 152 patients (75 females, 77 males) in this study. The mean age of the patients at surgery was 63.6 years (range 12 to 90 years). The minimum follow-up was 12 months (mean 3.1 years, range 12 to 49 months). Arthrodesis with external fixator (83 patients, 52.2%) showed less blood loss and less peri-operative complications (1.6%) but a high rate of post-operative, pin-track infections (35.5%); loose pins (12.7%); and pin fractures (4.8%), and therefore risk factors for instability and nonunion (30.9%). Revision rate was 22.6% for arthrodesis with external fixator, and the primary union rate was 65.6%. Intramedullary arthrodesis (69 patients, 43.4%) showed a similar re-infection rate to external fixation (16.1% and 15.9%, respectively) but a significantly lower revision rate (5.4%, p < 0.001). Eighty percent of patients with intramedullary arthrodesis showed very good patient-related outcomes regarding pain, function and daily life activities in the questionnaire.

CONCLUSION: Despite similar results regarding patient satisfaction and everyday competences in questionnaires, intramedullary arthrodesis of the knee is superior to the external fixator, as it results in fewer complications, lower revision rate, and union rates/loosening.