Articulating Spacers as a Modified One-Stage Revision Total Knee Arthroplasty: A Preliminary Analysis

Introduction: Periprosthetic joint infection (PJI) following primary total knee arthroplasty (TKA) is a challenging complication for surgeons and patients alike. Although two-stage revision arthroplasty remains the gold standard PJI management in the United States, one-stage revision has had success in many parts of Europe. The aim of this study was to retrospectively review: 1) ultimate treatment success; 2) necessary antibiotic duration; 3) change in knee range of motion (ROM); and 4) final Knee Society Scores (KSS) in a case series of patients managed with retention of articulating antibiotic spacers following PJI. Materials and Methods: A retrospective review was performed on all patients treated for chronic PJI after primary TKA with retention of articulating antibiotic spacers at a minimum of one-year follow-up. Descriptive analysis was utilized to evaluate demographic characteristics, discharge destination, follow-up and antibiotic durations, Knee Society Score (KSS), and rates of treatment failure. Paired-Samples t-Tests were utilized to evaluate mean changes in flexion and extension between the preoperative and postoperative time periods. Results: Our final cohort included 29 patients who were managed with articulating spacer retention at a mean follow-up of 16.8 (range, 12.0 to 23.1) months, with 21 patients (72.4%) medically unfit for multiple surgeons and eight patients (27.6%) satisfied with their function. Mean age was 61.3 (range, 41 to 85) years and mean Charlson Comorbidity Index (CCI) was 6.1 (mean, 0 to 12). The predominant infecting organism was Methicillin-Resistant Staphylococcus aureus (MRSA), which was involved in eight patients (27.6%). There was a significant increase in postoperative knee flexion (+14.7; p<0.001) and no decrease in postoperative knee extension (+2.3; p=0.361). Treatment success in our cohort was 79.3% (23 patients), with four patients (13.8%) having chronic wound drainage and two patients (6.9%) requiring multiple spacer exchanges. Sixteen patients (55.2%) were able to complete their antibiotic regimen, with the remaining patients unable to discontinue their antibiotics by latest clinic follow-up. Discussion. One-stage exchange arthroplasty offers the advantage of a single procedure with analogous failure rates compared to two-stage exchange, decreases hospitalization, and improves cost-effectiveness, which is paramount in today's healthcare environment. To our knowledge, this is the first study in the United States to evaluate outcome scores, function, and success rate of a modified one-stage revision TKA technique. Although we are unable to make definitive conclusions based on the s all sample size, the outcomes in this study are encouraging.