Mid-term clinical outcomes and survivorship of medial-pivot total knee arthroplasty—a mean five year follow-up based on one thousand, one hundred and twenty eight cases

The unique medial-pivot (MP) design of ADVANCE® system largely simulates the movement of a normal knee joint and a high mid- and long-term success rate has been reported in limited populations. The aims of this study are to investigate the mid-term clinical outcomes and survivorship based on a large cohort with 1128 cases. One thousand seven patients received 1276 ADVANCE® MP TKAs from January 2011 to April 2016 in our institution were retrospectively investigated. The range of motion (ROM), the Knee Society Score (KSS), the Knee Society Function Score (KSFS), the Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, and the Forgotten Joint Score (FJS) were used to evaluate clinical outcomes and Kaplan-Meier survival curve was used to calculate the survivorship. In an averaged five year follow-up, the results of 879 patients (1128 knees) were successfully obtained and the clinical outcomes of 1107 knees were recorded. One hundred forty-eight knees (11.6%) were lost to follow-up. Excellent mid-term ROM, KSS, KSFS, and WOMAC score were recorded. A total of 53 complications were identified and most complications were related to the discordance of femoropatellar joint. Taking revision for any reason as end point, the overall survivorship was 99.2% at seven years. When taking all cases lost to follow-up as failures, the survivorship was 83.8% at five years and 50.6% at seven years. For MP designs, the intermediate clinical outcomes are good to excellent and the mid-term survivorship related to reasons other than infection is also satisfactory.