Results of the First Fifty Minimally Invasive Oxford Unicompartmental Knee Arthroplasty

Abstract

Purpose: To report the advantages and the defects through an analysis of the early results of minimally invasive unicompartmental knee arthroplasty (UKA). Materials and Methods: The first fifty consecutive minimally invasive UKA for medial osteoarthritis that were followed up for at least 2 years (2 years-2 years 10 months) were included. The surgical parameters, clinical parameters, radiological parameters and complications were examined. Results: The average preoperative knee score was 47.7, which improved to 82.7, 86.7, 87.9 and 89.4 at 6 weeks, 6 months, 1 year and 2 years after surgery, respectively. The average function score was 42.2, which improved to 71.5, 77.4, 81.3 and 84.7 at the 6 weeks, 6 months, 1 year and 2 years follow up, respectively. The average range of knee motion was 124.6˚ preoperatively, which changed to 128.4˚, 134.2˚, 136.8˚ and 138.5˚ at 6 weeks, 6 months, 1 year and 2 years, respectively. The preoperative tibiofemoral angle was 2.5˚ of varus, which changed to 3.4˚ of valgus postoperatively. Three revisions to total knee arthroplasty were performed due to two fractures of the medial tibial condyle and one dislocation of the femoral component. Conclusion: The early postoperative results of minimally invasive UKA showed satisfactory improvement in the knee score, function score and recovery of the range of motion. However, surgeonsmust be aware of the severe complications that require a revision procedure.