A Single Surgeon, 10 Year Experience with the Oxford Partial Knee System: What a Difference Experience, Instruments, Implants, and Technique Can Make

Partial knee (unicompartmental) arthroplasty (PKA) for medial compartment disease of the knee has a long and well documented history of successful results over long periods of follow up. The Oxford Partial Knee Replacement has been available in the U.S. since 2004. After completing an FDA required instructional course, surgeons may use the device. Both the implant and the instruments have evolved since its introduction in 2004. This paper outlines the authors continuous cohort of 249 patients, 286 knees from 2004 to 2014 with minimum 2 year follow up, and reports the results while discussing the impact of experience, instruments and implants, and technique on the outcome of patients in this series. For the aggregate group of 286 knees, there were 17(5.9%) all-cause revisions to TKA, including 2(0.7%) dislocations, resulting in a (83%) survivorship at ten years. The survivorship at ten years for retained implants was 97% if non-implant related causes are not included. At one year, there were 89% excellent and good results, 5% fair, and 6% poor. At two years, there were 93% excellent and good, 1 % fair, and 5.5% poor.  The causes for the poor results at one and two years were tibial sided failure or persistent pain. Three (12%) of patients with a poor result at one year had converted to good and excellent at two years. The use of the Oxford Mobile Bearing™ PKA has been shown to be a useful part of the surgeon’s surgical armamentarium when dealing with anteromedial osteoarthritis or osteonecrosis of the knee. PKA has been shown to have a lower morbidity and mortality and is cost effective when compared to total knee arthroplasty. The author’s experience, as demonstrated in this study, adds validity to the concept that understanding the pathoanatomy of anteromedial osteoarthritis and gaining surgical experience through increased surgical volume, adherence to well documented technique, and the use of a time proven implant, can be accomplished with a high degree of successful outcomes for patients with the appropriate indications.