IS UNICOMPARTMENTAL KNEE ARTHROPLASTY CONTRAINDICATED IN YOUNG ACTIVE PATIENTS?

Abstract

Introduction: The indications for unicompartmental knee arthroplasty (UKA) can be contentious. Concerns exist about implanting a UKA in younger individuals and it has been reported that the procedure is contra-indicated in patients under the age of 60. The suggestion is that younger patients may compromise their outcome after surgery by their increased activity levels. However, the number of publications with data on UKA in young patients is minimal and the age/activity related criteria for UKA remains unknown.

Aim: The aim is twofold: 1) to confirm that younger UKA patients have higher activity levels than older patients, and 2) to test the hypothesis that younger, more active patients have inferior outcome when compared to older less active patients.

Materials and methods: Fifty consecutive patients undergoing UKA who were under 60 years old at the time of surgery (Group Y) and 50 patients over 60 years (Group O) were recruited. Indications were anteromedial arthritis with full thickness lateral compartment cartilage, a functioning ACL and a correctible varus deformity. All patients underwent Oxford UKA using the minimally invasive technique. This device employs an unconstrained fully congruous meniscal bearing. Outcome was evaluated using the American Knee Society Score (AKSS). Activity level was documented using the established Tegner Activity Score.

Results: The average age of patients for group Y and O was 55 years and 68 years respectively. Minimum follow up for both groups was 2 years. Pre-operative AKSS scores were comparable for each group (Group Y = 38.8, Group O = 35.8) and patients in both groups significantly improved after surgery. A significant difference in Tegner score was found between groups after surgery (Group Y = 3.9, Group O = 2.6). It was found that 40% of younger patients regularly participate in high demand activities like skiing, tennis, hard manual labour and swimming. No statistically significant difference in any other post operative knee scores or complication rate were found despite adequate study power.

Conclusions: Younger patients have increased activity levels after UKA when compared to an older age group. There is no evidence that the outcome of UKA in younger more active patients will be inferior to those who are older and more sedentary.