The effect of activity on the outcome of cementless mobile bearing unicompartmental knee replacements.
Mohammad HR., Judge A., Dodd C., Murray D.
BACKGROUND: Many surgeons consider high activity levels a contraindication to Unicompartmental Knee Replacement (UKR). Cementless fixation is of particular concern given the lack of cement to augment primary stability. We assessed the effect of pre and post-operative activity levels on the outcomes of cementless UKRs. METHODS: A prospective cohort of 1000 medial cementless mobile bearing UKR were analysed. Patients were categorised by their pre-operative and highest post-operative Tegner Activity Score (TAS) and results compared between groups. Outcomes of interest included implant survival, Oxford Knee Score (OKS) and the American Knee Society Score - Objective/Functional (AKSS-O/F). RESULTS: Increasing post-operative activity were not associated with higher revision rates. The 10-year survival of the high activity group (TAS ≥ 5, 96.7% (CI 91.3-98.8), and low/medium activity group (TAS ≤ 4, 98.1% (CI 96.5-99.0)) were not significantly different (p = 0.57). The mean 10-year OKS of the high activity group (46.5, SD 3.1) was significantly (p