Should patients aged 75 years or older undergo medial unicompartmental knee arthroplasty? A propensity score-matched study

Introduction With increasing life expectancies worldwide, more elderly patients with isolated medial compartment osteoarthritis may become suitable UKA candidates. However, there is a paucity of literature comparing outcomes between older patients (>= 75 years) and younger patients undergoing UKA. The aim of this study was to determine if there were differences in functional and HRQoL measures between older patients (>= 75 years) and younger controls (< 75 years) undergoing primary UKA. Materials and methods Prospectively collected registry data of 1041 patients who underwent primary, cemented, fixed-bearing medial UKA at a single institution from 2002-2013 were reviewed. Propensity scores generated using logistic regression was used to match older patients (>= 75 years, n = 94) to controls (< 75 years, n = 188) in a 1:2 ratio. Knee Society Scores, Oxford Knee Score, Short Form-36, satisfaction/expectation scores, proportion of patients attaining OKS/SF-36 PCS MCID and survivorship were analysed. Results Patients >= 75 years had significantly lower KSFS (67.1 +/- 17.9 vs 79.4 +/- 18.2, p < 0.001) and SF-36 PCS (47.3 +/- 10.1 vs 50.4 +/- 9.1, p = 0.01) as compared to the control group. In addition, a significantly lower proportion of patients >= 75 years attained MCID for SF-36 PCS when compared to the controls (50.0% vs 63.8%, p = 0.04). Survival rates at mean 8.3 +/- 3.0 years were 98.9% (95% CI, 96.7-100) in the older group versus 92.8% (95% CI, 86.8-98.8) in the younger group (p = 0.31). Conclusions Our findings highlight the need to counsel older patients regarding potentially reduced improvements in functional outcomes, despite advantages of lower revision. However, UKA in older patients continues to be a viable option for isolated medial compartment osteoarthritis