Abstract
Unicompartmental knee arthroplasty (UKA) has a long history that extends back nearly as far as the first tricompartmental designs. While initial results were erratic, with a greater understanding of patient selection and surgical techniques, more consistent and favorable results have been reported. While there has been somewhat of a resurgence in interest in UKA, the percentage of primary knee arthroplasties that are unicompartmental hovers around 6–8%. It is my belief that you should be doing more!
Several peer review studies suggest that with both fixed and mobile bearing designs, survivorship exceeds 90% at ten year. In our own initial series of 62 fixed bearing medial UKA, survivorship was 90% at 20 years.
UKA is an outstanding option for younger patients, who are amongst the most challenging to satisfy with a TKA. In a cohort of patients < 55 years old, Biswas et al. reported a mean KSS of just over 95 points and a mean UCLA activity score of 7.5. This is opposed to the report by Parvizi et al. who suggested 1/3 of young, active patients reported residual symptoms and limitations following modern TKA.
Most data suggests that UKA is a less morbid procedure than TKA. In a retrospective review of 605 UKA compared to 2235 TKA, Brown et al. found the risk of complications was 11% vs. 4.3% favoring UKA with a shorter length of stay and risk of discharge to an extended care facility, which also translates into lower costs for our health care system.
Finally, in the only randomised study that I am aware of that has compared UKA and TKA, UKA was associated with significantly better survivorship (90% vs. 79%). Further, UKA was associated with better ROM and functional scores at 5 and 15 years. Finally, recovery with UKA was faster and the risk of peri-operative complications was lower.
