Incidence and reasons for reoperation after minimally invasive unicompartmental knee arthroplasty.

The goal of this report is to review reoperations undertaken on the initial 221 unicompartmental arthroplasties performed using a minimally invasive technique. A comparison was then performed between these cases and the previous 514 open medial unicompartmental arthroplasties performed at our institution. In the minimally invasive group, 9 (4.1%) of 221 knees were revised (8 for component loosening, 1 for deep infection). Of 212 unrevised knees, 16 have required a total of 18 nonrevision reoperations. Overall, 25 of 221 knees required at least 1 reoperation (total reoperation rate, 11.3%). Despite an accelerated recovery and decreased hospital stay in our minimally invasive unicompartmental arthroplasties, the rate of revision due to aseptic loosening (3.7% vs 1.0%) and the overall reoperation rate (11.3% vs 8.6%) compare unfavorably with those performed with an open technique.