Minimally invasive versus conventional unicompartmental knee arthroplasty.

Introduction: Unicompartmental knee arthroplasty (UKA) has been proven to be a viable procedure in case of medial osteoarthritis of the knee joint. Minimally invasive surgery (MIS) techniques have been described to facilitate recovery after surgery. The aim of this study was to rule out major failure mechanisms and to obtain clinical data for comparison between a conventional and the MIS approach.
Materials and Methods: A consecutive series of 163 UKA (160 patients) were retrospectively included (83 conventional and 80 MIS interventions). Patients were invited for a clinical examination including clinical scores (KSS, Lequesne, UCLA, VAS, Feller- and Turba Patella Scores). Seven patients (4.3%) were lost to follow-up.
Results: Average follow-up was 4.6 ± 1.3 (1.5-6.8) years. Average age at operation was 67.5 ± 7.9 (45-81) years. Fifteen implants had been converted to TKA (9.2%). There were seven conversions to TKA in the MIS and 8 in the conventional group. Of the applied clinical scores there were better values for the Turba patella score in the MIS group. Differences of the other scores were not statistically significant.
Conclusion: Comparable functional results for both UKA procedures could be shown. There were no significant differences in terms of clinical scores or revision rates. The MIS approach in medial UKA did not show any major complications. Its use seems to be safe.