Unicompartmental knee arthroplasty is superior to high tibial osteotomy in post-operative recovery and participation in recreational and sports activities

Purpose: To compare (1) the recovery pattern of post-operative physical activity and function in the early post-operative period and (2) the difference of participation in recreational and sports activities pre- and post-operatively following unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO). Methods: In this prospective comparative study, 49 HTOs (49 patients) and 42 UKAs (42 patients) performed to treat medial compartmental knee osteoarthritis (OA) were included. The pain visual analog scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index score (WOMAC), Tegner activity score, Lysholm knee score, and the University of California at Los Angeles (UCLA) activity score were evaluated pre-operatively and post-operatively at three, six, 12, and 24 months. Participation in recreational and sports activities was also assessed pre-operatively and 24 months post-operatively. Results: Pre-operatively, although there were no differences in VAS, WOMAC, and Lysholm scores between the two groups, the UKA group had inferior Tegner and UCLA scores (p < 0.05). At post-operative three and six months, the UKA group showed superior VAS, WOMAC, and Lysholm scores (p < 0.05 for all). However, at 12 and 24 months post-operatively, both groups had similar outcome scores (p > 0.05 for all). When all the baseline scores were adjusted for the mean changes, the UKA group showed a significantly better UCLA score than the HTO group until 12 months after the operation (p = 0.008). The rate of return to sports activity was 94.1% in the UKA group and 75.0% in the HTO group at 24 months post-operatively (p = 0.031). Conclusion: These findings indicate that UKA had better short-term functional outcomes and return to recreational and sports activities than did HTO in patients with medial OA.