Purpose: The aim of the present study was to compare the clinical outcomes of mobile-bearing unicompartmental knee arthroplasty (MB-UKA) and open-wedge high tibial osteotomy (OWHTO) for advanced isolated medial osteoarthritis (OA).
Methods: Patients with advanced medial compartment OA (Ahlbäck grade ≥ II) who underwent either MB-UKA with Oxford Knee or OWHTO were included. The minimum follow-up was two years. Clinical outcomes were evaluated using the Hospital for Special Surgery (HSS) score, knee score (KS), and function score (FS) of the Knee Society Knee Scoring System. Pre-operative and post-operative values were compared within groups. Pre-operative and post-operative values and the degree of change were compared between the two groups. Radiologic progression of OA in either the lateral or patellofemoral compartment was evaluated.
Results: Forty knees (20 received MB-UKA, 20 received OWHTO) were enrolled. The mean age was higher in the MB-UKA group (67.9 ± 9.0 years) than in the OWHTO group (58.4 ± 5.5 years). The HSS score, KS, and FS were significantly increased post-operatively in both groups. The preoperative HSS score, KS, and FS were significantly lower in the MB-UKA than in the OWHTO group; however, only the post-operative HSS score was significantly higher in the MB-UKA group. The changes in HSS score and KS were also greater in the MB-UKA group. There was no significant difference in OA progression.
Conclusions: Although there was an age difference between the two groups, MB-UKA demonstrated superior short-term clinical outcomes to OWHTO for advanced isolated medial OA. In particular, MB-UKA was more effective in terms of pain relief.
Keywords: Advanced isolated medial osteoarthritis; Clinical outcomes; Mobile-bearing unicompartmental knee arthroplasty; Open-wedge high tibial osteotomy.