Background and Objectives: Medial unicompartmental knee arthroplasty (UKA) has emerged as an effective surgical option for isolated medial compartment osteoarthritis (OA), offering advantages in bone preservation, knee kinematics, and postoperative recovery compared with total knee arthroplasty (TKA). Although numerous studies have evaluated the mid- to long-term outcomes of UKA, reports focusing on cohorts with follow-up periods exceeding 10 years remain relatively limited. The purpose of this study was to analyze the long-term clinical and radiological results of medial fixed-bearing UKA using the Miller-Galante prosthesis. Methods: Sixty-eight patients who underwent UKA at a single institution with at least 10 years of follow-up were retrospectively reviewed. Clinical outcomes were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and knee range of motion (ROM). Radiological parameters including the hip-knee-ankle axis angle (HKA) and osteoarthritis (OA) grade using the Kellgren-Lawrence (K-L) grading system were evaluated. Implant survivorship was evaluated using Kaplan–Meier survival analysis. Results: A total of 68 patients were included with a mean age of 56.8 ± 7.5 years at surgery and a mean follow-up of 170.9 ± 37.3 months. Significant improvement in the WOMAC score was observed from 48.9 ± 17.2 preoperatively to 23.8 ± 27.7 at final follow-up (p = 0.002). The cumulative survival rates were 97.1% at 10 years and 84.8% at 15 years with conversion to total knee arthroplasty as the endpoint. Significant improvement in the HKA was observed from 172.5° ± 4.4° to 174.3° ± 4.8° postoperatively (p = 0.002), though residual varus alignment persisted. Progressive OA was observed in the lateral tibiofemoral and patellofemoral compartments (both p < 0.001) but showed no correlation with the WOMAC score. The failure group showed trends toward higher body mass index (BMI) and smaller preoperative HKA angle compared to the non-failure group. Conclusions: The long-term outcomes of medial fixed-bearing UKA using the Miller–Galante prosthesis were generally favorable, with significant functional improvement and acceptable implant survivorship. Although overall varus alignment was corrected, some residual varus deformity remained, and OA progression was observed in the lateral tibiofemoral and patellofemoral compartments over time. However, given the retrospective design and limited sample size, these findings should be interpreted with caution.
Lim et al. (Tue,) studied this question.