Medial Opening-Wedge High Tibial Osteotomy Delivers Meaningful Early Outcomes Even in KL-3 Osteoarthritis: A 24-Month Stratified Cohort Analysis

Objectives: Medial opening-wedge high tibial osteotomy (MOWHTO) is a joint-preserving procedure designed to correct varus malalignment and reduce medial compartment overload in knee osteoarthritis (OA). Although historically reserved for early-stage disease, recent evidence suggests that patients with more advanced radiographic degeneration may still benefit from the procedure. However, the relationship between Kellgren–Lawrence (KL) grade and postoperative clinical outcomes remains controversial. This study aimed to evaluate early-term pain reduction and functional improvement following MOWHTO by comparing patients with low-grade OA (KL1–2) and moderate OA (KL3).
Methods: This retrospective observational study analyzed 73 consecutive adults who underwent standardized biplanar MOWHTO between May 2020 and May 2023 at a single tertiary center. Patients were stratified into KL1–2 (n=58) and KL3 (n=15) groups. Pain and function were assessed preoperatively and at 6, 12, and 24 months using the Visual Analog Scale (VAS), KOOS, and WOMAC index. Radiographic alignment parameters and complications were recorded.
Results: Preoperative VAS scores were high in both groups (KL1–2: 7.79±0.89; KL3: 8.27±0.70; p=0.066). At 24 months, VAS scores decreased significantly (KL1–2: 3.33±1.15; KL3: 1.87±0.74), with KL3 patients exhibiting greater pain reduction (ΔVAS: 6.40±1.06 vs. 4.47±1.52; p<0.001). KOOS scores improved substantially in both groups (KL1–2: 53.1±8.2 to 85.4±5.8; KL3: 43.9±7.6 to 76.7±6.3), with similar functional gains (ΔKOOS: 32.3±6.0 vs. 32.8±8.9; p=0.85). WOMAC scores improved significantly (KL1–2: 51.9±3.6 to 30.8±7.1; KL3: 61.4±4.3 to 34.9±5.6), with greater improvement in KL3 (ΔWOMAC: 26.5±8.2 vs. 21.2±7.4; p=0.034). The overall complication rate requiring surgery was 12.3%, and 24-month arthroplasty-free survival was 96.0%.
Conclusion: MOWHTO provides meaningful early-term improvements in pain and function across all KL grades. Despite worse baseline status, KL3 patients achieved comparable or greater symptomatic relief. These findings support MOWHTO as a viable op-tion for carefully selected patients with moderate OA seeking to delay arthroplasty.

Keywords: High Tibial Osteotomy, osteoarthritis knee, pain measurement, treatment outcome