Opening wedge high tibial osteotomy yields comparable to superior outcomes to unicompartmental knee arthroplasty at 2 years of follow-up in patients suffering from Ahlbäck III knee osteoarthritis: A propensity score-matched analysis.

PURPOSE

To compare the clinical outcomes between opening wedge high tibial osteotomy (OWHTO) and unicompartmental knee arthroplasty (UKA) in patients with Ahlbäck Grade 3 medial compartmental knee osteoarthritis (OA) using a propensity score matching (PSM) analysis.

METHODS

This retrospective study included all OWHTO and UKA procedures performed between 2016 and 2021 at a single institution. Inclusion criteria were patients diagnosed with medial knee OA, specifically Ahlbäck Grade 3 arthritis. Clinical outcomes were assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS). Radiographic parameters included hip-knee-ankle (HKA), medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA) and joint line convergence angle (JLCA). Primary outcomes included improvement in clinical scores at 3, 12 and 24 months post-operatively. Secondary outcomes included radiographic parameters, complication rates and re-intervention rates. One-to-one PSM was conducted based on gender, age and preoperative KOOS pain scores.

RESULTS

After evaluating eligibility using PSM, a total of 50 knees in the UKA group and 50 knees in the OWHTO group were included. There was no significant difference between groups in preoperative overall KOOS, but the UKA group had better overall KOOS at 3 months ( < 0.001). However, the overall KOOS at 12 and 24 months were superior in the OWHTO group compared to the UKA group (12 months; 84.6 ± 4.9 vs. 86.4 ± 2.9,  = 0.022, 24 months; 84.9 ± 5.3 vs. 87.0 ± 3.7,  = 0.022). As for post-operative radiological parameters, HKA, MPTA, LDFA and JLCA were higher in the OWHTO group at 24 months post-operatively. No significant differences were noted in the rates of complication or re-intervention between groups.

CONCLUSIONS

OWHTO can provide outcomes equal to or better than UKA at 24 months post-operatively in patients with advanced knee OA.

LEVEL OF EVIDENCE

Level Ⅲ, Prospective designed retrospective comparative study.