International Orthopaedics - 2026-04-18 - Journal Article
Does postoperative alignment influence outcome after medial opening wedge high tibial osteotomy? A long-term follow-up study.
Jung WH, Khare H, Singh R, Kim DH, Takeuchi R
Topics
Key Takeaway
Non-optimal postoperative HKA alignment after MOWHTO does not worsen patient-reported outcomes in retained knees but causes significantly earlier conversion to TKA (log-rank χ²=29.11, p<0.001) at mean 11.5-year follow-up.
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Summary
This study asked whether postoperative HKA alignment after MOWHTO predicts patient-reported outcomes and implant survivorship at long-term follow-up. 203 knees were stratified into optimal vs. non-optimal HKA groups; PROMs (KSS, KSFS, Oxford Knee Score, WOMAC) and TKA conversion rates were compared. Non-optimal alignment produced greater loss of correction (higher ΔHKA, p<0.001) and earlier TKA conversion, but PROMs were equivalent in knees that survived without conversion.
Key Limitation
PROM analysis excluded converted knees, creating survivorship bias that artificially equalizes functional scores between alignment groups and likely underestimates the true functional penalty of non-optimal alignment.
Original Abstract
BACKGROUND
Medial opening wedge high tibial osteotomy (MOWHTO) is a widely used procedure for treating varus knee osteoarthritis. While achieving an appropriate postoperative coronal alignment is considered important, it is not well established whether optimal alignment actually translates into better patient-reported outcomes.
METHODS
We retrospectively evaluated 203 knees in 173 patients, who underwent MOWHTO. Based on postoperative hip-knee-ankle (HKA) alignment, patients were classified into optimal and non-optimal groups. Clinical outcomes were assessed using the Knee Society Score, Knee Society Functional Score, Oxford Knee Score and WOMAC. Conversion to Total Knee Arthroplasty (TKA) was defined as failure. Surgical survivorship was analysed using Kaplan-Meier method and the log-rank test. Patient Related Outcome Measures (PROM) analysis included only patients who retained their native knee at final follow-up.
RESULTS
Preoperative and early postoperative HKA angles were similar between groups. However, at a mean follow-up period of approximately 11.5 years, patients in the non-optimal group showed significantly greater loss of correction, reflected by a higher ΔHKA (p < 0.001). Among patients who did not undergo TKA, postoperative PROMs were comparable between the two groups. Although the overall rate of conversion to TKA was similar, survivorship analysis showed that failure occurred significantly earlier in the non-optimal alignment group (log-rank χ 2 = 29.11, p < 0.001).
CONCLUSION
While optimal alignment after MOWHTO does not appear to improve patient-reported outcomes, it is associated with better long-term survivorship of the osteotomy. In contrast, non-optimal alignment is linked to earlier failure and earlier conversion to TKA, suggesting that alignment accuracy primarily influences longevity rather than long-term function.