Objective: High tibial osteotomy (HTO) is an established joint-preserving procedure for medial compartment osteoarthritis with varus deformity. While it can delay the need for total knee arthroplasty (TKA), the long-term survival of HTO varies, and predictive factors remain under investigation.
Materials and
Methods: This retrospective cohort study evaluated patients who underwent medial opening-wedge HTO between 2005 and 2017. Inclusion criteria were isolated medial osteoarthritis with varus alignment and a minimum 5-year follow-up. Patients were grouped based on whether they later required TKA. Pre-operative, post-operative, and final radiographic parameters – including mechanical tibiofemoral angle (mTFA) and medial proximal tibial angle – were measured by two blinded observers. Statistical analyses were performed to compare groups and identify potential predictors of failure.

Results: A total of 327 patients (295 females, 32 males) were reviewed; 34 (10.4%) underwent subsequent TKA at an average of 7.6 years post-HTO. Pre-operative mean mTFA was 12.48±4.25°, corrected post-operatively to −0.76±3.82° (p<0.001). Patients requiring TKA showed less optimal post-operative alignment and greater progression of lateral or patellofemoral joint degeneration. Higher pre-operative deformity and undercorrection after HTO were associated with increased risk of conversion to TKA.

Conclusion: Medial opening-wedge HTO can offer substantial joint preservation benefits, but a subset of patients progresses to TKA within a decade. Achieving appropriate mechanical alignment correction and careful patient selection are crucial for improving long-term survival. Understanding radiographic and demographic risk factors may help guide surgical planning and enhance native knee preservation in active populations.