Satisfactory 10-year survivorship of medial opening wedge high tibial osteotomy for isolated medial compartment osteoarthritis and varus alignment: An analysis from a high-volume institution.

PURPOSE

Medial opening wedge high tibial osteotomy (MOWHTO) is a reliable joint-preserving surgical procedure for isolated medial compartment knee osteoarthritis (OA) and overload. The aim of this study was to evaluate the long-term survivorship and clinical outcomes of patients undergoing MOWHTO and to identify the risk factors associated with an increased risk of failure.

METHODS

This was a retrospective study of prospectively collected patients who underwent MOWHTO for isolated medial OA and overload between 2002 and 2023. Clinical outcomes were evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Tegner activity score. Radiographic analysis included hip-knee-ankle (HKA) angle and medial proximal tibial angle (MPTA). Survivorship was intended from conversion to total knee arthroplasty (TKA). Logistic regression was used to identify risk factors, and p values < 0.05 were considered significant.

RESULTS

Four hundred thirty-one patients who underwent MOWHTO were included for analysis. Males were 82.5%, and the mean age was 49.1 ± 8.0 years. The KOOS increased in any subsection at mean 5.7 ± 4.5 years of follow-up (p < 0.001). Complication rate was 35.9% and reoperation rate was 25.5% at mean 9.6 years of follow-up. Removal of metal hardware due to pain and/or discomfort was the main cause of reoperation in 22% of the patients. The cumulative rate of conversion to TKA at 5 years was 2.2%, at 10 years 17.8% and at 15 years 37.1%. Age (odds ratio [OR]: 1.05, p = 0.017), wedge thickness (OR: 1.08, p = 0.015), medial femoral condyle OA (OR: 3.41, p = 0.029), medial tibial plateau OA (OR: 2.04, p = 0.044), post-operative HKA (OR: 1.25, p = 0.031) and post-operative MPTA (OR: 1.26, p = 0.04) were associated with an increased risk of failure.

CONCLUSION

MOWHTO yields satisfactory 10-year survivorship in patients with medial compartment isolated knee OA and overload. Age, preoperative stage of OA, cartilage wear and post-operative alignment are relevant patient-related risk factors for reduced survivorship.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.