No significant post‐operative limb length difference following medial opening wedge high tibial osteotomy in a multi‐ethnic Southeast Asian population

Abstract

Abstract Purpose This study aims to assess the significance of post‐operative change in limb length in medial opening wedge high tibial osteotomy (MOWHTO), and evaluate the correlation between correction angles and changes in limb length. We hypothesize that opening wedge height and correction angles directly correlate to changes in limb length. Methods The medical records and radiographs of 91 MOWHTO patients were retrospectively evaluated for relevant radiographical parameters both pre‐ and post‐operatively. The exclusion criteria are: (i) concurrent distal femur osteotomy in the same setting, (ii) other previous unilateral lower limb surgeries prior to MOWHTO and (iii) failure to follow‐up with post‐operative radiographs. A linear regression model was performed and a line of best fit, Pearson's correlation coefficient (r) and coefficient of determination (R2) were computed. Chi‐squared test was also performed, and results with P 8 mm) and smaller (< 8 mm) opening widths. There was a weakly positive correlation between limb length change versus actual (R2 = 0.140, 95%CI [‐0.068, 0.336]) and planned correction angles (R2 = 0.196, 95%CI [‐0.012, 0.387]). Conclusion In conclusion, post‐MOWHTO change in limb length is statistically significant, but the clinical significance is minimal. Further studies are required to assess other factors. Development of a reliable mathematical model that predicts post‐MOWHTO limb length change would be useful in predicting the anatomical outcomes. Level of evidence Level III. Retrospective Cohort Study.

Keywords

• Osteoarthritis
• High tibial osteotomy
• Opening wedge
• Limb length
• Knee