Summary

Proximal tibio-fibular overlap of more than 22.5mm may suggest presence of tibial torsion.

Abstract

Purpose

This study aims to investigate the relationship between proximal tibio-fibular overlap with femoral and tibial torsion in an Asian population with knee osteoarthritis (KOA).

Methods

A retrospective analysis was performed of 344 patients planned for operation between September 2018 to April 2024. 135 patients with 164 knees were included for further analysis after exclusion of those with previous lower limb procedures or patellar malalignment. Proximal tibio-fibular overlap was measured on plain X-Ray films, while femoral anteversion and tibial torsions were assessed on computed tomography (CT) images. The relationships between tibio-fibular overlap with femoral and tibial torsion were determined with the Pearson correlation coefficient.

Results

The mean tibio-fibular overlap, femoral anteversion and tibial torsion was 14.5mm, 20.0° and 20.5° respectively. Overall, a moderate positive Pearson correlation of tibio-fibular overlap with tibial torsion (ρ=0.454, p<0.01 respectively) was observed. By observing the trend on a scatter plot, we found that a tibio-fibular overlap above 22.5mm would predict for high tibial torsion (>30°). Tibio-fibular overlap was weakly related to femoral anteversion (ρ=0.349, p<0.01). The intra- and inter-observer ICC values were 0.88 and 0.87 for tibio-fibular overlap, 0.85 and 0.82 for femoral torsion and 0.83 and 0.78 for tibial torsion.

Conclusion

This study reports a positive relationship between proximal tibio-fibular overlap and tibial torsion. We suggest that further evaluation of tibial torsion is recommended for knees with proximal tibio-fibular overlap of more than 22.5mm.