The position, orientation and morphology of the peroneus longus tubercle in hallux valgus – A weight-bearing CT assessment

Background

Hallux valgus (HV) may be associated with a dysfunctional peroneus longus, however there is very little research into the link between these pathologies. The peroneus longus tubercle (PLT) may serve as a surrogate marker for peroneus longus function. Our objective was to compare the position, orientation and morphology of the PLT in feet with and without HV.

Methods

In this single center series, we analyzed weight-bearing CT scans of 20 feet (12 patients) with HV and 20 feet (12 patients) without HV. Groups were age matched. We compared differences between groups for recently reported measurements assessing the PLT: tubercle-to-floor distance (T-F distance), bisecting angle of the PLT, tubercle-to-metatarsals angle (T-MT angle), and cross-sectional areas and roundness of the PLT.

Results

The T-F distance was significantly lower in the HV group (p = 0.001). The bisecting angle was lower (less vertical) in the HV group (p = 0.017). T-MT angle was lower in the HV group (p = 0.041). There was no difference in the cross-sectional area or roundness of the PLT between groups.

Conclusion

We found patients with HV had differences in orientation of the PLT (with a less vertical tubercle). This could indicate a relationship between direction of pull of the peroneus longus and HV. There were no differences in size of the PLT suggesting strength of the peroneus longus may not play a role in developing HV. Further research is needed to build upon this preliminary work and determine the link between the observed differences and the pathogenesis of HV.