Assessment of tibialis anterior tendon insertion variations in relation to hallux valgus utilizing magnetic resonance imaging

Abstract

Background: Hallux valgus is a deformity characterized by lateral deviation of the big toe and medial deviation of the first metatarsal, causing difficulty in walking and requiring various treatments. Despite its multifactorial etiology, the role of the tibialis anterior tendon in hallux valgus and its variations in the morphology of tibialis anterior tendon distal insertion sites have not been fully explored. This study aimed to evaluate the effect of such variations on hallux valgus using magnetic resonance imaging. Methods: This was a retrospective study and included 115 individuals aged 18 years and older who underwent foot radiographs and MRI. The participants were divided into a hallux valgus group of 53 patients and a control group of 62 people based on radiographic measurements. Tibialis anterior tendon distal attachment was classified into five types according to the attachment morphology. Statistical analyses were performed to evaluate the relationship between the tibialis anterior tendon types and hallux valgus severity. Results: Among the participants, patients who underwent foot radiography and MRI due to any medical indication 70.4% were female, with a mean age of 43.83 ± 15.25 years. In terms of tibialis anterior tendon distal attachment, the most common type was Type 5 (40.9%), followed by Type 2 (34.8%). Type 4 was not observed in any case. In all participants, the mean hallux valgus angle was 20.63 ± 8.42o, and the mean intermetatarsal angle was 9.69 ± 2.68o. Tibialis anterior tendon distal attachment Type 5 was significantly associated with an increased hallux valgus angle but not with the intermetatarsal angle. We found a significant relationship between the diameter of the tibialis anterior tendon and hallux valgus angle. Conclusions: This study revealed a significant association between hallux valgus and Type 5 tibialis anterior tendon distal attachment, suggesting that tibialis anterior tendon morphology influences hallux valgus severity. The findings underscore the importance of considering variations in tibialis anterior tendon distal attachment sites in the etiopathogenesis and treatment planning of hallux valgus.