Associated Deformities and Hypermobility in Hallux Valgus: An Investigation with Weightbearing Radiographs

Abstract

Background: Hallux valgus has been reported to recur after surgical correction in patients subsequently diagnosed with hypermobility of the first ray, pronation of the foot, and pes planovalgus. An objective means of assessing the foot for these deformities preoperatively may avert a poor outcome. This investigation evaluated the efficacy of full-length weightbearing radiographs to recognize associated deformities in patients with hallux valgus before surgery. Methods: This study compared five parameters from anteroposterior and four parameters from lateral weightbearing pedal radiographs of patients with moderate to severe hallux valgus to a control group to identify differences in the alignment of the midfoot and the first metatarsal-medial cuneiform joint. An examination for clinical evidence of hypermobility was also performed on both groups. Results: The hallux valgus group demonstrated increased abduction and dorsiflexion of the midfoot. The mean talonavicular coverage angle and lateral talo-first metatarsal angle of this group was greater than the mean values for the controls. Radiographic evaluation also revealed differences in the alignment of the first metatarsal-medial cuneiform joint in the sagittal plane. The hallux valgus group possessed a mean of 2 mm of dorsal translation and 2° of dorsiflexion at this joint compared to the controls. Conclusions: Weightbearing radiographs permit the recognition of associated malalignments of the foot in patients with hallux valgus. The comparisons performed in this study identified deformities consistent with pes planovalgus and hypermobility of the first ray in patients with moderate to severe hallux valgus. The results of our study support a recommendation for a thorough evaluation of full-length, biplanar weightbearing radiographs via the measurement of midfoot and first ray alignment for concomitant deformities of the foot in patients with hallux valgus.