Assessment of three-dimensional hallux valgus deformity utilizing full weightbearing computed tomography scans.

BACKGROUND

Hallux valgus (HV) is a complex triplanar deformity.

PURPOSE: To utilize preoperative weightbearing computed tomography (WBCT) of patients with HV deformity to characterize the true triplanar nature of the deformity, as well as to assess first metatarsophalangeal joint pathology.

STUDY

DESIGN

Retrospective case series.

METHODS

A retrospective study of adult patients with HV deformity treated between 1/2020 and 7/2024.

RESULTS

Sixty-four patients were included. Inter-rater reliability for all radiographic measurements demonstrated good to excellent agreement. WBCT findings demonstrated that 38 patients (59 %) exhibited both first metatarsal pronate and tibial sesamoid subluxation, while 7 patients (11 %) showed neither deformity. 51 patients (80 %) presented true sesamoid subluxation. The rate of pseudo-sesamoid subluxation was 9 % (6/64 patients). WBXR findings showed that 42 patients (66 %) had moderate HV deformity with 37 patients (58 %) demonstrating an abnormal HVA, 20 patients (31 %) with mild HV, and 2 patients (3 %) with severe HV. 37 patients (58 %) observed with first metatarsal joint degeneration and 30 patients (47 %) exhibited erosion of the intersesamoid crista. The tibial sesamoid subluxation grade demonstrated a statistically significant and meaningful moderate correlation with HVA, degeneration of the first metatarsal joint and erosion of the intersesamoidal crista, but a slightly less meaningful moderate correlation with HV deformity.

CONCLUSION

WBCT provides a reproducible, three-dimensional assessment of HV deformity, offering more accurate evaluation of first metatarsal pronation, sesamoid subluxation, and degenerative of both the first metatarsophalangeal joint and the intersesamoidal crista compared to conventional radiographs.