Hallux anatomy: much ado about shoes-an attempt to prove that constrictive V-shaped toe-box shoes deform the hallux.

Purpose: A question still remains as to whether constrictive toe-box shoes (TBS) cause disability only due to pain on pressure points or if they can cause permanent changes in the hallux anatomy. The aim of this study is to compare the hallux morphology in 3 groups classified according to their use of constrictive or open TBS.

Methods: 424 patients were classified into 3 groups: group A used open TBS daily; group B used constrictive TBS daily; group C used both open and constrictive TBS. Hallux's angles, presence of exostoses and shape of the distal phalanx (DP) were analyzed on dorsoplantar weight-bearing radiographs and compared amongst groups.

Results: The intermetatarsal (IMA), metatarsophalangeal (MTPA), DASA, PASA, interphalangeal (IPA), obliquity (AP1), asymmetry (AP2) and joint deviation (JDA) angles for group A were 10°, 8°, 5°, 4°, 9°, 3°, 5°, 3°; for group B were 9°, 19°, 5°, 6°, 12°, 2°, 8°, 2°; and for group C were 10°, 10°, 4°, 4°, 12°, 3°, 8°, 1°. Only the differences in the MTPA, IPA and AP2 were statistically significant (p < 0.05). The prevalence of exostoses on the tibial side of the DP was 22, 36, and 29% in groups A, B and C, respectively (p < 0.05). We found similar distributions of the different DP shapes in the three groups.

Conclusions: Our results suggest that the use of constrictive TBS, even if used only occasionally, could change hallux anatomy from a young age increasing MTPA, IPA and AP2. Moreover, we have found that DP exostoses are present as a "normal variation" in patients who wear an open TBS, but their prevalence is higher in those wearing constrictive toe-box shoes. This could be due to a reactive bone formation secondary to the friction caused by the inner border of the shoe.

Level Of Clinical Evidence: 3.