Is there a relationship between forefoot alignment and ingrown toenail? A case-control study.

Biomechanical imbalance between the hallux and the second toe and external compression of the lateral nail fold are proposed as the main reasons for ingrown toenail. Therefore, any anatomical predisposition facilitating this compression may play a role in the occurrence of ingrown toenail. The purpose of this study is to investigate the relationship between forefoot alignment and ingrown toenail. The authors retrospectively reviewed radiographs of 81 patients with ingrown toenails and compared them with 100 healthy subjects regarding forefoot alignment. Hallux valgus angle (HVA), intermetatarsal angle (IMA), and interphalangeal angle (IPA) were measured, and feet were classified according to digital formula as Egyptian, Greek, and square. The mean HVA was 14.5° ± 5.0° in the case group and 13.2° ± 5.9° in the control group. The mean IMA was 9.1° ± 2.5° in the case group and 8.6° ± 3.1° in the control group. The mean IPA was 11.9° ± 4.1° in the case group and 12.0° ± 5.1° in the control group. There was no statistically significant difference between the groups regarding HVA, IMA, or IPA (P = .123, P = .198, and P = .925, respectively). The distribution of foot types between groups was also similar (P = .967). This study has failed to demonstrate any abnormality in forefoot alignment in patients with symptomatic ingrowing toenails, and it is suggested that treatment should not be based on the correction of the anatomy if no abnormality exists.