The association between foot alignment and the development of ingrown toenails: A case-control study in a young adult military population.

BACKGROUND: This case-control study aimed to explore an association between foot alignment and development and presentation of the ingrown toenail. METHODS: Radiographs were evaluated for hallux interphalangeal angle (HIA), hallux valgus angle (HVA), talonavicular coverage angle (TNC), talo-first metatarsal (Meary's) angle, and calcaneal pitch angle (CP), as well as medial sesamoid position in a cohort of 103 young and healthy patients (mean age of 20.5 years) with ingrown toenails. A control group of 63 patients was included, and the radiographic parameters were compared. Subgroup analysis was performed in patients with lateral (n = 65) or medial (n = 38) nail fold involvement. RESULTS: The overall study group demonstrated a larger TNC and Meary's angle and smaller CP than the control group, while no significant difference was found regarding the HIA and HVA. The lateral nail fold group had a larger HIA when compared to the medial nail fold group. Multiple regression analysis revealed that for ingrown toenail development, the only risk factor was a decrease in the CP. In the case of lateral nail fold involvement, an increase in the HIA found to be the only factor. CONCLUSION: A lower medial longitudinal arch seems to be a predisposing factor in developing an ingrown toenail. The lateral nail fold involvement was associated with lateral deviation of the distal phalanx. The result of this study could provide information on prevention, treatment, recurrence, and patient counseling of an ingrown toenail in otherwise young and healthy individuals.