Foot, Toe, and Nail Changes: Are They Interdependent?

Introduction: The toes are the distal extension of the foot increasing its weight-bearing area and the security of the stance. The nails are the acral part of the toes and are so intimately linked with the distal interphalangeal joint, its ligaments, and tendons that they were also called musculoskeletal appendages. The big toe is of particular importance for gait and stance. Anatomic alterations of the foot and toe lead to pathological changes of the nails, both directly as well as indirectly. Methods: The author evaluated the clinical photographs of 1,663 patients examined for toenail conditions. Results: It was found that a normal straight axis of the first ray of metatarsal and phalanx bones occurred in less than 10% of the patients with hallux valgus and hallux valgus interphalangeus being extremely frequent. The commonest nail changes observed were compression nail (n = 247), ingrown nail (196), onychomycosis (192), disappeared nail bed (191), congenital malalignment (118), pincer nails (118), and nail overcurvature (114). The most frequent foot-toe abnormalities were hallux valgus (775) and hallux valgus interphalangeus (1,277). Conclusion: Although a direct causal relationship is hard to prove it was realized that most of the nail changes were associated with foot and toe abnormalities. The study reveals that assessing toenail changes requires examination of the entire foot, best in relaxed, standing, and walking conditions.