Foot alignment characteristics in patients with Freiberg's disease.

Background: Freiberg's disease is defined as aseptic necrosis of the metatarsal heads. It is more common in female patients and primarily affects adolescents aged 11-17 years. The second metatarsal is most frequently involved, accounting for approximately 68 % of cases. This study aimed to assess foot alignment in patients with Freiberg's disease using a mapping system to evaluate radiographic images.

Methods: The study cohort included 13 patients (14 feet) diagnosed with Freiberg's disease at our hospital between January 2010 and December 2022, with appropriate loading-position radiographs (Group F). The control group (Group C) comprised 14 patients with no abnormal foot alignment on the healthy side who had bilateral standing dorsoplantar images taken for other conditions. Foot alignment was evaluated using a mapping system.

Results: Mapping results on frontal radiographs showed medial deviation of the first metatarsal head and lateral deviation of the fifth metatarsal head and base in patients with Freiberg's disease, with significant differences between Groups F and C (P < 0.05). Significant differences were also observed in the M1/M2, M3/M4, and M2/M4 angles (P < 0.05). No significant differences were found between the groups in Meary's angle or calcaneal pitch on lateral radiographs.

Conclusion: This study demonstrated that patients with Freiberg's disease exhibit specific radiographic abnormalities in foot alignment. These abnormalities may increase stress on the metatarsal head, potentially contributing to the development of the disease. Our findings offer a novel perspective on its etiology and progression. Further research is needed to determine whether these abnormalities reflect a congenital predisposition or result from ongoing pathological changes.

Level of evidence: Level Ⅲ, retrospective comparative study.