Stress Fracture of the Fifth Metatarsal in Foot Deformity Secondary to Neuromuscular Disease: Experiences of Deformity Correction Treatment-A Report of 3 Cases and Review of the Literature.

Fractures at the proximal metaphyso-diaphyseal junction of the fifth metatarsal are associated with high rates of delayed union. When these fractures are the result of repeated stress in patients with equinovarus hindfoot, which in turn is caused by neurological disorders, delayed union is the rule. Therefore, in neurological patients with stress fractures, optimal treatment would be to achieve a plantigrade foot enabling them to relieve the fifth metatarsal overload, which prevents the consolidation. We report 3 cases of fifth metatarsal stress fracture resulting from an equinovarus hindfoot deformity caused by a neuromuscular disease. Our surgical indication was to correct the foot deformity with no direct action on the fracture. Once a good alignment (plantigrade foot) was obtained, stress causing the fracture disappeared, and union was achieved with optimal biomechanical function in all 3 fractures. When stress fracture of the fifth metatarsal is caused by a secondary foot deformity, treating the deformity can lead to healing the fracture efficiently and should be considered prior to indicating surgical stabilization of the fracture itself. Primary treatment of the fracture with no correction of the deformity leads to therapeutic failure. LEVELS OF EVIDENCE: Therapeutic, Level IV.