Analysis of foot structure in athletes sustaining proximal fifth metatarsal stress fracture

Background: In the past, several studies provided anecdotal descriptions of high-arched feet in individuals sustaining proximal fifth metatarsal stress fractures. This relationship has never been supported by scientific evidence. Our objective was to examine whether athletes who sustained this injury had an exceptional static foot structure or dynamic loading pattern. Materials and Methods: Ten injured professional soccer players who regained full professional activity following a unilateral proximal fifth metatarsal stress fracture and ten control soccer players were examined. Independent variables included static evaluation of foot and arch structure, followed by dynamic plantar foot pressure evaluation. Each variable was compared between injured, contra-lateral uninjured, and control feet. Results: Static measurements of foot and arch structure did not reveal differences among the groups. However, plantar pressure evaluation revealed relative unloading of the fourth metatarsal in injured and uninjured limbs of injured athletes compared with control, while the fifth metatarsal revealed pressure reduction only in the injured limbs of injured athletes. Conclusion: Athletes who sustained proximal fifth metatarsal stress fracture were not characterized by an exceptional static foot structure. Dynamically, lateral metatarsal unloading during stance may either play a role in the pathogenesis of the injury, or alternately represent an adaptive process. Clinical Relevance: Footwear fabrication for previously injured athletes should not categorically address cushioning properties designed for high-arch feet, but rather focus on individual dynamic evaluation of forefoot loading, with less attention applied to static foot and arch characteristics.