Radiographic Evaluation of Foot Structure following Fifth Metatarsal Stress Fracture

Abstract

Correlation between foot structure and stress fracture risk has not been adequately evaluated or proven. The purpose of this study was to compare foot structure in fracture cases versus control with respect to radiological parameters in stress fractures of the fifth metatarsal. The study group consisted of 50 consecutive athletes with a diagnosis of fifth metatarsal stress fracture and a control group matched for sport type and age. Fifth metatarsophalangeal (MTP-5) angle, fourth-fifth intermetatarsal (IMA4-5) angle, fifth metatarsal lateral deviation (MT5-LD) angle were measured on standing antero-posterior (AP) radiographs. Talo first metatarsal (T-MT1) angle, talo-calcaneal (TC) angle, and calcaneal pitch (CP) angle were measured on a standing lateral view, and MT5-LD angle was measured on a 30-degree medial oblique view. Significant inter-group differences were found for TC angle (p < 0.001) and calcaneal pitch angle (p < 0.001) on lateral radiographs, and for IMA4-5 angle (p = 0.003), MT5-LD angle (p = 0.002) on AP radiographs, and for MT5-LD angle (p < 0.001) on the 30-degree medial oblique radiographs. Fifth metatarsal stress fractures were found to be associated with elevated T-MT1 angle and CP angle representing a cavus foot and the increased curvature of fifth metatarsal. In addition, the extent of fifth metatarsal curvature on a 30-degree medial oblique view was found to be more related to the risk of fracture than on the AP view.