Morphologic Analysis of the Fifth Metatarsal Stress Fracture: The Precise Coronal and Sagittal Location.

Abstract

From a biomechanical standpoint, the main pathologic abnormality of fifth metatarsal stress fracture is the location where repetitive tensile stress concentrated. Decreasing tensile force in this region would be a proper treatment. Therefore, the purpose of this study is to evaluate the precise sagittal and coronal location of the fifth metatarsal stress fracture. Between June 2012 and May 2013, 38 athletes with a fifth metatarsal stress fracture were treated. To evaluate the precise sagittal location of the fracture, the entire length of the fifth metatarsal was measured and the distance from tuberosity to the fracture line was measured. To evaluate the precise coronal location of the fractures, coronal computed tomography images were obtained for incomplete fracture cases. The fracture location was classified as four quadrants. Thirty patients were classified into zone III fracture. However, the fracture is located in zone II for remaining eight cases. The median value of ratio between whole length and the distance from tuberosity to the fracture was 0.35 (range, 0.29–0.40) Among 33 incomplete fracture cases, there were 28 patients whose fracture developed in plantolateral quadrant, four patients at the lateral side and a patient for plantar side. The main pathologic abnormality is at the plantar lateral side because of the repetitive stress concentrated there.