Risk Factors Associated With Foot and Ankle Insufficiency Fractures in Postmenopausal Sedentary Women.

BACKGROUND: Insufficiency fractures occur in bones with low elastic resistance. In contrast to stress fractures, which affect normal bones and have been extensively studied, insufficiency fractures of the foot and ankle have been the subject of little research. The objective of this study was to identify risk factors associated with the development of foot and ankle insufficiency fractures.

METHODS: The study included 55 postmenopausal sedentary women with foot and ankle insufficiency fractures and 51 women in the control group. The data collected were the fracture site, body mass index, use of corticosteroids, T scores of the femur and lumbar spine measured by bone densitometry, and serum 25-OH vitamin D level. The calcaneal pitch (CP), talar-first metatarsal, and metatarsus adductus (MA) angles were measured on radiographs.

RESULTS: In 49 patients (89%), fractures occurred in the metatarsals. All metatarsals were affected, and the most common fracture site was the base of the fifth metatarsal, with 21 cases (33%). Twenty patients (36%) in the study group reported chronic use of corticosteroids and had lower bone mineral density levels than controls ( P < .05). The factors associated with fracture development ( P < .05) were the CP and MA angles and low lumbar bone mineral density.

CONCLUSION: Insufficiency fractures in this population were associated with low bone mineral density and unfavorable biomechanical characteristics such as pes cavus and metatarsus adductus.

LEVEL OF EVIDENCE: Level IIIB, case-control study.