The Association of a Varus Hindfoot and Fracture of the Fifth Metatarsal Metaphyseal-Diaphyseal Junction

Abstract

Background Fractures to the fifth metatarsal metaphyseal-diaphyseal junction (Jones fracture) have high nonunion rates. Surgical intramedullary screw fixations have excellent results but a high refracture rate. This has been associated with inadequate screw size and too early return to activity. Hypothesis Varus hindfoot alignment overloads the lateral column of the foot and acts as a predisposing factor to the development of and failure of treatment of Jones fractures. Study Design Case series; Level of evidence, 4. Methods Twenty-one primary Jones fractures (20 patients) treated surgically with a 4.5-mm cannulated screw were retrospectively reviewed. Detailed clinical and radiographic data and outcomes were recorded, including measurements of hindfoot alignment. Results A 100% union rate with return to prior activity level and no refractures were found at a mean follow-up of 49 months. Clinical varus was present in 16 feet, whereas radiographic measurements revealed 18 of 21 hindfeet to be in varus. The mean calcaneal pitch angle was 28.5°, and the mean Meary angle was 13° convex upward. Patients with varus alignment were fitted postoperatively with lateral hindfoot and forefoot posted orthotic inserts to correct alignment. Conclusion The majority of patients sustaining Jones fractures have evidence of varus hindfoot alignment. This may be a predisposing factor to developing the fracture or refracture after fixation. Postoperative varus unloading (lateral hindfoot and forefoot posting) orthotic insert appears to be helpful in preventing reinjury or refracture of Jones fractures.