The Use of Percutaneous Screw Fixation without Fracture Site Preparation in the Treatment of 5th Metatarsal Base Non-Union

Abstract

Category: Midfoot/Forefoot, Trauma Introduction/Purpose: Non-union following a proximal 5th metatarsal fracture can cause considerable pain with high morbidity with loss of work. Although many authors advocate early surgical management of zone 3 injuries (Jones fracture), zone 1 and 2 fractures are generally expected to heal with conservative management. Uncommonly, zone 1 and 2 fractures can develop non- unions. The aim of this study was to evaluate the efficacy of closed intramedullary screw fixation for non-unions of the 5th metatarsal base. Methods: We performed a prospective study involving all 5th metatarsal base non-unions treated in our department over 2 years. Only minimally-displaced adult fractures were considered for this study. The fracture pattern was categorised using the Dameron classification (zone 1 – styloid process, zone 2- meta-diaphyseal area, zone 3 – proximal diaphysis). All non-unions were fixed percutaneously under radiographic guidance, without fracture site preparation. Zone 1 injuries were fixed using a 3 mm headless compression screw and zone 2 and 3 with an intramedullary 4 mm screw. Results: Out of 30 patients included in this study, a minimum of 6 month clinical follow up was obtained. The average time from injury to treatment was 6 months (range 3-36 months). There were no smokers in this patient cohort. There were 12 zone 1 injuries, 9 zone 2 injuries and 9 zone 3 injuries. All patients achieved union by 3 months post screw fixation, with 29 out of 30 achieving union by 6 weeks. All patients had resolution of symptoms. There were no complications. Conclusion: We conclude that percutaneous fixation of 5th metatarsal base non-unions, without fracture site preparation, achieves excellent results. We believe that the screw alters the strain of the fracture, thus promoting fibrous to osseous conversion and therefore union.