The use of Percutaneous screw fixation without fracture site preparation in the treatment of 5th metatarsal base non-union
M. Grant, A. Molloy, L. Mason
Introduction: Non-union following a proximal fifth metatarsal 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 3mm headless compression screw and zone 2 and 3 with an intramedullary 4mm screw.
Results: Out of 19 patients included in this study, a minimum of 6 month clinical follow up was obtained. The average time from injury to treatment was 5.4 months (range 3-12 months). There were no smokers in this patient cohort. There were 12 zone 1 injuries, 3 zone 2 injuries and 4 zone 3 injuries. All patients achieved union by 3 months post screw fixation, with 18 out of 19 achieving union by 6 weeks. All patients had resolution of symptoms. There were no complications.
Conclusions: 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.
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