Surgery for non-union after 5th metatarsal fractures - the good guy becomes the bad guy!

M. Sheridan, E. Kokkinakis, N.J. Madeley, C.S. Kumar

¹Glasgow Royal Infirmary, Glasgow, United Kingdom

²University of Glasgow, Glasgow, United Kingdom 

Introduction: The majority of the 5^th metatarsal fractures are successfully treated conservatively and only a few patients require surgical fixation for symptomatic non-union. The tuberosity avulsion fractures are generally considered benign injuries with the more distal fractures showing a propensity to develop delayed/non-union. We studied a cohort of patients who underwent surgery for the treatment of non-union and report on the outcome and the rate of complications and requirement for additional surgery.

Methods: All patients, who required surgery to their fifth metatarsal, from June 2008 to May 2018, were included in this retrospective study. Demographic and clinical outcome data and radiographic classification of fracture types were collected, reviewed and analysed.

Results: 35 patients had undergone surgery for 5^th metatarsal fractures during this time period and 31 of these had been operated for a painful non-union. 12 were tuberosity avulsion fractures (Lawrence and Botte Type 1) and 23 were Type 2 and 3. Five patients (14.3%) experienced a further symptomatic non-union after initial surgery; Type 1 fractures were 11 times more likely to result in non-union (p=0.0375). Wound complications were seen in 14.3% of the sample whilst 22.9% of the group required some form of further surgery, with a significant association between Type 1 fractures and the need for further surgery (p=0.0107).

Conclusion: This study is the first of its kind reporting specifically on the outcome after surgical fixation of a non-union of the fifth metatarsal fractures. Overall, surgery had a good outcome with a low complication rate, though it is interesting to note that Type 1 fractures which traditionally have a low non-union rate after conservative treatment are associated with a significantly increased incidence of non-union if operated for symptomatic non-union and require additional surgery.

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