Fifth Metatarsal Fracture Pattern Mapping and Associated Outcomes - An Observational Cohort Study

AR Gomaa, J Apata-Omisore, S Aslam, L Marsh, A Paramasivan, N Ward, A Galhoum, L Mason

Introduction: Fifth metatarsal fractures have been regularly classified by zones, with the description of a Jones fracture commonly being misrepresented. The aim of this study was to map the fracture patterns across the entire metatarsal shaft, and correlate with their outcomes.

Methods: A historic cohort study was completed of all fifth metatarsal fractures presenting to our unit between February 2016 - July 2021. Fracture patterns were individually mapped and designated as zone 1-shaft, including designation of fractures which bridge each zone (zone 1-2 etc). Fracture patterns were cumulatively combined using GNU Image Manipulation Program to show the combined fracture map patterns per outcome. The clinical notes were examined to assess patient outcome.

Results: 1331 fractures were included in this study and presented graphically as fracture maps by outcome. The number of fractures which did not propagate across more than 1 zone was 78.59% (1046/1331). The fracture type which had the highest rate of discharge at VFC without reattendance was Zone 1 fractures (360/519, 69.36%), with the lowest being fractures where the fracture spanned zone 1-shaft (p<0.001). The total number of fractures that underwent surgery was 1.35% (18/1331). The fracture pattern which had the highest rate of surgical intervention was a fracture that spanned zone 2-3 (5/43, 11.63%) followed by a fracture that spanned zone 1-3 (1/11, 9.9%). The number of appointments given to patients ranged from discharged from VFC to 7 face to face appointments. The patients with the lowest discharge rate prior to 4 appointments was zone 2-3.

Conclusions: In our series, almost a quarter of fractures spanned across the previously described fracture zones. This would explain the low inter-observer rating in previous studies. The classic Jones fracture would span zones 2/3, which in our series had the highest rate requiring surgery and lowest rate of discharge before 4 appointments.