FIFTH METATARSAL FRACTURE PATTERN MAPPING AND ASSOCIATED OUTCOMES: AN OBSERVATIONAL COHORT STUDY

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.