Treatment of Avulsion Fractures of the Base of the Fifth Metatarsal with Walking Boot and Hard-Soled Shoes: A Comparative Study

CATEGORY: Midfoot/Forefoot, Trauma INTRODUCTION/PURPOSE: Acute avulsion fractures of the base of the fifth metatarsal are common and usually treated non- surgically with satisfactory outcomes. Forms of conservative treatments are described such as elasticated bandaging, immobilization in a cast, walking boot and hard-soled-shoes. The aim of this study was to compare the clinical and functional outcomes, time to return to the previous activities, time and rate of fracture healing of the patients with avulsion fracture of the base of the fifth metatarsal treated in a hard-soled-shoes (HSS) or in a walking boot (WB). Our null hypothesis is that a less rigid immobilization without restriction of the ankle yields the same final results. METHODS: A retrospective and comparative study of 72 patients with acute avulsion fractures of the base of the fifth metatarsal treated with the WB or the HSS, from March 2014 to November 2018. The average age of the patients was 41,25 (range, 11-88) and there were 56 female and 16, male. 39 were treated with the WB and 33, with the HSS. Patients with comorbities that could interfere in the rate and time of bony healing (diabetes and inflammatory joint disease), associated ankle ligament lesions and loss of follow-up were excluded. Patients were followed regularly until they were clinically asymptomatic and able to return to their previous activities (work, daily activities, sports). We retrospectively reviewed medical records containing the visual analogue scale (VAS) for pain and the american orthopaedic foot and ankle society (AOFAS) score of each visit as well as radiographic exams to evaluate time and rate of fracture healing. RESULTS: Patients of both groups had similar VAS and AOFAS scores in 8 (p=0,34 and p=0,83) and 12 (p=0,25 and p=0,79) weeks. Age and gender distribution in the two groups were equal (p=0,23 and p=0,34, respectively). Time taken to return to the previous activities were not significant different between both groups, with the HSS group taking 8,33 weeks and the WB taking 9,73 weeks (p=0,10). The mean time for bone consolidation was significant higher in the HSS group, taking 8,64 weeks while in the WB took 7,18 weeks (p<0,001). Only 1 case of non-union was observed in the WB group and none in the HSS group. CONCLUSION: Our study concluded that avulsion fractures of the base of the fifth metatarsal can be treated equally with the HSS or the WB. Both types of immobilization showed to be equivalent in terms of clinical and function evaluation, return to the previous activities without difference in the rate of the fracture consolidation.