Conservative versus Surgical Treatment for the Fifth Metatarsal Diaphyseal Fractures: A Retrospective Comparative Study
Authors: Pongpinyopap Warongporn , Rungprai Chamnanni 
Published: November 2020

Category: Midfoot/Forefoot; Trauma Introduction/Purpose: The fifth metatarsal fracture is the most common metatarsal fracture accounting for 56-68% of all metatarsals. Most of the previous studies have focused on fractures of the proximal fifth metatarsal. Whereas the current evidence has still remained controversial regarding appropriate treatment for the fifth metatarsal diaphyseal fracture. To date, there has been no comparative study between nonsurgical and surgical management in such fractures. The purpose of this study was to compare the outcomes and complications following conservative versus surgical treatment for displaced diaphyseal fractures of the fifth metatarsal bone. The primary outcome was time to union. Secondary outcomes were functional outcome scores (SF-36 and FAAM), VAS, time to return to activities of daily living (ADL), sports activities as well as complications. Methods: A retrospective study with prospective outcomes measurement was performed by reviewing charts and collecting data between January 2016 and December 2018. We included patients aged 18 or over, diagnosed with closed isolated fracture of the fifth metatarsal diaphyseal bone, all fractures had more than 2 mm of displacement in any planes of radiographs (AP, oblique, lateral), treated within 3 weeks after injury, minimal follow-up time of 6 months. Exclusion criteria were previous history of ipsilateral fifth metatarsal diaphyseal bone, pathological or stress fracture, proximal fifth metatarsal fracture, underlying diabetes, neuropathy, inability to walk such as cerebrovascular disease. All patients in surgical group were treated with ORIF with plate and screws. Postoperatively, early ROM exercise and heel weight bearing in walking boot were instructed. Whereas, patients in conservative group were immobilized with short leg cast in first six weeks and subsequently changed to walking boot or hard- soled shoes. Results: There were forty-five patients enrolled in the study, twenty patients treated with ORIF and twenty-five patients treated with casting. No significant differences were demonstrated with regard to demographic data. The mean union time of ORIF group was 8.7+-1.8 weeks, which was significantly shorter than the casting group (16.0 +- 4.18 weeks) (p<0.001). There was a significant improvement of functional outcomes (SF-36, FAAM) in both groups (p<0.001) but no statistically significant difference between two groups (p>0.05). An average time to return to ADL was significantly faster in ORIF group (8.6+-3.1 weeks) (p<0.001). The overall complications in casting group were significantly higher (28%,p<0.05) including painful malunion (3 patients, 12%), delayed union (2 patients, 8%) and persistent pain from CRPS (2 patients, 8%). Conclusion: Both casting and ORIF demonstrated significant improvement of functional outcomes compared to pre-operative status as measured with VAS, SF-36, and FAAM. Even though there was no significant difference of functional outcomes between two groups. ORIF group had significantly faster union time, time to return to ADL, and lesser in overall complications. The authors prefer early surgical treatment in fractures with more than 2 mm displacement, active, high-demand patients. However, randomized controlled trials with longer follow-up would be required.