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Rates of nonunion are higher for the fracture in Figure A compared to Figure B when treated nonoperatively
6%
68/1181
Fracture in Figure A should be treated with a hard-soled shoe and allowed to weight bear as tolerated
83%
981/1181
Both fractures are best managed with 6 weeks of short leg casting and non-weight-bearing
8%
89/1181
Fracture in Figure A requires surgery given decreased vascularity and healing potential
2%
23/1181
CT scan helps guide management at time of injury in Figure B
1%
14/1181
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The fracture in Figure A represents a zone 1 (pseudojones) fracture of the 5th metatarsal base, while Figure B depicts a zone 2 (jones) fracture of the 5th metatarsal base. Figure A can be treated with a hard-soled shoe and immediate weight bearing as tolerated. Fifth metatarsal base fractures have several variations based on the anatomic location of the fracture on radiographs. Zone 1 fractures are avulsions of the fifth metatarsal base by the peroneus brevis and do not extend into the 4th-5th metatarsal articulation. Zone 2 fractures do, however, extend into the 4th-5th metatarsal articulation and are importantly distinguished due to their poor blood supply and vascular watershed, placing them at higher risk for nonunion (15-30%). Therefore, fixation of zone 2 fractures with intramedullary fixation or, less commonly, open reduction and internal fixation (ORIF) is recommended in competitive athletes or those with any degree of displacement. While zone 2 fractures can be treated nonoperatively, rate of refracture is higher (up to 33%) and return to weight-bearing and activity can take substantially longer. Rosenberg et al. review treatment strategies for acute fractures of the 5th metatarsal base as well as treatment for nonunions. They advocate nonoperative management and weight-bearing of zone 1 fractures and attempted casting and non-weight-bearing of zone 2 fractures, adding that in high level athletes screw fixation should be considered given nonunion rates as high as 28%. They conclude by discussing management of nonunions with autogenous bone grafting and stable fixation +/- incorporation of electrical stimulation therapies. Porter et al. reviewed cannulated screw fixation of jones fractures and noted clinical and radiographic rates of healing reaching near 100%. Return to athletics was a mean of 7.5 weeks. They concluded that using a cannulated screw for fixation of these fractures was effective and reduced time out of sport for athletes. Mologne et al. compared casting vs. early screw fixation in jones fractures. They noted that 44% of the casting group failed to heal (6) or sustained a refracture (2). 18/19 patients treated with screw fixation healed uneventfully. Additionally, time to union was significantly faster in the screw group (7.5 weeks), compared to the cast group (14.5 weeks). They conclude that early screw fixation is effective in treating jones fractures. Incorrect Answers: Answer 1: Rates of nonunion are higher for jones fractures (Figure B) than pseudojones fractures (Figure A). Nonunion of pseudojones fracture rarely occurs but is often asymptomatic. Answer 3: Short leg casting and non-weight-bearing can be used to treat jones fractures with a risk for nonunion. However, this would be excessive treatment for a pseudojones fracture. Answer 4: Figure B, NOT Figure A represents a jones fracture that has a vascular watershed zone and difficulty healing. Answer 5: CT is not indicated at the time of injury as radiographs provide adequate information (location and displacement) to decide if fixation is necessary. CT can be useful to evaluate for nonunion later if needed.
2.0
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