Treatment of Oblique Fracture of the 5th Metatarsal
For an oblique fracture of the 5th metatarsal shaft, nonoperative management with early weight-bearing as tolerated using either a hard-soled shoe or CAM-walker boot is the recommended first-line treatment, as this approach achieves excellent functional outcomes with a 98-99% union rate. 1, 2
Initial Assessment and Imaging
- Obtain three-view radiographs (anteroposterior, lateral, and oblique) to confirm the diagnosis and assess fracture displacement and angulation. 3
- Apply Ottawa ankle rules: radiographs are required if there is point tenderness at the base of the 5th metatarsal or inability to bear weight for four steps. 3
- Assess immediately for vascular compromise (blue, purple, or pale foot) requiring emergent intervention. 3
- Check for open wounds requiring clean dressing coverage. 3
Nonoperative Treatment Protocol (First-Line)
Most oblique shaft fractures, even when displaced, can be successfully managed nonoperatively:
- Immobilize with either a CAM-walker boot or hard-soled shoe—both achieve similar functional outcomes, though the CAM-walker boot shows faster radiographic healing (7.2 vs 8.6 weeks). 4
- Allow immediate weight-bearing as pain tolerates from day one. 2, 5
- Provide multimodal analgesia starting with scheduled acetaminophen, adding opioids cautiously if needed. 3
- Avoid NSAIDs if renal dysfunction is suspected. 3
Evidence supporting nonoperative management:
- A large prospective cohort of 142 displaced oblique spiral fractures treated nonoperatively achieved 98% union rate with excellent long-term functional outcomes (FAAM ADL scores 95.5, sports scores 92.7). 1
- Only 2 of 142 patients (1.4%) required surgical intervention for painful nonunion. 1
- Average time to union is 3.7 months with 100% patient satisfaction. 2
Indications for Surgical Intervention
Consider operative fixation (percutaneous K-wires, plate, or screw) only if:
- Displacement exceeds 3-4 mm 6
- Angulation exceeds 10 degrees 6
- Painful nonunion develops after adequate nonoperative trial 1
- Patient requires rapid return to high-level athletics (not applicable for most patients) 6
Follow-Up Strategy
Routine fracture clinic follow-up is unnecessary for most patients:
- Discharge from emergency department with structured written advice and helpline access for concerns. 5
- A study of 339 patients showed only 1% required operative intervention when discharged without routine follow-up, demonstrating safety of this approach. 5
- If follow-up is arranged, see at 6 and 12 weeks to confirm healing. 1
Rehabilitation and Return to Activity
- Introduce early physical training and muscle strengthening once pain allows, followed by long-term balance training. 3
- Avoid prolonged immobilization beyond 6 weeks as this causes stiffness and muscle atrophy. 7
- Average return to prior activity level is 8-10 weeks regardless of immobilization method. 4
Critical Pitfalls to Avoid
- Do not apply compression wraps too tightly—this compromises circulation. 3
- Do not place ice directly on skin if using cryotherapy. 3
- Do not routinely refer for fracture clinic follow-up—this adds no clinical value and wastes resources. 5
- Address smoking preoperatively if surgery becomes necessary, as it increases nonunion risk. 7