Is nonweightbearing with a boot and crutches (assistive devices) acceptable for a metatarsal base and cuboid avulsion fracture?

Management of Metatarsal Base and Cuboid Avulsion Fractures

Direct Answer

Yes, nonweightbearing with a boot and crutches is acceptable but overly conservative—weight-bearing as tolerated in a boot is actually the preferred approach for these stable avulsion fractures, as it leads to faster return to activity without compromising healing. 1, 2, 3

Treatment Algorithm

Initial Assessment

• Obtain standard three-view radiographs (AP, lateral, and oblique) to confirm the fracture pattern and rule out displacement 4
• Verify this is truly an avulsion fracture (Zone A at the 5th metatarsal base) rather than a Jones fracture (Zone B/C), as the latter requires different management 5
• Assess for any displacement >2mm, which would alter treatment 6

Weight-Bearing Protocol

For nondisplaced avulsion fractures:

• Weight-bearing as tolerated (WBAT) in a walking boot is the evidence-based standard 1, 2, 3
• A multicenter randomized controlled trial demonstrated that WBAT in a hard-soled shoe was noninferior to casting, with patients returning to activity in 37 days versus 43 days in casts 3
• Prospective studies show full weight-bearing can be achieved within approximately 9 days, with average sick leave of only 19 days 1
• Soft dressings with WBAT allow return to pre-injury activity in 33 days compared to 46 days with casting 2

If you choose nonweightbearing:

• This is acceptable but unnecessarily restrictive for stable avulsion fractures 5
• Consider this approach only if there is concern for Zone B/C involvement (peroneus brevis tension injury) rather than simple Zone A avulsion 5
• Use bilateral crutches to reduce pressure on the affected limb and prevent contralateral musculoskeletal complications 4

Immobilization Options

• Walking boot (preferred): Allows earlier mobilization and similar healing rates to casting 1, 3
• Hard-soled shoe: Noninferior to casting with faster return to activity 3
• Short leg cast: More restrictive without proven benefit for simple avulsions 2, 3

Follow-Up Protocol

• Clinical reassessment at 2-3 weeks to ensure appropriate healing progression 7
• Radiographic follow-up at 4-6 weeks to confirm union 7
• Average radiographic healing occurs by 44-65 days 2
• All patients typically return to full activity within 96 days 2

Critical Pitfalls to Avoid

Overtreatment with prolonged immobilization:

• Unnecessary nonweightbearing leads to muscle atrophy, joint stiffness, and delayed return to function without improving outcomes 4, 8
• Long-term immobilization increases risk of falls, contralateral limb pain, and psychological/socioeconomic consequences 4

Misclassification of fracture type:

• Zone A avulsions (plantar fascia mechanism) heal well with WBAT 5
• Zone B/C fractures (peroneus brevis mechanism) may require stricter immobilization or surgical fixation 5
• Jones fractures have high nonunion risk and require different management 9

Inadequate imaging:

• Ensure radiographs include the entire base of the 5th metatarsal, as this is commonly overlooked 8
• Do not confuse accessory ossicles (os vesalianum) with fractures 8

Special Considerations

For patients with diabetes and neuropathy:

• More caution is warranted with potential need for knee-high device and partial weight-bearing 6
• These patients may not perceive pain appropriately and can ambulate despite fracture 4

For patients with poor bone quality:

• Additional protection may be needed, but weight-bearing is still generally encouraged 6

Outcome expectations:

• 92% patient satisfaction with functional boot treatment 1
• No increased nonunion rates with WBAT compared to casting 2, 3
• Zero nonunion cases reported in comparative studies of avulsion fractures 3