Zone 1 Fifth Metatarsal Fractures: Weight-Bearing Recommendations
Zone 1 (tuberosity avulsion) nondisplaced fractures of the fifth metatarsal do NOT require non-weight-bearing status and can be managed with immediate weight-bearing as tolerated. 1, 2
Evidence-Based Weight-Bearing Protocol
Immediate weight-bearing as tolerated is safe and may improve outcomes compared to prolonged non-weight-bearing. 1 The most compelling evidence comes from a study showing that longer periods of non-weight-bearing were the most significant predictor of poor functional outcomes, with strong associations to worse global outcomes, discomfort, and reported stiffness. 2 This directly contradicts the traditional approach of enforced non-weight-bearing.
Key Management Points
Conservative treatment with protected weight-bearing is appropriate for nondisplaced zone 1 fractures: 1, 3, 4
- Allow progressive weight-bearing as tolerated from the outset 1
- Immobilization options include either a CAM-walker boot or hard-soled shoe—both achieve similar clinical and functional results 4
- The CAM-walker boot shows slightly faster radiographic healing (7.2 weeks vs 8.6 weeks) but similar return to activity times (8.3 vs 9.7 weeks) 4
- Total immobilization period averages 4-6 weeks 5
Critical Distinction: Zone 1 vs Other Zones
Zone 1 fractures are mechanically distinct from Jones fractures (zone 2) and warrant different treatment. 6 Zone 1 fractures result from lateral band plantar fascia avulsion and can be treated with immobilization and weight-bearing, whereas zones B and C (more distal) result from peroneus brevis tension and may require stricter non-weight-bearing or surgical intervention. 6
Indications for Orthopedic Referral
Most nondisplaced zone 1 fractures do NOT require surgical consultation, but refer if: 3
- Displacement >2mm 5
- Comminution present 3
30% involvement of the cuboid-metatarsal articulation surface 3, 5
- Delayed union develops 3
Rehabilitation Strategy
Avoid prolonged immobilization beyond clinical necessity: 1, 7
- Early introduction of physical training and muscle strengthening after initial immobilization 1, 7
- Balance training should follow strengthening exercises 1, 7
- Prolonged immobilization leads to stiffness and muscle atrophy without improving outcomes 1, 7, 2
Common Pitfalls to Avoid
The primary error is excessive restriction of weight-bearing. 2 Keeping patients non-weight-bearing for extended periods (mean 17 days in one study) was directly associated with worse outcomes. 2 The evidence strongly supports that non-weight-bearing should be kept to a minimum for acute tuberosity avulsions. 2
Do not confuse zone 1 avulsion fractures with Jones fractures (zone 2), which occur at the metaphyseal-diaphyseal junction within 1.5 cm of the tuberosity and require different management including potential non-weight-bearing for 6-8 weeks or surgical intervention. 3, 5