What is the appropriate management of a stress fracture in an otherwise healthy active adult?

Management of Stress Fractures in Healthy Active Adults

For low-risk stress fractures, initiate activity modification with immobilization (walking boot or cast) for 6–8 weeks until pain-free on palpation, followed by a graded return-to-activity protocol; high-risk fractures require immediate cessation of activity, prolonged immobilization, and orthopedic referral for potential surgical intervention. 1

Risk Stratification: The Critical First Step

The most important initial decision is determining whether the stress fracture is high-risk or low-risk, as this fundamentally changes management:

High-risk stress fractures include navicular, medial malleolus, talus, proximal fifth metatarsal (Jones fracture), proximal second metatarsal, hallux sesamoids, anterior tibial diaphysis, and lateral femoral neck. 1, 2 These require aggressive management because they are prone to delayed union, non-union, or avascular necrosis. 1

Low-risk stress fractures include postero-medial tibial diaphysis, metatarsal shafts (except proximal second and fifth), distal fibula, medial femoral neck, femoral shaft, and calcaneus. 2 These can be managed reliably with rest and exercise limitation. 2

Management of Low-Risk Stress Fractures

Initial Immobilization Phase

• Continue immobilization with a walking boot or cast until the patient is pain-free on palpation over the fracture site. 1
• A minimum of 6–8 weeks of protected weight-bearing or immobilization is typically required before advancing activity. 1
• NSAIDs are appropriate for pain relief. 1
• For metatarsal stress fractures specifically, complete non-weight bearing in a removable boot for the first 2 weeks is recommended. 3

Return-to-Activity Protocol

The key pitfall here is returning too quickly. Requiring complete resolution of bony tenderness can unnecessarily delay return to running; functional pain-free walking is an adequate benchmark. 1

• Patients must achieve pain-free walking for 45–60 minutes daily before progressing to running. 1
• Implement a graded run-walk program: 1
  • Begin with 1-minute running intervals alternating with walking
  • Increase running duration by 1–2 minutes each session
  • Perform sessions on alternating days for the first 2–4 weeks
  • If pain occurs, rest and resume at the previous lower intensity
  • Overall progression should be guided by the patient's pain response

Follow-Up Strategy

• Clinical follow-up should continue until the patient is pain-free; thereafter, a controlled increase in activity is permitted. 1
• For uncomplicated low-risk fractures, additional imaging is generally unnecessary when clinical improvement is evident. 1
• If symptoms recur with increased activity, repeat imaging and re-evaluation of the original diagnosis are recommended. 1
• When symptoms persist despite adequate conservative therapy (≥ 6–8 weeks), advanced imaging should be obtained to assess for complications such as delayed union or non-union. 1

Management of High-Risk Stress Fractures

High-risk stress fractures require immediate cessation of activity with orthopedic referral to assess the need for surgical intervention. 2 These have increased rates of fracture propagation, displacement, delayed union, and non-union. 2

• Complete non-weight-bearing status with crutches and immobilization with cast or walking boot is necessary. 1
• Surgical consultation may be appropriate for patients with stress fractures in high-risk locations, nonunion, or recurrent stress fractures. 4
• Follow-up MRI at 6-8 weeks is recommended to assess healing, particularly for high-risk fractures. 1

Diagnostic Imaging Considerations

If the diagnosis is uncertain or symptoms persist:

• MRI without IV contrast is the definitive diagnostic study for suspected stress fractures when plain radiographs are negative or indeterminate, owing to its excellent sensitivity. 1
• MRI is superior to bone scintigraphy for specificity and also provides prognostic information that guides return-to-activity timelines. 1
• Plain radiographs have limited sensitivity (approximately 30-70%) even on follow-up films obtained 10–14 days after injury. 1
• For each one-unit increase in MRI grade, expect an additional ~48 days before full return to sport. 1

Special Populations Requiring Modified Management

Patients with osteoporosis or receiving bisphosphonates have a significantly higher risk of progression from an incomplete to a complete fracture and therefore require more conservative management with longer immobilization periods. 1, 5

• Extended monitoring and potentially longer immobilization periods are necessary due to increased risk of progression to complete fracture. 5
• Vitamin D and calcium levels should be evaluated with supplementation if deficient. 1

Critical Pitfalls to Avoid

• Failure to recognize high-risk fractures (e.g., navicular, talus, medial malleolus, proximal fifth metatarsal) can lead to non-union or avascular necrosis; these injuries require early aggressive management and closer follow-up. 1
• Premature return to activity based on patient impatience or competitive pressures should be avoided, as the minimum protocols are non-negotiable. 5
• Trabecular stress injuries (e.g., talus) result in longer recovery times compared with cortical injuries. 1