Should the patient remain non-weight-bearing (nwb) until additional imaging is obtained?

Non-Weight-Bearing Status Pending Additional Imaging

For suspected stress fractures or occult fractures with negative initial radiographs, patients should remain non-weight-bearing until definitive imaging (MRI) is obtained to confirm or exclude the diagnosis, as unrecognized fractures—particularly high-risk locations like the femoral neck—can progress to displacement, nonunion, or avascular necrosis if weight-bearing continues. 1

Clinical Decision Framework

When Non-Weight-Bearing is Mandatory Until Further Imaging

High-risk fracture locations require strict non-weight-bearing precautions pending confirmatory imaging 1:

• Femoral neck stress fractures (lateral "tension-type"): These are inherently unstable and prone to displacement, with increased rates of delayed union, nonunion, and avascular necrosis if not recognized promptly 1
• Femoral head stress fractures: High risk in healthy patients with similar complications if diagnosis is delayed 1
• Suspected Charcot neuro-osteoarthropathy in diabetic patients: Immediate immobilization with a below-knee offloading device should be initiated while awaiting diagnostic testing, as continued weight-bearing minimizes development of deformity 1

After initial negative radiographs with high clinical suspicion, patients should remain non-weight-bearing until MRI is performed 1. MRI has excellent sensitivity and allows for definitive diagnosis, preventing delayed diagnosis that could significantly increase morbidity 1.

When Immediate Weight-Bearing May Be Permitted

Low-risk stress fractures can typically be managed with activity modification rather than strict non-weight-bearing 1:

• Medial "compression-type" femoral neck stress fractures: These are low-risk and can be treated with a non-weight-bearing regimen, but this is after diagnosis is confirmed 1
• Most other stress fractures: Once diagnosed, patients are typically followed clinically until pain-free, then can increase activity in a controlled manner 1

Specific Clinical Scenarios

For suspected insufficiency fractures (pelvis, sacrum, hip in osteoporotic patients):

• If radiographs are negative but clinical suspicion remains high, patients should remain non-weight-bearing until MRI or bone scintigraphy is performed 1
• Weight-bearing radiographs are preferred when feasible, as they may detect dynamic abnormalities not apparent on non-weight-bearing images 1, 2

For acute trauma with negative initial radiographs:

• If Ottawa rules are positive but radiographs are negative, consider MRI before allowing full weight-bearing in high-risk anatomic locations 1, 2
• Follow-up radiographs at 10-14 days have increased sensitivity (30-70%) compared to initial radiographs, but this delay risks progression of undiagnosed fractures 1

Common Pitfalls and Caveats

Critical errors to avoid 1:

• Allowing weight-bearing based solely on negative radiographs in high-risk locations (femoral neck, femoral head): Radiographs have only 15-35% sensitivity for stress fractures initially 1
• Delaying MRI in favor of repeat radiographs: This 10-14 day delay allows potential progression of unstable fractures 1
• Assuming all stress fractures are low-risk: Lateral femoral neck and femoral head fractures require immediate recognition and often surgical fixation 1

Special populations requiring heightened vigilance 1:

• Osteoporotic patients or those on bisphosphonate therapy: Prone to progression of incomplete stress fractures to completion 1
• Diabetic patients with neuropathy: May not have typical pain response, increasing risk of unrecognized progression 1
• Elderly patients: Bone scintigraphy may not show abnormalities for several days post-injury; corticosteroid users may have less sensitive bone scan results 1

Imaging Timeline Recommendations

Optimal approach when initial radiographs are negative 1:

1. Maintain non-weight-bearing status immediately upon clinical suspicion
2. Obtain MRI without IV contrast as next study: This is the preferred imaging modality with excellent sensitivity for stress fractures 1
3. If MRI unavailable or contraindicated: Consider bone scintigraphy or CT, though these are less sensitive than MRI 1
4. Avoid routine follow-up radiographs at 10-14 days as the primary diagnostic strategy in high-risk locations, as this delay may allow fracture progression 1

After diagnosis is confirmed, most stress fractures do not require additional imaging and patients are followed clinically until pain-free 1. The exception is when complications are suspected (osteonecrosis, delayed healing, or progression to complete fracture), at which point repeat MRI or CT may be indicated 1.