What are the next steps for a patient with a femur fracture showing no signs of healing 5 months post-injury, with no change in bone placement?

Delayed Femur Fracture Healing at 5 Months

For a femur fracture showing no healing progression at 5 months, you should immediately obtain MRI without contrast to evaluate for complications such as osteonecrosis, infection, or occult pathology causing delayed union, followed by CT without contrast if MRI is equivocal or to assess for completion of fracture or other structural causes of nonunion. 1

Immediate Diagnostic Workup

Primary Imaging Strategy

• MRI without IV contrast is the gold standard next step for evaluating delayed healing after conservative therapy, as it can identify complications including osteonecrosis (particularly critical in femoral fractures), infection, tumor, or osteoid osteoma that may be preventing healing 1
• CT without IV contrast serves as a complementary study when MRI findings are equivocal or to identify possible etiologies such as osteoid osteoma or suspected completion of fracture 1
• Contrast-enhanced imaging (either MRI or CT with IV contrast) may be useful specifically if osteonecrosis or tumor is suspected as the cause of persistent symptoms 1

Critical Pitfall to Avoid

• Do not simply repeat plain radiographs at this stage - at 5 months without healing progression, cross-sectional imaging is mandatory to identify the underlying cause of delayed union 1
• Femoral fractures, particularly those involving the femoral neck or head, are high-risk for progression to osteonecrosis if not recognized promptly, with increased rates of delayed union, nonunion, displacement, and avascular necrosis 1

Surgical Intervention Considerations

When to Proceed with Definitive Fixation

• If the fracture was initially managed conservatively or with temporary stabilization, delayed definitive osteosynthesis should be performed as soon as the patient is medically optimized 1, 2
• For femoral shaft fractures specifically, early definitive osteosynthesis (within 24 hours in stable patients) reduces local and systemic complications, but this window has clearly passed 1, 3
• Delayed healing at 5 months suggests either inadequate initial fixation, biomechanical instability, or an underlying pathologic process 1, 4

Device Selection Based on Fracture Pattern

• Intramedullary nailing is the preferred operative approach for femoral shaft fractures showing delayed union 2, 5
• For distal femur fractures treated with locking plates, healing complications (nonunion, delayed union, implant failure) occur in 0-32% of cases, with 75% of implant failures occurring after 3 months and 50% after 6 months 4
• If this represents an atypical femoral fracture (stress fracture pattern), intramedullary nailing is indicated, and delayed healing should be anticipated even after fixation 5

Medical Optimization Strategy

Metabolic and Pharmacologic Assessment

• Immediately discontinue bisphosphonates if the patient is on antiresorptive therapy, as atypical femoral fractures related to prolonged bisphosphonate use (3-5 years) present as stress fractures with delayed healing 5
• Assess for secondary causes of osteoporosis and optimize vitamin D (800 IU/day) and calcium supplementation 3, 5
• Consider parathyroid hormone analogs (teriparatide or abaloparatide) for high-risk patients to prevent other fractures, though the effect on healing of the existing fracture remains unclear 5

Risk Stratification

• Patients with osteoporosis, those on bisphosphonate therapy, and elderly patients are at high risk for fracture completion if stress fractures are not managed appropriately 1
• Lateral tension-type femoral neck stress fractures are inherently unstable and prone to displacement, representing high-risk fractures that often necessitate percutaneous screw fixation 1

Expected Timeline and Prognosis

Realistic Expectations

• Return to full function after femoral fractures typically requires 7-13 months, even with optimal treatment 6
• Complications of healing including nonunion, delayed union, and implant failure represent ongoing problems with femur fracture treatment, occurring in up to 32% of cases depending on fracture location and fixation method 4
• Implant failures, when they occur, typically happen late (75% after 3 months, 50% after 6 months), so continued vigilance is warranted 4