M84.75 Atypical femoral fracture

Name of the Condition

• Atypical Femoral Fracture

Summary

An atypical femoral fracture is a specific type of incomplete or complete fracture of the femur, typically occurring in the subtrochanteric or diaphyseal region. These fractures are often associated with minimal or no trauma and may present with prodromal symptoms like thigh or groin pain. They are distinct from typical osteoporotic fractures and are linked to factors such as long-term bisphosphonate use or other metabolic bone conditions.

Causes

Atypical femoral fractures result from a combination of mechanical stress and underlying bone fragility. Prolonged use of antiresorptive medications (e.g., bisphosphonates) is a well-documented cause, as these drugs may alter bone remodeling. Other contributing factors include metabolic bone disorders, vitamin D deficiency, or conditions that impair bone quality, even in the absence of significant trauma.

Risk Factors

• Long-term use of antiresorptive or antiangiogenic medications.
• History of low-trauma fractures or osteoporosis.
• Vitamin D deficiency or calcium insufficiency.
• Chronic kidney disease or other metabolic disorders affecting bone health.
• Female gender, particularly postmenopausal individuals.

Symptoms

• Persistent, dull, or aching pain in the thigh or groin, often preceding the fracture.
• Sudden, severe pain if the fracture occurs, which may be accompanied by a snapping sensation.
• Swelling, bruising, or visible deformity in the affected leg.
• Difficulty bearing weight or walking.

Diagnosis

Diagnosis involves a thorough patient history, physical examination, and imaging. X-rays are primary for identifying characteristic fracture patterns (e.g., transverse or short oblique lines, cortical thickening). MRI or bone scans may be used to detect early or incomplete fractures. Laboratory tests to assess bone metabolism or rule out other conditions may also be performed.

Treatment Options

• Immediate immobilization (e.g., casting or bracing) to stabilize the fracture.
• Surgical intervention, such as intramedullary nailing, for displaced or complete fractures.
• Discontinuation or modification of causative medications (e.g., bisphosphonates) under medical guidance.
• Bone-strengthening therapies, including calcium, vitamin D, or anabolic agents.
• Physical therapy to restore mobility and strength post-recovery.

Prognosis and Follow-Up

Prognosis depends on fracture severity, treatment timing, and underlying factors. Most patients recover with appropriate management, but healing may be prolonged. Follow-up includes regular imaging to monitor bone healing and assess for complications. Long-term monitoring of bone health and medication use is often recommended.

Complications

• Delayed or nonunion of the fracture.
• Infection, particularly with surgical intervention.
• Nerve or vascular damage due to fracture displacement.
• Recurrence of fractures in the same or other bones.
• Chronic pain or functional impairment.

Lifestyle & Prevention

• Ensure adequate calcium and vitamin D intake through diet or supplements.
• Engage in weight-bearing exercises to maintain bone density, as advised by a healthcare provider.
• Avoid high-impact activities that increase fracture risk, especially if on bone-modifying medications.
• Regular bone density screenings for at-risk individuals.
• Promptly report persistent thigh or groin pain to a healthcare provider.

When to Seek Professional Help

Seek immediate medical attention if you experience sudden, severe thigh or groin pain, especially if accompanied by swelling, bruising, or inability to bear weight. Early evaluation is critical to prevent progression to a complete fracture.

Tips for Medical Coders

When coding for atypical femoral fracture, use ICD-10-CM code M84.75. Document the fracture location (subtrochanteric or diaphyseal), any associated risk factors (e.g., medication use), and clinical findings (e.g., imaging results) to support the diagnosis. Ensure clear differentiation from typical fractures or other bone disorders.