S79.149 Salter-Harris Type IV physeal fracture of lower end of unspecified femur

Name of the Condition

Salter-Harris Type IV physeal fracture of lower end of unspecified femur

Summary

A Salter-Harris Type IV physeal fracture of the lower end of the unspecified femur is an injury involving the growth plate (physis) at the distal femur, typically occurring in children or adolescents. This fracture disrupts the physis and involves a fracture through the metaphysis, physis, and epiphysis, as defined by the Salter-Harris classification system. The injury may result in displacement of bone fragments and potential damage to the growth plate, which is critical for longitudinal bone growth.

Causes

Salter-Harris Type IV physeal fractures of the lower femur are usually caused by acute trauma, such as falls, sports-related injuries, or direct blows to the knee or thigh. The force transmitted across the growth plate can cause it to separate and fracture through multiple bone regions. In some cases, repetitive stress or overuse may contribute to the injury, particularly in active children and adolescents.

Risk Factors

• Age: Most common in children and adolescents, as growth plates are weaker than surrounding bone.
• Activity level: Participation in high-impact sports or activities with a risk of falls (e.g., gymnastics, soccer, skateboarding).
• Growth spurts: Periods of rapid growth may temporarily weaken the physis, increasing susceptibility to injury.
• Anatomical factors: Variations in bone structure or alignment may predispose to injury.

Symptoms

• Pain and swelling at the knee or thigh, often worsening with movement.
• Difficulty bearing weight or walking.
• Visible deformity or misalignment of the affected limb.
• Limited range of motion in the knee joint.
• Tenderness to touch over the fracture site.

Diagnosis

Diagnosis typically involves a physical examination to assess pain, swelling, and deformity. Imaging studies, such as X-rays, are used to visualize the fracture pattern and confirm the Salter-Harris Type IV classification. Additional imaging, like CT or MRI, may be ordered to evaluate joint involvement or soft tissue damage. Clinical history, including details of the injury mechanism, is also considered.

Treatment Options

Treatment depends on fracture severity and displacement. Nonsurgical options include immobilization with a cast or brace and activity restriction. Surgical intervention may be necessary for displaced fractures to realign bone fragments and stabilize the growth plate. Post-treatment, physical therapy is often recommended to restore function and strength.

Prognosis and Follow-Up

Prognosis varies based on fracture severity, treatment timing, and potential growth plate damage. Early intervention improves outcomes, but there is a risk of growth disturbances or joint alignment issues. Regular follow-up with imaging and clinical assessments is essential to monitor healing and detect complications.

Complications

• Growth arrest or limb length discrepancy due to growth plate damage.
• Malunion or nonunion of the fracture.
• Joint stiffness or arthritis from improper healing.
• Neurovascular injury in severe cases.
• Chronic pain or functional limitations.

Lifestyle & Prevention

• Use protective gear during high-impact activities (e.g., helmets, pads).
• Ensure proper training and technique in sports to reduce injury risk.
• Maintain bone health with adequate nutrition (e.g., calcium, vitamin D).
• Avoid overuse or repetitive stress on growing bones.

When to Seek Professional Help

Seek immediate medical attention if there is severe pain, inability to bear weight, visible deformity, or signs of neurovascular compromise (e.g., numbness, discoloration). Prompt evaluation is critical to prevent complications and ensure appropriate treatment.

Tips for Medical Coders

When coding S79.149, ensure the documentation specifies a Salter-Harris Type IV physeal fracture of the lower femur without side specification. Verify that the injury involves the metaphysis, physis, and epiphysis. Confirm the absence of laterality (right/left) to avoid miscoding. Document the fracture mechanism and any associated injuries for complete coding accuracy.