S82.866K Nondisplaced Maisonneuve's fracture of unspecified leg, subsequent encounter for closed fracture with nonunion

Name of the Condition

• Nondisplaced Maisonneuve's fracture of unspecified leg, subsequent encounter for closed fracture with nonunion

Summary

A Maisonneuve's fracture is a specific type of ankle injury involving a fracture of the proximal fibula (upper portion of the smaller lower leg bone) combined with a tear of the syndesmotic ligaments and often an associated injury to the medial malleolus or deltoid ligament. The term "nondisplaced" indicates that the fractured bone fragments remain in their normal alignment. This injury typically results from rotational forces applied to the ankle, commonly seen in trauma such as falls or sports injuries. The "subsequent encounter" designation refers to follow-up care after the initial treatment phase, and "closed fracture with nonunion" indicates the skin remains intact but the fracture has failed to heal properly over time.

Causes

The fracture is caused by external rotational forces applied to the ankle, often during activities that involve twisting or turning. Common scenarios include falls, motor vehicle accidents, or sports-related impacts where the foot is planted and the body rotates forcefully. The mechanism typically involves the talus rotating outward, stressing the syndesmotic ligaments and causing the proximal fibula to fracture. Nonunion may develop due to inadequate immobilization, poor blood supply to the fracture site, or excessive movement during healing.

Risk Factors

• Participation in activities with high rotational stress on the ankle, such as soccer or basketball.
• Previous ankle injuries or ligamentous instability.
• Improper footwear or uneven terrain increasing fall risk.
• Age-related factors that may affect bone density or ligament integrity.
• Smoking or other factors that impair bone healing.

Symptoms

• Persistent pain at the fracture site, often worsening with activity.
• Swelling or bruising around the ankle or proximal fibula.
• Difficulty bearing weight on the affected leg.
• Instability or a feeling of the ankle "giving way."
• Possible deformity if the fracture has shifted (though nondisplaced initially).

Diagnosis

Diagnosis typically involves a physical examination to assess pain, swelling, and stability, followed by imaging studies. X-rays are used to confirm the fracture and assess alignment, while CT or MRI may be ordered to evaluate for nonunion or associated ligament damage. The "subsequent encounter" context implies prior treatment, and the presence of nonunion is confirmed by imaging showing a persistent fracture line with no bridging bone. Clinical correlation is essential to distinguish nonunion from delayed healing.

Treatment Options

Treatment focuses on promoting fracture union and restoring ankle stability. Options may include prolonged immobilization with a cast or brace, surgical intervention (e.g., internal fixation with plates or screws), or bone grafting to stimulate healing. Physical therapy is often recommended to improve strength and mobility once the fracture shows signs of healing. The choice of treatment depends on the severity of nonunion, patient activity level, and overall health.

Prognosis and Follow-Up

Prognosis varies based on the success of treatment and the patient's adherence to rehabilitation. Nonunion fractures may require extended healing times or additional interventions. Regular follow-up with imaging is necessary to monitor progress. Most patients can return to normal activities, but some may experience long-term ankle stiffness or instability. Close monitoring by an orthopedic specialist is recommended to address complications promptly.

Complications

• Persistent pain or chronic instability.
• Delayed or failed healing (nonunion).
• Arthritis in the ankle joint due to prolonged instability.
• Nerve or blood vessel damage in severe cases.
• Infection (rare, but possible with surgical intervention).

Lifestyle & Prevention

• Avoid high-impact activities until cleared by a healthcare provider.
• Use proper footwear and avoid uneven surfaces to reduce fall risk.
• Engage in strength and balance exercises to support ankle stability.
• Follow post-treatment guidelines strictly to promote healing.

When to Seek Professional Help

Seek immediate medical attention if you experience:

• Sudden, severe pain or swelling.
• Inability to bear weight on the affected leg.
• Visible deformity or open wound at the fracture site.
• Signs of infection (e.g., fever, redness, or pus).

Tips for Medical Coders

Document the encounter as a "subsequent" visit for a closed fracture with nonunion. Ensure clinical notes specify the fracture type (Maisonneuve's), location (unspecified leg), and the presence of nonunion. Coding requires confirmation of prior treatment and evidence of failed healing, such as imaging reports or provider documentation. The "closed" designation applies if the skin remains intact, and "nonunion" must be clearly supported by clinical findings.