S82.864M Nondisplaced Maisonneuve's fracture of right leg, subsequent encounter for open fracture type I or II with nonunion

Name of the Condition

• Nondisplaced Maisonneuve's fracture of right leg, subsequent encounter for open fracture type I or II 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 indicates this is a follow-up visit for an established fracture, while "open fracture type I or II" refers to a break in the skin with minimal contamination (wound length <1 cm for type I, 1–10 cm for type II). The "with nonunion" modifier specifies that the fracture has failed to heal properly after an expected time frame.

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. The open nature of the fracture suggests the injury involved a forceful impact that broke the skin, such as a direct blow or a severe twist. Nonunion may result from inadequate immobilization, poor blood supply to the fracture site, infection, or excessive movement before 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.
• Inadequate initial treatment or follow-up care.

Symptoms

• Persistent pain and swelling localized to the proximal fibula and ankle, even after initial treatment.
• Difficulty bearing weight on the affected leg.
• Instability or a feeling of the ankle "giving way."
• Visible or palpable gap at the fracture site (if nonunion is significant).
• Possible signs of infection, such as redness, warmth, or drainage (if the fracture is open).
• Limited range of motion in the ankle joint.

Diagnosis

Diagnosis is based on clinical evaluation and imaging studies. The provider will assess the patient's history of trauma, examine the ankle for swelling, tenderness, and instability, and review prior treatment. X-rays are typically used to confirm the fracture and assess alignment, while CT or MRI may be ordered to evaluate for nonunion or associated ligament damage. The open fracture status is determined by examining the wound for size, contamination, and exposure of the fracture site. Nonunion is diagnosed when imaging shows no progress in healing over an expected time frame (usually 3–6 months) or persistent pain and instability despite treatment.

Treatment Options

Treatment focuses on stabilizing the fracture, promoting healing, and addressing nonunion. For open fractures, wound care is prioritized to prevent infection, including cleaning and possible debridement. Immobilization with a cast or brace may be used initially, but surgical intervention is often required for nonunion, such as internal fixation with plates or screws, bone grafting, or ligament repair. Physical therapy is typically recommended to restore strength and range of motion once healing is underway. Antibiotics may be prescribed for open fractures to reduce infection risk.

Prognosis and Follow-Up

Prognosis depends on the severity of the fracture, the success of treatment, and the patient's overall health. With proper intervention, many patients recover function, but nonunion may lead to chronic pain or instability. Follow-up visits are essential to monitor healing, adjust treatment, and address complications. Imaging studies may be repeated to assess progress. Long-term outcomes can include reduced mobility or the need for additional surgery if nonunion persists.

Complications

• Nonunion or delayed union, requiring further intervention.
• Infection, particularly with open fractures.
• Chronic ankle instability or arthritis.
• Nerve or blood vessel damage.
• Difficulty returning to pre-injury activities.
• Persistent pain or swelling.

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 exercises to strengthen the ankle and lower leg muscles.
• Follow post-treatment instructions carefully to support healing.
• Quit smoking or avoid other habits that impair bone healing.

When to Seek Professional Help

Seek immediate care if you experience:

• Severe pain, swelling, or bruising that worsens.
• Inability to bear weight on the affected leg.
• Signs of infection, such as fever, redness, or drainage.
• New or worsening instability in the ankle.
• Persistent pain or lack of improvement after treatment.

Tips for Medical Coders

Document the encounter type (subsequent), fracture status (open type I or II), and nonunion clearly. Note the location (right leg) and confirm the Maisonneuve's fracture mechanism (proximal fibula with syndesmotic ligament tear). Include details on wound size, contamination, and any surgical or therapeutic interventions. Ensure the nonunion is supported by clinical findings or imaging to justify the modifier.