S82.866Q Nondisplaced Maisonneuve's fracture of unspecified leg, subsequent encounter for open fracture type I or II with malunion

Name of the Condition

• Nondisplaced Maisonneuve's fracture of unspecified leg, subsequent encounter for open fracture type I or II with malunion

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, leading to instability in the ankle joint. The "subsequent encounter" designation refers to care provided after the initial treatment phase, while "open fracture type I or II" indicates the skin was breached during the injury (type I: wound less than 1 cm; type II: wound 1–10 cm without extensive soft tissue damage or contamination). "Malunion" signifies that the fracture has healed in a non-anatomical position, potentially affecting function.

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. Open fractures occur when the force is sufficient to penetrate the skin, often due to high-energy trauma or a sharp bone fragment piercing the tissue. Malunion may develop if the fracture was not properly aligned during initial treatment or if healing was compromised.

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.
• Delayed or inadequate initial fracture management, which may contribute to malunion.

Symptoms

• Persistent pain and swelling localized to the proximal fibula and ankle.
• Difficulty bearing weight on the affected leg.
• Instability or a feeling of the ankle "giving way."
• Visible or palpable deformity if malunion is significant.
• Possible signs of prior open fracture, such as scarring or tissue damage.

Diagnosis

Diagnosis is based on clinical evaluation and imaging studies. A physical examination assesses pain, swelling, instability, and deformity. X-rays of the ankle and lower leg are used to confirm the fracture, assess alignment, and identify malunion. CT or MRI may be ordered to evaluate soft tissue damage, ligament integrity, or the extent of malunion. The history of the injury and prior treatment is critical to determine the "subsequent encounter" and "open fracture" status.

Treatment Options

Treatment focuses on managing symptoms, addressing malunion, and restoring function. Non-surgical options include pain management, physical therapy to improve strength and stability, and orthotic devices (e.g., braces) to support the ankle. Surgical intervention may be considered for significant malunion or persistent instability, involving realignment of the fracture or ligament repair. Wound care is essential for open fracture remnants, and follow-up imaging monitors healing.

Prognosis and Follow-Up

Prognosis depends on the severity of malunion, functional impact, and response to treatment. Most patients experience improved stability and reduced pain with appropriate management, though some may have long-term limitations in activity. Regular follow-up appointments monitor healing, functional progress, and address complications. Physical therapy is often recommended to optimize recovery and prevent future injuries.

Complications

• Chronic ankle instability or pain.
• Progression of malunion affecting gait or mobility.
• Post-traumatic arthritis due to joint misalignment.
• Nerve or vascular damage from the initial injury or malunion.
• Infection risk if open fracture remnants are present.

Lifestyle & Prevention

• Wear supportive footwear and use ankle braces during high-risk activities.
• Improve ankle strength and flexibility through targeted exercises.
• Avoid uneven surfaces or situations with high fall risk.
• Address prior ankle injuries promptly to prevent instability.

When to Seek Professional Help

Seek immediate care if experiencing severe pain, inability to bear weight, visible deformity, or signs of infection (e.g., redness, pus, fever). Follow up with a healthcare provider if symptoms worsen, or if there is persistent instability or pain affecting daily activities.

Tips for Medical Coders

Document the encounter as "subsequent" to indicate care after the initial treatment phase. Specify "open fracture type I or II" based on wound size and tissue damage. Confirm "malunion" through imaging or clinical assessment, as this impacts coding and reflects healing complications. Ensure detailed notes on the fracture's alignment, prior treatment, and functional impact to support code assignment.