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

Name of the Condition

• Nondisplaced Maisonneuve's fracture of unspecified leg, subsequent encounter for open fracture type I or II with nonunion
• ICD-10 Code: S82.866M

Summary

A Maisonneuve's fracture is a specific type of ankle injury involving a proximal fibula fracture combined with a tear of the tibiofibular syndesmosis and often an associated medial malleolus or deltoid ligament injury. 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 a fracture where the skin is breached (type I: wound <1 cm; type II: wound 1–10 cm without extensive soft tissue damage or contamination). The "nonunion" modifier signifies that the fracture has failed to heal properly after an expected period.

Causes

The fracture is usually caused by external rotation of the foot, which can occur during activities like twisting the ankle, falls, or sports-related injuries. The rotational force disrupts the syndesmotic ligaments and may cause additional damage to the medial structures of the ankle. 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. Nonunion may result from inadequate immobilization, poor blood supply, infection, or excessive movement at the fracture site.

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.
• Factors affecting bone healing, such as smoking, diabetes, or nutritional deficiencies.
• Delayed or inadequate initial treatment of the fracture.

Symptoms

• Persistent pain at the proximal fibula or ankle, often worsening with activity.
• Swelling or bruising that may not resolve over time.
• Difficulty bearing weight on the affected leg.
• Visible or palpable instability in the ankle joint.
• Possible signs of nonunion, such as a lack of healing progress on imaging.
• Open wound (if present) with or without drainage, depending on fracture type.

Diagnosis

Diagnosis involves a thorough clinical evaluation, including a detailed history of the injury and symptoms. Physical examination focuses on assessing ankle stability, tenderness, and range of motion. Imaging studies, such as X-rays, are essential to confirm the fracture and evaluate alignment. Advanced imaging (e.g., CT or MRI) may be used to assess for nonunion, associated ligament injuries, or soft tissue damage. The "subsequent encounter" status and open fracture type are determined by clinical documentation of the healing phase and wound characteristics.

Treatment Options

Treatment depends on the severity of the nonunion and associated injuries. Options may include:

• Surgical intervention to stabilize the fracture (e.g., internal fixation with plates or screws).
• Bone grafting to promote healing in cases of nonunion.
• Wound care for open fractures, including debridement and antibiotics if infection is present.
• Immobilization with a cast or brace to protect the healing bone.
• Physical therapy to restore strength, range of motion, and function.
• Pain management and monitoring for complications.

Prognosis and Follow-Up

Prognosis varies based on the success of treatment and the extent of the injury. Nonunion may require additional interventions, and recovery can be prolonged. Regular follow-up with imaging is necessary to assess healing progress. Patients may experience residual ankle instability or pain, which could impact mobility. Long-term outcomes depend on adherence to treatment plans and rehabilitation.

Complications

• Persistent nonunion or delayed healing.
• Infection, particularly with open fractures.
• Chronic ankle instability or arthritis.
• Nerve or vascular damage from the initial injury or surgery.
• Reduced mobility or functional limitations.

Lifestyle & Prevention

• Avoid high-risk activities until fully healed and cleared by a healthcare provider.
• Use proper footwear and protective gear during sports or activities with fall risks.
• Maintain a healthy lifestyle to support bone healing (e.g., balanced diet, smoking cessation).
• Follow post-treatment guidelines for weight-bearing and activity restrictions.
• Engage in targeted physical therapy to strengthen the ankle and prevent future injuries.

When to Seek Professional Help

Seek immediate medical attention if:

• Pain or swelling worsens or does not improve with rest.
• There is new or increasing instability in the ankle.
• Signs of infection (e.g., redness, warmth, pus) are present.
• Difficulty bearing weight on the leg persists.
• Imaging shows no progress in healing after an expected period.

Tips for Medical Coders

Document the encounter as "subsequent" to reflect care after the initial treatment phase. Specify the open fracture type (I or II) based on wound size and soft tissue involvement. Clearly document the presence of nonunion, including clinical or imaging evidence of failed healing. Ensure all modifiers (e.g., open fracture type, nonunion) are accurately coded to reflect the current status of the injury.