M66.371 Spontaneous rupture of flexor tendons, right ankle and foot

Name of the Condition

• Spontaneous Rupture of Flexor Tendons, Right Ankle and Foot (ICD-10 Code: M66.371)

Summary

This condition involves the sudden tearing of one or more flexor tendons in the right ankle and foot, which can impair movement and cause pain. Flexor tendons are responsible for bending the foot and toes downward.

Causes

Causes may include underlying inflammatory conditions (e.g., arthritis), degenerative tendon changes, or certain medications (e.g., corticosteroids). Spontaneous ruptures typically occur without obvious trauma.

Risk Factors

• Age-related tendon degeneration
• Chronic inflammatory diseases (e.g., rheumatoid arthritis)
• Use of medications like corticosteroids or fluoroquinolones
• History of tendon disorders or repetitive strain

Symptoms

• Sudden pain and swelling in the right ankle/foot
• Difficulty or inability to flex the foot/toes downward
• Audible pop or snap at the time of rupture
• Visible contour changes in the tendon area

Diagnosis

Diagnosis starts with a physical exam to assess movement and swelling. Imaging (e.g., MRI or ultrasound) confirms the rupture and evaluates severity. Patient history helps identify risk factors.

Treatment Options

• Immobilization (cast/brace) to allow healing
• Physical therapy to restore strength and mobility
• Surgical repair for severe or complete ruptures
• Pain management and anti-inflammatory medications

Prognosis and Follow-Up

Recovery depends on treatment and tendon damage. Immobilization or surgery is often followed by physical therapy. Regular follow-ups monitor healing and functional recovery.

Complications

• Persistent weakness or limited mobility
• Re-rupture of the tendon
• Chronic pain or stiffness
• Infection (if surgical repair is performed)

Lifestyle & Prevention

• Avoid repetitive high-impact activities
• Maintain tendon health through regular exercise
• Manage underlying conditions (e.g., arthritis)
• Use proper footwear and ergonomic support

When to Seek Professional Help

Seek care if sudden pain, swelling, or loss of movement occurs in the right ankle/foot, especially after a pop or snap. Immediate evaluation is needed for suspected tendon rupture.

Tips for Medical Coders

Document the side (right ankle/foot) and confirm spontaneous rupture (no trauma). Include details on tendon involvement and any imaging or exam findings to support the diagnosis.