M20.011 Mallet finger of right finger(s)

Name of the Condition

• Mallet finger of right finger(s)
• ICD-10-CM Code: M20.011

Summary

Mallet finger of the right finger(s) is a condition characterized by the inability to extend the distal joint of one or more fingers on the right hand, typically due to a tendon injury. This injury often results from trauma, such as a sudden forceful flexion of the finger, and can lead to functional impairment if untreated.

Causes

Mallet finger occurs when the extensor tendon at the distal interphalangeal (DIP) joint is damaged, usually from a direct blow or forced flexion of the finger. Common causes include sports injuries, falls, or accidental impacts that stretch or tear the tendon, disrupting its ability to straighten the finger.

Risk Factors

• Participation in activities with high risk of finger trauma (e.g., ball sports, manual labor)
• Previous finger injuries or tendon damage
• Lack of protective gear during high-risk activities
• Age-related tendon degeneration, which may weaken tissue resilience

Symptoms

• Inability to actively extend the affected finger's DIP joint
• Pain or tenderness at the fingertip or DIP joint
• Swelling or bruising around the injury site
• Visible drooping of the fingertip when attempting to straighten the finger

Diagnosis

Diagnosis is based on clinical evaluation, including assessment of finger extension and tenderness at the DIP joint. Imaging, such as X-rays, may be used to rule out associated fractures or assess tendon integrity. Patient history of trauma or injury is critical for confirming the diagnosis.

Treatment Options

• Immobilization of the DIP joint in extension using a splint or brace for 6–8 weeks to allow tendon healing
• Nonsteroidal anti-inflammatory drugs (NSAIDs) for pain and swelling
• Physical therapy to restore range of motion and strength after immobilization
• Surgical intervention for severe or chronic cases with tendon retraction or avulsion fractures

Prognosis and Follow-Up

Most cases resolve with conservative treatment, though full recovery may take several months. Early immobilization improves outcomes, while delayed treatment increases the risk of permanent stiffness or deformity. Follow-up appointments monitor healing and adjust therapy as needed.

Complications

• Chronic stiffness or limited finger extension
• Persistent pain or weakness
• Development of a swan neck deformity (hyperextension of the middle joint)
• Re-injury if immobilization is discontinued prematurely

Lifestyle & Prevention

• Use protective gear (e.g., gloves) during high-risk activities
• Avoid forced flexion of the fingers after injury
• Gradually resume activities under medical guidance to prevent re-injury
• Maintain finger strength and flexibility through regular, gentle exercises

When to Seek Professional Help

Seek care if you cannot extend the finger, experience severe pain, or notice swelling or bruising after an injury. Prompt evaluation is essential to prevent long-term complications.

Tips for Medical Coders

Document the specific finger(s) affected and confirm the diagnosis of mallet finger. Ensure clinical notes support the injury mechanism (e.g., trauma, forced flexion) and any associated fractures. Code M20.011 is appropriate for right-sided involvement; specify laterality and exclude unrelated finger deformities.