M65.31 Trigger thumb

Name of the Condition

• Trigger thumb

Summary

Trigger thumb is a condition where the thumb catches or locks in a bent position, often due to inflammation or thickening of the flexor tendon sheath. This can cause pain, stiffness, and difficulty straightening the thumb. The condition may be acute or chronic and typically affects the dominant hand.

Causes

Inflammation or thickening of the flexor tendon sheath, often due to repetitive motion or overuse. Underlying conditions such as diabetes or rheumatoid arthritis. Trauma to the thumb or hand. Age-related degenerative changes in the tendon or sheath.

Risk Factors

• Repetitive thumb movements (e.g., gripping, texting)
• Diabetes or other metabolic disorders
• Rheumatoid arthritis or other inflammatory conditions
• Female gender and increasing age
• Prior thumb or hand injuries

Symptoms

• Thumb catching or locking in a bent position
• Pain or tenderness at the base of the thumb
• Stiffness, especially in the morning
• A popping or clicking sensation when moving the thumb
• Difficulty straightening the thumb without assistance

Diagnosis

Diagnosis typically involves a physical examination to assess thumb movement and tenderness. The provider may ask the patient to open and close the hand to observe locking or catching. Imaging studies like ultrasound may be used to evaluate tendon sheath inflammation.

Treatment Options

• Rest and activity modification to reduce strain
• Nonsteroidal anti-inflammatory medications (NSAIDs) for pain and inflammation
• Corticosteroid injections to reduce swelling
• Physical therapy to improve mobility
• Surgical release of the tendon sheath for persistent cases

Prognosis and Follow-Up

With appropriate treatment, most cases improve within weeks to months. Follow-up care ensures symptoms resolve and function is restored. Chronic cases may require ongoing management to prevent recurrence.

Complications

• Persistent locking or stiffness
• Reduced thumb mobility
• Chronic pain
• Need for surgical intervention if conservative treatments fail

Lifestyle & Prevention

• Avoid repetitive thumb movements or take frequent breaks
• Use ergonomic tools to reduce strain
• Maintain good hand and thumb flexibility through exercises
• Manage underlying conditions like diabetes to reduce risk

When to Seek Professional Help

Seek care if symptoms worsen, interfere with daily activities, or do not improve with rest. Prompt evaluation is important if locking is severe or accompanied by significant pain or swelling.

Tips for Medical Coders

Document the affected digit (thumb) and any underlying conditions (e.g., diabetes, rheumatoid arthritis) to support code assignment. Note the presence of locking, pain, or functional impairment, as these details may influence coding and reimbursement. Ensure documentation aligns with clinical findings and treatment provided.