M18.11 Unilateral primary osteoarthritis of first carpometacarpal joint, right hand

Name of the Condition

• Unilateral primary osteoarthritis of first carpometacarpal joint, right hand

Summary

Unilateral primary osteoarthritis of the first carpometacarpal joint, right hand, is a degenerative joint condition affecting the base of the right thumb. It involves cartilage breakdown, leading to pain, stiffness, and functional limitations, particularly with gripping or pinching tasks.

Causes

Osteoarthritis develops from cartilage degradation in the joint. In this condition, wear and tear over time causes cartilage breakdown, bone changes, and joint space narrowing at the first carpometacarpal joint of the right hand.

Risk Factors

• Age: more common in older adults.
• Gender: higher prevalence in women.
• Occupational: repetitive thumb use.
• Previous thumb injuries.
• Genetic predisposition to osteoarthritis.

Symptoms

• Pain at the right thumb base, worsened by movement.
• Swelling and stiffness.
• Reduced thumb strength.
• Difficulty pinching or gripping objects.
• Possible bony prominence at the joint.

Diagnosis

Physical examination assesses pain, swelling, and range of motion. Imaging, such as X-rays, evaluates joint space narrowing, bone spurs, or subchondral changes to confirm osteoarthritis.

Treatment Options

• Medications: NSAIDs for pain relief.
• Splints or braces: Limit thumb movement and provide support.
• Occupational therapy: Exercises to improve strength and function.
• Corticosteroid injections: Reduce inflammation.
• Surgery: For severe cases, options include joint fusion or replacement.

Prognosis and Follow-Up

Prognosis depends on severity and treatment adherence. Early intervention may slow progression, but joint degeneration can continue over time. Regular follow-up monitors symptoms and treatment effectiveness.

Complications

• Chronic pain.
• Reduced hand function.
• Joint deformity.
• Increased risk of falls due to grip weakness.

Lifestyle & Prevention

• Avoid repetitive thumb strain.
• Use ergonomic tools.
• Maintain a healthy weight to reduce joint stress.
• Perform thumb-strengthening exercises.

When to Seek Professional Help

Seek care if pain persists, worsens, or limits daily activities. Also, consult a provider for sudden swelling, redness, or loss of motion.

Tips for Medical Coders

Document laterality (right hand) and specify "primary" to distinguish from secondary osteoarthritis. Ensure clinical notes support unilateral involvement and exclude bilateral or secondary causes.