S63.044 Dislocation of carpometacarpal joint of right thumb

Name of the Condition

• Dislocation of carpometacarpal joint of right thumb

Summary

Dislocation of the carpometacarpal (CMC) joint of the right thumb is a complete separation of the joint surfaces at the base of the thumb, where the metacarpal bone detaches from the trapezium in the wrist. This disrupts alignment and function, often causing pain, instability, and reduced mobility. Unlike subluxation, dislocation involves full displacement of the joint.

Causes

Acute trauma, such as a direct blow to the thumb or a fall on an outstretched hand, is the primary cause. High-impact activities or sports injuries may also lead to this condition. Underlying joint laxity or hypermobility can increase susceptibility to dislocation.

Risk Factors

• Participation in contact sports or activities with a high risk of falls.
• History of previous thumb or hand injuries.
• Jobs or hobbies involving repetitive hand use or heavy manual labor.
• Genetic conditions affecting joint stability, such as hypermobility syndromes.

Symptoms

• Pain or tenderness at the base of the right thumb.
• Visible deformity or misalignment of the joint.
• Reduced range of motion or a feeling of instability.
• Swelling, bruising, or a popping/catching sensation during movement.

Diagnosis

A physical examination assesses thumb movement, alignment, and stability. Imaging tests, such as X-rays, confirm dislocation and rule out fractures or associated injuries. Clinical evaluation focuses on joint function and tenderness.

Treatment Options

• Reduction: Manual realignment of the joint under local or general anesthesia.
• Immobilization: Splinting or casting to stabilize the thumb during healing.
• Rehabilitation: Physical therapy to restore strength and mobility.
• Surgery: Required for severe cases or if closed reduction fails.

Prognosis and Follow-Up

Most cases heal with proper treatment, but recovery may take several weeks. Follow-up appointments monitor healing and mobility. Persistent instability or pain may require further intervention, such as surgery or ongoing therapy.

Complications

• Chronic instability or recurrent dislocation.
• Arthritis in the CMC joint over time.
• Nerve or tendon damage from the injury or treatment.
• Reduced grip strength or functional limitations.

Lifestyle & Prevention

• Use protective gear during high-risk activities.
• Avoid repetitive or forceful thumb movements.
• Strengthen thumb and wrist muscles through exercise.
• Maintain joint flexibility with regular stretching.

When to Seek Professional Help

Seek immediate care for severe pain, visible deformity, or inability to move the thumb. Prompt treatment improves outcomes and reduces complications.

Tips for Medical Coders

Document the laterality (right thumb) and specify dislocation (not subluxation) to ensure accurate coding. Include details of trauma, imaging results, and treatment to support medical necessity.