Cmc

CMC
Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Pain, swelling, reduced range of motion
Complications	Osteoarthritis
Onset
Duration
Types	N/A
Causes	Overuse, injury, genetic factors
Risks	Age, repetitive motion
Diagnosis	Clinical examination, imaging
Differential diagnosis	N/A
Prevention	N/A
Treatment	Medication, physical therapy, surgery
Medication	N/A
Prognosis	Variable
Frequency	Common
Deaths	N/A

CMC refers to the carpometacarpal joint of the thumb, which is a common site for osteoarthritis and other musculoskeletal disorders. This article provides a comprehensive overview of the anatomy, pathology, diagnosis, and treatment of conditions affecting the CMC joint.

Anatomy

The carpometacarpal joint of the thumb, also known as the trapeziometacarpal joint, is a saddle joint located at the base of the thumb. It is formed by the articulation between the trapezium bone of the wrist and the base of the first metacarpal bone. This joint allows for a wide range of motion, including flexion, extension, abduction, adduction, and opposition, which are essential for grip and pinch functions.

Ligaments

The stability of the CMC joint is maintained by several ligaments, including the anterior oblique ligament (also known as the beak ligament), the posterior oblique ligament, the intermetacarpal ligament, and the dorsoradial ligament. These ligaments prevent excessive movement and provide support during hand activities.

Pathology

The CMC joint is prone to degenerative changes due to its high mobility and the significant forces it endures during daily activities. The most common pathological condition affecting the CMC joint is osteoarthritis.

Osteoarthritis

Osteoarthritis of the CMC joint is characterized by the degeneration of articular cartilage, leading to pain, swelling, and reduced range of motion. It is more prevalent in women and typically occurs after the age of 40. Risk factors include repetitive use, previous injury, and genetic predisposition.

Other Conditions

Other conditions that can affect the CMC joint include rheumatoid arthritis, traumatic injuries, and ligamentous laxity.

Diagnosis

Diagnosis of CMC joint disorders is primarily clinical, based on patient history and physical examination. Key clinical signs include tenderness at the base of the thumb, swelling, and crepitus during movement.

Imaging

X-ray imaging is commonly used to assess the extent of joint degeneration and to rule out other conditions. Advanced imaging techniques such as MRI or CT scan may be used in complex cases.

Treatment

Treatment of CMC joint disorders depends on the severity of the condition and the patient's symptoms.

Conservative Management

Initial treatment often involves conservative measures such as:

• Nonsteroidal anti-inflammatory drugs (NSAIDs) to reduce pain and inflammation.
• Physical therapy to improve joint function and strengthen surrounding muscles.
• Splinting to immobilize the joint and reduce stress during activities.

Surgical Intervention

In cases where conservative management fails, surgical options may be considered. These include:

• Trapeziectomy: Removal of the trapezium bone to relieve pain.
• Ligament reconstruction: To restore joint stability.
• Arthroplasty: Joint replacement surgery for severe cases.

Prognosis

The prognosis for CMC joint disorders varies. Conservative treatment can effectively manage symptoms in many patients, while surgical interventions have a high success rate in relieving pain and restoring function.

Prevention

Preventive measures include avoiding repetitive thumb movements, using ergonomic tools, and performing exercises to maintain joint flexibility and strength.

See also

• Hand osteoarthritis
• Joint replacement
• Rheumatology