Also known as rhizarthrosis, is a degenerative condition affecting the joint at the base of the thumb, between the trapezium bone and the first metacarpal. It’s a common form of arthritis, particularly in older adults and women. The condition causes pain, stiffness, and decreased function in the thumb, affecting activities like grasping and pinching.

Here’s a more detailed look:

Symptoms:

• Pain: The most common symptom is pain at the base of the thumb, which can worsen with use and movement.

• Stiffness: Difficulty moving the thumb, especially during activities requiring fine motor skills.

• Weakness: Reduced strength in the thumb, making it harder to grasp or pinch objects.

• Swelling: The joint may become swollen and tender to the touch.

• Crepitus: A grinding or cracking sensation when moving the thumb.

• Deformity: In advanced cases, the thumb may develop a “Z-thumb” deformity, where the thumb joint is flexed at the base and the joint in the finger is hyperextended.

Causes

• Wear and tear:

Over time, the cartilage in the joint breaks down, leading to pain and stiffness.

• Genetics:

Some individuals may be more prone to developing TMC osteoarthritis due to genetic factors.

• Trauma:

Injuries to the thumb or wrist can contribute to the development of osteoarthritis.

• Ligament laxity:

Excessive looseness of the ligaments supporting the joint can increase the risk of cartilage damage.

Diagnosis:

• Physical Examination:

A doctor will assess the range of motion, tenderness, and any deformities in the thumb joint.

• X-rays:

X-rays can show signs of osteoarthritis, such as joint space narrowing, bone spurs, and changes in the joint surfaces.

Treatment:

• Non-surgical:

• Pain management: Over-the-counter pain relievers (NSAIDs), topical analgesics, and corticosteroid injections.

• Physical therapy: Exercises to strengthen the muscles around the thumb and improve range of motion.

• Splinting: Wearing a splint can help to rest the joint and reduce pain.

• Activity modification: Avoiding activities that aggravate the pain.

• Surgical:

• Trapeziectomy with ligament reconstruction: Involves removing the trapezium bone and reconstructing the ligaments to stabilize the joint.

• Arthrodesis: Fusing the joint to eliminate pain and improve stability.

• Arthroplasty: Replacing the joint with an artificial joint.

Prevention

• Maintaining a healthy weight: This can help reduce stress on the joints.

• Engaging in regular exercise: This can help strengthen the muscles around the thumb and improve joint function.

• Using assistive devices: Such as splints or ergonomic tools, to reduce stress on the thumb joint.

• Protecting the thumb from injury: Taking precautions to avoid trauma to the thumb.