Basilar Joint Arthritis
What is Basilar Joint Arthritis?
Arthritis is any condition that irritates or damages a joint. In a healthy joint, cartilage forms a protective, cushioning layer between bones, allowing for smooth, painless articulation. Osteoarthritis implies that this cartilage has worn out, causing the bones to rub against each other and damaging the joint. Basilar joint arthritis, also called CMC arthritis, is osteoarthritis of the joint between the thumb metacarpal and the trapezium, a small bone at the base of the thumb towards the wrist (Figure 1). It may also be called pantrapezial arthritis, indicating that arthritis surrounds the trapezium, affecting articulation of the trapezium with the scaphoid and trapezoid wrist bones. Damage to the basilar joint may also result in the growth of new bone alongside the existing bone, called a bone spur, which may appear as a noticeable bump at the joint.
Basilar Joint Arthritis is more common in women than men, and typically occurs after age 40. The likelihood of developing basilar joint arthritis can be increased by history of injury or fracture, as well as by repetitive motions for work-related or daily activities leading to overuse.
Signs and Symptoms:
The basilar joint allows the thumb a wide range of motion, allowing gripping and pinching activities. Thus, early symptoms of thumb arthritis may include pain at the base of the thumb with grip or pinch activities, such as opening jars or holding a pen for a prolonged period of time. A limited range of motion may be experienced as well as a tendency to drop things. Other signs of basilar joint arthritis may include swelling, stiffness, and tenderness at the base of the thumb, decreased strength, and decreased range of motion. Symptoms may worsen in cold, humid weather and may prompt swelling at the base of the thumb. The base of the thumb may become prominent as the joint begins to sublux, or slide partially out of alignment. Bumps may appear at the joint due to bone spur formation. In later stages, crepitus or grinding may occur with pinching and grasping activities.
Conservative options may include the use of a splint to support the joint, limit motion, and decrease pain. Anti-inflammatory medications, a steroid injection, activity modification, and physical therapy may also provide temporarily pain relief and reduce inflammation.
If conservative treatment is not effective, or if the patient has more advanced arthritis, surgical treatment may be recommended. Joint replacement surgery (arthroplasty) or joint fusion surgery (arthrodesis) may be suggested to stabilize the joint, alleviate pain, and improve motion.
Joint replacement surgery may include excision (removal) of the trapezium bone with interposition of a rolled tendon from the forearm in a procedure called LRTI, Ligament Reconstruction and Tendon Interposition (Figure 2).
An LRTI procedure may be augmented by placement of a Mini TightRope between the thumb metacarpal and index metacarpal bones. The Mini TightRope provides additional support and helps keep the metacarpal bones in their proper position. Two stainless steel buttons will hold the TightRope in position (Figure 3).
Joint fusion may be considered if practical for the patient. The surgeon will permanently fuse the bones in the affected joint by placing a metal pin across the two bones. This will hold the bones in the correct alignment as the bones fuse (grow together), and will also increase stability and reduce pain. While the fused joint will no longer be able to flex, it will allow weight bearing activities without pain.
Post Operative Rehabilitation:
Following surgery, rehabilitation will involve a period of thumb immobilization in a thumb spica cast or splint for up to six weeks, followed by slow, progressive range of motion and strengthening exercises with a therapist. May return to unrestricted activity at 10-12 weeks.