HAND/WRIST
First carpometacarpal (CMC) osteoarthritis (OA), also known as osteoarthritis at the base of the thumb, is a degenerative or “wear-and-tear” joint disease affecting the trapeziometacarpal joint. CMC arthritis is one of the most common sites of hand and wrist arthritis.
OA occurs when the smooth, protective cartilage over the end of bones is worn, leading to bone on bone rubbing. Disease progression can be categorized into four stages (Eaton and Littler Classification) which are important for determining treatment.Stage 1 is pre-arthritis, with a normal joint with possible joint widening due to inflammation of the synovial fluid. Stage 2 involves slight joint space narrowing with osteophytes (bone spur) < 2mm. In Stage 3, marked joint space narrowing and osteophytes >2mm are appreciated. Stage 4 is characterized by pantrapezial or scaphotrapezial-trapezoidal arthritis—disease affecting the joint between three adjacent wrist bones.
Presentation: Patients typically complain of pain at the base of the thumb. The CMC grind test is commonly positive, which involves firmly holding the joint while axially loading and rotating the thumb to elicit tenderness or crepitus (a grinding sound). X-rays taken at 3 different angles (PA stress, lateral, and pronated AP views) may show joint changes at one of the four stages. Evaluation for concomitant hand and wrist ailments must be completed.
Treatment: Initial treatment is nonsurgical with activity modification, thumb spica splinting, and NSAIDs. A corticosteroid injection into the joint may be helpful. If nonoperative treatment is unsuccessful, various surgical procedures can be considered. Ligament reconstruction and tendon interposition arthroplasty is the gold standard treatment for Stage 4 disease, which involves removing the diseased trapezium bone and replacing it with a coiled flexor carpi radialis tendon. The palmar ligament is reconstructed also using the flexor carpi radialis tendon. Other surgical options include arthrodesis, or fusing the bones of the joint together. After surgery, a cast is worn for several weeks and PT rehabilitation is started to help regain hand movement and strength.
Our guest blogger, Adam E. M. Eltorai is a medical student at Brown. He is completing a clinical rotation at Foundry Orthopedics. He will do his residency in Orthopaedic Surgery.
