Opposable thumbs may play a large part in human development, but they're also subject to considerable abuse over time. Joints in the thumb are prone to overuse and repetitive movement stresses as well as acute injuries. Many types of wear and tear damage as well as acute injury to the thumb joints can damage the joint, causing pain and make gripping and grasping objects difficult.
Arthritis
The basal joint in the thumb, also known as the carpo-metacarpal or CMC joint, often develops arthritis, especially in women, who are much more likely to have arthritis in the joint than men, according to the Milton S. Hershey Medical Center at Penn State University. Age, overweight, repetitive motion, weakness in the muscles around the joint and cumulative injuries over time all make arthritis development in the joint likely.
Deterioration of cartilage that covers the bones allows the bones to rub against each other, damaging the joint, the Mayo Clinic explains. Pain that radiates from the base of the thumb commonly occurs, especially when grasping objects or do tasks that require turning motions, like opening a jar. Bone spurs may form along the joint. Anti-inflammatory medications and corticosteroids may reduce swelling and pain in the joint. Surgical repair helps in severe cases.
De Quervain's Tendinitis
De Quervain's tendinitis develops in the tendons that attach to the thumb near the wrist. Tendons, which attach muscle to bone, are covered with tissue called synovium, which helps them move through a tunnel on the thumb side of the wrist, the American Academy of Orthopaedic Surgeons explains. Tendons can swell in pregnancy, from overuse or in cases of rheumatoid arthritis; the swelling irritates nearby nerves and causes pain and often numbness where the thumb meets the wrist.
Pain increases when grasping objects or turning the wrist. While De Quervain's tendinitis isn't caused by a joint problem, pain can be felt in the joint when the thumb moves and may travel up the tendons. Women are 8 to 10 times more likely to develop De Quervain's than men, says the Cleveland Clinic.
Ulnar Collateral Ligament Tear
The ulnar collateral ligament connects the proximal and distal bones of the thumb and stabilizes the metacarpophalangeal, or MCP joint. Force that pushes the thumb away from the hand tears the ligament and makes it difficult to grasp or pinch objects. The joint may swell and become discolored and painful. A partial tear heals in three to four weeks of immobilization, but a complete tear needs surgical repair to reconnect the two ends of the ligament.
