Thumb Arthritis

Basilar joint arthritis refers to degenerative arthritis with loss of normal cartilage at the base of the thumb. The thumb is different from the other fingers in the way it can swivel and rotate for pinch and grip activities. Most of this motion occurs between the thumb metacarpal bone and the trapezium bone (see figure). Over many decades of use, the cartilage between these two bones may slowly wear thin. Eventually, this results in loss of the normal joint space and pain from bone rubbing on bone. Bone spurs often then form at the edges of the joint and are an additional cause of pain. The ligaments which surround the joint may weaken with and leads to collapse of the joint.