basalarthrose

Basalarthrose, also known as basal joint arthritis or carpometacarpal (CMC) osteoarthritis, is a degenerative condition affecting the joint at the base of the thumb. Specifically, it involves the articulation between the trapezium bone (one of the small bones in the wrist) and the first metacarpal bone (the bone in the hand that connects to the thumb). This joint is crucial for the thumb's wide range of motion and its ability to pinch and grip.

The wear and tear on the cartilage in this joint leads to inflammation, pain, stiffness, and reduced function. Symptoms typically develop gradually and can worsen over time. Common complaints include pain at the base of the thumb, particularly during activities that involve gripping, pinching, or twisting. This pain can radiate into the thumb and wrist. Stiffness is also a hallmark symptom, making it difficult to move the thumb freely, especially in the morning. Swelling may be present around the affected joint. In more advanced stages, a visible bump or prominence may form at the base of the thumb, and the thumb may drift out of its normal alignment, leading to a "Z" deformity.

The exact cause of basalarthrose is not fully understood, but several factors are believed to contribute to its development. These include aging, genetics, previous injury to the thumb or wrist, and overuse. Women are more commonly affected than men, and it often appears in individuals over the age of 50. Repetitive stress on the thumb joint, such as from certain occupations or hobbies, can accelerate the degenerative process. Diagnosis is usually made through a physical examination, assessment of symptoms, and imaging tests like X-rays, which can reveal characteristic changes in the joint.