Shoulder arthritis occurs when the smooth cartilage lining the joint surfaces of the humerus (arm bone), scapula (shoulder blade), and clavicle (collarbone) becomes damaged and worn out. The glenohumeral joint, which is the ball and socket component of the shoulder, refers to where the ball part of the humerus moves on the socket part of the scapula. The joint surfaces are coated with an exceptionally smooth cartilage lining that helps lubricate the joint and enables smooth movement. The shoulder joint is renowned for being the most flexible joint in the body.
However, due to various reasons, the cartilage lining the joint surfaces can become damaged and unable to repair itself. Eventually, the worn-out cartilage is replaced by bare bone, which results in irreversible bone-on-bone arthritis when it occurs on both sides of the joint.
Shoulder arthritis is a common cause of shoulder pain, and it can be caused by a variety of factors such as age, injury, or overuse. Here are some of the most common causes of shoulder arthritis:
The signs and symptoms of shoulder arthritis include pain, stiffness, limited range of motion, weakness, and swelling in the shoulder joint. In some cases, a grinding or clicking sensation may also be felt when moving the shoulder. The pain may worsen with activity or at night, and it may be accompanied by a loss of strength or function in the affected arm.
Apart from conducting a thorough clinical examination that involves assessing the range of motion of the shoulder and the individual muscles surrounding it, other tests are typically necessary for the diagnosis of shoulder arthritis. These include
