Idiopathic destructive arthritis of the shoulder.

IDA of the shoulder is a condition found predominantly in elderly females. Although the shoulder is primarily involved, other joints such as the hip and knee can be affected, and concurrent OA is common at other joint sites. Clinical features include voluminous, often blood-stained effusions, together with features of rotator cuff rupture and restriction of shoulder movement. Laboratory parameters are usually normal and examination of the synovial fluid reveals large amounts of basic calcium phosphate crystals. The synovium is hypertrophied and vascular and shows fibrin deposition. It contains calcified material extracellularly. An acute inflammatory infiltrate is absent. Radiographs demonstrate soft tissue swelling and subchondral sclerosis with marked bony attrition involving the acromioclavicular and glenohumeral joints, as well as the humeral head and neck. Although some aspects of the disease seem distinct, many features are shared with other types of destructive arthritis of the shoulder. The pathogenesis of this disorder is at present obscure, but it is clear that an understanding of the processes involved will provide a vital contribution to our understanding of the response of the joint to insult. With a multidisciplinary approach and adequate communication between interested workers this aim could seen be within our grasp.