“Frozen shoulder” sometimes referred to as adhesive capsulitis occurs in up to two per cent of the general adult population. When it develops without warning or known cause, it is referred to as idiopathic. Accidents and injuries with tears of the rotator cuff and/or labrum (rim of fibrous cartilage around the shoulder socket) are possible known causes of this condition.
Women seem to develop this problem more often than men. In both groups (men and women), adhesive capsulitis tends to occur between the ages of 35 and 65 years. Again, the reason for this remains unknown. Typical symptoms are pain and stiffness limiting motion, especially overhead arm movements. Reaching behind the back is also restricted.
Arthroscopic examination inside the joint shows a thickened joint capsule, the connective tissue that surrounds the joint and helps hold it in the socket. Histologic examination (looking at the tissue under a microscope) show a tightly packed group of collagen fibers. Collagen is the basic building block of all soft tissue.
What happens in this condition over time is referred to as the natural history. There seem to be some well-defined and expected phases to this problem. First comes the painful stiffness and limited shoulder motion. Gradually the joint loosens up again. And eventually, most (if not all) motion is restored.
Studies show that it is possible to leave the shoulder alone (called benign neglect) and it will go through these phases successfully. Other studies suggest that conservative (nonoperative) care of any kind (benign neglect, steroid injection, physical therapy) results in improvements but not a complete restoration.
In up to half of all patients treated without surgery, mild pain, stiffness, and some loss of function are still reported five to seven years after the initial attack. Surgery to release the capsule and manipulate (move) the shoulder through its full motion seems to have the best results without complications and with full recovery of pain free motion.