Trauma may cause a fracture of the humerus (ball) or the glenoid (socket) of the shoulder joint. The majority of these injuries can be treated without surgery with a good, long-term result.Some fractures are better treated with surgery because they may carry a high risk of arthritis if left alone. Some are unlikely to heal, or may heal in the wrong position if not treated surgically.Fractures are either described as being displaced or non-displaced. Fortunately, nearly 80 percent of all shoulder fractures are non-displaced. This implies that the broken pieces remain near their anatomic position and treatment merely requires immobilization in a sling until the bone fragments heal. Most shoulder fractures heal in about six weeks. About 20 percent of shoulder fractures are displaced and may require some type of manipulation to restore normal anatomy. Occasionally the rotator cuff muscles are injured or torn at the same time as the fracture. This can further complicate the treatment.