Total shoulder arthroplasty involves implanting a prosthetic device to replace the bones that make up the ball and socket shoulder joint. The indications for a total shoulder arthroplasty include osteoarthritis, rheumatoid arthritis, post-traumatic arthritis, osteonecrosis and a previously failed shoulder replacement. Complications can occur at any time after the operation.
Loosening
There are two parts of a total shoulder arthroplasty; the humeral stem or ball and the glenoid or socket component. Either of these two components can loosen after they are placed in the operating room.
Humeral stem loosening is uncommon in osteoarthritis, but can occur in rheumatoid arthritis. Infection is always a possibility to cause humeral stem loosening.
Glenoid loosening is the most common cause of total shoulder arthroplasty failure according to the “AAOS Orthopaedic Comprehensive Review” edited by Dr Jay Lieberman of the University of Connecticut. Rheumatoid arthritis can also result in glenoid component loosening.
Infection
Infection of the shoulder arthroplasty can occur at any time after the replacement procedure. Less than six weeks after surgery, infection can be treated with open irrigation and removal of infected tissue. Infection that occurs after six weeks typically requires a removal of the prosthesis, intravenous antibiotics and a plan to reconstruct the shoulder joint.
Failure of Subscapularis Healing
The subscapularis is a muscle in the rotator cuff that is manipulated during the total shoulder arthroplasty procedure. Restoration of the subscapularis muscle is important for improving the outcome of the procedure.
Post-operative Stiffness
Post-operative stiffness can be a complication after total shoulder arthroplasty. The stiffness can lead to decreased range of motion in the shoulder. It is possible to actually have less shoulder range of motion post-operatively than before the operation.
Neurologic Injury
During the procedure either the musculocutaneous or the axillary nerve can be injured. The axillary nerve is the most commonly injured nerve after a total shoulder arthroplasty. During the surgery, muscle retractors can injure the musculocutaneous nerve. These neurologic injuries can cause numbess and tingling in the skin and lead to some muscle weakness.
Intraoperative Fracture
Placement of the prosethetic components into the shoulder bones can result in fracture. Osteoporotic bone or patients with rheumatoid arthritis are at a higher risk for fracture.
Instability
Shoulder instability can occur either early or late in the post-operative recovery. Early dislocations are associated with soft tissue injuries or implant position. Dislocation that occurs later into the post-operative period may be due to a rotator cuff tear, component loosening, or wear of the glenoid component.
About this Author
Gregory Waryasz is a graduate of Boston College and an M.D. candidate for May 2010 at Tufts University School of Medicine. He will be starting an orthopaedic residency at Brown University/Rhode Island Hospital in June of 2010. He is certified as a strength and conditioning specialist (CSCS) through the NSCA.
