Total shoulder replacement generally has a good rate of overall success. However, if a problem develops with the replacement shoulder, it is usually because the glenoid, or socket, component has failed. The glenoid part of an artificial shoulder prosthesis loosens in about 10 percent of cases. Sometimes the natural socket wears away so significantly or unevenly that there isn’t enough bone to keep the artificial shoulder in place or placed correctly.
In a recent study, two doctors tracked the success of glenoid bone grafting as part of total shoulder arthroplasty. They wanted to determine whether adding bone to the glenoid and securing the graft with screws could lead to a better result for some patients.
Out of 132 total shoulder arthroplasties, 21 patients received a large bone graft to correct a problem with the glenoid. The need for a bone graft was determined by two factors: (1) if there wasn’t enough bone present to securely attach the prosthesis and (2) if an unevenly worn glenoid would leave the component improperly aligned. This was determined by X-rays or computerized tomography (CT) before surgery.
In most cases, the surgeon took the bone graft from the part of the patient’s own humerus (upper arm bone) that was removed to insert the ball portion of the new shoulder joint.
Sixteen patients (17 shoulder arthroplasties) were studied afterwards (nine men and seven women). The average age of the patients was 56 years old. All the patients had some shoulder instability before the operation. Thirteen of the shoulders were studied for an average of 70 months.
Five of the arthroplasties failed, including two in a patient who had both shoulder joints replaced. In all five cases, the glenoid component loosened. However, the other 12 patients reported significant pain relief as a result of the procedure. All 12 reported satisfaction with the surgery. Nine of the 12 patients also had good stability between the glenoid and the humerus. Fourteen of the 17 bone grafts healed in the correct position. In all, nine of the 17 shoulders showed good function.
The researchers concluded that although the glenoid bone grafting procedure is a difficult one, it holds the potential to improve the outcome of total shoulder arthroplasties. The procedure can increase the amount of bone in the socket and allow for a more natural position of the glenoid component.