Total shoulder arthroplasty for glenohumeral arthritis associated with posterior glenoid bone loss: results of an all-polyethylene, posteriorly augmented glenoid component.

BACKGROUND: Posterior glenoid bone loss is commonly encountered in total shoulder arthroplasty (TSA). The purpose of our study is to report the clinical and radiographic findings of patients with a minimum of 2 years' follow-up treated with an all-polyethylene, augmented glenoid component.

METHODS: Twenty-two shoulders with posterior glenoid bone loss were treated by a single surgeon. All underwent primary TSA using a posteriorly augmented, all-polyethylene, stepped glenoid component. Outcome data included visual analog scale, Western Ontario Osteoarthritis of the Shoulder index, and Short Form 36 scores. Radiographic analysis was performed to evaluate bone-cement interface lucency, implant seating, and osseous integration of the central peg.

RESULTS: The mean follow-up period was 36 months. Average preoperative retroversion measured with computed tomography scan was 23.5°. In addition to statistically significant increases in forward flexion and external rotation, the visual analog scale score, Western Ontario Osteoarthritis of the Shoulder score, and Short Form 36 physical component summary score all improved significantly (P < .001). Twelve shoulders had osseous integration between the central-peg flanges, 6 had bone adjacent to the central-peg flanges but without identifiable osseous integration, and 1 showed osteolysis. The mean Lazarus score was 0.5. All glenoids had perfect seating scores. Two patients sustained a total of 3 episodes of prosthetic instability.

CONCLUSIONS: Early results of a posteriorly augmented, all-polyethylene, stepped prosthetic glenoid component to address posterior glenoid loss in TSA are encouraging. Continued evaluation will determine prosthetic longevity and maintained clinical improvement.