Total Shoulder Arthroplasty for Glenohumeral Arthritis Associated with Posterior Glenoid Bone Loss: Midterm Results of an All-Polyethylene, Posteriorly Augmented, Stepped Glenoid Component

Abstract

BackgroundThe purpose of this study is to report the minimum 5-year clinical and radiographic outcomes of patients undergoing anatomic total shoulder arthroplasty (aTSA) with a posteriorly augmented glenoid component. MethodsThirty-five shoulders with minimum 5-year follow-up underwent aTSA using a posteriorly augmented glenoid component for the treatment of glenohumeral osteoarthritis with posterior glenoid bone loss. Clinical outcomes included range of motion (ROM), Visual Analog Scale (VAS) for pain, and patient reported outcomes scores (PROS). Radiographs (XR) and computed tomography (CT) scans were obtained to assess glenoid morphology, retroversion, central peg osseous integration (CPOI) via Wirth score, Lazarus scores, and Yian scores. Postoperative outcomes were measured at minimum 2- and 5-year follow-up. Kaplan-Meier survival analysis was calculated. ResultsTwo patients experienced prosthetic instability requiring revision, leaving 33 shoulders with an average follow-up of 6.6 years. Average preoperative glenoid retroversion was 21.6˚. A significant improvement in pain, ROM, and PROS was noted at minimum 2-year and 5-year follow-up. Additionally, VAS pain, American Shoulder and Elbow Surgeons (ASES), and Quick Disabilities of the Arm, Shoulder, and Hand (DASH) scores improved between minimum 2-year and 5-year follow-up. The average Lazarus and Yian scores at final follow-up were 0.73 and 2.6, respectively. There was an increase in Lazarus score and decrease in Wirth score between 2- and 5-year follow-up. A significant correlation was identified between VAS pain scores and both Lazarus and Wirth scores. Survivorship free from revision was 92% at 8.8 years postoperatively. ConclusionsMidterm results of aTSA with a posteriorly augmented, stepped glenoid component demonstrate sustained improvements in clinical outcomes with low rates of radiographic loosening. Continued improvement in pain and function, as well as a minor progression of radiographic osteolysis, may be expected between 2- and 5-year follow-up. Additionally, the severity of radiographic loosening correlates with subjective pain levels.