Reverse shoulder arthroplasty with metallic augments to preserve bone and restore joint line in patients with glenoid bone loss

Abstract

BackgroundGlenoid bone loss poses significant challenges for reverse shoulder arthroplasty. In these patients, excess reaming can lead to further bone loss and medialization of the joint line. Metallic augments have been described as a technique for addressing this issue. However, there are currently no studies evaluating the effect of metallic augments on anatomic outcomes. This study evaluates the effect of metallic augments on the glenohumeral joint line and bone preservation. We hypothesize that metallic augments can preserve bone while preventing further medialization of the joint line in patients with preoperative glenoid bone loss. MethodsA prospective single-center, 2-surgeon consecutive case series was evaluated with postoperative computed tomography scans. Three-dimensional reconstruction was used to create models of the scapula and humerus. Comparisons were made with preoperative computed tomography scans using volumetric analysis to evaluate bone loss. The base of the coracoid was used as a constant landmark to assess the joint line position and, by proxy, the center of rotation. Further evaluation of the glenoid version and inclination was measured on the reconstructed models through standardized techniques. ResultsFifteen patients (16 implants) underwent preoperative planning and reverse shoulder arthroplasty with metallic augments from January 1, 2018, to January 1, 2021. The mean follow-up time was 13.1 months. Analysis revealed that augments prevented further medialization of the joint line and corrected the deficit on average by 10.2 mm (range 6.9-14.3; standard deviation 2.0). The mean bone volume removed during surgery was 1292 mm3 (range 525-2256; standard deviation 527), with this value inclusive of the baseplate post volume (∼800 mm3). Inclination and version were restored to acceptable limits in all cases. ConclusionsReverse shoulder arthroplasty with metallic augments reliably preserves bone and prevents medialization of the joint line in patients with preoperative glenoid bone loss. Further research is required to assess the long-term and functional outcomes of this technique.