Vault perforation after eccentric glenoid reaming for deformity correction in anatomic total shoulder arthroplasty

The management of glenoid deformity during anatomic total shoulder arthroplasty remains controversial. In this study, we evaluate variable correction of glenoid deformity by eccentric reaming. We hypothesize that partial correction of modified Walch B/C-type glenoid deformities can achieve 75% bone-implant contact area (BICA) with a reduced vault perforation risk compared with complete correction. Fifty shoulder computed tomographic scans with glenohumeral osteoarthritis were retrospectively evaluated. The Tornier BluePrint v2.1.5 software simulated 3 eccentric reaming scenarios including no, partial, and complete deformity correction. Each scenario was evaluated at 4 BICAs and using 3 implant fixation types. Three-dimensional surface representations were used to evaluate medialization and vault perforation. The patients had mean glenoid retroversion and inclination of 18.5° and 8.8°, respectively, and mean posterior humeral head subluxation of 76%. With 75% BICA, the 3 fixation types had glenoid vault perforation in 6%-26% and 26%-54% of cases for partial and complete glenoid deformity correction, respectively. The central and posterior-inferior implant components were most likely to perforate across all scenarios. Eccentric reaming for glenoid deformity correction increases the risk of vault perforation. Severe glenoid deformity required increased medialization to achieve 75% BICA. Pegged implants have increased chances of perforation compared with a keeled design; the central and posterior-inferior components were most likely to perforate during deformity correction. Partial deformity correction of modified Walch B/C-type glenoid deformities can achieve 75% BICA while reducing the risk of vault perforation compared with complete correction at the time of anatomic total shoulder arthroplasty.