Although TSA has been shown to significantly yield better outcomes than hemiarthroplasty, glenoid prosthesis loosening remains the most common complication. Inadequate primary fixation enables the glenoid component to move. In primary glenohumeral osteoarthritis (GHOA), glenoid involvement and proper morphology vary considerably. Postero-inferior glenoid hypoplasia could be associated with some degree of osteoarthritis. According to Walch, 24 % of glenoids in GHOA are type B2 or C (excessive posterior retroversion), which increases the challenge for the glenoid component fixation.
A total of 30 cases of TSR with glenoid type B2 (20 cases) and type C (10 cases) were reviewed. Mean follow-up was 11.2 months. A metal-backed (MB) glenoid component was implanted, with a posterior bone graft reconstruction. Pre- and post-operative clinical evaluation was done using the Constant-Murley score and the SST from Matsen.
There is no glenoid loosening, no joint narrowing and no radiolucent line. There was no bone graft osteolysis. With 4 patients revised (4 conversions from TSR to RSR for 3 instabilities and 1 secondary rotator cuff tear), on the overall 30 patients cohort, Constant score pain increased from 1.6 to 13.4, forward flexion from 92° to 146° and Constant score from 27 (36 %) to 70 (95 %). The statistical difference between pre- and post-operative values is greatly significant.
Although MB prostheses have been noted to have a higher rate of loosening than full-cemented PE, this is not our experience, even in case of glenoid type B2 or C, where the technical challenge is demanding and most of the time a posterior bone graft is necessary.