From a database of all RTSA performed by the senior author, shoulders with a Delta III-type prosthesis and minimum 12-month follow-up (71 shoulders) were included. Notching in shoulders with neutrally placed glenosphere base plates (Group 1) was compared to notching with 10-15° inferiorly tilted base plates (Group 2). The prosthesis-scapular border angle (PSBA) was also defined and used to determine whether the radiographically quantified amount of inferior tilt was predictive of scapular notching independent of group assignment.
There were no significant differences in the grade of notching or incidence of notching between groups 1 and 2 after adjusting for length of follow-up and prosthesis selection. The PSBA was also not predictive of scapular notching.
Despite previous biomechanical studies’ predictions that inferiorly tilting the glenosphere might reduce inferior scapular neck impingement and subsequent scapular notching, our data showed no difference at 1-year follow-up.