Baseplate version in reverse shoulder arthroplasty: does excessive retroversion or anteversion affect functional...

While bone grafting and augmented components can help restore reverse shoulder arthroplasty (RSA) baseplate version close to neutral, the indication for version correction in RSA is unclear. The purpose of this study was to compare the clinical outcomes of RSA baseplates in high degrees of retroversion and anteversion to components in more neutral version.

Patients who underwent RSA with minimum two year follow-up were identified from an institutional registry. An RSA system with a glenosphere that is two-thirds of a sphere was utilized. Post-operative radiographs were used to determine baseplate version, and patients were grouped into four categories: ≥ 10 degrees (moderate to severe anteversion; n = 14), 10 to -10 degrees (neutral; n = 69), -10 to -20 (moderate retroversion; n = 25), and ≤ -20 degrees (severe retroversion; n = 7). The outcomes of interest were ability to perform functions requiring internal rotation, external rotation and cross-body adduction, as well as complications and revisions.

There were no differences in final Simple Shoulder Test (SST), final American Shoulder and Elbow Surgeons score (ASES) or change in SST from pre- to post-operative across the four version groups. There was no linear correlation between baseplate version and final SST. There were no statistically significant differences in difficulty performing tasks related to internal rotation, external rotation, and cross-body adduction among the four baseplate version groups; however, patients with moderate to severe anteversion had a greater frequency of difficulty putting on a coat (86%) compared to patients with neutral version (42%), moderate retroversion (45%) and severe retroversion (0%) (p = 0.021). There were no differences in rates of complications and revisions across the four groups.

This study did not find evidence that high values of baseplate retroversion or anteversion were associated with inferior patient reported outcomes or functional rotation after reverse total shoulder arthroplasty.

Level 3, retrospective comparative study.