Effects of humeral component retroversion on functional outcomes in reverse total shoulder arthroplasty for cuff tear arthropathy.

Abstract

The currently recommended 0° to 30° humeral component retroversion angle for reverse total shoulder arthroplasty (RTSA) is based on expert opinion rather than anatomical or clinical evidence. Sixty-two patients who underwent RTSA for cuff tear arthropathy were reviewed retrospectively. The humeral component was inserted with 20° retroversion in 30 patients (group A) and with 0° retroversion in 32 (group B). The mean age at the time of operation was 66.2 years and 68.9 years, and the mean follow-up period was 43.3 months and 38.4 months in groups A and B, respectively. At the last follow-up, external rotation at the side was 47.2° ± 8.4° in group A and 43.9° ± 7.0° in group B, whereas internal rotation to the posterior was L3 and L2, respectively (P = .102 and P = .092). The ranges of motion between the 2 groups at the last follow-up were not significantly different. Most daily movements related to activities of daily living showed no significant differences between the 2 groups, with the exception of back washing/back doing up bra (1.5 ± 1.2 in group A vs 2.1 ± 0.8 in group B of 3 points, P = .026). Range of motion after RTSA did not significantly differ between 20° and 0° humeral component retroversion angle. Most daily movements did not differ between the 2 groups, but patients in the 0° retroversion angle group scored better on activities related to internal rotation.