Abstract
Objectives:
To evaluate differences in acromial morphology between patients undergoing primary and revision arthroscopic stabilization for posterior shoulder instability.
Methods:
A series of patients who underwent either primary or revision arthroscopic stabilization for posterior shoulder instability between 2001 and 2022 were identified. Primary and revision patients were matched based on age, gender, and sport (contact/throwing). Patient demographics were collected, and acromial morphology was evaluated in both groups using previously described MRI parameters including posterior acromial tilt (PAT), anterior acromial coverage (AAC), posterior acromial coverage (PAC), and posterior acromial height (PAH). Continuous variables were compared between groups using a two-tailed Student’s t-test.
Results:
Seventeen patients who underwent revision posterior shoulder stabilization during the study period were identified and matched to 17 patients who underwent primary posterior shoulder stabilization. Mean ages of the primary and revision patients at the time of initial surgery were 18.1 (±3.5; 13-27) and 18.6 (±4.3; 12-29), respectively (p = 0.66). Males comprised 35% of each group. Mean PAT in the primary and revision groups was 50.76° (±9.51) and 50.29° (± 7.47) (p = 0.88), while mean PAH was 13.34 mm (±6.50) and 15.25 mm (±4.75) (p = 0.35), respectively. Mean AAC in the primary and revision groups was 8.18° (±7.73) and 10.35° (±9.50) (p = 0.48), while mean PAC was 70.59° (±9.26) and 65.94° (±6.78) (p = 0.12), respectively.
Conclusions:
Measurements of acromial morphology including posterior height, tilt, and coverage were not significantly different in a case matched cohort of patients undergoing primary vs. revision arthroscopic posterior shoulder capsulolabral repair. Prior studies have demonstrated that a “higher and flatter” acromion may predispose patients to posterior shoulder instability; however, this does not appear to affect the risk of failure of arthroscopic posterior capsulolabral repair.