Long-term outcomes of open modified inferior capsular shift for traumatic anterior shoulder instability: over 20 years of follow-up

Abstract

Background: This study aimed to assess the long-term outcomes of the open modified inferior capsular shift procedure across more than 20 years in patients with traumatic anterior shoulder instability.

Methods: Participants in this study comprised 84 patients (86 shoulders; 67 men, 17 women). Mean follow-up was 28.0 years. We compared the recurrent instability rate after surgery, apprehension, revision rate, satisfaction, return to preinjury sporting activity, and patient background characteristics between recurrent and nonrecurrent groups. Twenty-seven patients who were examined directly were evaluated for differences in range of motion and muscle strength between affected and nonaffected sides. Clinical outcome scores used for this study were the Western Ontario Shoulder Instability Index and the Rowe score.

Results: Nine shoulders (10.5%) showed recurrent instability, as dislocation in 3 shoulders and subluxation in 6 shoulders, but no revisions were required. All patients with recurrent instability were males with new trauma. Three shoulders developed recurrent instability ≤5 years after surgery, and the remaining 6 shoulders showed recurrent instability >5 years after surgery. No significant differences in any patient characteristic were identified between the recurrent and nonrecurrent groups. Significant differences between affected and nonaffected sides were seen in the mean active range of motion or muscle strength for external rotation in the anatomic position or in 90° of abduction. Western Ontario Shoulder Instability Index and Rowe score were significantly worse in the recurrent group than in the nonrecurrent group. Patients reported that 84 shoulders (97.7%) were "much better." Most athletes (88.4%) had returned to sports activity at a level >70%.

Conclusion: We investigated long-term outcomes of the open modified inferior capsular shift procedure for traumatic anterior shoulder instability. Our data suggest that recurrent instability might result from new trauma even if a long time has passed since the open modified inferior capsular shift procedure, so follow-up should be continued as long as possible after surgery. As in other reports, satisfaction was high and clinical scores were good. We thus believe this surgical method offers good results even after more than 20 years.

Keywords: Shoulder instability; Western Ontario Shoulder Instability Index; long-term outcome; modified inferior capsular shift procedure; open procedure; traumatic instability.