Summary

Recurrent shoulder instability compared to primary instability was associated with higher rates of clinically important secondary injuries. Glenoid bone loss was more frequent in patients with 5 o more episodes and capsular laxity higher in patients with 2 or more episodes. Recurrence rate was 10.9% with minimum follow-up of 12 months (mean=33 m) and no differences among groups.

Abstract

Introduction

Anterior labrum disruption is the primary lesion that occurs when anterior shoulder dislocation happens. Other osseous and soft tissue injuries can be associated with the initial trauma as well. Consecutive instability episodes could generate or worsen these secondary injuries and alter surgical treatment and clinical results. Hypothesis: Instability episodes may generate and/or worsen secondary injuries associated with recurrent shoulder instability.

Objective

To compare secondary injuries in patients treated after first shoulder dislocation vs recurrent instability. To evaluate recurrent rates in these groups.

Methods

Retrospective, cohort study of patients with shoulder instability and surgical treatment. Group A, included patients treated after the first episode of anterior shoulder dislocation, Group B those with 2 to 4 episodes and Group C, those who suffered 5 or more episodes before surgery. Glenoid bone loss, chronic bony Bankart, HAGL lesions, Hill-Sachs off-track and complete cuff tears were considered clinically important secondary injuries. The 3 groups were compared. For continuous numeric variables ANOVA test was used and Chi-square or Fisher´s test for categorical variables. P values < .05 were considered statistically significant.

Results

One hundred and eighty-seven patients with anterior traumatic shoulder dislocation were included in this study. Patients demographics showed no statistically significant differences. Bony Bankart (p=0,44), Posteroinferior labrum tears (p=0,86), SLAP tears (p=0,55, ALPSA (p=0,38), Hill-Sachs (p=0,99) and anatomic variants (p=0,72) showed similar prevalence. The relationship between glenoid bone loss and number of episodes was statistically significant (p<0,01). Clinically important secondary injuries and capsular laxity also showed a significant association with number of episodes (p=0,02) and (p<0,01). Recurrence rate of patients with 1 year minimum follow-up was 10.9%, with no statistically significant difference among groups (p=0,52).

Conclusions

In this study, recurrent shoulder instability compared to primary instability was associated with higher rates of clinically important secondary injuries. Glenoid bone loss was more frequent in patients with 5 o more episodes and capsular laxity higher in patients with 2 or more episodes. Recurrence rate was 10.9% with minimum follow-up of 12 months (mean=33 m) and no differences among groups.