Immobilisation in external rotation after first-time traumatic anterior shoulder instability reduces recurrent instability: a meta-analysis.

IMPORTANCE: Cadaveric and MRI findings have demonstrated significantly less labral separation and displacement when the shoulder is placed in external rotation as compared with internal rotation.

OBJECTIVE: The purpose of the current study is to meta-analyse the randomised controlled trials in the literature to compare immobilisation in external versus internal rotation after first-time anterior shoulder dislocation.

EVIDENCE REVIEW: A literature search of MEDLINE, EMBASE and the Cochrane Library was performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomised controlled trials comparing immobilisation in external rotation versus internal rotation for first-time anterior shoulder dislocation were included.

FINDINGS: Nine randomised controlled trials with 795 patients were included. The mean age of included patients was 29 years, 82.4% were male and the mean follow-up was 25.5 months. As compared with immobilisation in internal rotation, compliance was significantly higher (74.5% vs 67.4%, p=0.01), and the rate of recurrent dislocations was significantly lower (22.2% vs 33.4%, p=0.02) with immobilisation in external rotation. Additionally, in patients 20-40 years old the rate of recurrent dislocations was significantly lower in those treated with immobilisation in external rotation than internal rotation (12.1% vs 31.4%, p=0.006). Immobilisation in external rotation also resulted in a higher rate of return to preinjury level of play (60.1% vs 42.6%, p=0.0001).

CONCLUSIONS AND RELEVANCE: Immobilisation of the shoulder in external rotation after a traumatic first-time anterior shoulder dislocation results in a higher compliance rate, a lower recurrent dislocation rate and a higher rate of return to play as compared with immobilisation in internal rotation.

LEVEL OF EVIDENCE: Level I.