Immobilization in external rotation after primary shoulder dislocation reduces the risk of recurrence in young patients. A randomized controlled trial

Abstract

Introduction: Patients that sustain anterior shoulder dislocation frequently experience recurrence. Immobilisation in external rotation has been proposed as a treatment that could lower this risk.

Hypothesis: There is a difference in recurrence rates between immobilization in internal or external rotation following a first-time anterior shoulder dislocation.

Patients and methods: Single-center randomized controlled trial. Fifty patients with a first episode of traumatic anterior dislocation were randomly assigned to immobilization in internal rotation (IR; 25 patients) or external rotation (ER; 25 patients) for three weeks. Clinical follow-up: 24 months. Additionally, some patients underwent a magnetic resonance imaging with intra-articular contrast (MR arthrography) within seven days after trauma, and then at three months.

Primary outcome: recurrence of dislocation. Secondary outcome: healing rate of labral lesions on MR arthrography.

Results: Follow-up rate in the IR and ER group was 92% and 96% respectively. Recurrence rate did not show a statistically significant difference overall (IR 47.8% vs. ER 29.2%; p=0.188), but showed a significant difference favouring ER in the 20-40 years subgroup (IR 50% vs. ER 6.4%; p=0.044). Labral lesions' healing rate was 46.2% vs. 60% (IR vs ER; p=0.680). The recurrence rate among those with healed vs. non-healed labrum (regardless of immobilization) was 11.1% vs. 77.7% (p=0.001).

Discussion: This study suggests that immobilization in ER compared to IR reduces the risk of recurrence after a first-time anterior shoulder dislocation in patients aged between 20 and 40 years.

Level of evidence: II, low-powered prospective randomized trial.

Keywords: (MeSH) Shoulder dislocation; (Non MeSH) Internal rotation; Conservative treatment; External rotation; Randomized controlled trial; Recurrence.