Does the position of shoulder immobilization after reduced anterior glenohumeral dislocation affect coaptation of a Bankart lesion? An arthrographic comparison

BACKGROUND: The position of immobilization after anterior shoulder dislocation has been a controversial topic over the past decade. We compared the effect of post-reduction immobilization, whether external rotation or internal rotation, on coaptation of the torn labrum. MATERIALS AND METHODS: Twenty patients aged <40 years with primary anterior shoulder dislocation without associated fractures were randomized to post-reduction external rotation immobilization (nine patients) or internal rotation (11 patients). After 3 weeks, magnetic resonance arthrography was performed. Displacement, separation, and opening angle parameters were assessed and analyzed. RESULTS: Separation (1.16 ± 1.11 vs 2.43 ± 1.17 mm), displacement (1.73 ± 1.64 vs 2.28 ± 1.36 mm), and opening angle (15.00 ± 15.84 vs 27.86 ± 14.74 °) in the externally rotated group were decreased in comparison to the internally rotated group. A statistically significant difference between groups was seen only for separation (p = 0.028); p values of displacement and opening angle were 0.354 and 0.099, respectively. CONCLUSION: External rotation immobilization after reduction of primary anterior shoulder dislocation could result in a decrease in anterior capsule detachment and labral reduction. LEVEL OF EVIDENCE: Level 2.