Evaluating displacement of the coracoacromial ligament in painful shoulders of overhead athletes through dynamic ultrasonographic examination

Abstract

Objective: To evaluate displacement of the coracoacromial ligament (CAL), using dynamic ultrasonography (US), for detecting instability-related impingement caused by overhead activities.

Design: Between-group survey.

Setting: Department of Physical Medicine and Rehabilitation in a tertiary care center.

Participants: Volunteer high school volleyball players with unilateral shoulder pain (n=10) and volunteer asymptomatic high school volleyball players with identical training activities as control subjects (n=16).

Interventions: Not applicable.

Main outcome measure: The displacement of the CAL was measured during throwing simulation using dynamic US. Both shoulders of all subjects were evaluated.

Results: During throwing simulation, the displacement of the CAL in the painful shoulders of overhead athletes increased significantly greater than the displacement in the asymptomatic shoulder (3.0+/-0.7 mm and 2.2+/-0.4 mm, respectively; P=.017). No difference was identified between the displacements of the CALs of bilateral shoulders of the control group subjects.

Conclusions: Dynamic US, by measuring the displacement of the CAL during simulation of throwing, may be helpful in detecting abnormal humeral head upward migration in overhead athletes.