Changes in Shoulder Rotation Based on Elevation in Children With Brachial Plexus Birth Injury

Area of Science:

• Pediatric Orthopedics
• Biomechanics
• Rehabilitation Medicine

Background:

• Lack of shoulder external rotation is a common complication in children with brachial plexus birth injuries.
• Glenohumeral (GH) dysplasia can develop, associated with progressive loss of passive external rotation.
• Current measurement techniques for shoulder rotation vary, with some advocating for arm adduction and others for 90° abduction.

Purpose of the Study:

• To compare active and passive shoulder external and internal rotation measurements.
• To evaluate these rotations in both adducted and abducted arm positions.
• To determine the optimal method for assessing shoulder range of motion in this population.

Main Methods:

• Fifteen children with brachial plexus birth injuries participated.
• Maximal active and passive internal/external rotation were measured in both adducted and 90° abducted arm positions.
• Three-dimensional motion capture analyzed scapulothoracic (ST) and glenohumeral (GH) joint angles using repeated measures ANOVA.

Main Results:

• Glenohumeral external rotation was significantly greater in abduction compared to adduction, both actively and passively.
• No significant differences were found in active or passive scapulothoracic rotation between adduction and abduction.
• Passive GH rotations were significantly greater than active GH rotations.

Conclusions:

• Shoulder rotation measurements are not interchangeable between adduction and abduction positions.
• Comprehensive assessment must include both adduction and abduction to accurately evaluate shoulder range of motion.
• Failure to measure in adduction may lead to missed early GH joint dysplasia in children with brachial plexus birth injuries.