Cut-off values of internal rotation in the glenohumeral joint for functional tasks in children with brachial plexus birth injury.

The aim of this study was to determine the cut-off values of the range of internal rotation motion in the isolated glenohumeral joint that is required for functional tasks in children with an upper root injury of the brachial plexus. Internal rotation motion was measured using a universal goniometer in 97 participants. The Mallet Hand to Spine and Mallet Hand to Belly tasks were assessed as functional tasks that require internal rotation of the shoulder. For the Hand to Spine task, 41° passive and 30° active internal rotation were necessary to reach the S1 level. For the Hand to Belly task, 42° passive and 29° active internal rotation were required to place the palm on the belly without wrist flexion. Of our participants, 97% could touch the belly with or without wrist flexion, but 28% could not reach S1 in the Hand to Spine task. The results of this study show the necessary amount of internal rotation of the shoulder that should be considered in treatment strategies. Level of evidence: III.