Three dimensional movement analysis of the upper limb during activities of daily living, in children with obstetric brachial plexus palsy: comparison with typically developing children

Residual shoulder dysfunction and deformity impacts on functional performance in children with obstetric brachial plexus palsy (OBPP). Clinical understanding of dynamic movement patterns of the upper limb is difficult with observation alone. Three-dimensional gait analysis has contributed significantly to understanding and management of gait dysfunction. In contrast, upper limb kinematic analysis is in its infancy due to the inherent challenges it presents. The aims of this study were to: determine test-retest reliability of three-dimensional upper limb motion analysis (3D-ULMA) in children with OBPP while performing functional tasks; determine its ability to identify discriminative upper limb spatiotemporal and kinematic characteristics between children with OBPP and typically developing children (TDC).

The test-retest reliability study of ten children with OBPP (mean 10 years, range 7-15 years, Narakas classification I-III) demonstrated inconsistent reliability. Despite this finding, as the first study to provide details of measurement error in this population it allowed more accurate interpretation of the variables analysed in the case-control study. The case-control study, involving 11 participants with OBPP and 10 TDC (mean 9 years 9 months, range 6-15 years), found that 3D-ULMA could characterise kinematic differences between children with OBPP and TDC while performing functional tasks. Children with OBPP demonstrated reduced external rotation in all tasks combined with reduced active control of internal rotation. Reduced glenohumeral joint motion was the main contributor to impaired function and altered scapulohumeral rhythm in children with OBPP.This finding emphasises the importance of maintaining glenohumeral joint integrity through available therapeutic and surgical interventions. A significant reduction in forearm supination was also found which concurred with previous research.

Future kinematic studies in children with OBPP should subgroup according to age and severity of involvement; examine timing of scapulothoracic joint motion and analyse thorax and neck motion.