Forearm rotational profile in obstetric brachial plexus injury

Children with obstetric brachial plexus palsy (OBPP) most commonly have weakness of supination. There is little previous information on later progress of forearm rotation movements, although severe supination contracture has been reported in a small proportion of children. The aims of this study were to evaluate forearm rotation after initial recovery from OBPP, to define the relationship with the severity of disease, and to assess which factors might limit rotation. Measurements of active and passive pronation and supination were recorded in 56 children (37 boys and 19 girls) who had had OBPP and did not have full recovery. The mean age was 8 years (minimum, 2.5 years). Care was taken to measure forearm rotation in isolation from shoulder movements. According to the Narakas classification for severity of the original brachial plexus lesion, there were 23 group I cases, 16 group II cases, 11 group III cases, and 6 group IV cases. Twenty-one children underwent reconstructive procedures for shoulder deformity. Mallet scores for shoulder function were available for all patients. Overall pronation was more limited than supination. Active movements were more limited than passive movements. Active pronation was less than normal in 48 children, active supination was less than normal in 36, passive pronation was less than normal in 22, and passive supination was less than normal in 9. Active pronation and active and passive supination were significantly limited in children with worse Mallet scores and in Narakas group IV children. Both active supination and passive supination were decreased in children with more severe elbow flexion contractures. No significant relationship was found between forearm rotation movements and the time of biceps recovery. Many children have persisting limitation of forearm rotation after OBPP. Despite the initial weakness of supination, pronation is more often reduced in the longer term. Patients with more severe OBPP and poorer recovery of shoulder function have greater limitation of forearm rotation.