We describe the early results of glenoplasty as part of the technique of operative reduction of posterior dislocation of the shoulder in 29 children with obstetric brachial plexus palsy. The mean age at operation was five years (1 to 18) and they were followed up for a mean of 34 months (12 to 67). The mean Mallet score increased from 8 (5 to 13) to 12 (8 to 15) at final follow-up (p <
0.001). The mean passive forward flexion was increased by 18° (p = 0.017) and the mean passive abduction by 24° (p = 0.001). The mean passive lateral rotation also increased by 54° (p <
0.001), but passive medial rotation was reduced by a mean of only 7°. One patient required two further operations. Glenohumeral stability was achieved in all cases.