Spontaneous recovery of shoulder abduction in obstetric brachial plexus injury patients with less than horizontal abduction at 3 months.

Abduction is one of the important shoulder functions that may be limited after an obstetric brachial plexus injury. We investigated the progress of spontaneous recovery of active abduction in a cohort of 68 conservatively treated obstetric brachial plexus injury patients without full recovery and with less than 90° abduction at 3 months. Of these 65 (96%) recovered at least 90° and 32 (47%) a full 170° of abduction. The median age of recovery to 90° was 9 months (IQR 7-12, range 5-65 and to 170° 24 months (IQR 12-36, range 5-84). The presence of active antigravity elbow flexion ≥90° at 4 months was not associated with recovery of abduction. The results suggest that most obstetric brachial plexus injury patients with isolated absent or slowly recovering shoulder movements recover at least 90° of abduction. In patients with absent or weak abduction, and otherwise satisfactory spontaneous recovery, surgical interventions should not be considered before 1 year of age.Level of evidence: III.