Reduced Clavicle Length Indicates the Severity of Scapular Misalignment in Obstetric Brachial Plexus Lesions

(1) Background: Although most brachial plexus birth palsies show some spontaneous recovery, secondary operations are likely to follow. Accordingly, due to the loss of muscle innervation, the growth of the affected limb and the shoulder girdle is reduced. This is associated with pathological scapula positioning and rotation. The objective of this work was to clarify the relationship between length differences of the two clavicles and different types of scapular dyskinesia. (2) Methods: Twenty-five patients suffering from brachial plexus birth palsy were included in this retrospective study. There were eighteen female and seven male patients with a mean age of 10 years (2 to 23 years). CT scans of the thoracic cage, including both shoulder joints and both clavicles, were obtained preoperatively between 2010 and 2012. Radiographic measurements were taken of the axial plane and 3D reconstructions were produced. Functional evaluations of possible movement and scapular dyskinesia were performed. (3) Results: We found an increasing difference in the length of the clavicle (both in absolute and relative terms) in the children with more pronounced scapular dyskinesia. Additionally, with increasing clavicle length differences, the scapula was positioned in a deteriorated angle compared to the healthy side. Significant positive correlations were identified for the age and absolute difference of the clavicle length and the length and width of the scapula on the affected side. (4) Conclusion: Scapular dyskinesia, which is a common finding in brachial plexus birth palsy, is strongly related to reduced clavicle growth. Reduced clavicle length (which is a relatively easily examinable parameter) compared to the healthy side can be used to estimate the extent of scapular malpositioning on the thoracic cage. The extent and severity of scapular dyskinesia increases with augmented differences in the length of the clavicle.