Secondary gleno-humeral joint dysplasia in children with persistent obstetric brachial plexus palsy

Abstract

The study aimed to evaluate the degree of gleno-humeral joint deformation in children with persistent obstetric brachial plexus palsy and its effect on limb function. Computer tomography was performed in 24 children in the mean age of 6.1 years. There were eight boys and 16 girls. Gleno-scapular angle, congruency of gleno-humeral joint and joint deformity according to Waters at all. criteria were measured. The mean functional score according to the Mallet classification system was 12.3 points. The joint was stabile in nine, subluxed in seven and dislocated in nine cases. Gleno-scapular angle in affected joints was 23.3 degrees and in non-affected 4.5 degrees. The glenoid was statistically more retroverted in older children. With more severe posterior incongruence there was statistically greater limitation of passive external rotation, active internal rotation and a poorer functional result according to Mallet. Abnormalities were found also in the humeral head, being deformed and smaller compared to the non-affected side in all cases. Glenoid retroversion, posterior subluxation/dislocation of humeral head and smaller humeral head size are the abnormalities, most often identified in CT examinations. Shoulder function and in particular, passive, external rotation are closely associated with the degree of deformity of the glenoid, as well as with the extent of posterior humeral head dislocation.

Fig. 1

Measurement method of gleno-scapular angle (α) and translation of humeral head. Percentage of dislocation of humeral head was measured according to the formula AB/AC x 100%

Fig. 2

a, b Computer tomography image in horizontal plane and 3D reconstruction with removal of acromions, coracoid process and distal part of clavicules of a ten-year-old boy. On the affected right side, severe deformity of glenoid and humeral head. Humeral head is additionally displaced in posterior direction

Fig. 3

Computer tomography image of both shoulders in an eight-year-old boy. On the right side, the humeral head is smaller, deformed and displaced in the posterior direction. The glenoid is convex and rertroverted because of deficiency of its posterior part

Graph 1

Correlation between congruency of gleno-humeral joint and functional score according to Mallet classification