Infantile dislocation of the elbow complicating obstetric palsy.

This is a report of three cases of complete dislocation of both the radius and ulna at the elbow in infants born with obstetric palsy. All three patients had painless elbow-flexion contractures. The pathologic anatomy included (a) medial and posterior displacement of the radius and ulna on the humerus, (b) laxity of the lateral capsule and collateral ligaments, (c) contracted medial capsule and collateral ligaments, (d) contracted biceps and triceps muscles, and (e) hypoplasia of the capitellum, trochlea, coronoid process, and olecranon fossa. Open reduction was attempted in all three of these patients and was successful in two.