Review Question - QID 214867

This patient has a lateral condyle nonunion. The family should be counseled about the potential to develop a slowly progressive ulnar nerve palsy.

Lateral condyle fractures are the second most common fracture in the pediatric elbow and are characterized by a higher risk of nonunion, malunion, and AVN than other pediatric elbow fractures. Diagnosis is made with plain elbow radiographs. Treatment may be nonoperative or operative depending on the degree of articular displacement. Indications for conservative management with the use of a long-arm cast includes < 2 mm displacement in all views and a medial cartilaginous hinge that remains intact; other fractures meet surgical indications. Cubitus valgus ± tardy ulnar nerve palsy may occur due to lateral physeal arrest or more commonly a nonunion; this is often a slow, progressive ulnar nerve palsy caused by stretch. This has an incidence of approximately 10% and may be treated with a supracondylar osteotomy after skeletal maturity and ulnar nerve transposition.

Toh et al. reviewed patients with nonunion of a fracture of the lateral humeral condyle. They report that disabling symptoms only rarely developed in nonunions that result from a Milch Type-II injury, while pain, instability, loss of range of motion, and ulnar nerve dysfunction are more common in nonunions resulting from a Milch Type-I injury. They concluded that a nonunion of a Milch Type-I fracture should be treated as soon as possible after injury, preferably before the patient reaches skeletal maturity.

Shimada et al. reviewed the results of osteosynthesis for the treatment of an established non-union of the lateral humeral condyle in sixteen children whose average age was nine years at the time of the operation. They reported dysfunction of the ulnar nerve in four patients. They concluded that the result was rated excellent in eight patients, good in seven, and poor in one; the patient who had a poor result had evidence of avascular necrosis of the fragment.

Figures A&B are the radiographs of a chronic nonunion of a humeral lateral condyle fracture. Illustration A depicts the Milch classification.

Incorrect Answers:
Answer 1: This patient has preserved elbow motion so disuse osteopenia of the ulnohumeral joint is unlikely
Answer 2: While lateral ligament instability is associated with these injuries, they often present at the time injury and are unlikely to progress to having gross instability. Moreover, her clinical examination suggests no evidence of instability
Answer 4: LATERAL overgrowth/prominence (spurring) is seen in up to 50% of patients regardless of treatment and families should be counseled in advance
Answer 5: There is no described association between lateral condyle nonunion and triceps insufficiency