Trochlear deformities in children after trauma have been reported after fracture of the distal humerus. Controversy exists as to their etiology and natural history. This reports consists of a cohort of 18 children with deformities of the trochlea after a distal humerus fracture. Injuries were classified as either a Salter-Harris II (transcondylar or transphyseal) in 12, a supracondylar in 5, and a Salter-Harris IV (lateral condylar) in 1. Nine patients underwent ORIF, 6 closed reduction and pinning, and 3 closed reduction alone. X-ray findings indicative of trochlear problems were evident at a mean of 3.4 months after surgery (range, 1-11 months). Clinically, the deformity manifested as a decrease in the carrying angle, ranging from 2 to 18 degrees. Eight patients underwent MR imaging, which revealed a low-signal intensity (T2) in the region of the medial defect. The articular surface remained smooth and intact. Bar formation was not observed. Intermediate (< 10 years) and long-term (> 10 years) follow-up revealed no progression of the cubitus varus and improvement in the x-ray findings.
This study presents interesting data regarding trochlear defects after distal humerus fractures. First, it shows that the defect can be recognized early and may be related to a vascular insufficiency. Second, the overlying articular surface remains intact and provides promise for recovery after transient vascular compromise. Third, a cubitus varus deformity develops and usually remains consistent over time. This stagnation offers promise for early corrective osteotomy. Most importantly, this entity of temporary ischemia must be differentiated from profound avascular necrosis or physeal bar formation, which is often progressive and unrelenting.
Journal of Pediatric Orthopaedics