Lateral condylar fracture of the humerus following posttraumatic cubitus varus.

Posttraumatic cubitus varus is widely regarded as just a cosmetic deformity. Six cases of lateral condylar fracture of the humerus in children with preexisting cubitus varus due to prior elbow fracture are presented. Five occurred following malunited extension-type supracondylar fractures of the humerus; the other occurred following a lateral condylar fracture complicated by lateral overgrowth. All cases were treated by anatomic reduction (two closed, four open) and percutaneous pinning of the lateral condylar fracture. Three of the six cases subsequently underwent supracondylar osteotomy of the distal humerus to correct the underlying varus malalignment. Biomechanical analysis suggests that both the torsional moment and the shear force generated across the capitellar physis by a routine fall are increased by varus malalignment. Posttraumatic cubitus varus may predispose a child to subsequent lateral condylar fracture and should be viewed as more than just a cosmetic deformity.