The Outerbridge-Kashiwagi (O-K) procedure has traditionally been used for the management of elbow osteoarthritis and posttraumatic sequelae, including posttraumatic arthritis, stiffness, contracture, and ulnar neuritis. The Outerbridge-Kashiwagi procedure involves exposure of the posterior elbow joint and the creation of a window posteriorly through the olecranon fossa to target anterior aspects of the elbow. Osteophyte formation on the olecranon, olecranon fossa, and coronoid may result in impingement and pain. Fenestration of the olecranon fossa allows for removal of loose bodies and osteophytes in the anterior and posterior compartments of the elbow without extensive soft-tissue dissection. The Outerbridge-Kashiwagi procedure is associated with favorable outcomes, resulting in good functional outcomes with minimal complications. Used mostly for the surgical management of adult osteoarthritis, the Outerbridge-Kashiwagi procedure has not been previously described for the management of pediatric supracondylar humerus fracture malunions. This video presents the pearls of and discusses the technique for the Outerbridge-Kashiwagi procedure for the management of an extension malunion of a pediatric supracondylar fracture resulting in anterior heterotopic bone formation and a subsequent block to elbow flexion.