The radiographs shows a coronal shear fracture of the capitellum with extension into the trochlea, which would be classified as a Type IV fracture under the Bryan and Morrey classification system which was modified by McKee to include this specific injury. The lateral radiograph in Figure B and Illustration A is an example of the "double bubble" sign representing an injury to both the trochlea and capitellum. The treatment of choice for a displaced Type IV fracture is open reduction internal fixation.
Dushuttle et al demonstrated that absence of the capitellum did not lead to valgus instability unless the medial collateral ligament was injured, suggesting that excision of highly comminuted fractures could be performed.
The reference by Grantham et al looked at a series of capitellum fractures and recommended the choice of treatment should be selective and individualized depending on age, character of the bone, and type of fracture.
McKee et al in their case review described this coronal injury pattern and their results for ORIF of these fractures.
Paul Tornetta, III, MD, and Michael Baumgaertner, MD, Editors. Orthopaedic Knowledge Update: Trauma 3. Amer Academy of Orthopaedic; 3 edition (July 31, 2005).
Dushuttle RP, Coyle MP, Zawadsky JP, Bloom H. Fractures of the capitellum. J Trauma. 1985 Apr;25(4):317-21.
PMID:3989889 (Link to Abstract)
Grantham SA, Norris TR, Bush DC. Isolated fracture of the humeral capitellum. Clin Orthop Relat Res. 1981 Nov-Dec;(161):262-9.
PMID:7307389 (Link to Abstract)
McKee MD, Jupiter JB, Bamberger HB. Coronal shear fractures of the distal end of the humerus. J Bone Joint Surg Am. 1996 Jan;78(1):49-54.
PMID:8550679 (Link to Abstract)