Pseudodefect of the capitellum: potential MR imaging pitfall.
OBJECTIVE
To describe the pseudodefect of the distal humerus at the junction of the capitellum and lateral epicondyle, which may simulate an osteochondral lesion on axial and coronal magnetic resonance (MR) images.


METHODS
MR imaging studies of the elbow in 32 patients and 22 asymptomatic volunteers were retrospectively reviewed. Thirty-two human humeri were also examined for normal anatomy of the junction of the capitellum and distal humerus.


RESULTS
Twenty-two of the clinical MR examinations and 14 of the studies on volunteers revealed the presence of the pseudodefect. A groove at the junction and the overhanging lateral edges of the capitellum account for the appearance of this pseudolesion.


CONCLUSIONS
Familiarity with the characteristic appearance and location of this pseudodefect will prevent its misinterpretation as an osteochondral fracture of the distal humerus.
Rosenberg
Z S
ZS
Department of Radiology, Hospital for Joint Diseases, New York, NY 10003.
Beltran
J
J
Cheung
Y Y
YY
D000293:Adolescent; D000328:Adult; D001847:Bone Diseases / Q000175:diagnosis; D003937:Diagnosis, Differential; D004551:Elbow Joint / Q000473:pathology*; D005260:Female; D006801:Humans; D006810:Humeral Fractures / Q000175:diagnosis; D006811:Humerus / Q000033:anatomy & histology / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies