Age / Sex : 21 / M

Chief complaint : left knee pain due to R/O) meniscus injury

What is your diagnosis?


Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).

Courtesy: 김선기 (Sun Ki Kim), 가톨릭대학교 인천성모병원(Incheon St. Mary’s Hospital, The Catholic University of Korea)

Dorsal defect of the patella

Discussion

Findings

 X-ray : Circumscribed lytic lesion surrounded by a sclerotic rim in the  

 superolateral quadrant of the left patella.

MRI :  Focal dimple and fissure of the subchondral bone with intact overlying cartilage at the superior aspect of lateral patellar facet.

1.Osteochondritis dissecans

2.Patellar osteoid osteoma

1.Van Holsbeeck M, Vandamme B, Marchal G, et al. Dorsal defect of the patella: concept of its origin and relationship with bipartite and multipartite patella. Skeletal Radiol. 1987;16(4):304–11.

2.Safran MR, McDonough P, Seeger L, Gold R, Oppenheim WL. Dorsal defect of the patella. J Pediatr Orthop. 1994;14:603–607.