Dorsal defect of the patella
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At the time the article was created Mohammad Taghi Niknejad had no recorded disclosures.
View Mohammad Taghi Niknejad's current disclosuresAt the time the article was last revised Mostafa Elfeky had no financial relationships to ineligible companies to disclose.
View Mostafa Elfeky's current disclosures- Dorsal defect of patella
Dorsal defects of the patella are benign subchondral lesions of unknown etiology and a normal developmental anomaly of the patella, which can be mistaken for a pathological process such as a focus of infection or osteochondritis dissecans.
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Epidemiology
Dorsal defect of patella occurs in males and females with equal frequency and is most frequently found in adolescents. It is bilateral in up to one-third of individuals.
Clinical presentation
This condition often is asymptomatic and an incidental finding on knee imaging, but it occasionally may be the cause of knee pain.
Radiographic features
Plain radiograph and CT
A rounded focus of radiolucency surrounded by a sclerotic margin in the superolateral quadrant of the patella.
MRI
On MR, this defect is similar to many other bony lesions:
- T1: low signal
- T2: high signal
Notably, the lesion has a sclerotic rim and is usually not associated with marrow edema, although this has been very rarely reported 7. The overlying cartilage is usually but not always intact 7.
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Treatment and prognosis
A dorsal defect of the patella is one of the skeletal "do not touch" lesions, therefore because of its characteristic location, it should not undergo biopsy.
Differential diagnosis
-
osteochondritis dissecans
- typically inferomedial 7
- articular cartilage involvement
Related pathology
Quiz questions
References
- 1. Safran M, McDonough P, Seeger L, Gold R, Oppenheim W. Dorsal Defect of the Patella. J Pediatr Orthop. 1994;14(5):603-7. doi:10.1097/01241398-199409000-00009 - Pubmed
- 2. van Holsbeeck M, Vandamme B, Marchal G, Martens M, Victor J, Baert A. Dorsal Defect of the Patella: Concept of Its Origin and Relationship with Bipartite and Multipartite Patella. Skeletal Radiol. 1987;16(4):304-11. doi:10.1007/BF00361473 - Pubmed
- 3. Robert Branstetter (Publisher), Salvador Beltran (Drawings). Orthopaedics. (2004) ISBN: 9780721629209 - Google Books
- 4. Neitzschman H & Gopal H. Radiology Case of the Month. What is the Cause of This Patient's Knee Pain? Dorsal Defect of the Patella. J La State Med Soc. 2005;157(1):13-4. - Pubmed
- 5. Narváez J, Narváez J, Clavaguera M, Gil M, Sánchez-Márquez A, Nolla-Solé J. Dorsal Defect of the Patella: An Uncommon Cause of Knee Pain. Arthritis Rheum. 1996;39(7):1244-5. doi:10.1002/art.1780390726 - Pubmed
- 6. William E. Brant, Clyde A. Helms. Fundamentals of Diagnostic Radiology. (2012) ISBN: 9781608319114 - Google Books
- 7. Kwee T, Sonneveld H, Nix M. Successful Conservative Management of Symptomatic Bilateral Dorsal Patellar Defects Presenting with Cartilage Involvement and Bone Marrow Edema: MRI Findings. Skeletal Radiol. 2016;45(5):723-7. doi:10.1007/s00256-016-2335-5 - Pubmed
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