This illustration of a cross-section through a dysplastic patella shows how the facets may be distorted.
What is the cause of patellar dysplasia?
Patellar dysplasia is generally considered something one is simply born with, but other possible causes may exist.
Peer-reviewed papersQuote from peer-reviewed paper:
"....there is no consensus as to whether patellofemoral dysplasia is genetic in origin, caused by imbalanced forces producing maltracking and remodelling of the trochlea during infancy and growth, or due to other unknown and unexplored factors...."
Citation: Zaffagnini S, Grassi A, Zocco G, Rosa MA, Signorelli C, Marcheggiani Muccioli GM. The patellofemoral joint: from dysplasia to dislocation. EFORT Open Rev. 2017 May 11;2(5):204-214. doi: 10.1302/2058-5241.2.160081. PMID: 28630757; PMCID: PMC5467684.
What symptoms can result from patellar dysplasia?
Patellar dysplasia may lead to subluxation or dislocation of the patella.
Peer-reviewed papersQuote from peer-reviewed paper:
"....Patellar dysplasia "is a major predisposing factor for instability of the patellofemoral joint....[but] represents an extremely challenging condition to manage."
Citation: Zaffagnini S, Grassi A, Zocco G, Rosa MA, Signorelli C, Marcheggiani Muccioli GM. The patellofemoral joint: from dysplasia to dislocation. EFORT Open Rev. 2017 May 11;2(5):204-214. doi: 10.1302/2058-5241.2.160081. PMID: 28630757; PMCID: PMC5467684.
Classification of Patellar Dysplasia
The Wiberg classification of the shape of the patella - based upon the relative lengths of the facets - is widely used to describe different patellar shapes.
Wiberg Type 1 patella
Wiberg Type 2 patellar dysplasia
Wiberg Type 3 patellar dysplasia
Wiberg Type 4 patellar dysplasia
Peer-reviewed papersQuote from peer-reviewed paper:
"....the Wiberg classification of anatomical shape of the patella obtained from radiological data may be a good clinical predictor of the risk of articular cartilage defects and the knee-related physical activity level of the patients...."
Citation: Gudas R, Šiupšinskas L, Gudaitė A, Vansevičius V, Stankevičius E, Smailys A, Vilkytė A, Simonaitytė R. The Patello-Femoral Joint Degeneration and the Shape of the Patella in the Population Needing an Arthroscopic Procedure. Medicina (Kaunas). 2018 Apr 24;54(2):21. doi: 10.3390/medicina54020021. PMID: 30344252; PMCID: PMC6037255.
Patellofemoral Dysplasia
Patellofemoral dysplasia is when the groove of the trochlea mirrors any abnormality in the shape of the patella.
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A patient with a shallow trochlea tries to understand the issues of potential surgery.