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The knee has unique anatomy regarding the relationship between the synovial and capsular layers, with interposed fat pads at certain locations.
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The extrasynovial impingement and inflammation syndromes about the knee are underdiagnosed and should be included in the differential diagnosis of anterior knee pain.
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MR imaging is the best imaging modality for evaluation of the anatomy and disorders of these extrasynovial compartments.
MR Imaging of Extrasynovial Inflammation and Impingement About the Knee
Section snippets
Key points
Summary
The fat pads of the knee are of great importance and are the main structures of the extrasynovial compartment. They have been underappreciated in the literature. The fat pads should be recognized as more than passive, space-occupying structures: they serve to protect the knee by remodeling their shape to adapt to the various degrees of flexion and assist in preserving the compartments of the knee joint by modulating direct contact.6 Fat pads are richly vascularized and innervated, functioning
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Cited by (27)
Abnormalities of the pericruciate fat pad: Correlations with the location and severity of chondral lesions of the knee
2023, European Journal of RadiologyPericruciate fat pad (PCFP) – A scoping systematic review of anatomy, histology, imaging, and clinical importance
2021, Translational Research in AnatomyCitation Excerpt :In the sagittal plane, the PCFP resembles a triangle with basis made of the posterior capsule of the knee. The PCFP is located posteriorly and proximally to the PCL [2,10], which forms the inferior arm of this triangle. The roof of intercondylar fossa is a superior arm and closes the area of the described triangle (Fig. 6).
ACR Appropriateness Criteria<sup>®</sup> Chronic Knee Pain
2018, Journal of the American College of RadiologyCitation Excerpt :In patients with chronic knee pain, referred pain from the lower back must be considered, especially if the knee radiographs are unremarkable and there is clinical evidence or concern for lumbar spine pathology. CT without intravenous (IV) contrast may be indicated to evaluate the patellofemoral anatomy in the setting of chronic knee pain related to repetitive patellofemoral subluxation or maltracking [15]. CT can also be used to evaluate trochlear morphology and the tibial tubercle-trochlear groove distance.
The imaging findings of impingement syndromes of the lower limb
2017, Clinical RadiologyMagnetic Resonance Signal Abnormalities Within the Pericruciate Fat Pad: A Possible Secondary Sign for Acute Anterior Cruciate Ligament Tears
2017, Canadian Association of Radiologists Journal
E.Y. Chang, MD, gratefully acknowledges grant support from the VA (Clinical Science Research and Development Career Development Award: 1IK2CX000749).
Conflicts of Interest: None.