The Fat Pad Doesn't Lie: Magnetic Resonance Imaging Findings in Friction Knee Syndromes

Purpose or Learning Objective: Through an anatomical review of the knee joint with special emphasis on the fat pads and adjacent soft tissues, we explain the different types of knee friction syndromes observed with magnetic resonance imaging in cases seen in our center.

Methods or Background: In the knee joint, several fat pads are located between the joint capsule and the synovial membrane, providing support and cushioning to the bones and joint surfaces and facilitating lubrication and joint stability. The causes of fat impingement syndromes vary and depend on the location of the fat pad, including friction between structures, acute trauma, altered joint mechanics, repeated microtrauma, and patellofemoral instability.

Results or Findings: Depending on their anatomical location, knee friction syndromes can be classified as follows:

– Infrapatellar fat pad impingement syndrome: Resulting from compression of the superolateral aspect of Hoffa's fat pad between the posterior aspect of the patella tendon and the lateral femoral condyle.

– Suprapatellar quadricipital fat pad impingement syndrome: Located above the patella, between the suprapatellar synovial recess and the quadricipital tendon.

– Pre-femoral fat pad impingement syndrome: Thought to be caused by a prominent suprapatellar osteophyte or friction of the patellar tendon with the lateral femoral condyle.

– Iliotibial band friction syndrome: Common cause of lateral knee pain related to intense physical activity, resulting in chronic inflammation of the fat adjacent to the iliotibial band.

– Cruciate ligament fat pad impingement syndrome: Occurs in people involved in intense physical activity and presents with pain in the posterior aspect of the knee that limits sports practice.

– Posteromedial knee friction syndrome: Thought to be due to narrowing of the space between the posteromedial femoral condyle and the sartorius and/or gracilis tendons.

Conclusion: Knee friction syndromes are often underdiagnosed because the imaging findings can be subtle, but magnetic resonance imaging is a very effective diagnostic method that allows an accurate assessment of the anatomical structures involved. It is very important to correlate the radiologic findings with the patient's clinical history by also looking for chondral, meniscal, ligamentous, or synovial pathology before attributing the cause of knee pain to friction syndrome.

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Artikel online veröffentlicht:
02. Juni 2025