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Hoffa fat pad impingement syndrome

Case contributed by Andrew Dixon
Diagnosis almost certain

Presentation

Anterior knee pain with hypermobility.

Patient Data

Age: 35 years
Gender: Female

MRI Knee

mri

Increased T2 signal within Hoffa's fat pad located between the proximal patellar tendon and lateral femoral condyle consistent with patellar tendon lateral femoral condyle friction syndrome also known as Hoffa fat pad impingement syndrome.

Annotated image

The patella height ratio of 1.4 is consistent with patella alta. Patella alta is usually defined as a height ratio of > 1.3. The normal ratio is 1.1.  Trochlear dysplasia with asymmetrically small medial facet which is < 40% the width of the lateral facet. 

Case Discussion

Underlying evidence of lateral patellar maltracking with patellar alta and trochlear dysplasia (asymmetrically small medial trochlear facets). The tibial tuberosity to trochlear groove distance is within normal limits.

Chondromalacia patella with generally increased cartilage signal and focal fissuring centrally and trace associated subchondral edema.

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