Case 5
History:
26 year old female with sudden severe right knee pain and no history of injury
Findings:
Sagittal MR images through intercondylar notch showing curvilinear fluid signal along the expected course of infrapatellar plica within Hoffa's fat space.
Diagnosis:
Infrapatellar Plica Injury
Discussion:
The plicae of the knee are normal but inconstant synovial folds, remnants from the embryologic development. Plica syndrome is a clinical syndrome during which thin, pliable synovial plica becomes abnormally thickened, edematous, or fibrotic, leading to clinical symptoms most frequently involving the mediopatellar plica or, sometimes, the suprapatellar plica. Inferior plica injury is increasingly more recognized. An injury of the infrapatellar plica is typically suggested when abnormal T2 hyperintensity signal is encountered along the expected course of the infrapatellar plica.
References:
- Kosarek FJ, Helms CA. The MR appearance of the infrapatellar plica. AJR 1999;172:481 –484.
- Jacobson JA, Lenchik L, Ruhoy MK, Schweitzer ME, Resnick D. MR imaging of the infrapatellar fat pad of Hoffa. RadioGraphics 1997;17:675 –691.
