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Skeletal Radiol (2013) 42:151152 DOI 10.1007/s00256-012-1398-1
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Prepatellar Morel-Lavalle effusion
Noushin Yahyavi-Firouz-Abadi & Jennifer L. Demertzis
Received: 29 December 2011 /Revised: 2 March 2012 /Accepted: 6 March 2012 /Published online: 18 April 2012 # ISS 2012
Keywords Degloving . MRI . Injury
Diagnosis
Prepatellar Morel-Lavall
e effusion (closed degloving injury)
Discussion
Lateral radiograph of the left knee shows prepatellar soft tissue swelling. MR images demonstrate a T2-hyperintense unilocular prepatellar fluid collection located between the subcutaneous fat and underlying fascia. The collection extends beyond the transverse and craniocaudal boundaries of the prepatellar bursa, with the medial and lateral margins reaching the level of the femoral epicondyles at the midcoronal plane, and the superior and inferior margins extending from the mid-thigh to beyond the tibial tubercle. These findings are indicative of a prepatellar Morel-Lavalle effusion and are distinguished from prepatellar bursitis by
location beyond the anatomic confines of the prepatellar bursa. Quadriceps muscle signal intensity is normal, excluding muscle contusion as the cause of the patients pain. Other post-traumatic subcutaneous lesions in the differential diagnosis such as fat necrosis, pseudolipoma, and coagulopathy-related hematoma are unlikely given the anatomic location, imaging characteristics, and clinical history [1]. The patient was successfully treated with activity restriction, ice, and compression wraps.
Maurice Morel-Lavalle first described closed degloving injuries of the hip and pelvis in 1853 [2]. Excessive shearing force or repetitive compressive trauma causes separation of the skin and subcutaneous fat from underlying deep fascia resulting in disruption of perforating...