Yasmin Pirani MD, Presenter: Nothing to Disclose

Mehool Shukla MD, Abstract Co-Author: Nothing to Disclose

Amit D. Malhotra MD, Abstract Co-Author: Nothing to Disclose

Marc Andre Friedman MD, Abstract Co-Author: Nothing to Disclose

It is becoming increasingly evident that edema along the superficial aspect of the medial collateral ligament (MCL) is not specific for ligamentous injury, especially in the patient without a history of trauma. Medial compartment osteoarthosis and medial meniscal tears have been implicated as causes in prior studies. The purpose of this study is to analyze whether obesity alone may also result in this imaging finding. 

All knee MRI studies performed from March 2010 to March 2011 were examined for superficial MCL edema on PACS and lack of trauma history on the computerized medical record. 42 cases were identified. Each study was analyzed for medial femorotibial osteoarthrosis and medial meniscal tears. The Body Mass Index (BMI) for each patient was calculated with a value of 30 or greater considered obese. 

Of the 42 patients, 21 (50%) demonstrated osteoarthosis and medial meniscal tears. 8 (19%) patients demonstrated osteoarthosis without medial meniscal tears. 13 (31%) patients demonstrated neither osteoarthrosis or medial mensical tears, and of those patients, 12 (92%) were obese with an average BMI of 36.

In patients with superficial MCL edema without a history of trauma, and no evidence of medial osteoarthrosis or medial meniscal tears, the vast majority are obese.  Increased stresses or altered biomechanics from obesity may play a role in this imaging finding.

In the absence of trauma, edema superficial to the MCL is not synonymous with a sprain, and may be the result of medial compartment osteoarthrosis, medial meniscal tear, or secondary to obesity.

Pirani, Y, Shukla, M, Malhotra, A, Friedman, M, The Role of Obesity in Superficial Medial Collateral Ligament Edema in the Atraumatic Setting.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034528.html