Robert J. Ward MD, Abstract Co-Author: Nothing to Disclose

Jorge Mendoza MD, Presenter: Nothing to Disclose

Eric Wong MD, Abstract Co-Author: Nothing to Disclose

Tobias Robert Chapman MS, Abstract Co-Author: Nothing to Disclose

Timothy E. McAlindon MD, MPH, Abstract Co-Author: Nothing to Disclose

Jeffrey B. Driban PhD, Abstract Co-Author: Nothing to Disclose

To distinguish osteoarthritic from traumatic etiologies in medial collateral ligament (MCL) abnormalities on knee MRI.

The study was IRB approved. 114 knees were retrospectively selected for MCL abnormality by radiology report. The knees were divided into groups based on chart-reviewed history and interpreted findings (e.g., meniscal injury). Two groups were analyzed: 1) Group 1 (14 knees): positive traumatic history, normal medial meniscus, normal ACL, and abnormal MCL, and 2) Group 2 (20 knees): non-traumatic history, abnormal medial meniscus, normal ACL, and abnormal MCL. The MCL was divided into proximal, middle, and distal thirds. A semiquantitative score (1-3 scale) for periligamentous edema was performed for each third. Absolute MCL thickness was measured at its greatest value for each third. A proximal to middle thickness ratio (P:M) was calculated. An independent sample t-test assessed group differences in P:M thickness. Group differences in periligamentous edema were analyzed via a Mann-Whitney Test with Bonferroni corrections (p < .0167 for significance).

Group 1(trauma group; 1.95±0.97) had a greater P:M than group 2 (no trauma but abnormal meniscus group; 1.38±0.48; t(32)=2.27; p=.03). Group 1 had significantly greater edema scores in the proximal third of the MCL (U =56, z=-3.06, pGroup 1; U=81, z=-2.19, p=.03).

MCL abnormality related to meniscal injury/arthritis appears to be distinguishable from trauma. Posttraumatic MCL injury involves periligamentous edema centered about the proximal third of the ligament while with meniscal injuries the edema is centered about the middle third or juxtameniscal region. Similarly, relative MCL thickening is present in the proximal third of the ligament following trauma compared to atraumatic degenerative knees.

Distinguishing between traumatic and atraumatic MCL injury is helpful in raising pretest probability for associated injuries in the two populations during diagnostic MRI interpretation.

Ward, R, Mendoza, J, Wong, E, Chapman, T, McAlindon, T, Driban, J, MCL Periligamentous Edema: Sprain or Nontraumatic Meniscal Pathology?.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9012278.html