Grading medial collateral ligament injury: comparison of MR imaging and instrumented valgus-varus laxity test-device. A prospective double-blind patient study.

PURPOSE The role of MR imaging in grading medial collateral ligament (MCL) injury of the knee in comparison to other grading methods (clinical findings and instrumental measurement) is hardly documented in the literature. The purpose of this study is to compare the results of MR imaging in grading acute MCL injuries to the results of a clinical grading by an instrumented valgus-varus laxity tester (VVLT). MATERIALS AND METHODS Twenty-one patients clinically suspected of acute MCL injury were tested by VVLT, a well documented and instrumented test-device. All patients subsequently underwent MR imaging of the knee. MCL injury was graded independently by VVLT and MR imaging using a classification method with reference to Petermann. RESULTS Nineteen patients had corresponding grading results by VVLT and MR imaging (kappa, 0.83; S.E., 0.10); 14 patients had a Grade I, four a Grade II and two patients had a Grade III MR imaged MCL injury. Associated lesions were also depicted on MR imaging (bone contusion (n = 3), ACL disruption (n = 2) and medial meniscal rupture (n = 1)). CONCLUSIONS This study shows a very high degree of agreement between the results in grading acute MCL injuries with MR imaging and an instrumented valgus-varus laxity tester (VVLT). MR imaging depicted important, clinically undetected, additional lesions which can determine the treatment of MCL injury.