What is the significance of Magnetic Resonance Image appearances of deep medial collateral ligament in undiagnosed medial knee joint pain?

Introduction: anatomically, the MCL is composed of two distinct components, the superficial MCL (sMCL) and the deep MCL (dMCL).The aim of this study is to describe signs on MRI that best define injury to the dMCL. Methods: MRI scans of patients referred for investigation of medial knee pain from a Tertiary level University Hospital in Central London were retrospectively reviewed by two musculoskeletal radiologists. Case notes and MRI request forms were reviewed to extract relevant clinical information. The knees were scanned using a dedicated knee coil on a GE 1.5 T scanner. The meniscofemoral and meniscotibial components of the dMCL were identified and note was made of their contours, thickness, and attachments. If oedema was present, its distribution was recorded. Results: total of 51 MRI images reviewed. 38 out of 51 patients reviewed had signs of injury to dMCL or sMCL. Out of these, the meniscotibial ligament was affected in 3 cases and the meniscofemoral ligament in 24 cases. In ten of these it was clearly torn; it was thickened and/or wavy in the other fourteen. Oedema was present in all cases of MCL injury except one, with the pattern of oedema being deep to the dMCL in seven cases, surrounding the dMCL in twelve cases, superficial to or surrounding sMCL in three and present in all areas in the remaining fifteen. Conclusion: our study results demonstrate that oedema surrounding the deep portion of the MCL and thickened, wavy or torn meniscofemoral and meniscotibial ligaments may represent isolated injury to the deep MCL. [ABSTRACT FROM AUTHOR]