The MCL acts like a junction box with a number of structures attached/ continuous with it. We need to assess a number of other structures as well and we can do this in a structured way.
- Make sure you look at the distal attachment of the sMCL
- Posterior Oblique ligament and Postero Medial Capsule ( these are posterior extensions of the sMCL)
- Medial Patella Retinaculum ( Anteriorly)
- FIND THE PROXIMAL sMCL TEAR
Image Above: Yellow arrow indicates moderate grade tear of the proximal superficial MCL.
2. Inferior Extension of Tear to the distal attachment of the MCL. Look for stripping from the tibial insertion.
Image above: The Superficial MCL attaches distally to the proximal tibia and when that also tears you see high T2 signal along the tibial margin where the ligament gets stripped off the tibia.( yellow arrows)
3. Anterior Extension of tear to the Medial Patella Retinaculum
Image Above: The superficial MCL is incontinuity anteriorly with the Medial Patella Retinaculum. When the MCL tears it can extend into the medial patella retinaculum ( red arrows) seen as increased T2 signal and ill definition. Yellow arrow = Tear of MCL. Blue arrow= Posterior Oblique Ligament.
Superior Extension to the Medial Patello Femoral Ligament.
Images above; The Medial Patello Femoral Ligament ( MPFL), Green Arrow, is an important structure for patella stability and can be torn in dislocations. Its is continuous with and not a separate structure to the Medial Patella Retinaculum so the best way to find it is
- Find the adductor tubercle ( Orange arrow) on the axial scans.( This marks the superior margin of the MPFL)
- The medial ” retinacular” thickening between the level of the adductor tubercle superiorly, and the level of the origin of the MCL inferiorly ( medial epicondyle) is the MPFL.
4. Posterior Extension to the Posterior Oblique Ligament
Image Above: Like the MPFL the Posterior Oblique Ligament ( Blue arrow) is not a separate structure but a continuation of the MCL posteriorly where it attaches to the capsule and meniscus body. In the case above it is intact. MCL is torn ( yellow arrow).
Dont worry if this is confusing, when you see them on the dicoms it will become much clearer. Its difficult on static images to get a sense of the anatomy but this is an introduction and we will follow up in the workshop with dicoms you can scroll through to get a better sense of where these structures are. For the moment just get familiar with the terms and rough locations.