Morphology of the medial collateral ligament of the knee

Abstract

Background: Quantitative knowledge on the anatomy of the medial collateral ligament (MCL) is important for treatment of MCL injury and for MCL release during total knee arthroplasty (TKA). The objective of this study was to quantitatively determine the morphology of the MCL of human knees.

Methods: 10 cadaveric human knees were dissected to investigate the MCL anatomy. The specimens were fixed in full extension and this position was maintained during the dissection and morphometric measurements. The outlines of the insertion sites of the superficial MCL (sMCL) and deep MCL (dMCL) were digitized using a 3D digitizing system.

Results: The insertion areas of the superficial MCL (sMCL) were 348.6 ± 42.8 mm2 and 79.7 ± 17.6 mm2 on the tibia and femur, respectively. The insertion areas of the deep MCL (dMCL) were 63.6 ± 13.4 mm2 and 71.9 ± 14.8 mm2 on the tibia and femur, respectively. The distances from the centroids of the tibial and femoral insertions of the sMCL to the tibial and femoral joint line were 62.4 ± 5.5 mm and 31.1 ± 4.6 mm, respectively. The distances from the centroids of dMCL in the tibial insertion and the femoral insertion to the tibial and femoral joint line were 6.5 ± 1.3 mm and 20.5 ± 4.2 mm, respectively. The distal portion of the dMCL (meniscotibial ligament - MTL) was approximately 1.7 times wider than the proximal portion of the dMCL (meniscofemoral ligament - MFL), whereas the MFL was approximately 3 times longer than the MTL.

Conclusions: The morphologic data on the MCL may provide useful information for improving treatments of MCL-related pathology and performing MCL release during TKA.

Figure 1

Medial aspect of the knee. (A). Photograph showing the medial side of the right cadaveric knee joint. (B). the distances from the centroid of femoral insertion and tibial insertion to the joint line. sMCL = superficial medial collateral ligament, dMCL = deep medial collateral ligament, POL = posterior oblique ligament. ME = medial epicondyle, MGT = medial gastrocnemius tubercle, MAT = medial adduct tubercle.

Figure 2

Dissected insertions of the MCL. (A). Photograph showing the three parts of the sMCL (right cadaveric knee). (B). Schematic diagram illustrating the width of sMCL at the proximal, middle and distal parts.

Figure 3

The experimental sequence.

Figure 4

Posteromedial corner of the knee. (A). Photograph showing the posterior portion of the sMCL was firmly attached to the medial meniscus of the knee (right knee); (B). the anterior portion of the sMCL was cut and everted, the posterior portion of the sMCL was connect to the meniscus.

Figure 5

Dissected deep medial structures of the knee. (A). Cadaveric view of the femoral and tibia attachment of medial structures of the knee (left knee); (B). Schematic diagram illustrating the length and width of the meniscofemoral ligament and meniscotibial ligament. MM = medial meniscus, MFL = meniscofemoral ligament, MTL = meniscotibial ligament.

Figure 6

Femoral insertion and medial epicondyle of the sMCL. (A). sMCL attachment on the femoral condyle; (B). the medial epicondyle under the anterior poriotn of the sMCL insertion; and (C). bony locations of the sMCL and dMCL insertions and medial epicondyle on the femoral condyle.