Morphometric assessment of the medial collateral ligament of the canine stifle joint.

Objective: The study provides a morphometric assessment of the medial collateral ligament (MCL) of the canine stifle joint.

Study Design: Eighty-six stifle joints were collected from 43 canine cadavers and dissected to free them of soft tissue and expose the collateral ligaments. The MCL insertion sites were identified with Chinese ink on intact stifle joints and also marked with radiopaque paste after removal of the MCL. Mediolateral photographs and radiographs of each stifle joint were taken after MCL was removed for morphometric assessment. Measurements were taken in two groups: a group of Beagles (group 1), and a group composed of different breeds (group 2).

Results: In all stifle joints, the MCL had an hourglass shape. It inserted in the distal femur and the proximal tibia, and was also intimately attached to the medial meniscus and more loosely to the proximal tibial epiphysis in its central portion. The MCL tibial insertion (TI) site had the largest surface area. Its proximal and distal position relative to the tibial plateau was located at 8.24 ± 1.17% and 15.54 ± 1.50% respectively of the total tibial length in group 1, and at 8.86 ± 1.93% and 15.53 ± 2.11% respectively, of the total tibial length in group 2. These values were not statistically different.

Conclusion: The MCL of the canine stifle joint has an insertion site on the femur and on the tibia and is also attached on the medial meniscus. The location of the MCL TI site seems to be relatively homogeneous in dogs.