Effect of transection of the caudal menisco-tibial ligament on medial femorotibial contact mechanics.

OBJECTIVE: To evaluate the effect of transection of the medial caudal menisco-tibial ligament on contact mechanics in a canine cadaveric model of cranial cruciate ligament (CCL) rupture and tibial plateau leveling osteotomy (TPLO).

STUDY DESIGN: Ex vivo biomechanical study.

SAMPLE POPULATION: Unpaired pelvic limbs (n=8) from 28-35 kg dogs.

METHODS: Cadaveric pelvic limbs with CCL-deficient stifles stabilized with TPLO were axially loaded using a material testing machine with 30% body weight and a stifle angle of 135 degrees. Medial compartment femorotibial contact force and area, peak and mean contact pressure, and peak pressure location were measured with pressure sensors. A paired t-test was used for comparison; P<.05 was considered significant.

RESULTS: Transection of the caudal menisco-tibial ligament resulted in a significant decrease in contact area, from 145 +/- 24 to 71 +/- 25 mm(2) (P<.001) and a significant increase in peak pressure magnitude from 2.9 +/- 0.4 to 4.1 +/- 0.5 MPa (P<.001). Transection of the caudal menisco-tibial ligament caused a significant increase in load in the caudal portion of the medial compartment (P<.001).

CONCLUSIONS: Our results suggest that transecting the caudal menisco-tibial ligament eliminates the load bearing function of the medial meniscus and results in significant changes in medial femorotibial contact mechanics.

CLINICAL RELEVANCE: The abnormal cartilage contact stresses after transection of the caudal menisco-tibial ligament may have a negative impact on the cartilage homeostasis and predispose to further degeneration of the medial compartment after TPLO.