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.