Summary
Purpose
A cadaveric study of ovine stifles was performed to examine the contribution of the
meniscofemoral ligament to the cranio-caudal and internal-external rotatory laxity
of this joint in sheep.
Methods
Twenty ovine stifles were harvested, denuded of muscular attachments, and the femur
and tibia fixed in bone pots. These were inserted into a four degree-of-freedom rig
incorporated into a materials testing machine. Forces up to a maximum of 100N were
applied in the cranial and caudal directions, and the resultant translations and coupled
rotations measured. Tibial internal and external rotations in response to a 6Nm torque
were also measured. These parameters were assessed at 30, 60, 90 and 110 degrees of
flexion in twenty intact stifles. In ten stifles a small posterior arthrotomy was
used to divide the caudal cruciate ligament (CCL), followed by division of the meniscofemoral
ligament (MFL). The sequence of division was reversed for a further ten stifles. The
effects of each intervention on the above parameters were evaluated.
Results
Division of the MFL resulted in an increase in caudal translation at all angles of
flexion in both the intact and CCL deficient stifle. There was also an increase in
internal rotation of the tibia after application of a 6Nm torque. This was significant
at 30 and 110 degrees of flexion in the intact stifle and at all angles of flexion
in the CCL-deficient stifle.
Conclusions
These results indicate a secondary role for the MFL in the cranio-caudal and internal/external
rotatory stability of the ovine stifle joint. This is the first study demonstrating
a functional role for the MFL in any species, and may have a bearing on stifle injuries.
Keywords
Knee injury - caudal cruciate ligament - posterior cruciate ligament - meniscofemoral
ligament - lateral meniscus - stifle joint
