STEVE: The stifle in a horse is analogous to the knee in a human. It’s the joint that exists between the femur and the tibia. It has a tendon that extends from the quadriceps down into a patella, and a patellar tendon attaches to the top of the tibia. This is, you know, a typical situation in all horses that I’m aware of. They both have two stifles, most people have two knees, and essentially it can be a source of lameness problems.

Obviously, if they have the ability to lock this up, when we see a horse rest one limb, or hind limb, and not the other, when they have the ability to take the patellar tendon and lock it up over the little trochlear notch on the femur and it will actually take the contractile away from the muscle group, so they can do this without exerting any energy. They can release that just by a slight flexion of the, or a little bit of extension of the quadriceps, and pull it up over that, and they’ll do the same thing on the opposite side.

The only problem that can exist is when there is a little bit of laxity in those tendons that tend to lock up or create an upward fixation of the patella which basically is an area where the patellar tendon locks up over that trochlear on the femur and will basically create a lameness deficit, or a locked up stifle. In this particular case we go ahead and internal blister. To remedy this, we internal blister the ligaments on the stifle. I think I’ve had like 100% success, doing that over that over the last 25, 30 years.

ALEX: That mostly young horses, or older?

STEVE: No, you can see it in both. You can see it at any age.