If you’ve ever had a lameness exam performed on your horse, or if you’ve had a possible purchase horse evaluated with a pre-purchase exam, then chances are you’ve seen your vet perform a flexion test. Do you know just how flexion tests work, and why they’re used?
So What Is a Flexion Test?
A flexion test is tool your vet can use to determine any areas in your horse’s legs which may be or become problematic, causing lameness. In performing a flexion test, your vet will flex a particular joint in a single leg for a certain amount of time (usually between 30 seconds and one minute). Then, as soon as he releases the joint, an assistant trots the horse away from him in a straight line. As the horse trots away, the vet watches for an uneven gait, head bobbing, shortened stride, stiffness, and unusual placement of the feet and legs. If flexing the joint has made the horse considerably sore, then the horse will trot off lame or favoring the leg that had just been flexed.
Why Is a Flexion Test Useful?
Flexion tests can be used in a number of different situations. They’re frequently performed as an aspect of a pre-purchase exam, because even if a horse doesn’t appear lame under saddle or in hand, performing a flexion test can reveal areas that are actually sore and which could potentially cause the horse to go lame in the future.
Flexion tests are also used to determine which areas of the leg are painful when a horse already appears “off.” Performing flexion tests on the joints in each leg can help to steer the vet towards just where the pain begins. This is especially helpful if the horse is stiff or sore in multiple legs, since flexion tests can show additional sore areas which the vet might have overlooked if he’d only focused on the leg which was the most painful.
What Do the Results Mean?
The results of a flexion test are not diagnostic, since they don’t allow the vet to pinpoint the exact issue at hand, but rather give him an idea of the general area in which the pain originates. After performing a flexion test, the vet will likely need to perform additional tests to arrive at a concrete diagnosis.
After performing a flexion test your vet will typically perform a set of four nerve blocks on the affected leg. Beginning from the bottom of the leg, the vet will inject a local anesthetic to “block” the nerves in the targeted area which would typically transmit pain signals to the horse’s brain. The anesthetic is fast-acting, so within about fifteen minutes after administering the first block, the vet will flex the horse again and have him trotted off. If the horse trots off sound, then the problem originated in the blocked area, and the vet can focus in on that particular source. If the horse trots off lame, then the pain originates in a different area, and the vet will continue performing nerve blocks, moving up the leg until the origin of the issue is found.
Radiographs may also be used to help diagnose the specific issue at hand, but flexion tests go a long way to helping your vet narrow down the source of your horse’s lameness.
First Image Source: marksewen.co.nz/equine-services
Second Image Source: south40equine.com