Flexion test

A flexion test is a veterinary procedure performed on a horse, generally during a prepurchase or a lameness exam. The animal's leg is held in a flexed position for 30 seconds to up to 3 minutes (although most veterinarians do not go longer than a minute), and then the horse is immediately trotted off and its gait is analyzed for abnormalities and uneveness. The flexion places stress on the joint capsule and soft tissue of the joint, and sometimes the cartilage and bone, usually accentuating any lameness that is present, such as arthritis. The horse may take a few uneven steps, or may be lame for several minutes following the procedure.

False positives may occur, however, especially if excessive force was placed on the joint, and many horses can continue to perform their jobs quite well despite having "failed" a flexion test. It is therefore important for an owner to continue to perform diagnostics if she suspects there is a problem. Additionally, a vet may flex both fore or hindlimbs separately for comparison, to determine which limb is experiencing an unknown lameness, or if the few uneven steps are "normal" for the horse.

Flexion tests are rather nonspecific, as each test flexes multiple joints (such as the stifle and the hock, or the pastern and the navicular area). So while they can help localize a lameness issue to one particular leg, or even to a few joints in the leg, they can not pinpoint it. In lameness exams, the next step is usually to perform nerve blocks.

References

*King, Christine, BVSc, MACVSc, and Mansmann, Richard, VDM, PhD. "Equine Lameness." Equine Research, Inc. 1997