The “Lameness” Exam
While it may be a common term, the phrase “lameness exam” is a bit of a misnomer, as it presumes a problem. Similarly, “soundness exam” implies the horse is free of gait abnormalities. Perhaps the term “gait evaluation” is the best name, as it provides an accurate description of what the veterinarian is doing: examining your horse’s gait.
There are a number of reasons to request a gait evaluation. Maybe it is part of a pre-purchase exam, and you want to get a baseline idea of a horse’s soundness. Maybe you have noticed a decline in your horse’s performance, or he is exhibiting behavioral problems under saddle, and you want to rule out a physical cause. Or maybe you, your friend, or your trainer have noticed that your horse is exhibiting a limp. Regardless of the reason, the process is pretty similar in each case.
First, the vet will take a good look at how your horse moves in-hand at a walk and trot, usually both in a straight line and on the longe. Canter transitions may be requested to get a better idea of how the horse moves. If the problem is only appreciated under saddle, you may be asked to ride your horse, although this is often not necessary. The veterinarian will examine your horse from head to toe, looking for areas of injury or pain within the muscles, tendons, and bones. The back, neck, and head are also examined. The vet may then perform flexion tests on the horse, selectively stressing a region of the limb to see whether this causes pain and increases lameness.
If a lameness (limp or gait irregularity) is identified, the vet may elect to proceed with diagnostic analgesia. This involves injecting a local anesthetic either into a joint or alongside specific targeted nerves. This selectively numbs an area of the leg. If the lameness improves after the “block,” the source of pain is narrowed down to the area numbed by anesthesia. Sometimes multiple blocks are performed to localize the source of injury.
After lameness localization, it is usually time to move onto diagnostic imaging. Digital radiographs (X-rays) are most commonly used, but ultrasound is also frequently employed if a soft tissue injury is suspected. Depending on the results of diagnostics, a variety of treatments may be recommended, ranging from rest and controlled rehabilitation to shoeing changes, anti-inflammatory therapy, intra-articular injections, or regenerative medicine.
It is important to remember that “sound is as sound does.” The veterinarian looks at the horse with a critical eye to pick up any little asymmetry or gait irregularity. For the high level athlete, it is usually important to address any small issue before it develops into a bigger, performance-impacting problem. For the weekend pleasure horse, however, some small issues may be very tolerable and manageable for the level of work that the horse is expected to perform. The veterinarian’s role is to keep you informed of the diagnosis and available options so that you can make the best decisions for yourself and your horse.