Lameness arising in the front feet accounts for most soundness issues in horses. However, it has been and continues to be difficult for veterinarians to diagnose a specific injury or source of pain within the foot because the structures can be tough to capture with imaging equipment. Over time, as medical knowledge has expanded, radiography has improved, and MRI has been incorporated into equine practice, we’ve learned a lot about the hoof capsule’s complex anatomy and physiology. The more we understand, the more injuries we can identify. This knowledge has opened doors to many treatment options in the veterinarian’s toolbox. With an accurate diagnosis, the veterinarian can formulate a proper treatment plan and provide an accurate forecast on the horse’s prognosis.
In spite of these advances, it’s still important for veterinarians to complete a thorough clinical exam. Visual and hands-on assessment of the horse can provide important clues as to the problem. This information often yields a wealth of knowledge that will help guide the need for diagnostic imaging.
History and Signalment
Knowing the horse’s age, breed, and use, as well as the duration of lameness and how quickly it came on, can help the veterinarian formulate a list of possible correlating problems. For example, a 6-year-old Warmblood show jumper coming up lame following a recent class might be dealing with a soft-tissue injury. Alternatively, a 17-year-old Quarter Horse used for team roping with intermittent forelimb lameness over several months might be dealing with a joint or bone-related injury.
Lameness Exam Findings
A veterinarian can learn much and narrow down possible problems simply by completing a thorough clinical exam. Clues that can help include:
- How the horse moves and travels on different surfaces (packed dirt vs. loose sand);
- How the foot lands and takes off from the ground during travel;
- The lead on which the lameness is most pronounced;
- Response to hoof testers; and
- Response to flexion tests.
Additionally, veterinarians can learn a lot by evaluating hoof capsule conformation and health. Distortions in growth, weakness of the hoof walls, contraction of the heels, and uneven wear of the wall or shoe can result from pain or injury in different parts of the foot, how the horse compensates, and predisposing factors to specific injuries.
Finally, they might be able to determine the cause of lameness with specific diagnostic nerve blocks. Using a local anesthetic drug, the veterinarian can desensitize different parts of the foot to detect the location of pain within the hoof capsule. For example, the commonly used palmar digital nerve block desensitizes the sole and back third of the foot, whereas a navicular bursa block generally targets that structure—which cushions the bone from the deep digital flexor tendon—alone. Following a nerve block, the vet assesses the horse to see if he travels differently.
Based on these exam findings, the veterinarian can use digital radiography to assess suspected bony problems, then pursue more advanced imaging if necessary.
Magnetic resonance imaging has been labeled the “gold standard” for veterinarians to image the horse’s foot. It can provide detailed information about soft tissue, bone, and fluid within the hoof capsule. It can often help veterinarians identify abnormalities they may not otherwise recognize using other diagnostics. Evaluating the horse’s foot using MRI is noninvasive, safe, and can be done with good accuracy either in a standing sedated horse or a horse lying down under general anesthesia. Though MRI is a great option, it does pose some limitations. It’s expensive, and in some parts of the country MRI unit availability is limited. Additionally, MRI imaging requires interpretation by a trained professional and often reveals more than one abnormality. For this reason veterinarians often look for other clues to help pinpoint a horse’s problem before pursuing an MRI exam or, later, to help determine the significance of the MRI findings.
In summary, front foot lameness is common and continues to frustrate horse owners and challenge veterinarians. Fortunately, owner-provided information and a thorough lameness exam can help practitioners start meaningful investigations. MRI has improved our understanding of the horse’s foot and serves as a valuable tool but is not an absolute necessity.