Tools for diagnostics: How do we determine where you horse is hurt?

Each case, presented at the Equine All- Sports Medicine Center, will go through a complete examination process, with specific phases during that process. In this presentation we will show you how we will perform a complete exam, so you know what to expect when you visit our center.

Each exam will include the following steps: History Physical exam Diagnostic blocks Imaging with X-ray and ultrasound When needed: advanced techniques as scintigraphy, MRI and CT-scan

History:

We will start with taking the history: Information about: How long do you own the horse? How long is the complaint present? How did it develop; sudden onset or gradually? Is it getting better with work or worse?

History: Did you give any medication and what was the effect? Did you have a vet examine the horse and what was the outcome? Where there any changes in feeding, training, saddle or tack just before onset of the complaint?

History: What kind of work is your horse doing? What are specific difficulties for your horse in its’ discipline? How did your horse progress in its’ discipline? What is the present level you horse is performing at and what are your goals?

It will take minutes to get a good history. We will have a seat in our office to take the time and comfort to go through the history. Provide us with as much information as you think we may need; records, video, your personal ideas, etc. A complete exam starts with a complete history!

Physical exam:

Inspection: Just walking around the horse in stance to evaluate the conformation of the horse. Evaluation of joint effusion (wind puffs, etc), bumps and swellings that are visible from a distance

Gait evaluation: The horse will be evaluated in walk and trot on a straight line on a hard surface. After that, the horse will be walked in a serpentine to evaluate flexion and ease of motion

The horse will be evaluated in the arena on softer footing in walk, trot and canter on a lunge or, when needed, under saddle.

Flexion tests: With flexion tests, we will put stress on specific structures. In the front limb, flexion tests of the fetlock and knee can be performed The fetlock flexion tests will load the joint and the joint-related structures and ligaments of the coffin joint, pastern joint and fetlock joint, as well as the navicular region.

Flexion tests: In the hind limb, flexion tests of the hock, stifle and fetlock can be performed. When the test is positive (horse is showing pain or is more lame after the test), we can try to isolate more the specific joints of fetlock, pastern, coffin, hock and stifle.

Rotation tests: When putting torque or rotational forces on the distal limb, the collateral ligaments of the coffin joint, pastern joint and fetlock joint are stressed. When the horse shows pain or is more lame after these tests, there are symptoms present pointing at these structures.

Wedge test: When the horse is standing with its’ foot on a wedge under the toe, specific stress is put on the navicular region and the Deep Digital Flexor Tendon in the distal foot. A positive result of this test is indicative for navicular pathology as well as the tendons and ligaments associated with the navicular region.

Percussion: When the foot is pounded with a little hammer, sensitivity of the structures of the hoof capsule, the horn structures as well as the bony structures in the foot is tested. Positive results of this test show location of the pain in the foot.

Hoof tester: With a hoof tester localized pressure is applied to several structures in the foot. Positive result of this test is indicative for a cause of pain in the foot, like a sole abscess, bruise or contusion of the soft tissue structures (not bone) within the hoof capsule.

Diagnostic block: Because it is impossible to ask the horse where it is hurting, we have to perform another technique to get answers about exact location of pain. A common technique is to inject some local anesthetic around the nerves that transmit sensitive information.

Starting at the lowest point, first the heel and the sole of the hoof are desensitized. When the horse is much better after this block or even sound, the origin of the lameness is clearly located in the blocked region. When there is no change in lameness, a higher point for blocking is performed.

With the next block the entire lower foot is blocked, as well as a part of the fetlock region. A third block can be performed a bit higher, resulting in desensitizing of nearly the entire fetlock region.

In specific cases also joints can be blocked. By injecting (under strict sterile conditions) a joint, information can be obtained about the cause of pain in that joint. Also tendon sheaths and the navicular bursa can be targeted with a diagnostic block to determine of there is pain caused by this structure.

Not always diagnostic blocks will be performed. Sometimes the lameness is so mild, that the result of a block is nearly impossible to evaluate. The injected local anesthetic fluid can make it difficult to make a interpretation of ultrasound images later during the examination. The injected fluid can alter the image. Sometimes the block needs to be performed later during the examination procedure, or even at another day.

Mobility of the spine: At the center we have specific expertise about the equine spine. Any horse examined for lameness will also be evaluated for pathology of the spine. Often spine problems (“back pain”) can cause secondary limb lameness, or limb lameness can cause spinal pathology.

A good impression of the mobility of the spine and the symmetry of that mobility is a good initial screening method for back problems. The neck, thorax, lumbar and sacral spine will be evaluated for mobility to the left, right, up, down and for rotation. With testing for some reflexes we can get information about ability to show evasive movement as well as information about the nervous system.

Diagnostic imaging: When all tests are performed, in most cases we are able to narrow the cause of lameness down to a specific area. Based on the anatomy of that area, we need to decide in cooperation with the owner which imaging techniques are needed to get a better idea what is going on.

X-ray: With digital X-ray the bone structures can be evaluated. Especially the condition of joints is often the region of interest, but also the attachment sites of ligaments and tendons can be evaluated. In the hoof X-ray can provide valuable information about angles of the bone structures in the hoof capsule.

Ultrasound: With Ultrasound soft tissue can be imaged. Especially tendons and ligaments are very good structures for ultrasonography, but also joints can be evaluated with ultrasound to get an image of cartilage (not visible on X-ray) and the joint capsule. Ultrasonography of muscles is also providing very useful information.

A great tool with the modern ultrasound imaging equipment is Doppler color flow imaging. With color flow imaging it is possible to visualize blood flow activity. When there is inflammation present in a structure, it shows up on the screen as red and blue This technique makes it possible to get an idea about the real-time activity of blood vessels around the tissue of interest, great for diagnosing active inflammation in joints (arthritis), tendons (tendonitis) and ligaments (desmitis).

Nuclear Scintigraphy: Nuclear Scintigraphy (“bone scan”) is a technique that will image active bone metabolism. It is a great tool for finding a location of high bone activity, quite often associated with arthritis. Especially for the spine this is a great imaging tool, because parts of the spine are nearly impossible to image with X-ray and ultrasound

Nuclear Scintigraphy is a expensive technique, so we will discuss any case with you when we think we may need it and make an evaluation about costs and advantage to perform bone scan. We have a great partnership with the Veterinary Teaching Hospital of MSU, were we an have all scintigraphy performed, or we can refer you to any other facility.

MRI: MRI uses magnetic field to make very detailed images of all kind of tissues. In lameness cases it seems to be very valuable in cases of foot pain (navicular region, coffin bone and all soft tissue structures in the foot) and hock pathology. When we think we may need MRI we will discuss all options and cost with you.

We have a great partnership with the Veterinary Teaching Hospital of MSU, were we an have all MRI performed, or we can refer you to any other facility.

Enjoy the time with your horse and have fun watching this one!