Lameness evaluation is a common procedure in our practice. Because of the wide range of horse breeds and uses in our area, we see a variety of different lamenesses. Evaluation of the lame horse begins with a complete history of the animal and its particular problem. The age, sex, and breed of the animal is determined and the onset, progression and duration of the lameness is discussed.with the client.
In general the exam begins with the discovery of which leg is lame. The hoof tester is used to rule out an abscess if the leg in question is obvious. An abscess is a very common cause of lameness which may or may not be accompanied by swelling and heat. If an abscess is not obvious then the horse is observed moving. In the forelegs the lameness is determined by the "head nod" ( the head and neck nodding down on the sound leg and then up as the lame leg strikes the ground). In the hind end the "hip hike" is the issue (the pelvis raising up as the lame leg hits the ground while the pelvis sinks with the weight of the sound limb as it hits the ground). This is best observed on a flat, firm area. If the lameness is subtle then observing the horse on a longe line, on harder ground or under saddle may be necessary. It is important to note that the large majority of lameness problems occur in the forelegs because more of the horse's weight is borne here (60%) and the large majority of these lamenesses orginate from the foot.
Once the affected leg is determined, then the next step is palpation or feeling of the leg. Palpation of the length of each leg is carefully done to determine any sore, painful, hot or reddened areas indicative of inflammation. Manipulative procedures such as "flexion tests" may also be performed to compare the degree of lameness before and after each limb is flexed and the horse moves out to evaluate his reaction.
Local nerve blocks are also an integral part of the lameness exam. In this procedure a small amount of local anaesthesia is injected around the nerves that supply a given portion of the leg thereby removing feeling from this part of the leg. If the horse is sound following the "block" then we know that this is the area causing the lameness. But, if the horse is still "off", then we move further up the limb with these blocks until we have caused the lameness to disappear (if the lameness is in leg).
When the particular area of lameness is determined then we have several diagnostic options to further identify the problem. Most commonly we use radiographs to evaluate the area in question. Some cases may require diagnostic ultrasound to evaluate lamenesses involving tendons or other soft tissues as opposed to bone. More advanced imaging techniques are scintigraphy (bone scans), MRI, and thermography available at a variety of referral veterinary practices.
Following the determination of the precise cause of the lameness, a plan is formulated. This plan may involve rest, drugs, injections, physical therapy, complementary therapies (acupuncture, chiropractic), and farrier care.
LAMENESS TOPICS
" Upward fixation of the patella"
see YOU TUBE for lots of videos on this topic
Upward fixation of the patella is a condition seen primarily in young horses recently put into work. In this condition the medial (inside) and middle patellar ligaments become locked over the bottom of the femur. This locking prevents flexion of the stifle joint so that the leg is carried rigid extension. Usually after a couple of strides the patella will spontaneously shift to its normal position allowing the horse to walk normally. If the condition becomes persistent then there are several treatment options available. The oldest and most commonly prescribed treatment is exercise to increase the tone of the quadriceps muscle. Working up and down hills or in deep bedding will increase muscle tone. If this is unsuccessful then the patellar ligaments (medial and middle) may be injected with caustics or incised with multiple needle punctures. If these treatments along with exercise do not resolve this condition, then a medial patellar desmotomy may be preformed. This involves severing the medial patellar ligament. This should be done with caution as it may have future complications. In the past the use of systemic estogens have also been used to treat upward fixation of the patella.
Diagram of upward fixation of the patella.
Anatomy of the Stifle.
UNIVERSITY OF MINNESOTA NEUROMUSCULAR LAB STUDIES
FOR SUMMARIES OF MANY DISORDERS GO TO THEIR WEBSITE
YOU TUBE has many excellent videos demonstrating the disorders listed on the University of Minnesota Veterinary School's website. Just type in the disorder's name on the You Tube site.
Examples of these described disorders: Stringhalt, Equine Motor Neuron disease, Shivers, fibrotic myopathy, etc.
EVALUATE ONE OF OUR FORELIMB LAMENESS CASES VIA YOU TUBE:
DIAGNOSING LAMENESS CASES VIA THE UNIVERSITY OF PA VET SCHOOL
The University of PA Veterinary School has an excellent website that horses owners can access. One of the most interesting aspects is the lameness section where you can view the diagnosis of a few cases.
Diagram of upward fixation of the patella.
Anatomy of the Stifle.