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Lameness is one of the major causes of poor performance in the equine athlete. There are a number of conditions that cause soreness in different joints and for this reason we as veterinary surgeons have developed a number of techniques to assess and identify the source of the lameness. I will take you through the process of examination and identification of the site of soreness that will allow us to identify and implement the best treatment modality to reduce and remove the pain.
The start of the lameness examination for a vet is always the call when you as the owner report a problem. The range of complaints can be from the obvious, my horse is sore at the walk, through to a resentment of flexion on one rein or the other, or a sudden change in demeanor, or soreness. Anyone of these problems can be attributed to lameness. It is important to tell the vet everything, from it happened since a change in shoeing, I have started jumping the horse, or I think he may have slipped in the paddock. All these things help the vet to begin to piece together the cause of the soreness.
It is important that the horse is sore when the examination commences, this may sound like an obvious statement, but if your horse is given several days off from work, all soreness may have subsided. It is then impossible for your vet to truly find the site of the soreness. Some gentle work may be required the day before to ensure that something is visible for the vet to see. The other thing is please do not give the horse any pain killers such as Bute as this will mask any soreness. Please discuss with your vet before giving this. |
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The next part of the examination starts when a horse is pulled out for a trot up. At this stage the horse is examined in hand at the start and is trotted up and down on a hard surface. The surface should be flat and even so that the gait of the horse can be assessed. The trot is the best gait to start the assessment as it is a two beat movement so each limb can be assessed.
It is important if you want your vet to be able to work up lameness that you have the facilities to do the examination properly. The ideal situation is an even flat surface that is harder than grass to trot the horse up and down on. This allows the vet to assess the horse at a walk and trot. It is easier to see lameness that way, rather than trotting on a forgiving surface such as soft grass or an arena. In an ideal world your horse will be willing to trot in a straight line on the surface; many horses unfortunately rarely do this so it is important that other options are available. You as the horse handler are also important when trotting a horse up for your vet. You should be trot the horse is a straight line and also be willing to allow the horse to have a free head so that we can assess for head movement as the horse trots. I also like people when handling horses to have a bit in the horse’s mouth. The reason for this is that you as the handler have slightly more control of the horse rather than just a head collar. It is important that you have control of the horse at all times. A lunging surface is helpful for looking at the horse on a circle, and for those horses which are not willing to trot in a straight line.
When a horse trots away from me, I assess for evenness of the pelvis as the horse trots. If there is soreness the points of the hip will move up and down by a different amount on the lame leg. When a horse trots back to me I listen for evenness of the foot fall, i.e. does the horse land with even weight on each leg. Then I assess for movement of the head. When there is lameness in the front leg, the head will go up in the air as the lame leg hits the ground, and comes down when the sound leg hits the ground. The reason for this is that the horse will try and move weight away from the sore spot and hence when the lame leg hits the ground the horse will try and move weight along the back by lifting the head.
If there is no evidence of lameness in a straight line but there is a report of soreness, I will then consider lunging the horse on a circle. The reason for this is that the circle will put added pressure on the inside leg. At the lunge the horse will then be lunged on both reins at the trot and canter, this allows an assessment to be made of the hind and forelegs as the horse moves. Often mild lameness in both front legs will not show up in a straight line but when on a circle there will be lameness on the inside leg when lunged to the right and left.
Once the initial lameness examination has been performed then the examination continues by palpation of the legs. This will include making an assessment for any extra heat in any joints, swellings or reduced range of motion. This is all done with the horse standing.
The next step of the examination is flexion tests. This involves flexing individual groups of joints and holding them in a fully flexed position for a period of 30-40 seconds, after which the horse is asked to trot away in a straight line. If lameness is seen in one front leg, then both front legs will undergo flexion tests and an assessment made of all the results. Flexion tests have previously been subject to intense scrutiny when used as part of a pre-purchase examination. My interpretation of them is that they are a subjective test of soreness and by no means does a negative result indicate no pain and equally a positive result can be normal. It all depends on the force exerted on the joints when flexion occurs and the vet interpreting them. Indeed I will interpret the results of a flexion test different from another vet. It is not an easy area to assess, nor give a definitive answer as to what is a positive flexion test. Flexion tests are merely an extension of the clinical examination and as such should be used to assess for any changes and pain. They are not the definitive result that many people think.
For some problems it may be necessary to assess the horse when ridden as some rider complaints may only be evident when the horse is ridden. An example of this is back problems, or problems when jumping i.e. horse continually landing on one leg or jumping across the jumps.
This is now the finish of the initial examination. This examination allows us to assess the site of soreness, and make suggestions for further diagnosis. A thorough lameness examination can involve so much more but this will be covered in the next in the series of the lame horse.
By Michael A Tweedie, M.A., VetMB, MRCVS, Tel: 0434 318 471 Email: info@kensingtonbanks.com.au |