Identifying Joint Disease
Joint pain can be mild to severe; even mild joint pain that is unnoticeable in terms of lameness to the rider can be performance limiting. A sore joint may stop a show jumper landing on the correct lead after the fence or it may cause the horse to roll unnecessary poles of higher fences. A dressage horse may show asymmetry of limb action during complex dressage movements. Polo ponies may find it difficult to stop and turn sharply and race horses with joint pain may be slower than their expected potential. Joint pain is as a result of joint inflammation, so left untreated some inflamed joints will settle down with rest. Some chronically inflamed joints go on to become osteoarthritic. Early identification of joint inflammation and appropriate treatment can reduce the chances of chronic joint pain and therefore poor performance and lameness issues.
Often riders will call and say they think there is a problem with a horse, and I now look at higher level competition horses on a regular basis to monitor for joint pain. The first thing is to ask the rider to describe the problems they think they are having. I then palpate the horse’s limbs for obvious filling of the joints, as in most cases an inflamed joint will have an effusion, which is where the inflamed lining of the joint produces an excess amount of fluid. Some effused joints can be identified by visual inspection as the joint bulges. In some instances, particularly with the fetlock joint, it is possible to feel a palpable thickening of the joint capsule. Some joints will feel warm to the touch.
The next step is to trot the horse up on a firm flat surface and see how it moves. One of the advantages of regular checks is the vet gets to know what it normal for the horse and is then able to spot subtle gait changes. Flexion tests are a valuable way of identifying a problem with a joint, most inflamed joints will result in lameness after flexion test. The horse will then be evaluated under saddle, on the lunge in a school and on a hard surface. The rider will be asked to demonstrate the problems they are having, this may be during complex dressage movements or jumping obstacles.
Often it is possible to identify a specific joint causing the problem by clinical examination, but a lot of the time it is necessary to anaesthetise or block sequentially joints on the limb in question. Once a joint is blocked the horse is put back in the situation that demonstrated the lameness the best, i.e. on the lunge, on the hard or flexion test. Often there is little for the vet to visually see and the response to blocking must be assessed by the rider.