LAMENESS EXAMINATION

Lameness is one of the major reasons for poor performance in the equine athlete. Lameness is not always obvious and subtle lameness can present in a number of ways, ranging from the sudden development of muscle pain, wanting to run in or out during a race, resentment of certain exercises or a general reluctance to work.

When approaching a lameness problem with your horse we ask for a comprehensive history. Every little detail is important to us, from a change in shoeing to increases in work schedule or a sudden noticeable change in your horse’s demeanor. We also ask for a detailed medical history including any previous lameness issues, past treatments or surgeries as well as any past or present medications. This information helps us put together an overall clinical picture that will help us in the diagnosis and management of your horses’ lameness issues.

One often overlooked, but very important thing to bear in mind, is that the right facilities will often help us reach our diagnosis in an accurate and time efficient manner.

WHAT TO EXPECT DURING A LAMENESS EXAMINATION

We will ask you to trot your horse in a straight line on an even, hard surface. A driveway is often the best place for a trot up. If the lameness is subtle, it is often very helpful for us to observe the horse on the lunge or under saddle. So, it is ideal if access to an arena is available. A power source is also necessary if radiographs are going to be taken.

We take safety very seriously, so we ask that all horses presented for a lameness examination are done so with a bit in their mouth. We also ask that a person over the age of 18 be present on the day of the examination to hold the horse in case radiographs need to be taken.

This may seem like an obvious statement, but often soreness will subside after a period of a few days rest, and this can make it difficult for us to see the true clinical picture and isolate the site of lameness. Bearing this in mind, some gentle work may be required the day before the examination to ensure that the lameness is evident on the day of the lameness examination.

We also ask that horses are not given phenylbutazone (bute) within 48 hours of the lameness examination because anti-inflammatory medications will often mask soreness and necessitate a repeat examination at a later date.

So, when lameness examination is booked, we will get a detailed history and a description of the current issues from you at the time of the booking. This often allows us to gauge the how difficult the problem will be to properly assess, so that we can book out sufficient time in our day to work through your horses lameness issue. It is important to us that you and your horse get the most out of every consultation so we always try to choose a time for the examination that suits everyone involved.

STEP 1

The lameness examination commences with the horse walking and trotting in straight line. This allows us to assess lameness evident in a straight line as well as the symmetry of your horses’ movement. We will assess the foot flight of each limb, and the movement of the head, neck and pelvis. At this point, we will also often perform flexion tests. Then we will decide which is the most appropriate way to proceed with the examination. Sometimes we will ask you to lunge your horse because some lameness will only become evident on the circle. Equally, sometimes lameness may become evident in both legs depending on which rein the horse is working. If the complaint has only been noticed under saddle then we may ask you to ride the horse so we can accurately assess the problems that you have noticed. The aim of the clinical examination is get as much information as possible before deciding where to direct further efforts towards isolating the cause of the lameness.

 

STEP 2

The next step in the lameness examination is often the use of nerve blocks. Flexion tests are the not the only method for isolating the site of lameness, and can sometimes be misleading, so we often combine flexion tests with the use of peri-neural (around the nerve) nerve blocks. A peri-neural nerve block involves injecting local anaesthetic around nerves in the leg in a certain commonly accepted pattern. A knowledge of anatomy allows us to understand the path of the nerves as they travel down the leg and by injecting local anaesthetic at certain sites we can dull pain originating from areas below the sites of local anaesthetic placement. After waiting a certain amount of time for the local anaesthetic to take effect, we trot the horse again. If the lameness has been abolished by the nerve block, we have a very strong indication that the lameness is originating from a site below the level of the block. We can then use diagnostic imaging modalities in a targeted and strategic manner to diagnose the problem. If the lameness is not abolished, the next appropriate step is to administer another nerve block at a point higher in the leg and assess the lameness again. This process can be time consuming, but it will often allow us to definitively isolate the site of the lameness.

In some cases, instead of performing peri-neural nerve blocks, we will elect to perform intra-articular (joint) nerve blocks. This is when local anaesthetic is injected into a joint such as the fetlock in a sterile fashion. One of the main benefits of an intra-articular nerve block, is that it does allow us to make an assessment of whether the lameness is isolated to a joint or whether there may also be some soft tissue involvement. Another benefit, is that a positive response to an intra-articular nerve block is often a good indication that the horse will respond to intra-articular therapy.

STEP 3

Once the site of soreness has been isolated, we will discuss with you the most appropriate imaging modality or modalities to use to reach a final diagnosis. It is very important to work through the process of lameness isolation instead of just simply jumping to diagnostic tests. The reason for this is that many horses will have radiographic changes in multiple areas that may or may not be causing lameness. In other words, they may or may not be clinically significant. However, if we have isolated the site of lameness and there are radiographic changes in that area we can be quite certain that those radiographic changes are clinically significant.

 

We always aim, to discuss all the options available to you and your horse at every step of the way. We will offer our opinion to help you in your decision making process. We encourage all our clients to communicate with us and if you have a question or a concern we are always happy to discuss your case further.