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Hoof Balance And The Wider Musculoskeletal System - The Detection Of Early Stage Pathology

Monday, October 22, 2018  ‹ Back To Latest News List

Hoof Balance And The Wider Musculoskeletal System 
The Detection Of Early Stage Pathology
By Yogi Sharp DipWCF   

The equestrian performance world is becoming more competitive, horses are becoming finely tuned athletes and like their human counterparts even the slightest of physiological changes can affect performance. The importance of having a team of professionals who work closely together and understand the physiology of the horse, has never been more fundamental in succeeding in equestrian competition. 

The study of the relationship between hoof balance and the wider musculoskeletal system (axial skeleton) is still in its infancy, however, with the widely used expression of “no foot, no horse” it’s easy to see that this relationship is recognised as being a huge factor in achieving peak performance from our horses. 

The hoof is the horse’s point of contact with the ground, the biomechanics of this interaction dictate the physiological effects of movement on the given animal, however this doesn’t mean it’s the farrier’s fault if this relationship isn’t ideal.  We must understand that the form of the hoof follows the forces that act upon it, conformation and hoof growth have direct effects on hoof morphology. From the second the farrier puts down a finished hoof, these components are having a negative effect on physiology, a farrier can not change a horse’s conformation after the point at which its growth plates have closed. What he can do, is facilitate a more balanced interaction with the ground by assessing the individual and shoeing it accordingly. 

Even with ideal conformation, normal hoof growth has negative effects on the internal structures of the hoof (Moleman et al 2006, Van Heel et al 2004,2005) but coupled with conformational defects which every horse will have, you have a complexed array of physiological effects. Curtis (2002) discussed how the forces acting upon the hoof are infinitely different in each horse, however you can predict the predispositions of certain conformations and how they will morph the hoof. For the most part (assuming correct farriery) hoof distortion is caused by poor conformation due to the uneven loading from above, not the other way round. However, it is the farrier’s job to recognise the imbalances and look to re-establish balance.
   
Picture 1 and 2 Normal hoof growth causes an increased moment around the distal interphalangeal joint, increases load on the deep digital flexor tendon and the navicular area, this means that just leaving your horse too long between shoeing already predisposes it to serious issues.   

Dr Kilmartin discussed in depth the relationship between hoof balance and the wider musculoskeletal system. He stated that even a small amount of imbalance can cause a change in muscle development and tension in the upper body, the imbalances and their effects are too many to count (Curtis 2002).  An example Kilmartin gives is a simple medio-lateral imbalance, something that will be present in the majority of horses. 

In cases of medio-lateral imbalance in one of the forelimbs the medial wall of the hoof is more vertical and the lateral wall is flaring out.  Looking at the sole of the hoof the medial wall is higher than the lateral wall.  In these cases, the Transverse, Ascending, and Descending Pectoral muscles are working along with the Subscapularis and Brachiocephalic to keep the fore limb under the body.  These horses again consistently show pain or reactivity over the cartilage of the scapula. 

This horse will probably not show any structural change, but its performance would drop and over time it may aquire a pathology.

Picture 3 - A common conformation defect, base narrow, the load is born on the lateral aspect of the hoof causing compression, wear and contraction. You can clearly see that the lateral heels are crushed and underrun. The lateral aspect of the entire limb is loading predisposing the animal to a range of physiological dysfunction, including predisposing the horse to hock pathologies. The hoof has morphed according to the forces acting upon it.

Picture 4 - A lateral extension has been fitted to support the lateral aspect of the limb and widen the stance of the horse to help regain central loading of the hoof. The farrier has assessed the unique conformation and done what he can to re-establish a balanced relationship with the ground, however the farrier hasn’t and can not change the horse’s conformation.

Establishing that hoof balance is subject to the forces acting upon it, can affect the horse’s physiology way beyond just the digit or limb. A farrier can aid in helping to reduce the negative effects this conformation has on the rest of the musculoskeletal system but isn’t responsible for the morphology and cannot change the conformation.  We can see that every horse is going to have physiological changes, unless it has 100% perfect conformation; and to maintain that horse working at peak performance it needs to be continually assessed for the inevitable musculoskeletal dysfunctions. It is vitally important that to keep a horse in peak physiological condition, it must be looked at holistically, with each professional, from physios to vets to trainers working together. 

The problem is, many of these pathologies will be sub clinical and may not be diagnosed until it’s too late.  The screening modalities available to these professionals may not pick up sub clinical dysfunction and/or may be far too expensive to use on a regular monitoring basis.  How beneficial would it be if there was a screening modality which could sync these professionals with the information they needed to keep the horse in peak performance mode by picking up physiological changes at their earliest stage?   

Veterinary Digital Infrared Thermal Imaging, more commonly known as thermography, is a very usefull tool in detecting early stage pathologies.  It is a test of the autonomic sympathetic nervous system and as such can pick up any physiological dysfunction within the horse. The horse’s body will start to display physiological changes, reacting to dysfunction, way before that dysfunction is visible by other screening modalities and certainly before anything is detectable by sight or touch. If this modality is used clinically it can be used to help keep performance horses at their peak, it will highlight sub-clinical physiological issues which can then be treated pre-emptively. 

The problem in the past with the technology has been the lack of standardised protocols.  A recent topical review (E F J Ring and K Ammer 2012) stated that thermal imaging has developed considerably since it first became available, has become financially more viable, technically more reliable and considerably more portable. As in many other areas of imaging, computerisation has had a dramatic effect on both ease and reliability of use.  Recent studies have shown, standardised protocols are essential for this technique, and this must also be applied to the image processing and the selection of repeatable regions of interest. This review also discussed the many, many physiological dysfunctions the technology can help with diagnosing. 

The secret to utilising this uniquely useful modality is having the correct team, an imaging technician who follows the correct protocols, an interpreting vet who is experienced and qualified in reading the images and the subsequent professional who understands what information the modality has the capabilities of showing.

For instance, take Kilmartin’s example of the possible physiological effects of a simple hoof imbalance, he expressed how the shoulder muscles would come under strain in order to facilitate the imbalance, these physiological changes would likely remain subclinical with only a drop in performance as a symptom. 

The adjacent images provided by SyncThermology (5,6,7 & 8) identified physiological changes and allowed corrections to be made at an early stage.       

These images show hyperthermic asymmetries over the shoulders, with the experienced interpretation of specialised vets providing valuable information to the subsequent professional, be it vet or physio.  This horse could be treated while the issue was still subclinical, before it became an acute dysfunction. Not only does this give information to these professionals to aid their diagnosis, but if as a team they decide the issue may be caused by a foot imbalance, this information could provide subsequent valuable information to the farrier if coupled with foot x-rays. In an elite performance horse this simple process could keep the athlete at peak performance and increase the longevity of its career.   

The following image is a part of a veterinary report from SyncThermology. This particular case shows how veterinary DITI can be a valuable tool in the detection of early stage pathologies and coupled with the appropriate subsequent screening modality can aid in earlier diagnosis. 

This horse had had other modality tests before its thermal imaging which had not been able to pick up any structural changes. Thermal imaging highlighted an area for further investigation at the back of the carpus. Further investigation including Scintigraphy correlated thermographic findings and a diagnosis was made.

*Please view Case Study Image 9*

Conclusion 

We have all heard the old adage “prevention is better than cure.” Well I’ll add to that and say “early stage detection is better then post trauma treatment.” 

Our human athletes are constantly being monitored and treated preventatively, granted this is more difficult with an animal who can’t inform us of little niggles.  But there is the technology and a modality available to owners now which can monitor their horse’s physiological state and help to maintain their wellbeing as well as their human counterparts. 

In sports where splits of a second or millimetres of height in a jump can be the difference between winning or losing, the smallest of subclinical imbalances, from the hoof to the poll can be that difference. 

As a farrier, who comes under daily pressure to “make my horse go better.” The knowledge and expertise of the other professionals involved in the care of the horse is paramount, and a screening modality that can “sync” this team together can only be a massive advantage. 

All thermal images in this document are ©SyncThermology