Equine Arthritis

Equine Arthritis

Arthritis is a common problem for both us and our horses, suffered by 1 in 6 adults [1] and the cause of 60% of lameness cases [2]. Also known as Osteoarthritis (OA) and degenerative joint disease (DJD), arthritis is not uncommon during an equine athlete’s career or elderly years, ultimately resulting in loss of articular cartilage, bony changes and reduced joint space, giving rise to pain and discomfort, reduced range of motion and athletic ability [3,4]. Occurring predominantly in synovial joints of the horse, the knee, hock and fetlock are most commonly affected by the disease [5], impairing their ability to transfer load and allow movement [3]. The physiological process leading to this point is shown below in a diagram by Joint Performance.

Indications that your horse is suffering from OA include swelling, stiffness, reduced motion of a joint, lameness, reluctance to work, altered performance/behaviour and difficulty or reluctance to lay down [5,6]. If you suspect this is the case, read more on how you could receive diagnosis for the condition [7].

Causes

Trauma – Like in human athletes such as boxers or runners, particular joints in the horse undergo intense stress and impact throughout their career. Coupled with other factors such as fatigue, speed, poor surface or conformation, these forces through the joint can be exacerbated [3]. As a result, bones suffer microtrauma and cartilage is damaged. This is particularly the case for joints affected in the forelimb of the horse as they receive 60-65% of the horse’s body weight and bear the brunt of various types of loading [9].

Immobilisation - Contrary to what you may think, immobilisation and lack of exercise can also trigger OA. This is because without mechanical stimulation, cartilage can atrophy or degenerate. So while excessive forces can have negative consequences and wear away cartilage, no exercise will also result in loss of cartilage [3].

Conformation – Every horse is uniquely conformed and unfortunately, some are less well put together than others. Conformation defects such as ‘calf knees’, ‘knocked knees’ and ‘bowed knees’ create an altered gait and so the horse is prone to loading his or her joints abnormally, giving rise to greater forces through the joints and earlier wear and tear than a horse with cleaner limbs [10]. As conformation traits are closely related to breed, it unsurprising that research shows that some breeds are predisposed to the development of OA such as the Icelandic and quarter horse due to straight hocks and poor carpal conformation respectively [11,12].

Shoeing – Hitting the spotlight increasingly more is the importance of foot balance and how less is sometimes much more for trimming and shoeing. This is because the balanced hoof is responsible for absorbing high impact vibrations and trauma [3]. Incorrect shoeing risks throwing the foot out of balance and a change of loading up the limb as the horse places his or her foot on the ground. Sudden changes to the horse’s hoof angle and loading can be very harmful and induce articular changes [3].

Ageing process – In humans, ageing is one of the most likely causes of arthritis [3]. However in horses, cases are more evenly distributed from as early as 2 years old depending on use and training regime. Certain disciplines such as horseracing accelerate the rate at which natural cartilage degeneration would occur. As the horse gets older, biochemical properties of the cartilage begin to change. Around the age of 15, a metabolic shift causes increased cell death within cartilage and fibrous tissues which contribute to OA [14]. However, research has found a large range of cases start earlier within the age range of 8 to 30 years old [13].

Treatment

There is currently no cure for arthritis, however there are treatment options and management practices that can be implemented to prevent or reduce inflammation and the damage it causes.

In some instances, your vet may recommend medication to treat your horse’ arthritis. This may consist of steroid injections (anti-inflammatories) to reduce chronic inflammation, hyaluronic acid which contributes to normal joint fluid [6,8], Polysulfated glycosaminoglycans (PSGAGs) which can be injected into both the joint and muscle and are believed to stimulate the production of synovial fluid or Interleukin-1 receptor antagonist protein (IRAP), an inhibitor of a protein that accelerates joint damage [8]. Oral anti-inflammatories such as Bute or the more advanced treatment such as stem cell therapy are also potential options. To learn more about these, read here or speak to your vet.

Although medical treatment may be your first port of call, there are other things you can do yourself to manage and/or prevent further degradation.

Exercise 

1. Warm up slowly – We all know the importance of warming up to gradually increase temperature and flexibility of the tendons, ligaments and muscles to limit the risk of damage (straining or stretching structures) and this in increasingly important for arthritic horses as joints may take longer to loosen up. A warm up could consist of anything from a 15-20 minute hack to 15 minutes walking on a loose rein large then onto 20m and 15m circles or even some lateral work in walk on a loose rein.

2. Little and often – Current domesticated management practices mean our horses are often stood still for long periods of time which can allow joints to stiffen. Allowing your horse to move in a turnout paddock, the school or during a short walk a few times a day could really help improve joint mobility.

3. Avoid repetitive concussion/high impact activities – Try and vary what you do with your horse and avoid high impact activities such as galloping or jumping for long periods frequently. Why not hack one day, school another, try poles once a week and lunge for one session? This will not only spread loading on the joints but have a positive effect on mental attitude as work load is varied and engaging.

4. Always cool-down – We all think of warming up our horse before exercise but what about a cool down? The physiological principles are still the same for a cool down, muscles and tendons need to cool before returning to the yard and decrease in size and flexibility to reduce the chance of injury. Muscles also require time after exercise to process lactic acid built up during the session to reduce the severity of delayed onset muscle soreness and stiffness [16]. For a horse that is already stiff, the lack of a cool down could be crippling.

5. Use a good surface – To prevent abnormal loading of joints, ensure you try and ride on a consistent and shock absorbing surface to minimise the effects on your horse.

Feeding

1. A healthy weight/good diet – Unsurprisingly, excess weight on joints increases the stresses and pressure running through them [18]. To increase the longevity of your horse being ridden and being able to move comfortably, a healthy weight must be maintained by a good fibrous diet. Our recent blog on weight management explains further.

2. Supplements – Joint supplements are a good compliment to medicinal treatment to encourage long lasting effects. The combination of ingredients usually provide the horse’s body with a continual supply of components that are necessary to maintain healthy joints that are not abundant enough in their body naturally [15]. There are many types available with varying degrees of efficacy, both with medicinal ingredients and natural. Learn more about supplements with smartpak.

Management

1. Plenty of turnout – Gentle movement on a regular basis, if not all the time, prevents atrophy of the cartilage and so turnout not only gives joints the mechanical stimulation they need, but prevents them seizing up and helps relieve stiffness [18]. Furthermore, movement and exercise will keep surrounding structures such as muscles strong to support and stabilise the joints.

2. Good shoeing/trimming – As discussed in causes, foot balance is a huge precursor of OA and therefore ensuring your horse has consistent and good natural foot balance is essential to prevent OA worsening [17]. Take a look below for some further links on foot balance to learn more.

3. Professional advice - Always liaise with your vet – It may seem obvious but just checking in with your vet on a regular basis to discuss your horse’s progress could be useful. It doesn’t have to be an expensive call out, just a phone call to hear more about a recommended local physio and some exercises that could help or get some advice on the best supplements which could really help maintain your horse’s condition.

Arthritis may not be curable  and sometimes even preventable but there are solutions to keep your horse active and comfortable while still enjoying your time in the saddle together. With the right management and intervention from the vet, older horses and even younger ones suffering with OA can live a healthy life and provide enjoyment for their human companions for many years to come. 

If you are an owner managing a  horse with OA, please let us know in the comments how you prefer to tackle it and what you have tried and tested.

Written by Ruth Box BSc, EEBW @ruth_box6910 Email Ruth

Further Reading

Trackener Life kits enable monitoring of factors that help manage conditions such as arthritis. By regularly checking activity, movement and heart rate, it is possible to tell on the app whether or not your horse is less mobile perhaps because he is feeling stiffer or in pain. Read more about how it could you and your horse here.

Remedial farriery Part 5: Principles of foot balance by Peter Milner BVetMed BSc PhD CertES(Orth) MRCV and Ian Hughes DWCF
Equine Arthritis: Everything you need to know - A great printout by XL Vets
Bony Changes in the Equine Neck by The Horse.com

References

[1] https://www.nhs.uk/Conditions/Arthritis/
[2] USDA, L., & Lameness, V. S. (2000). Laminitis in US Horses. USDA: APHIS: VS, CEAH, National Animal Health Monitoring System N, 348. https://www.aphis.usda.gov/animal_health/nahms/equine/downloads/equine98/Equine98_dr_Lameness.pdf (Accessed 12/04/2018)
[3] Schlueter, A. E., & Orth, M. W. (2004). Equine osteoarthritis: a brief review of the disease and its causes. Equine and Comparative Exercise Physiology, 1(4), 221-231.
[4] https://www.jointperformance.com.au/what-is-equine-arthritis/
[5] https://www.horsejournals.com/arthritis-horses-understanding-treating-joint-disease
[6] https://www.scarsdalevets.com/managing-arthritis-in-the-horse/
[7] https://www.scarsdalevets.com/wp-content/uploads/2015/03/DocsEquine-Arthritis-XL.pdf
[8] https://equusmagazine.com/lameness/coping-with-arthritis-in-horses-8356
[9] Back W, Schamhardt HC, Hartman W and Barneveld A (1995). Kinematic differences between the distal portions of the forelimbs and hind limbs of horses at the trot. American Journal of Veterinary Research 56: 1522–1528.
[10] Goble DO (1992). Medical evaluation of the musculoskeletal system and common integument relevant to purchase. Veterinary Clinics of North America Equine Practice 8: 285–302.
[11] Axelsson M, Bjornsdottir S, Eksell P, Haggstrom J, Sigurdsson, H and Carlsten J (2001). Risk factors associated with hindlimb lameness and degenerative joint disease in the distal tarsus of Icelandic horses. Equine Veterinary Journal 33: 84–90.
[12] Goodman NL and Baker BK (1990). Lameness diagnosis and treatment in the Quarter Horse racehorse. Veterinary Clinics of North America Equine Practice 6: 85–108.
[13] Fuller CJ, Barr AR, Dieppe PA and Sharif M (1996). Variation of an epitope of keratan sulphate and total glycosaminoglycans in normal equine joints. Equine Veterinary Journal 28: 490–493.
[14] https://www.equisearch.com/articles/arthritis-in-horses-18029
[15] https://www.smartpakequine.com/content/Arthritis-in-Horses
[16] http://www.horsechannel.com/horse-health/why-should-you-cool-out-your-horse-after-a-ride.aspx
[17] https://www.thesprucepets.com/equine-arthritis-1886858
[18] http://www.xlvets-equine.co.uk/sites/xlequine.co.uk/files/Arthritis.pdf