Tendinitis (Musculoskeletal System)
What is it ?
Tendinitis is, etymologically speaking, inflammation of the tendon, whereas desmitis is inflammation of a ligament. Tendinitis or desmitis can be recognised by four easily identifiable clinical signs: redness, burning, pain (on palpation, lameness is not always present) and tumefaction (= swelling or oedema).
There are many causes of tendinitis. The most common is tendon fatigue, relating to fatigue of the muscle to which it is attached. Damaged fibres become inflamed and worn. The tendon no longer functions properly during movement and the damage is aggravated. Repeated or prolonged exercise and/or exercise the horse is not used to (particularly in terms of intensity) may cause tendinitis. It is therefore important to manage training carefully.
A horse's physical structure is another possible cause of tendinitis. Certain knock-kneed horses tend to develop tendinopathies more often than others due to poor distribution of the load and forces involved in movement. Food and terrain quality also play a major role, both in terms of general condition and level of training, and ground support and resonance.
b. Systemic effects
From an anatomical perspective, tendons and ligaments are made up of type I collagen fibres, arranged in a three-strand helix containing cells (fibroblasts and tenocytes) within a matrix comprising water, amino acids and glycoproteins.
Tendinitis (or tendinopathy) is the partial or total rupture of these fibres. The extent of the rupture determines the type of tendinitis, of which there are four:
Type I tendinitis : partial rupture with pain possible when the horse begins working, which then subsides as the animal warms up.
Type II tendinitis : partial rupture with persistent pain when the horse is at work, which may increase with the intensity of the exercise.
Type III tendinitis : partial rupture with permanent and intense pain, preventing the horse from training.
Type IV tendinitis : total fibre rupture, making all movement impossible and possibly requiring surgery.
a. Standard tests
The diagnosis involves several stages of examination.
Firstly, the vet will conduct a 3-step physical examination: static visual while the horse is not moving (the legs and any deformed areas are examined), followed by palpation and a dynamic examination to assess any musculoskeletal discomfort.
b. Possible further tests
Secondly, imaging—particularly ultrasound—can be highly useful in locating and assessing the severity of the damage. It enables us to see and follow the progression of the accumulation of inflammatory fluid, along with the formation of the haematoma caused by rupture of the fibres.
a. Main treatment guidelines
Regardless of the treatment, rest is essential and highly beneficial, as it enables the tendon to start to rebuild itself. Depending on the location and severity of the tendinitis, the vet will prescribe rest of varying degrees and lengths, from a few days to several months (or even a whole year), moderate and controlled exercise to outings in the paddock. Strict rest in the box is sometimes necessary. Rest must not be the only treatment, however.
Leaving it up to nature is often not sufficient for adequate recovery, and other more innovative techniques improve the quality of healing in terms of time and minimising the risk of relapse. The aim is to recreate the fine balance between physical strength and elasticity for the exercise for which the tendon is intended.
Optimal management should :
Control inflammation (to minimize the vicious circle of self-exacerbation and to manage pain).
Rebuild fibres (heal tendons) with functional collagen fibres (type I) rather than less elastic scar fibres (type II).
Managing inflammation :
Blocking the inflammatory cascade is essential for preventing the vicious circle of self-exacerbation caused by the mediators.
Some of the main techniques used by vets are:
l Surgery, cleansing of the tendon and removal of the haematoma and necrotic tissue, to achieve more rapid reconstruction
l Oral or injectable anti-inflammatory drugs
External topical treatments such as poultices, clay, cold-hosing and topical anti-inflammatory gels. The aim is to reduce inflammation and to promote drainage of the oedema and haematoma around and within the lesion. To this end, Laboratory Audevard brings you TENDILAX ANTIPHLOGISTIC, a Kaolin-based green clay that helps drain toxins, absorb excess fluid and improve vasodilation. Ask your vet for advice.
Tissue reconstruction :
Stimulation of tendon fibre synthesis and selection of type I collagen for restoring quality tissue is essential for ensuring functional repair. This means re-establishing initial elasticity and strength to reduce the risk of relapse.
Some of the main techniques used by vets are:
PRP (injection of platelet-rich plasma into the lesion: this contains growth factors that stimulate type I collagen synthesis)
Stem cell (injection of stem cells into the lesion after culture).
Bone marrow (injection of precursor cells into lesions = autograft)
Equine rehabilitation and physiotherapy. Gradual increase in weight on the damaged tendon to encourage the fibres to orient in the axial direction and form into bundles (static exercises, moving on firm terrain, in water, handling, massages, laser, shock waves etc.).
b. Nutritional solutions
Nutritional supplements may also be recommended by your vet. These products provide support for horses during tendon healing. For example, Audevard Laboratory offers EKYFLEX TENDON, which contains plants (fucus, Centella asiatica and bromelain) and provides additional nutritional support for horses being treated for tendon- or ligament-related musculoskeletal disorders.
c. Prevention measures
It is essential to train on good quality terrain in order to maintain your horse's tendons and ligaments. Regular exercise with a good warm-up beforehand is also a good way of reducing risks.
Tendinitis and desmitis are the result of a self-exacerbating inflammatory process and it is therefore important to identify any changes as soon as possible. Make sure you feel your horse's legs and particularly the tendons regularly, especially during intensive training or unusual exercise. If you have any doubts, ask your vet for advice.