Tendinitis/tendonitis is inflammation of a tendon. Tendinitis or tendonitis (from the Greek Τενοντίτις 'itis' denoting inflammation or swelling used to be thought of as a painful Inflammation Inflammation ( Latin, inflamatio, to set on fire is the complex biological response of vascular tissues to harmful stimuli such as Pathogens A tendon (or sinew) is a tough band of Fibrous connective tissue that usually connects Muscle to Bone and is capable of withstanding tension Many times, the tendon tissue is torn. A bowed tendon is a horseman's term for a tendon after a horse has sustained an injury that caused the tendon fibers to be torn, and then healed with "bowed" appearance.
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Description of a Tendinitis in Horses
Tendonitis usually involves disruption of the tendon fibers. Tendinitis or tendonitis (from the Greek Τενοντίτις 'itis' denoting inflammation or swelling used to be thought of as a painful Inflammation It is most commonly seen in the superficial digital flexor tendon (SDFT) in a front leg--the tendon that runs down the back of the leg, closest to the surface. Tendinitis is uncommon in the deep digital flexor tendon (DDFT) of a front leg or either the SDFT or DDFT in a hindleg.
When the SDFT is damaged, there is a thickening of the tendon, giving it a bowed appearance when the leg is viewed from the side. Bows usually occur in the middle of the tendon region, although they may also be seen in the upper third, right below the knee or hock (high bows), and lower third, just above the fetlock (low bows). Fetlock is the common name for the metacarpophalangeal and metatarsophalangeal Joints (MCPJ and MTPJ of the Horse.
For pictures of bowed tendons and the structures involved, see [1] and [2].
![[2]](http://www.horsetackreview.com/dbpix/bowedtendon-l.jpg){kind=link}
Causes and Factors of Tendinitis in Horses
Excessive Strain
Excessive strain on a tendon can damage its collagen fibers. A tendon (or sinew) is a tough band of Fibrous connective tissue that usually connects Muscle to Bone and is capable of withstanding tension This is most commonly seen in performance horses that gallop or jump, who usually strain a tendon as a result of fetlock overextension when their weight is loaded on one leg. The overextension of the fetlock causes overstretching of the flexor tendons, resulting in the rupture of tendon fibers. Horses in intense training, especially those that were not conditioned properly, may damage many collagen fibers. This may occur gradually or suddenly.
After the fibers are torn, the tendon hemorrhages and collects fluid (edema), creating swelling and lameness in the area as well as increasing the pressure. Bleeding, technically known as hemorrhaging / haemorrhaging (see American and British spelling differences) is the loss of Blood from Oedema (or Edema in American English formerly known as dropsy or hydropsy, is the increase of Interstitial fluid in any organ &mdash swelling Lameness in Horses and other Equidae is a term used to refer to any number of conditions where the animal fails to travel in a regular and sound manner on all four The increase in pressure may damage the tendon further by destroying the cross-linking of undamaged collagen fibers and preventing the flow of blood to the area. A tendon (or sinew) is a tough band of Fibrous connective tissue that usually connects Muscle to Bone and is capable of withstanding tension Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells such as nutrients and oxygen—and transports Waste products
The SDFT
The middle third of the SDFT is most likely to suffer from tendinitis for several reasons.
The SDFT is narrower in its middle third than its top or bottom sections, making it weaker. The top and bottom of the SDFT has a better supply of blood as well, with the top third supplied by the vessels from the knee, and the bottom third supplied by the vessels in the fetlock. Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells such as nutrients and oxygen—and transports Waste products Vessels are a Post-rock band from Leeds, UK. Vessels were born from the ashes of A Day Left in September 2005 The middle third has a poor supply of blood, relying on the tiny vessels of the peritendon (the membrane that surrounds the tendons). If this supply is for some reason compromised, the collagen fibers in the area may die, weakening the tendon in that area and making it more likely to tear.
The SDFT branches at the fetlock, creating a sling under the back of the joint. Thus, overextension of the fetlock is more likely to overstretch the SDFT than the DDFT, which simply travels straight down behind the fetlock and pastern, to attach to the coffin bone. Fetlock is the common name for the metacarpophalangeal and metatarsophalangeal Joints (MCPJ and MTPJ of the Horse. The equine forelimb is the front or thoracic limb of the Horse.
Other Factors
- Poor conformation: long, sloping pasterns and a long-toe, low-heel shape to the hoof (seen commonly in Thoroughbreds) predisposes a horse to tendinitis. Equine conformation refers to the correctness of a horse's bone structure musculature and its body proportions in relation to each other HoofRearHoovesjpg|thumb|200px|right|Rear hooves of a horse]] A hoof is the tip of a Toe of an Ungulate Mammal, strengthened by a thick horny ( The Thoroughbred is a horse breed
- Poor trimming and shoeing: such as a farrier that causes a hoof shape that predisposed the horse to tendon injuries (such as a long-toe and low-heel), or one that shoes a horse with toe grabs, which artificially create a long-toe and low heel by lifting the toe up. A farrier is a specialist in Equine hoof care including the trimming and balancing of a horse's hoof and the placing of shoes to the horse's
- Improper conditioning: such as working a horse at an intensity that it has not yet been conditioned for, working an unfit horse, and continuing to work an extremely fatigued horse. The horse ( Equus caballus) is a hoofed ( Ungulate) Mammal, one of eight living species of the family Equidae.
- Poor footing: working a horse on uneven or slippery footing can cause tendon strain, as well as deep, “thick” footing.
Each of these factors encourage the overextension of the fetlock and knee during work. Fetlock is the common name for the metacarpophalangeal and metatarsophalangeal Joints (MCPJ and MTPJ of the Horse. Several of these factors at once can add up.
- Direct trauma to a tendon: such as when a horse hits its front leg with a hind hoof. A tendon (or sinew) is a tough band of Fibrous connective tissue that usually connects Muscle to Bone and is capable of withstanding tension
Bandage Bows
Bandage bows are caused by applying a bandage too tightly, creating an acute pressure injury to the tendons. The compression may cause the area to swell once the bandage is removed, giving a "bowed" appearance. However, the damage is usually just to the skin and not to the tendon itself.
Horses with bandage bows usually respond to sweats or poultices. These treatments must be applied under a bandage that is not tightly fitted and the bandage should only be left on for a few hours. Cold hosing, NSAIDs and DMSO may also help.
Signs of Tendinitis in Horses
Signs of acute tendinitis include swelling, heat, and pain when the affected area is palpated. If mild, swelling may not be readily apparent, although there will still be heat and pain in the area as well as mild lameness. If more severe, the injury is usually accompanied by moderate lameness (2-3 on a scale of 5) with obvious swelling.
It is important not only to palpate the SDFT but the branches of the SDFT, the DDFT, check ligament, and suspensory ligament as well. These structures could have been damaged at the same time as the SDFT. Both legs should be checked, although tendinitis usually only occurs in one leg.
When the tendon is healed, it will still have a thickened, bowed appearance that feels firm and woody. However, all heat, lameness, and pain should disappear.
Treatment of Tendinitis in Horses
Several treatments for SDFT tendinitis have been attempted and rejected either on welfare grounds or due to lack of efficacy. These include:
- Blistering and firing (rejected on welfare grounds)
- Carbon fibre implants (proven to be ineffective. Carbon is extremely strong, but inflexible, causing increased strain on adjacent normal tissue)
- Surgical drainage (tendon splitting)of core lesion tissue (mixed opinions of benefit)
The best treatment is rest and anti-inflammatory drugs, with gradual return to exercise. Extracorporeal shockwave therapy is now more commonly used as an adjunctive therapy. Proximal check ligament desmotomy has been shown to return horses to work faster, but is thoughht by some to predispose to suspensory ligament injury. Mesenchymal stem cells, derived from the affected horse's bone marrow or fat are currently being used as a potential therapy for SDFT tendinitis and other injuries. Mesenchymal stem cells or MSCs are Multipotent Stem cells that can differentiate into a variety of cell types
Prognosis of Tendinitis in Horses
The prognosis for return to full work depends on:
- The damage to the tendon: if there was not obvious disruption of the tendon fibers, or if the damage was minimal and healed quickly and completely, the horse has a better prognosis for returning to full work.
- The treatment used: horses with moderate or severe tendinitis have a better prognosis if managed conservatively (rested, brought back to work slowly), with about 50-60 percent returning to training. If they undergo surgery and are rehabilitated correctly, up to 70-80 percent return to full work.
- Use of the horse: horses that are used for athletic events that strain their tendons (eventing, racing) are less likely to return to their previous level of performance than those in less strenuous work (dressage, pleasure and trail riding). Eventing is an equestrian event which comprises Dressage, cross-country and Show-jumping. Dressage (pronounced dress-ahhzh /ˈdrɛsɑʒ/ (a French term most commonly translated to mean "training" is a path and destination of competitive Horse training
- New treatments developed by VetCell Bioscience Ltd. and Vet-Stem involve the use of autologous mesenchymal stem cells to regenerate torn tendons.
The best way to ensure that an injured horse returns to full work is to rehabilitate the animal correctly. This includes slowly bringing the horse back into training, and giving the horse light exercise each day as the tendon is healing. An impatient trainer who rushes to bring the horse back to intense training is likely to cause re-injury of the tendon.
Prevention of Bowing and Reducing the Risk of Re-injury to Tendons
- Checking the Legs: especially after hard work, it is important to feel each leg for swelling and heat, and to palpate it for pain.
- Correct Trimming and Shoeing: a good farrier will trim the horse's feet correctly, preserving the pastern-hoof angle, and will properly support the horse’s heels. A horseshoe is a U-shaped item made of metal or of modern synthetic materials nailed or glued to the Hooves of Horses and some other Draught A farrier is a specialist in Equine hoof care including the trimming and balancing of a horse's hoof and the placing of shoes to the horse's
- Bandaging: using properly applied exercise bandages can help prevent the overextension of the fetlock. Polo wraps are bandage materials usually made of fleece for a horse's legs
- Correct Conditioning: with a base of long, slow distance work, and a fitness schedule that is not increased too rapidly.
- Suspending Training: if any sign of heat, swelling, or pain is detected.
Sources
King, Christine, BVSc, MACVSc, and Mansmann, Richard, VDM, PhD. "Equine Lameness. " Equine Research, Inc. 1997. Pages 400-415, 532-533.
See also
The equine forelimb is the front or thoracic limb of the Horse.Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic