Osselet is
arthritis
Arthritis is a term often used to mean any disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, swelling, and decreased range of motion of the affected joints. In some ...
in the
fetlock joint of a horse, caused by trauma.
Osselets usually occur in the front legs of the horse, because there is more strain and concussion on the fetlock there than in the hind legs. The arthritis will occur at the joint between the
cannon bone
Good conformation in the limbs leads to improved movement and decreased likelihood of injuries. Large differences in bone structure and size can be found in horses used for different activities, but correct conformation remains relatively simil ...
and
large pastern bone, at the front of the fetlock.
Definition
Osselets refers to the inflammation of the connective tissue that is around the cannon bone and the fetlock joint. Inflammation can involve arthritis and can become a degenerative joint disease. The condition is a job risk for young thoroughbreds and is usually caused by stress and due to the trauma of repeated hard training in young horses.
The first thing that appears on a horse with osselets is a swelling in the front part of the fetlock joint, there may be synovial strains on the sides of the joint. It is painful for the horse to flex the joint and usually causes lameness.
Fetlock joint
Definition
Fetlock
Fetlock is the common name in horses, large animals, and sometimes dogs for the metacarpophalangeal and metatarsophalangeal joints (MCPJ and MTPJ).
Although it somewhat resembles the human ankle in appearance, the joint is homologous to the b ...
is the common name for the metacarpophalangeal and metatarsophalangeal joints of horses, is a rotatory joint that can exhibit the greatest range of motion of any equine joint.
The fetlock joint is formed between the large metacarpal or metatarsal bone ( in the hindlimb and forelimb) and the proximal sesamoid bones.
Relation with osselet
Osselets is caused by stress on the fetlock, which results in a stretching of the joint capsule.
If the inflammation damages the cartilage of the joint, swelling in that area can become chronic and permanent. The joint capsule can also thicken.
Causes and effects
Osselets is caused by stress on the fetlock, which results in a stretching of the joint capsule. The early stage is called ''green osselets'', and is characterized by a hot, soft swelling at the fetlock. If inflammation damages the
cartilage
Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck an ...
of the joint, the swelling may become chronic and permanent.
Eventually, the bones of the joint will become involved, causing arthritis,
pain, stiffness, and
periostitis
Periostitis, also known as periostalgia, is a medical condition caused by inflammation of the periosteum, a layer of connective tissue that surrounds bone. The condition is generally chronic, and is marked by tenderness and swelling of the bone an ...
(new bone growth). The fibers of the joint capsule will also increase in size. The long pastern bone may also eventually chip at its front edge, which will leave bone fragments in the joint.
Horses with short, upright
pastern
The is a part of the leg of a horse between the fetlock and the top of the hoof. It incorporates the long pastern bone (proximal phalanx) and the short pastern bone (middle phalanx), which are held together by two sets of paired ligaments to fo ...
s are predisposed to develop osselets, as this conformation promotes concussion of the fetlock joint.
Other contributors to the horse contracting the osselets include uneven tensions in the fetlock joint (usually due to poor or unbalanced footwear), irregular terrain and hasty conditioning. The latter often causes muscle fatigue and does not protect the horse's joints from tripping or "bad steps" while working.
Diagnosis
The horse will suffer pain in flexion, or when the animal presses on the affected front of the fetlock, it is indicative of osselets, as is the short and short march that is the result of when both frontal fetlocks are involved. (Shoulder problems can also cause a horse to move that way, so watch carefully.) The heat and swelling around the fetlock will be obvious when a horse has osselets.
Treatment
When it first appears, it can be cured with rest, which is very important for treatment. To relieve inflammation, it is advisable to apply cold compresses for several days. Anti-inflammatory medications administered orally or by injection may also be used. Another treatment would be to inject corticosteroids into the joint. However, if this kind of medication is used while the horse continues its continuous training or racing, they will inevitably lead to the destruction of joint surfaces.
See also
*
Equine forelimb anatomy
Good conformation in the limbs leads to improved movement and decreased likelihood of injuries. Large differences in bone structure and size can be found in horses used for different activities, but correct conformation remains relatively simil ...
*
Equine anatomy
Equine anatomy encompasses the gross and microscopic anatomy of horses, ponies and other equids, including donkeys, mules and zebras. While all anatomical features of equids are described in the same terms as for other animals by the Internation ...
References
{{Reflist
Equine injury and lameness