{{No footnotes, date=February 2020 Ringbone is

exostosis An exostosis, also known as a osteochondroma, is a benign chondrogenic lesions derived from aberrant cartilage from the perichondral ring. Exostoses can cause chronic pain ranging from mild to moderate, but rarely severe, depending on the shape, s ...

(bone growth) in the pastern or coffin joint of a

horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 mi ...

. In severe cases, the growth can encircle the bones, giving ringbone its name. It has been suggested by some authors that such a colloquial term, whilst commonly used, might be misleading and that it would be better to refer to this condition as

osteoarthritis Osteoarthritis is a type of degenerative joint disease that results from breakdown of articular cartilage, joint cartilage and underlying bone. A form of arthritis, it is believed to be the fourth leading cause of disability in the world, affect ...

of the inter- phalangeal joints in

ungulate Ungulates ( ) are members of the diverse clade Euungulata ("true ungulates"), which primarily consists of large mammals with Hoof, hooves. Once part of the clade "Ungulata" along with the clade Paenungulata, "Ungulata" has since been determined ...

s (Rogers and Waldron, 1995: 34–35). Ringbone can be classified by its location, with "high ringbone" occurring on the lower part of the large pastern bone or the upper part of the small pastern bone. "Low ringbone" occurs on the lower part of the small

pastern The pastern is a part of the leg of a horse between the fetlock and the top of the hoof. It incorporates the Equine_forelimb_anatomy#Metacarpal_bones, long pastern bone (proximal phalanx) and the Equine_forelimb_anatomy#Middle_phalanx, short past ...

bone or the upper part of the

coffin bone The coffin bone, also known as the pedal bone (U.S.), is the Phalanx bones, distal phalanx, the bottommost bone in the Limbs of the horse#Legs, front and rear legs of horses, cattle, pigs and other ruminants. It is encased by the horse hoof, hoo ...

. High ringbone is easier seen than low ringbone, as low ringbone occurs in the hoof of the horse. However, low ringbone may be seen if it becomes serious, as it creates a bony bump on the

coronet In British heraldry, a coronet is a type of crown that is a mark of rank of non-reigning members of the royal family and peers. In other languages, this distinction is not made, and usually the same word for ''crown'' is used irrespective of ra ...

of the horse.

Causes

* Excessive tension on the

tendons A tendon or sinew is a tough band of dense fibrous connective tissue that connects muscle to bone. It sends the mechanical forces of muscle contraction to the skeletal system, while withstanding tension. Tendons, like ligaments, are made of ...

ligaments A ligament is a type of fibrous connective tissue in the body that connects bones to other bones. It also connects flight feathers to bones, in dinosaurs and birds. All 30,000 species of amniotes (land animals with internal bones) have ligam ...

, and

joint A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw- ...

capsules of the pastern area can strain the

periosteum The periosteum is a membrane that covers the outer surface of all bones, except at the articular surfaces (i.e. the parts within a joint space) of long bones. (At the joints of long bones the bone's outer surface is lined with "articular cartila ...

. The body compensates by growing bone at the stresspoint. Strain on the

extensor In anatomy, extension is a movement of a joint that increases the angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extend ...

tendon, the superficial digital

flexor In anatomy, flexor is a muscle that contracts to perform flexion (from the Latin verb ''flectere'', to bend), a movement that decreases the angle between the bones converging at a joint. For example, one's elbow joint flexes when one brin ...

tendon branches, the collateral ligaments, and the distal sesamoidean ligaments are all common factors. If these tissues are stretched or torn, and the joint is unstabilized by the injury, new bone is produced to help to stabilize the joint. *

Osteoarthritis Osteoarthritis is a type of degenerative joint disease that results from breakdown of articular cartilage, joint cartilage and underlying bone. A form of arthritis, it is believed to be the fourth leading cause of disability in the world, affect ...

(the endstage of degenerative joint disease) of the pastern or coffin joint is a very common cause of articular ringbone. Bone is then produced to try to immobilize the joint and to relieve the chronic inflammation of the joint capsule. This process may take years, and

lameness A limp is a type of asymmetric abnormality of the gait. Limping may be caused by pain, weakness, neuromuscular imbalance, or a skeletal deformity. The most common underlying cause of a painful limp is physical trauma; however, in the absence ...

will continue until the joint is completely immobilized. * Trauma to the periosteum can cause bone growth on the pastern bone. However, this is usually not progressive unless nearby

soft tissue Soft tissue connective tissue, connects and surrounds or supports internal organs and bones, and includes muscle, tendons, ligaments, Adipose tissue, fat, fibrous tissue, Lymphatic vessel, lymph and blood vessels, fasciae, and synovial membranes.� ...

was also harmed and thus the joint instability was affected. * Poor

shoeing Shoe-throwing showing the sole of one's shoe or using shoes to insult are forms of protest in many parts of the world. Shoe-throwing as an insult dates back to ancient times, being mentioned in verse 8 of Psalm 60 and the similar verse 9 of P ...

and conformation, such as long, sloping pasterns, upright pasterns, long-toes with low heels, pigeon toes, splay foot, or unbalanced feet may predispose the horse to ringbone, as they create uneven stress on the pastern and coffin joint, unequal tension on the soft tissues, or worsen the concussion that is absorbed by the pastern area.

Signs

Ringbone usually occurs in the front legs but can also be in the hind legs, and is usually worse in one leg than the other. Ringbone is most often found in mature horses, especially those in intensive training. High ringbone: The horse will have a bony growth around the pastern area, and the pastern will have less mobility. The horse will show pain when the pastern joint is moved or rotated. Early cases will have a

score of 1-2 out of 5, with little or no bony swelling seen, although possibly felt when compared to the opposite pastern. Lameness will worsen to a grade 2–3 on a scale of 5 as the ringbone worsens. Low ringbone: The horse will have moderate lameness (grade 2–3), even in early cases, because of the closeness of the ringbone to the other structures in the hoof. When severe or very advanced, the bony growth will be able to be seen on the coronet.

Treatment

Ringbone is degenerative (unless it is caused by direct trauma). Treatment works to slow down the progress of the bony changes and alleviate the horse's pain, rather than working to cure it. Shoeing: The

farrier A farrier is a specialist in equine hoof care, including the trimming and balancing of horses' hooves and the placing of shoes on their hooves, if necessary. A farrier combines some blacksmith's skills (fabricating, adapting, and adju ...

should balance the hoof and apply a shoe that supports the heels and allows for an easy breakover. NSAIDs: or non-steroidal anti-inflammatory drugs help to alleviate the pain and reduce inflammation within and around the joints. Often NSAIDs make the horse comfortable enough to continue ridden work, which is good for the horse's overall health. Joint injections: The pastern joint can be injected directly, typically with a form of

corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are invo ...

and

hyaluronic acid Hyaluronic acid (; abbreviated HA; conjugate base hyaluronate), also called hyaluronan, is an anionic, nonsulfated glycosaminoglycan distributed widely throughout connective, epithelial, and neural tissues. It is unique among glycosaminog ...

. Extracorporeal shockwave therapy: A high intensity specialized

percussion A percussion instrument is a musical instrument that is sounded by being struck or scraped by a percussion mallet, beater including attached or enclosed beaters or Rattle (percussion beater), rattles struck, scraped or rubbed by hand or ...

device can help to remodel new bone tissue and decrease pain. Arthrodesis: the fusion of the two bones of the pastern joints eliminates the instability of the joint, and thus the inflammation. This procedure may then eliminate the horse's lameness as well. However, surgical alteration of the joint can promote the growth of bone in the area, which is cosmetically displeasing. Arthrodesis of the coffin joint is usually not performed due to the location of the joint (within the hoof) and because the coffin joint needs some mobility for the horse to move correctly (unlike the pastern joint, which is very still). Interleukin-1 receptor antagonist protein (IRAP) blocks IL-1 from binding to tissues and inhibits the damaging consequences of IL-1. Microcurrent technology: Tissue, including muscle, tendons, ligaments, skin and bone, is formed from a large mass of similar cells that perform specific functions. These cells use tiny sequences of electric current, measured in millionths of an amp, to organise, monitor and regulate a stable state within the body. When there is injury, damage or disease to a tissue, there is disruption to the normal electrical current within the cells and things fail to work properly. By introducing the correct sequences the body's natural electric circuitry is replicated and kick starts and accelerates normal functioning.

Prognosis

If the ringbone is close to a joint, the prognosis for the horse's continued athletic use is not as good as if the ringbone is not near a joint. Ringbone that is progressing rapidly has a poorer prognosis as well. Horses that are not performing strenuous work, such as jumping or working at speed, will probably be usable for years to come. However, horses competing in intense sports may not be able to continue at their previous level, as their pastern joints are constantly stressed.

Sources

King, Christine, BVSc, MACVSc, and Mansmann, Richard, VDM, PhD. 1997. "Equine Lameness." Equine Research, Inc. Pages 694–699. Rogers, J and Waldron, T. 1995. "A Field Guide to Joint Disease in Archaeology". Chichester: John Wiley & Sons. Equine injury and lameness