Arthrodesis, also known as artificial

ankylosis Ankylosis is a stiffness of a joint due to abnormal adhesion and rigidity of the bones of the joint, which may be the result of injury or disease. The rigidity may be complete or partial and may be due to inflammation of the tendinous or muscular ...

or syndesis, is the artificial induction of

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 ...

ossification Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in ...

between two

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, an ...

s by surgery. This is done to relieve intractable

pain Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...

in a joint which cannot be managed by pain medication, splints, or other normally indicated treatments. The typical causes of such pain are fractures which disrupt the joint, severe sprains, and

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 ...

. It is most commonly performed on joints in the spine,

hand A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each " ...

ankle The ankle, or the talocrural region, or the jumping bone (informal) is the area where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular ...

, and

foot The foot ( : feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg mad ...

. Historically,

knee In humans and other primates, the knee joins the thigh with the human leg, leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest join ...

and hip arthrodeses were also performed as pain-relieving procedures, but with the great successes achieved in hip and knee

arthroplasty Arthroplasty (literally " e-orming of joint") is an orthopedic surgical procedure where the articular surface of a musculoskeletal joint is replaced, remodeled, or realigned by osteotomy or some other procedure. It is an elective procedure that ...

, arthrodesis of these large joints has fallen out of favour as a primary procedure, and now is only used as a procedure of last resort in some failed arthroplasties.

Method

Arthrodesis can be done in several ways: * A bone graft can be created between the two bones using a bone from elsewhere in the person's body (autograft) or using donor bone ( allograft) from a bone bank.http://bonebank.com/ ** Bone autograft is generally preferred by surgeons because, as well as eliminating the risks associated with allografts, bone autograft contains native bone-forming cells (

osteoblast Osteoblasts (from the Greek combining forms for "bone", ὀστέο-, ''osteo-'' and βλαστάνω, ''blastanō'' "germinate") are cells with a single nucleus that synthesize bone. However, in the process of bone formation, osteoblasts functi ...

s), so the graft itself forms new bone (osteoinductive), as well as acting as a matrix or scaffold to new bone growing from the bones being bridged (osteoconductive). The main drawback of bone autograft is the limited supply available for harvest. ** Bone allograft has the advantage of being available in far larger quantities than autograft; however, during the treatment process the bone goes through following harvest, which usually involves deep-freezing and may also involve demineralization, irradiation and/or freeze-drying, kills living bone or bone marrow cells. This significantly reduces the immunogenicity (risk of graft rejection) such that no antirejection drugs are needed, and combined with appropriate donor screening practices, these processing and preservation practices can significantly reduce the risk of disease transmission. In spite of all of this processing, cancellous allograft bone retains its osteoconductive properties. Furthermore, certain processing practices have been shown to also retain the acid-stable osteoinductive proteins in cortical bone grafts, so that many bone allografts can be considered both osteoconductive and osteoinductive. * A variety of synthetic bone substitutes are commercially available. These are usually

hydroxyapatite Hydroxyapatite, also called hydroxylapatite (HA), is a naturally occurring mineral form of calcium apatite with the formula Ca5(PO4)3(OH), but it is usually written Ca10(PO4)6(OH)2 to denote that the crystal unit cell comprises two entities ...

- or tricalcium phosphate-based granules formed into a coralline or trabecular structure to mimic the structure of cancellous

. They act solely as an osteoconductive matrix. Some manufacturers have recently begun supplying these products with soluble bone-forming factors such as

bone morphogenetic protein Bone morphogenetic proteins (BMPs) are a group of growth factors also known as cytokines and as metabologens. Originally discovered by their ability to induce the formation of bone and cartilage, BMPs are now considered to constitute a group of ...

to attempt to create a synthetic product with osteoinductive properties. * Metal implants can be attached to the two bones to hold them together in a position which favors bone growth. * A combination of the above methods is also commonly employed to facilitate bony fusion. At the completion of surgery and healing, which takes place over a period of several weeks to over a year, the two adjoining bones are fused and no motion takes place between them. This can have the effect of strengthening the bones, as in anterior cervical fusion.

Use in horses

Arthrodesis is used in horses as a salvage procedure to treat severe breakdown injuries, such as failure of the suspensory apparatus, subluxation, fracture, or collateral ligament rupture. It is also performed in horses with osteoarthritis, primarily of the distal hock joints, to fuse these low-motion joints so they no longer produce pain for the animal.

References

WebMD definition

Method

Use in horses

See also

References

See also