Arthrodesis
Encyclopedia
Arthrodesis, also known as artificial ankylosis
or syndesis, is the artificial induction of joint
ossification
between two bone
s via surgery
. This is done to relieve intractable pain
in a joint which cannot be managed by pain medication
, splint
s, or other normally-indicated treatments. The typical causes of such pain are fracture
s which disrupt the joint, and arthritis
. It is most commonly performed on joints in the spine
, hand
, ankle
, and foot
. Historically, knee
and hip arthrodeses were also performed as pain relieving procedures, however with the great successes achieved in hip and knee arthroplasty
, arthrodesis of these large joints has fallen out of favour as a primary procedure, and now are only used as procedures of last-resort in some failed arthroplasties.
It can be done in several ways:
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 actually strengthening the bones, as in anterior cervical
fusion.
Ankylosis
Ankylosis or anchylosis 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 structures outside the joint or of...
or syndesis, is the artificial induction of joint
Joint
A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...
ossification
Ossification
Ossification is the process of laying down new bone material by cells called osteoblasts. It is synonymous with bone tissue formation...
between two bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
s via surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
. This is done to relieve intractable pain
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
in a joint which cannot be managed by pain medication
Analgesic
An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....
, splint
Splint (medicine)
A splint is a device used for support or immobilization of limbs or of the spine.It can be used:* By the emergency medical services or by volunteer first responders, to immobilize a fractured limb before the transportation; it is then a temporary immobilization;* By allied health professionals such...
s, or other normally-indicated treatments. The typical causes of such pain are fracture
Fracture
A fracture is the separation of an object or material into two, or more, pieces under the action of stress.The word fracture is often applied to bones of living creatures , or to crystals or crystalline materials, such as gemstones or metal...
s which disrupt the joint, and arthritis
Arthritis
Arthritis is a form of joint disorder that involves inflammation of one or more joints....
. It is most commonly performed on joints in the spine
Vertebral column
In human anatomy, the vertebral column is a column usually consisting of 24 articulating vertebrae, and 9 fused vertebrae in the sacrum and the coccyx. It is situated in the dorsal aspect of the torso, separated by intervertebral discs...
, hand
Hand
A hand is a prehensile, multi-fingered extremity located at the end of an arm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs...
, ankle
Ankle
The ankle joint is formed where the foot and the leg meet. The ankle, or talocrural joint, is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus bone in the foot...
, and foot
Foot
The foot 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 made up of one or more segments or bones, generally including claws...
. Historically, knee
Knee
The knee joint joins the thigh with the leg and consists of two articulations: one between the fibula and tibia, and one between the femur and patella. It is the largest joint in the human body and is very complicated. The knee is a mobile trocho-ginglymus , which permits flexion and extension as...
and hip arthrodeses were also performed as pain relieving procedures, however with the great successes achieved in hip and knee arthroplasty
Arthroplasty
Arthroplasty is an operative procedure of orthopedic surgery performed, in which the arthritic or dysfunctional joint surface is replaced with something better or by remodeling or realigning the joint by osteotomy or some other procedure.-Background:Previously, a popular form of arthroplasty was...
, arthrodesis of these large joints has fallen out of favour as a primary procedure, and now are only used as procedures of last-resort in some failed arthroplasties.
It 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.
- Bone autograft is generally preferred by surgeons because, as well as eliminating the risks associated with allografts, bone autograft contains native bone-forming cells (osteoblastOsteoblastOsteoblasts are mononucleate cells that are responsible for bone formation; in essence, osteoblasts are specialized fibroblasts that in addition to fibroblastic products, express bone sialoprotein and osteocalcin.Osteoblasts produce a matrix of osteoid, which is composed mainly of Type I collagen...
s), so the graft actually forms new bone itself (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, 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 anti rejection 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.
- 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
- A variety of synthetic bone substitutes are commercially available. These are usually hydroxyapatite or tricalcium phosphateTricalcium phosphateTricalcium phosphate is a calcium salt of phosphoric acid with the chemical formula Ca32. It is also known as tribasic calcium phosphate or "bone ash" ....
based granules formed into a coralline or trabecular structure to mimic the structure of cancellous boneBoneBones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
. They act solely as an osteoconductive matrix. Some manufacturers have recently begun supplying these products with soluble bone-forming factors such as bone morphogenetic proteinBone morphogenetic proteinBone morphogenetic proteins 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 pivotal morphogenetic signals, orchestrating tissue...
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 actually strengthening the bones, as in anterior cervical
Cervical vertebrae
In vertebrates, cervical vertebrae are those vertebrae immediately inferior to the skull.Thoracic vertebrae in all mammalian species are defined as those vertebrae that also carry a pair of ribs, and lie caudal to the cervical vertebrae. Further caudally follow the lumbar vertebrae, which also...
fusion.