Last Updated on August 8, 2023
The term arthrodesis indicates surgically produced fusion of the joint. It is important to differentiate it from ankylosis which is a fusion of joints or stiffness of joints resulting from a disease process. Thus arthrodesis is surgically produced ankylosis.
Syndesis or artificial ankylosis are other names given to arthrodesis.
Arthrodesis aims to block the movement of the joint.
This procedure is performed typically in a painful joint that is not relieved by other means. It is also performed in flail or unstable or deformed joints as in polio to provide better kinematics to the limb.
Arthrodesis was a very common procedure in the past and almost all joints including the shoulder, hip, elbow, and knee. With improvement in orthopedic treatments and the advent of arthroplasty, arthrodesis is rarely performed on large joints now except in cases where arthroplasty has failed or cannot be done.
In modern times, it is used in hand, ankle, and foot joints. Arthrodesis is a standard part of many stabilization procedures of the spine. The idea is to let the vertebra fuse while it is immobilized by metal implants so that the spine when loaded is not unstable.
It is also done as a standalone procedure to block the growth on one side of the spine [say posterior] to control/contain/ cure deformities using the normal growth potential of the anterior part of the spine and thus resulting in differential growth of the spine.
In the spine, it is more commonly called spinal fusion.
Indications for Arthrodesis
- Painful diseased joints
- Infection
- Osteoarthritis
- Inflammatory arthritis
- Posttraumatic arthritis or instability
- Tumor Surgery including Joint
- Bone excision could be followed by arthrodesis
- Spinal fusion as a part of surgery in spinal fixation
- Failed arthroplasties
Arthrodesis versus Arthroplasty
Before arthroplasty was available, every diseased joint was considered for joint fusion including the major joints like hip or knee joints.
But arthroplasty has changed the outlook. Joint mobility can be retained by choosing arthroplasty over arthrodesis in most of cases of large joints. Thus, indications to fuse large joints like hip, knee, shoulder elbow, wrist, and ankle have reduced drastically.
The evolution of custom-made prostheses has led to increased use of prostheses in tumor surgery too.
However, arthroplasty is avoided in the presence of infection.
Small joints of the foot and to a lesser extent hand and wrist can still be well managed by arthrodesis.
The main disadvantage of joint fusion is that it sacrifices the movement of the joint. Thus the function of the limb is definitely compromised. For example, in the lower limb, fusion or hip or knee leads to drastic increase in energy requirements for ambulation.
Arthrodesis Knee with K-nail, Image Credit – RadiopaediaTherefore the fusion is contemplated only in patients in which the advantages outweigh the disadvantages.
Nowadays, the procedure of joint fusion is most commonly performed on joints in the spine, hand, ankle, and foot.
Interestingly, it is also used as the procedure of last resort in some failed arthroplasties.
Types of Arthrodesis
- Intraarticular
- The joint surfaces are bared and fused.
- Permit greater correction of deformity
- Permit removal of diseased bone and apposition of healthy bone
- Extraarticular
- Joint is not exposed
- Fusion is achieved by fusing bone block bypassing the joint.
- Especially useful in treating children
- Also beneficial where large amounts of necrotic bone or active infection, as in tuberculosis.
- Combined intraarticular and extraarticular.
The Procedure of Arthrodesis
The exact procedure would depend on the joint involved. An outline of the general intraarticular procedure is mentioned here.
- The involved joint is opened with a suitable approach and both the articular surfaces are exposed.
- The cartilage is removed from the joint surfaces along with any necrotic bone if present to reveal oozing bone surfaces
- Both ends are shaped for maximum compression at the arthrodesis site.
- The surfaces are apposed together and then fixed with suitable implants.
- Bone grafting is done in most cases to facilitate bone union
- Allograft may be used in large joints as the quantity of the graft needed is more
- Different joints are kept in different positions depending on the function of the joint and energy consumption for activity.
- Patient demands/profession could be a factor in the position of limbs or digits.
The basic idea is to induce the fusion of the joint in a desirable position and hold the bones in a desirable position till the fusion is strong enough to hold without an internal or external implant.
Complications of Arthrodesis
Joint fusion surgery carries the risk of all complications associated with the surgical procedure. These are
- Infection
- Wound healing issues
- Nonunion of the fused bones
- Awkward gait in lower limb procedure
- Implant failure
- Stress on adjacent joints
Arthrodesis of Different Joints
Hip Arthrodesis
Fusion of the hip joint is most commonly done in a select group of patients that include failed total hip arthroplasty, young laborers with unilateral painful hip, etc. As hip arthroplasty advances are made, it is done less and less commonly.
It is not done in cases where bilateral hips are involved, limb length discrepancy is greater than 2.0 cm or there is the presence of degenerative changes in adjacent joints.
The optimum hip fusion position is
- 20-35 degrees of flexion
- 0-5 degrees of adduction
- 5-10 degrees of external rotation
Hip fusion surgery is able to provide pain relief. Adjacent joint degeneration is a common complication.
Read more details on Hip Arthrodesis.
Knee Arthrodesis
Knee joint fusion surgery is done in cases of failed arthroplasty or complete loss of extensor mechanism.
Painful ankylosis after infection or trauma, knee joint neuropathic arthrpathy and tumor resection are other indications.
The knee is placed oimThe optimal position of the knee during fusion is
- Valgus 5 degrees
- 0-10 degrees of external rotation
- 0-15 degrees of fleion
The procedure is contraindicated in active infection
Absolute contraindications is presence of active infection.
Knee joint fusion is avoided if the ipsilateral hip or ankle has degenerative changes or bilateral knee fusion is required.
[Know more about knee arthrodesis]
Ankle Arthrodesis
It involves fusion of the tibiotalar joint. It is often done in case of painful ankle due to infection or trauma, degenerative changes of the ankle causing intractable pain, chronic instability and avascular necrosis of the talus.
The optimal position for ankle fusion is
- Zero dorsiflexion
- 5-10 degrees of external rotation
- 5 degrees of hindfoot valgus
- 5 mm of posterior translation of the talus
In mild deformities of the ankle, arthroscopic arthrodesis may be done.
[Read more about ankle arthrodesis]
Shoulder Arthrodesis
Shoulder fusion, like hip and knee is performed less commonly today because arthroplasty has been quite successful in these joints.
The goal of shoulder fusion is to provide a stable base so that hand and elbow function is optimized.
Shoulder fusion surgery is indicated in paralytic disorders affecting shoulder muscles, tumor removal and reconstruction, and painful shoulder ankylosis following infection.
It is contraindicated in ipsilateral fused elbow and contralateral fused shoulder . It is not done if there is no useful scapulothoracic motion.
The position of the shoulder is optimized so that person can reach the mouth using the affected limb for feeding purposes.
The position for shoulder fusion is 20-30 degrees of abduction, 20-30 degrees of forward flexion, and 20-30 degrees of internal rotation.
[Read more about shoulder arthrodesis]
Elbow Arthrodesis
It is uncommon and is usually performed as a salvage procedure to provide a stable elbow when arthroplasty has failed. It is also considered in cases of nonunion, segmental bone loss, and severe arthritis.
Optimum position differs for each individual but as a general guide 90 degrees of flexion is the most optimum position.
Wrist Arthrodesis
Surgical wrist fusion is a salvage procedure to provide the patient with a pain-free immobile wrist in a maximum functional position.
The procedure is indicated in wrist arthropathy not amenable to conservative treatment.
[Read more about Wrist Arthrodesis]
Arthrodesis of Foot
Calcaneocuboid, talonavicular and talocalcaneal joints are mainly fused to correct hindfoot and midfoot issues. Sometimes, all these joints are fused and the procedure is called triple arthrodesis.
Metatarsophalangeal and phalangeal joints can be fused if the indication arises.
Arthrodesis of Joints of the Hand
The hand is a complex organ and different joints of the hand are fused in different positions to maximize the functional outcome. The metacarpophalangeal joints and interphalangeal joints are the joints that can be fused. They are discussed in detail in a separate article.
Prognosis
Arthrodesis means the loss of one joint and thus increasing the energy expenditure of limb function. Apart from that it also results in the awkwardness of the movement. The patient should be prepared to live with that. It is always a good idea to simulate joint immobilization before surgery is carried out by applying an immobilizing cast.
A well-done fusion results in a pain-free stable joint at the cost of the motion of the joint.
