Candidates for Arthrodesis
Arthrodesis is sometimes the better surgical treatment option for people with arthritis. This procedure is mostly performed on ankles and wrists but it can be performed on other joints too. Arthrodesis may still be the better option for ankles, wrists, thumbs, toes, fingers and top vertebrae in the neck.
Several non-surgical methods will be attempted to correct the problem before resorting to surgery. But if medications, injections, special shoes or types of physical therapy do not work, then the patient would have to go through surgery. Before that, a thorough evaluation will be done to determine the patient’s overall health and any risk factors.
The Arthrodesis Procedure
The procedure can be performed in several ways:
Bone graft- A bone graft can be made between the two bones using a bone from elsewhere in the person’;s body (autograft) or using donor bone (allograft) from a bone bank. Surgeons generally prefer bone autograft because it eliminates the risks associated with allografts. Also, bone autograft contains native bone-forming cells (osteoblasts) 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 major disadvantage of bone autograft is that it has limited supply available for harvest
Bone allograft, however, has the advantage of being available in far larger quantities than autograft. In the treatment process the bone goes through following harvest, which usually involves irradiation and deep-freezing, and kills the bone forming cells. This greatly reduces the immunogenicity (risk of graft rejection) such that no anti-rejection drugs are necessary. The process also makes the allograft function only as an osteoconductive matrix.
Synthetic bone substitutes – Usually, these are hydroxyapatite based granules formed into a coralline or trabecular structure to imitate the structure of cancellous bone. These act primarily as an osteoconductive matrix. There is a variety of synthetic bone substitutes available and some manufacturers have recently begun supplying these products with soluble bone-forming factors such as bone morphogenetic protein to attempt to create a synthetic product with osteoinductive properties.
Metal implants – In this procedure, the metal implants can be attached to the two bones to hold them together in a position that favors bone growth.
Combination of methods – Combination of any method is commonly used to facilitate bony fusion.
Recovery may take place over a period of several months to over a year, during which the two adjoining bones are fused and no motion takes place between them. The result may be an actual strengthening of the bones, as in anterior cervical fusion.
The risk of failure of the joint to solidify is at least 7% of the time. It can reach up to 25% more if risk factors like smoking are present. Rarely, the alignment of the end result may be unsatisfactory and can cause pain or even an altered gait, which may require another surgery. Other complications include local infection and nerve damage.
Who should get Arthrodesis?
This procedure is needed when a patient has painful, damaged or unstable joint, where the loss of movement does not in itself produce unacceptable immobility. Arthrodesis is often performed in the spine, tarsus, wrist and the interphalangeal joints. It is not commonly done for joints in the shoulder or the knee. Arthrodesis is not recommended when there is a risk that other joints will become stiff – for example, the hip with an already arthrodesed knee on the same limb; or if the second hip is highly likely to stiffen.
What happens after the procedure?
After surgery, your thumb and wrist will be placed in a cast or splint for up to 6 weeks. When the cast is removed, you may meet with a physical therapist to help regain hand strength and movement. Recovery may be slow but you should be able to return to your normal activities within 6 months of surgery.
After the pins are removed how long do you have to be in a cast?
The average immobilization time until all casts are removed is about 4 to 7 months. But the pins are not taken out if the internal fixation operative technique is used. There also are external fixation techniques as well as arthroscopic arthrodesis.