Arthrodesis, or Fusion
Arthrodesis is the process where two bones that are separated by a joint are made to grow together into one bone. This is a common technique used to treat a variety of problems in the foot and ankle. It can be used for painful arthritis, deformities and instability problems.
Cartilage is the smooth material that lines the end of a bone at a joint. The cartilage surfaces of the bones at a joint rub against each other, and allow a gliding motion between the bones that is almost frictionless.
Surgery
During an arthrodesis surgery, the cartilage surfaces are removed from the ends of the bones. Next, the surfaces of the bone are broken with a device like a tiny chisel. Finally, the broken bone surfaces are placed together, and held with screws, wires or plates.
Your body has a complex mechanism that heals broken bones, and with arthrodesis this normal process will heal the two separate bones together into one mass of bone.
After surgery, we treat your joint as if there was a fracture, because the healing process is the same for both. It is important to immobilize the joints and avoid walking on the foot or ankle for 6 weeks after surgery. No weightbearing for 6 weeks.
Bone Graft
With some arthrodesis procedures a bone graft may be used to improve the chances of bone union. That is usually the case if there will be any gaps between the surfaces of the bone. Bone graft can be taken from the ankle or the iliac crest, above the hip. The hospital has a “bone bank” of cadaver bone that can be used for bone graft material in place of your own bone. This is usually best used to add onto any of your own bone graft, rather than as a substitute for your own bone graft.
Indications
Arthrodesis is a useful technique to treat painful arthritis that cannot be relieved with non-surgical means. There are no useful joint replacement options for most foot and ankle arthritis.
Arthrodesis can also used to deal with deformities. Corrections of alignment are made, and then when bones are fused together the correction will be maintained.
The time it takes for an arthrodesis to heal is similar to the time it takes for a fracture to heal. With most fusions I would like you to be nonweightbearing for six weeks. You will wear a cast during that time to help hold the bones together. After that I will allow you to bear weight using a walking cast or CAM Walker for the next six weeks. It generally will take three months for the bones to heal together.
NonUnion
A Nonunion, or Pseudarthrosis, occurs when the bones do not fuse together. That is called a nonunion. Occasionally a non-union will be seen on Xrays, but it is not symptomatic. If that is the case, we generally ignore it. However, most non-unions are painful.
The treatment of a non-union can include bracing, the use of a Bone Growth Stimulator, or further surgery to try to obtain fusion. That may require removal of any implants, application of bone graft, and either internal or external fixation.