Knee Fusion (Arthrodesis)
What is knee fusion?
Knee fusion, which is also called knee arthrodesis or tibiofemoral fusion, is a procedure where the thigh and leg bone are joined together, eliminating any rotation of the knee joint. This is performed as one of the last options to obtain a stable, pain-free knee when, for example, a patient has irreparable damage to the knee joint where reconstruction has failed and knee replacement is no longer an option. Knee fusion is accomplished by removing any remnant of the joint and putting the shin bone and thigh bone in intimate contact. The bone ends must be held still for a few months to allow them to heal together. This can be achieved with internal fixation (rod or plate) or external fixation.
Who can benefit from knee fusion?
Your doctor may consider this procedure after a failed knee replacement (especially if infected), if pain is present and debilitating, if a tumor is present around the joint, if arthritis from previous trauma is present, and if a long-standing joint or blood infection is present. Usually other salvage methods are attempted first, and fusion is considered a last resort.
What happens during a knee fusion procedure?
Knee fusion is a major surgery, so it is performed in the hospital setting, and sometimes a post-operative stay in a rehabilitation unit is needed. Damaged cartilage and bone from the ends of the thigh and leg bone will be removed to facilitate the healing process. Then the ends of the bones will be joined together with metal plates or rods. Sometimes the surgeon will carefully remove a small piece of bone from your pelvic bone as bone graft to help join the bones together. Depending on the type of hardware, the device may stay in place permanently after the bone heals. The procedure takes about two to three hours. Patients stay in the hospital after the procedure for two to four days. If complications occur, the hospital stay may be longer. Sometimes, patients are discharged to a rehabilitation hospital to help with recovery. Pain and swelling will occur after surgery, but keeping the leg elevated reduces swelling and maintains circulation. Your doctor will prescribe pain medications while you recover from this procedure.
What are the risks and benefits of knee fusion?
Knee fusion is generally a safe procedure. Once the thigh and leg bones are fused, the joint is stable and immobile. Patients will lose flexibility and motion in the leg, but should feel pain relief. Like any surgery, there are risks, and patients may experience blood clots, nerve damage, or infection. Other long-term complications include mild lower back pain. Also, joints close to the knee, like the hip, may suffer from arthritis over time since more stress is passed to the hip. Smokers have additional risks such as pseudarthrosis, a condition where bones are unable to fuse. Pain may persist if the bone does not properly fuse. In cases when the bone does not fuse or the internal hardware breaks, a second surgery with additional bone grafting may be necessary.