Sometimes arthritis of the knee may result from a limb that is aligned with uneven weight across the joint. This may be because of previous injury or an inherited disposition. In these cases, especially in a young or middle-aged patient, an osteotomy may be an option. This takes the pressure off the damaged area of joint surface without resorting to joint replacement. Typically, people who have bowed legs and get more wear of the articular cartilage on the inside of the knee may benefit from an osteotomy. This is an operation that is better for younger and more active patients. The arthritis must be limited to one part of the knee only as the osteotomy takes the weight off the damaged cartilage and puts it onto good cartilage elsewhere in the joint.Before suggesting an Osteotomy, we would try to control your symptoms with physiotherapy, anti-inflammatory medication and, possibly, key-hole surgery. If these treatments are not successful, then an Osteotomy would be considered.
Under general anaesthetic, an 8 cm incision is made over the upper part of the tibia (shin bone) on the inside. The bone is cut almost all the way across using X Rays to guide the cut. The alignment of the tibia is then carefully adjusted by opening this cut in the bone until the desired alignment is reached. The degree of correction is planned in advance of surgery and matched during the procedure. The bone is then fixed with a plate that is held in place with screws. This is a called on opening wedge osteotomy. The triangular gap in the bone will fill in with new bone over the next few months post surgery.
After an Osteotomy
Most patients are ready to go home after 48 hours. The plate and screws are made of titanium and are very strong so you can partially bear weight on the operated leg with crutches. After six weeks, if the x-rays show the tibia is healing well you can progress to full weight bearing and dispense with your crutches as the discomfort settles.
Long term outlook
This operation is designed to improve the symptoms of knee arthritis but it cannot cure the disease. The aim is to make day to day life more manageable. It will eventually get worse and further surgery will almost certainly be necessary. It will be necessary to remove the plate once the osteotomy has united as it will be in the way when further surgery is required in the future. This is a much smaller procedure and can be done as a day case generally about a year after the osteotomy. Studies have shown that osteotomy can delay the need for a knee replacement for up to 10 years and this is often enough to keep the knee comfortable until, for example, the patient retires from work. The advantage over a knee replacement in the younger patient is that it does not involve placing an implant into the knee itself, and once it has healed, you can lead a busy, vigorous life, even returning to sport in some cases.For the patient in their late fifties or early sixties, however, a unicompartmental knee replacement may be a better alternative.