Knee Osteotomy is a good alternative to total knee replacement surgery in a young or middle-aged patient suffering with unicompartmental arthritis of the knee joint.
A normal joint has a good cartilage and thick meniscus and it allows body weight to pass equally through both the condyles of the knee joint. However, as the arthritis progresses, the cartilage on one side of the knee joint wears faster than the other side, causing the deformity of the leg. If the inside or the medial side of the joint is worn then a varus deformity (bow-legged) will develop. On the contrary a valgus deformity results (knock-knees) when the outside, or lateral side, of the joint is worn. Deformity redirects the burden of our body weight only through the damaged condyle of knee while the healthier part of the knee is spared. Over a period of time this vicious cycle leads to the progression of the arthritis.
Osteotomy means surgically breaking the bone under control condition. It can be done on femur bone for knock-knee deformity or on tibia bone for bowleg deformity. An osteotomy realigns the bone into a better position, it shift the weight-bearing forces to the healthier condyle of the knee joint, thereby "unloading the worn side' of the joint.
Osteotomy of tibia bone is done for varus deformity of knee, while femur osteotomy is done for valgus deformity. Either osteotomy can be done by close wedge method or open wedge method.
For the operation to be effective the arthritis needs to be confined to one area of the knee only, and the rest of the joint must be healthy. The ideal patient for a knee osteotomy is a young, active person, who has arthritis limited to one side of the knee joint causing significant pain, disability and deformity.
The other criterion is the ability of patient to cooperate with non-weight bearing ambulation and rehabilitation for 8-10 weeks.
However, before suggesting an osteotomy, one must try physiotherapy, anti-inflammatory medication and, if necessary, keyhole surgery to control symptoms.
Patient must understand when bone is cut, it needs time to heal, and therefore, rehabilitation from this surgery is lengthy and may be difficult if you are not prepared for it. The total healing time is 8 – 12 weeks, and can take longer. Most patients need physical therapy to regain their knee motion.
The osteotomy can improve the symptoms of knee arthritis but cannot cure the disease, hence will fail with time, and total knee replacement eventually will be required.
Sometimes overcorrection or under correction of deformity is possible. Other potential complications include problems with healing of the osteotomy (a nonunion), continued pain from arthritis, blood clots, and infection.
When done in the right patients, knee osteotomy is usually successful at decreasing pain caused by arthritis. Osteotomy can delay conversion to knee replacement from few years to over a decade.
"Because of this, knee osteotomy is generally reserved for young, active patients, who want to delay the time until knee replacement"
Unfortunately, performing this surgery in the wrong patient can have poor outcomes. Even though many people want to avoid knee replacement surgery, the knee osteotomy is not right for everyone.
As the osteotomy is fixed with a plate, plaster cast is not necessary; rather a removable knee brace is sufficient for 2 – 3 weeks. Most patients are ready to go home after 3 - 4 days. You will need a walker to ambulate toe touch non-weight bearing for 6 – 8 weeks. Knee bending will be allowed and when you are comfortable. Progressing weight bearing is allowed thereafter depending on your x-ray.
The advantage of osteotomy over knee replacement in the younger patient is that once it has healed, it allows you to lead a busy, vigorous life and even returning to sports. In our social circumstances, sitting cross leg and squatting on the floor is allowed, but only after osteotomy has healed.
Knee Osteotomy is a good alternative to total knee replacement surgery in a young or early middle-aged patient having mal-alignment of the knee joint and likely to progress to knee arthritis. It is also a good choice for patients with early unicompartmental osteoarthritis of the knee joint.
Knee osteotomy does not make any changes with in the knee joint, rather it corrects the mechanical alignment (realign) of the lower limb, thereby shifting shift the weight-bearing forces to the healthier condyle of the knee joint, and 'unloading the worn side' of the joint.
Proper case selection is necessary for good outcome of knee osteotomy patients.