The knee osteoarthritis affecting only one side of the joint is the reason for “bow-legged” or
“knock-knee” deformities. The process to treat such a condition is known as osteotomy. In the procedure, the weight of the body is shifted to the healthy side of the knee joint by repositioning the angle. Thus shifting the stress more towards the healthy side. This also results in less pain and detain the requirement of joint replacement therapy.
The knee joint is made up of three types of bones. The thigh bone or femur, the shin bone or tibia, and patella or knee cap. The femur joins the tibia to make the main weight-bearing part of the knee. The patella situated at the front of the knee functions as a fulcrum. This gives the thigh muscle a mechanical benefit in making the knee straight. The three bones together are enclosed by cartilage. They are white-colored highly polished surfaces allowing frictionless motion of the bones against each other. And when this cartilage gets damaged the problem of osteoarthritis appears.
The three compartments of the knee joints are— tibiofemoral compartment which is the weight-bearing compartment and is further divided into (i) medial and (ii) lateral tibiofemoral compartments. The medial compartment is on the inner part of the knee while the lateral compartment is on the outer part of the knee. These two compartments are responsible for carrying most of the weight at the time of walking and running.
The third compartment is patellofemoral which is the space at the front of the knee. This part is responsible for activities involving a lot of knee bending like going up and downstairs, squatting, or coming out of the chair.
The condition of osteoarthritis generally affects one of the compartments than others. The most commonly affected one is the medial compartment in comparison to others.
The reasoning behind the osteotomy surgical procedure is to correct the tibial or femoral bone through surgical correction. This shifts the patient’s body weight from the arthritic compartment to the more healthy non-affected compartment. Then the osteotomy is held in place with the help of a strong surgical plate and screws for the bones to get adjusted in the new place.
The main benefit of the process is that it helps in preserving the original knee joint instead of replacing it with a prosthetic knee replacement or arthroplasty.
Who is a suitable candidate for an osteotomy?
This procedure is most suitable for young, active persons, suffering from osteoarthritis in only one compartment of the knee. The process helps in preserving and increasing the life of the natural knee joint and postponing the need for knee replacement surgery for a long time.
Reasons for performing an osteotomy
Osteotomy is mainly needed by persons suffering from arthritic pain at the affected area of the joint of the knee compartment. The purpose of performing the procedure is to reduce the pain in the affected area by transporting the body weight to the normal side of the knee, therefore, postponing the need for joint replacement. The process improves the chances of indulging in high-level activities as running which is not possible with joint replacement surgery.
Before the procedure, various tests are done to evaluate the extent of arthritis. There may be x-rays of various magnanimity to adjudge the damage of the knee compartment like special x-rays known as 4-foot x-rays which captures the whole length of the lower limb. This makes the surgeon decide where and how to align the bodyweight to get the best possible outcome. An MRI scan will also be conducted to make an exact evaluation of the left out cartilage, ligaments, and meniscus.
Kinds of osteotomy around the knee joint
High Tibial Osteotomy (HTO)
The most usual osteotomy of the knee is high tibial osteotomy, done via the opening wedge technique. The process is performed in the case of OA on the inner side of the knee. In this procedure, an opened wedge is made on the medial side of the upper tibia for shifting the weight to the outer side of the knee.
Distal Femoral Varus Osteotomy (DFVO)
The procedure is apt in the case of outer compartment knee arthritis. The process includes making an opening wedge on the lateral part of the lower femur bone for shifting the force on the healthier medial portion.
Tibial Tubercle Osteotomy (TTO)
When there is a case of arthritis of the patellofemoral joint the above-mentioned therapy is used.
Process of Osteotomy Performed
Opening wedge osteotomy
In opening wedge osteotomy, a wedge is made by the surgeon by cutting through the upper tibia, just under the knee joint, on the medial side. Sometimes a piece of bone is added usually taken from the pelvic area(autograft) or by using cadaveric bone(allograft) for holding the opened wedge and enabling the healing process. For stabilizing the knee a plate is used during osteotomy. This enables to shift the body weight to a more stable lateral compartment.
Closing wedge osteotomy –
This process includes the removal of a wedge of the bone generally just under the joint in the upper part of the tibia. For those people who are suffering from arthritis affecting the medial part, the bone wedge is taken from the outer part of the tibia. After removing the wedge the edges of the bones are held together with the help of either a metal plate or staples.
Whether to perform a closing or opening wedge procedure depends solely on the surgeon, counting the best option for you for your condition.
The surgical process
After you are admitted to the hospital on the day of surgery, the most suitable anesthetic at hand for you will be considered by your anesthetic. And also you will be given the options for postoperative pain control. Antibiotics will be given to you at the time of the procedure to reduce the chances of infection.
At the time of the procedure, utmost care is taken to safeguard the nerves and blood vessels adjoining the knee joint. Generally, a drain tube is put around the injury for 24 hours. By using dissolving sutures all the cuts are closed and the leg is covered in a well-padded dressing. A brace is needed for a brief period after the procedure.
After shifting in the ward many things will be monitored as temperature, blood pressure, heart rate, circulation, and sensation in your feet, etc. an x-ray may also be done.
While in hospital, directions will be provided by a physiotherapist on some of the leg exercises to be done while in the bed and how to use the crutches for walking. It is very common to be on crutches for up to 6 to weeks in a closing wedge osteotomy and sometimes up to 10 weeks in an opening wedge procedure.
The main attention of the physiotherapist will be on recapturing the movement of the knee, improving mobility, and growing the strength of the muscle near the knee joint.
Tips will be given to control the inflammation in the knee. After gaining mobility and comfort, you will be discharged from the hospital. There may be some swelling in your leg for the first month, with some stiffness in the knee. It’s quite common to be on painkillers during this time. To get the best outcome of the surgery, it is quite essential to follow the exercise regime on regular basis.
Usually, it takes near about 6 months for you to rehabilitate after the osteotomy procedure. Maintaining strength and motion is the most important thing during the healing process. The exercise regime should be followed particularly. Physiotherapy usually begins by the first week of the procedure.
The result of the osteotomy is quite good for patients with the correct indications, as it lessens pain and improves knee functions. It also helps in postponing the need for knee replacement surgery.
Frequently asked questions
It may take about 6 to 9 months for most people to return to the sports arena after the surgery. It depends on the criteria as pre-operative activity level, the gravity of arthritis, as well as the progress made during rehabilitation.
Returning to office setting work is possible between 2 to 3 weeks but it’s not possible for manual labor or work needing a lot of walking. It may take a longer period of time between 6 weeks to 3 months.
The main advantage of osteotomy is that it postpones the oncoming of knee replacement surgery in the future. People may get arthritis on another side of the knee or their arthritis may progress within the same compartment of the knee. At this stage, knee replacement may be needed.
Surgery at later stages may be needed to remove the plates mostly after one or two years of surgery. The procedure takes a day and the recovery period is very less. It is always better and safe to remove the plates at this stage so that it doesn’t hinder future treatments if required.
Generally, people may experience pain for 3 to 4 weeks after the surgery which may be dealt with painkillers. After proper healing of the osteotomy, the pain-related issues of arthritis get minimal as weight is shifted on the more healthy cartilage.