Slick cartilage allows the ends of the bones in a healthy knee to move smoothly against each other. Osteoarthritis damages and wears away the cartilage — creating a rough surface.
When the cartilage wears away unevenly, it narrows the space between the femur and tibia, resulting in a bow inward or outward depending on which side of the knee is affected. Removing or adding a wedge of bone in your upper shinbone or lower thighbone can help straighten this bowing, shift your weight to the undamaged part of your knee joint and prolong the life span of the knee joint.
Risks of knee osteotomy may include:
- Infection in the bone or in the surrounding soft tissues
- Failure of the pieces of bone to knit together
- Injuries to nerves or blood vessels around the knee
Your surgeon will study X-rays of your knee to determine if osteotomy is appropriate and how much correction of the deformity is needed.
Because you'll be receiving anesthesia, you'll need to refrain from eating or drinking before the procedure. If you take daily medications, follow your surgeon's instructions on whether to take them the morning of your surgery.
During the procedure
After you're anesthetized, your surgeon will make an incision over the area of bone to be remodeled. Depending on the location of the arthritis damage within your knee, the surgery may involve your shinbone or your thighbone. The most common form of knee osteotomy involves the shinbone.
In the simplest variety of knee osteotomy, your surgeon removes a wedge of bone. The cut edges of the bone are brought together and fastened in place with metal hardware. Another option is to cut the shinbone or thighbone and insert a wedge of bone, either from your pelvis or a bone bank. Metal hardware secures the pieces.
After the procedure
Depending on the complexity of the surgery and how well you recover, you might stay in the hospital for a night or two. You'll need to use crutches for approximately two months for your bone to heal properly. Rehabilitation may take as long as six months and will include exercises designed to:
- Strengthen your thigh muscles (quadriceps)
- Increase your knee's range of motion
- Improve your balance
Occasionally a brace is used to support the bone while it heals.
In most cases, knee osteotomy relieves arthritis pain and postpones the need for a total knee replacement by 10 to 15 years.