Knee Replacement Surgery

Knee Replacement is sometimes recommended for advanced stage arthritis that does not respond to nonoperative treatments. A Partial or Total Knee Replacement is a surgical procedure which involves the replacement of worn-out parts in the knee with an artificial joint. The replacement parts are made of metal and plastic. Most of the ligaments and all of the tendons remain intact, which allows the knee to function appropriately.

Causes of Arthritis

The most common cause of chronic knee pain and disability is arthritis. Although there are many types of arthritis, most knee pain is caused by just three types: osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis.

• Osteoarthritis.This is an age-related “wear and tear” type of arthritis. It usually occurs in people 50 years of age and older, but may occur in younger people, too. The cartilage that cushions the bones of the knee softens and wears away. The bones then rub against one another, causing knee pain and stiffness.
• Rheumatoid arthritis.This is a disease in which the synovial membrane that surrounds the joint becomes inflamed and thickened. This chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain, and stiffness. Rheumatoid arthritis is the most common form of a group of disorders termed “inflammatory arthritis.”
• Post-traumatic arthritis.This can follow a serious knee injury. Fractures of the bones surrounding the knee or tears of the knee ligaments may damage the articular cartilage over time, causing knee pain and limiting knee function.

Description of the Procedure

Knee replacement is more accurately described as knee “resurfacing” because only the surface of the bones are actually replaced. <1cm of bone is typically removed to allow the implant to “re-cap” the prepared bones surfaces.

There are four basic steps to a knee replacement procedure.

• Prepare the bone.The damaged cartilage surfaces at the ends of the femur and tibia are removed along with a small amount of underlying bone.
• Position the metal implants.The removed cartilage and bone is replaced by metal components that recreate the surface of the joint. These metal parts may be cemented or “press-fit” into the bone.
• Resurface the patella.The undersurface of the patella (kneecap) is cut and resurfaced with a plastic button.
• Insert a spacer.A medical-grade plastic spacer is inserted between the metal components to create a smooth gliding surface.

Recovery from Knee Replacement

Knee replacement surgery generally takes 1½ to 3 hours in the operating room. Directly following the surgery, the patient is brought to a recovery room where vital signs are monitored. Once the patient has been stabilized, he/she can move out of the recovery room.

There are several components to the rehabilitation and recovery process. Each one is integral to the entire course of healing. These components include:

• Physical therapy. During the first several days/weeks of physical therapy, some degree of discomfort and stiffness is expected. As the therapy continues, your body will adjust to the new prosthetic, allowing it to operate as part of your leg. Even after physical therapy is concluded, the knee needs to continue being active. Walking or other mild activities are perfect to increase mobility over time. It may take 12-18 months for your muscles to fully strengthen.
• Incision care.A sterile dressing will be applied in the operating room. If dry, this dressing will often remain for 1 week. Afterwards, it can be removed and covered with a dry dressing. You must keep the incision dry for the first 10-14 days. Do not soak the knee for 4 weeks after surgery.
• DVT prophylaxis. Lower extremity surgery poses an increased risk for blood clots. In mobile patients, Aspirin 2x/day for 6 weeks will thin the blood enough to minimize this risk. In patients with a history of clotting, decreased mobility, or GI issues, alternatives such as Eliquis, Lovenox, Arixtra, or Coumadin will be prescribed.
• Follow-up.For the first year following surgery, scheduled follow-up appointments will ensure that recovery is going as planned. We would like to see you at 2 weeks, 6 weeks, 3 months, and one year after your surgery. After that, annual visits may be expected to keep your knee in peak condition.