According to the American Academy of Orthopaedic Surgeons, surgeons perform approximately 581,000 knee replacement surgeries each year. A knee replacement involves cutting away damaged bone and cartilage from the leg bones—namely the femur, tibia and patella—and replacing it with an artificial joint made of metal alloys, high-grade plastics and polymers. Swelling in the leg is normal after surgery and can last for up to 3 to 4 months. There are several methods for controlling swelling in the operative leg.
Cooling the surgery site causes vasoconstriction, or a narrowing of the blood vessels, reducing bloodflow to the area and thereby reducing the swelling. The American Academy of Orthopaedic Surgeons recommends applying an ice pack for 15 to 20 minutes at a time to reduce swelling.
It is common for a patient undergoing a knee replacement to wear compression stockings after the surgery. These stockings fit snugly around the leg and assist in reducing the swelling from fluid pooling in the leg. Patients should wear these stockings during prolonged periods of standing or sitting upright, as well as during activity. Activity increases blood flow and will, in turn, increase swelling.
Knee replacement patients can reduce swelling by lying down and elevating the leg above the level of the heart. This positioning encourages proper blood flow in and out of the leg. If swelling gets severe during the day, patients can lie down for 30 minutes to an hour to reduce the fluid buildup.
Georgetown University Hospital recommends that patients start ankle pumps immediately after surgery to promote proper blood flow and reduce the risk of blood clots and swelling. Patients can repeat these exercises 20 times per hour while they are awake. Surgeons may also prescribe a continuous passive motion machine to assist in restoring normal range of motion to the knee. This machine will also promote proper blood flow and reduce swelling.