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Ask a Doctor

Below are some of the most frequently asked questions regarding Sports Medicine and Orthopaedics.

How do I know when I need a hip or knee replacement?

Answer: When you have pain in your hip or knee, particularly with activity such as walking, getting in and out of a chair, going up and down stairs, et cetera, which does not respond to medications and keeps you from participating in your normal activities, you may be a candidate for joint replacement.

How long will I be in the hospital?

Answer: Most patients are in the hospital for two or three nights.

How long will the replacement last?

Answer: The majority of new total knee and hip replacements can now be expected to last well into the second and even third decade.

How long will I have to recover?

Answer: Most patients use a walker for the first couple of weeks, followed by a cane for three or four weeks. Patients typically return to driving when they have adequate strength and movement in the right leg and when they are no longer taking pain medications. Patients return to work based on their individual progress and the requirements of their occupation. Of course, everyone is an individual, but those are reasonable expectations.

How old do I have to be?

Answer: There are no absolute age limits. No one should have a joint replacement before they really need it, but there is no arbitrary amount of time that you have to endure severe joint pain before you have it surgically repaired.

What is osteoarthritis of the hip or knee?

Answer: The knee is made up of the end of the femur (thigh bone), top of the tibia (shin bone), and back of the patella (knee cap). The hip is a ball and socket wherein the ball is on top of the femur (thigh bone) and the socket (acetabulum) is in the pelvis. These bones are covered with cartilage, which is like the smooth glistening surface on the end of a chicken bone. When this wears through to the bone, the joint swells and hurts in response. This is referred to as osteoarthritis, and is also referred to as degenerative joint disease, or “wear and tear” arthritis.

What is a total joint replacement?

Answer: The answer to number 6 above describes the hip and knee joint and the changes seen with arthritis. The resulting mechanical problem causes bone to rub against bone. A joint replacement basically resurfaces these bones. In the case of the knee, a new surface is placed on the end of the femur (thigh bone), top of the tibia (shin bone), and back surface of the patella (knee cap). A new “shock absorber”, which is made of a high-grade polyethylene (a medical grade plastic) is then placed between the new surfaces to substitute for the lost cartilage. Very little bone is actually cut – usually two to ten millimeters, or less than 1/4 inch. In the hip, a new surface is placed on the socket and a new ball is used to replace the diseased ball, again with a new shock absorber surface in between. The muscles are divided in line with their fibers, but not cut across.

What is the difference between a “partial” and a “total” knee replacement?

Answer: As described above, a total knee replacement replaces all of the bone surfaces in the knee whereas a partial knee (also referred to as a “unicondylar” knee arthroplasty for the last 25+ years) only replaces one area in the knee. In very select individuals, a partial knee replacement may be an alternative, but it has certain limitations. Partial knee replacement doesn’t allow for correction of any angulatory deformity or contractures and may be subject to further deterioration in the remaining areas of the knee with time. While hospitalization is sometimes shorter with a partial knee replacement, long-term durability of the components raises some concern.

What type of anesthesia and pain medicine will be used?

Answer: General anesthesia, or “going to sleep”, is commonly used, but there are other options which may be used in addition or instead. Regional anesthetic, such as an epidural or spinal, is an attractive alternative. An epidural anesthetic is most commonly known for its frequent use during childbirth. In total joint replacement, it allows the patient to undergo the surgical procedure and then additionally can provide excellent pain relief during the early postoperative phase. Patients who choose epidural anesthetic can then either stay awake, be sedated, or have a general anesthetic in addition. Femoral nerve blocks are also becoming more popular. In this procedure, local anesthetic is injected around the main nerve that provides sensation to the knee, and a pump continues to deliver medicine after surgery to relieve pain. Finally, pain medications can be administered by mouth or by i.v. via a PCA, or “patient controlled analgesia” pump, which allows the patient to push a button and get computer-controlled administration of medication.