What can I realistically expect from a knee replacement?
Before making the decision to have a knee replacement, it is important that you understand what you can and cannot get with a knee replacement.
Knee replacement is a quality-of-life improvement procedure, and more than 90％ of patients who have a knee replacement experience significant relief or loss of knee pain and a significant improvement in their ability to perform activities of daily living.
However, knee replacement does not turn you into a super athlete, nor does it give you the ability to do things that you could not do before your disease. After surgery, we will recommend that you give up some activities, including running, jumping and competitive sports. Under normal use, the polyethylene pad of the artificial joint will also experience some wear and tear. Excessive activity and excess weight can accelerate wear and tear, resulting in loosening and pain.
Is knee replacement surgery painful?
In the early stages, due to immature surgical techniques and poor pain management, some patients may feel significant pain after surgery, especially during post-operative exercises, so many patients may become fearful of surgery because of other people’s experiences with pain.
In fact, just like any other surgery, some pain will be felt after joint replacement, but it is not unbearable. The current multimodal perioperative pain management program, which includes preoperative hyper-analgesia, intraoperative periwound closure, and postoperative use of various analgesic pumps, will greatly reduce pain or even be pain-free. And postoperative analgesics can also be given orally, intramuscularly or intravenously for pain and will make you feel as comfortable as possible. Pain mainly occurs within a few days after surgery and can be tolerated and will gradually decrease.
The Department of Bone and Joint Surgery at China-Japan Friendship Hospital was the first in China to launch a “pain-free ward” management model at the end of 2011, which has been successfully applied to eliminate the fear of pain in knee replacement surgery patients.
What should I do before surgery?
Pre-admission preparation
The knee and lower extremities must not have skin infections or breakouts.
The body must not have other potential foci of infection, such as swollen gums.
In principle, you should not take any medication that affects blood clotting such as aspirin for 1 week before surgery (you will need to inform your supervisor of the medication you are currently taking upon admission).
Prepare a walker or a pair of crutches (for early postoperative walking exercises).
Bring personal toiletries.
Post-admission examination.
After admission, your doctor will conduct a detailed history and physical examination, and the nurse will give you an admission orientation. In addition to this, the following tests will be routinely performed.
Blood and urine tests (including routine blood and urine tests, liver and kidney functions, coagulation functions, and viral tests such as hepatitis)
X-rays (including chest X-ray, frontal and lateral and axial knee films, full-length films of the lower limbs, etc.).
Electrocardiogram examination.
Cardiac ultrasonography (for patients with long-term hypertensive heart disease, cardiac ultrasonography may be required).
The day before surgery
The nurse will give you a pre-operative briefing.
The day before surgery, you will shower, clean your skin and the nurse may prepare the skin of your surgical area.
The nurse will give you an enema the evening before the procedure.
You will abstain from food and water after 10:00 p.m. the night before surgery.
If you are nervous, you may request sedative medication from the doctor on duty before 10:00 p.m. before surgery.
On the day of surgery
Do not swallow water when you brush your teeth and rinse your mouth in the morning.
Empty your urine.
Remove all jewelry, dentures, contact lenses, etc. (wrap rings that cannot be removed in gauze).
If there are medications that you must take daily, please take them under the supervision of your doctor.
If your surgery is the first one, someone will come to the ward to pick you up and take you to the operating room around 7:30 am; if you are not the first one, please wait quietly in the ward.
Once the patient enters the operating room, family and friends will wait in the surgical waiting area.
What type of anesthesia will I use for my surgery?
There are usually two types of anesthesia to choose from – intradural (lumbar or epidural or a combination of both, commonly known as “semi-anesthesia”) and general. With lumbar or epidural anesthesia, you are awake, but you do not feel your legs. With general anesthesia, you will be asleep during the entire procedure. Whichever type of anesthesia is used, it has no effect on the outcome of the surgery. Both types of anesthesia are safe and each has its own advantages. Before the surgery, the anesthesiologist will consult with you and your family to determine the type of anesthesia based on your specific situation.
How is the surgery performed?
The artificial joint used today usually consists of three parts: the femoral component (made of highly polished metal), the tibial component (consisting of a wear-resistant, highly cross-linked polyethylene pad and a metal bottom bracket), and the patellar prosthesis (also made of highly cross-linked polyethylene, most patients do not need a patellar replacement).
To perform the procedure, the surgeon makes an incision in the front of the knee to expose the joint.
Once the joint is opened, the worn joint surface is cut away at the end of the femur and the upper tibia under the precise guidance of an osteotomy template. The osteotomy template ensures that the right thickness of bone is removed to allow the joint to maintain a normal line of force. Bone spurs are also removed and soft tissues are loosened to allow the joint to maintain internal and external and anterior-posterior balance.
A trial mold of the artificial joint is mounted to the osteotomized bone surface for testing to ensure proper size and orientation in all aspects.
The femoral component and tibial buttress are fitted separately (cemented to the bone surface with “bone cement”) and a polyethylene liner is fitted to the tibial buttress (this polyethylene liner can later be replaced separately if it wears out while the rest of the bone is intact).
Finally, the wound is irrigated and sutured, and a drainage tube is usually placed. A tourniquet is used during the procedure, so there is only a small amount of bleeding. The drainage tube drains the bleeding out of the joint after the procedure (this drainage tube is removed 24-48 hours after the procedure).
The entire procedure takes about one and a half to two hours, and patients under general anesthesia are monitored in the anesthesia recovery room for a period of time after the procedure and sent back to their rooms after they are fully awake.