Q: What is knee arthroplasty?
A: “Knee replacement” is technically called “knee surface replacement” and involves replacing worn cartilage with bionic material to make the joint surface smooth again. Generally, the worn and damaged joint surface is removed (8-9mm thick) and replaced with cobalt-chromium-molybdenum and high-grade polyethylene. Many people think of knee replacement as “chopping off” the entire knee joint and replacing it with a metal joint, but this is a complete misconception. It is like repairing a small hole in a tooth and putting in a tooth protector to keep the tooth in use, not pulling out the entire tooth and replacing it with a new one. Knee surface replacement is just like this tooth protector to protect the joint, and the surgery is done to preserve important ligaments and other structures.
Normal knee joint surface Destruction of worn joint surface Knee surface after replacement
Q: What diseases require knee replacement?
A: There is no way to repair the damage to the cartilage of the articular surface and knee replacement is currently the best treatment for severe wear and tear of the articular surface. Knee arthroplasty is mainly used for destructive diseases of the joint surface caused by various reasons, mainly various kinds of arthritis, commonly used in severe osteoarthritis, rheumatoid arthritis, gouty arthritis, psoriatic arthritis, traumatic arthritis, osteonecrosis of the femoral condyle, etc.
Knee replacement can correct severe knee deformities
Q: What is the likelihood of success?
A: Success cannot be measured by a quantitative score, but by whether you can say “yes” to the following three questions: 1) Are you satisfied with the procedure, 2) Did it meet your expectations, and 3) Assuming you have never had the procedure, would you be willing to have it now? About 98% of patients will answer “yes” to all three questions one year after surgery.
Q: How long is the recovery time?
A: Recovery time after surgery varies from patient to patient. However, for most patients, they will need to use crutches or a walker for 1 month after surgery. For the next few weeks, you can go out with a cane or walk around indoors or in a small area without any help. Generally, after 3 months, and possibly a little longer, you can gradually return to a normal functional state without any assistance.
Q: Should I go to a rehabilitation facility or go home after I am discharged from the hospital?
A: This question varies from person to person, and most say that patients can be discharged home. Because of the lack of specialized rehabilitation facilities in China, patients still have the guidance of their primary care physicians for most of their post-operative rehabilitation work. At the time of discharge, the attending physician will explain to you about the precautions and rehabilitation techniques to be taken after going home.
Q: When will I be able to start driving?
A: If you have had surgery on your right knee, you should not drive for at least 1 month after surgery, but you can drive as soon as you feel comfortable after 1 month. If you have had surgery on your left knee and are driving an automatic car, you can drive as long as you are comfortable. However, if you are taking narcotic analgesics, you cannot drive. Some doctors will only allow them to drive after they have seen the patient for 4-6 weeks. Therefore, it is still necessary to check with your surgeon to be sure.
Q: When can I travel?
A: You can travel as long as you feel comfortable. In general, when traveling for long periods of time, stand up and stretch your legs or walk around at least every hour. This is important to help prevent deep vein thrombosis.
Q: When can I return to work?
A: This depends on your occupation. If you work mostly sitting, then you can return to work in about 1 month. If the job is more physically demanding, it can take up to 3 months to fully return to work. Sometimes patients’ recovery time varies widely and can be longer or shorter.
Q: What activities can I do after surgery?
A: You can resume most activities as long as you can tolerate them, including walking, gardening and playing golf. Some of the best activities, such as swimming and riding a stationary bike, help to move the joint and build muscle strength. Sports that expose the joint to high impact stress, such as running, jumping, and physical sports such as single or double tennis, should be avoided.
Q: How long will the artificial joint last?
A: It varies depending on the patient’s condition. Each year after joint replacement, you increase the likelihood of needing a second surgery by 1 percent. For example, 15 years after surgery, approximately 10% of patients will need a second revision. At 20 years after surgery, approximately 15% of patients will require revision.
Q: How long is the hospital stay for surgery?
A: Generally 5-7 days (depending on the condition and can be extended if necessary).
Q: How long does the surgery take?
A: The surgery takes about 60 minutes (from incision to suturing), and the entire procedure (including pre-operative skin preparation and disinfection, anesthesia and post-operative recovery) takes about 1.5 to 2 hours.
Q: How soon can I get out of bed?
A: Usually you can get out of bed on the 3rd to 4th day after surgery, but it will still depend on the patient’s condition.
Q: How long do I need to use the walker after surgery?
A: Generally, you can walk with a walker within 4~6 weeks after surgery (adjusted according to the patient’s recovery) to avoid falls.
Q: Are there any restrictions on activities after surgery?
A: There is no restriction. During the hospitalization period, a passive motion machine (CPM) will be used to help the knee joint bend at an angle of 90 degrees or more. Generally, you can walk with a walker for 4-6 weeks after surgery, and then you can walk without a walker (adjusted according to the patient’s recovery) to avoid falls. After discharge from the hospital, all rehabilitation exercises must continue and gradually increase the amount of activity, with adequate rest after exercise to restore strength.
Q: How long does it take for the redness and swelling of the knee to go down after surgery?
A: Generally, the redness and swelling will slowly subside 3 to 4 months after surgery, depending on individual blood circulation.
Q: Why is there a tingling sensation next to the open wound after surgery?
A: It is because the superficial nerve (infrapatellar branch of the saphenous nerve) is damaged by the surgical wound, but it does not affect the rehabilitation and daily activities, and will gradually improve after about 1 year.
Q: When will I be able to take a bath (shower), or can the wound be wet?
A: If the wound is not oozing, you can take a shower 3 days after surgery. Initially, you can use plastic wrap to keep the wound dry, and if it gets wet, dry it promptly and change the dressing.
Q: When can I fully immerse my knee in the tub or pool?
A: You can fully immerse your knee in water 2 weeks after surgery as soon as the wound is fully healed and the stitches have been removed for 3-4 days. For intradermal suture wounds, you can enter the water 2 weeks after surgery.
Q: When should I put on a knee brace and when should I not?
A: The knee brace is usually worn at night for the first few days after surgery or for walking until you are able to perform straight leg raises on your own. Most patients do not need to use it.
Q: How much of the Continuous Passive Motion Manipulator (CPM) should I use?
A: The CPM can be used soon after surgery for a total of 8 hours per day, gradually increasing the bending angle. Nowadays, active functional exercises after anesthesia are mostly advocated, usually without CPM, and your primary care physician or specialized rehabilitation physician will help you with flexion and extension exercises. Active exercise is beneficial in preventing deep vein thrombosis.
Q: How long does the bandage need to be applied to the wound?
A: The bandage needs to be applied for 1 week and the dry sterile gauze changed daily, sometimes longer, to protect the wound from clothing or knee brace irritation.
Q: When are the wound sutures or staples removed?
A: The sutures or staples are usually removed 2 weeks after surgery, while patients with diabetes or rheumatoid arthritis usually need to have their wounds removed longer, approximately 3 weeks after surgery, due to their poor wound healing ability. With intradermal suture wound closure, no suture removal is required.
Q: How long do I need to take pain medication after surgery?
A: Pain medication is usually required for 3 months, starting with some stronger-acting pain medications, such as narcotic painkillers. After 1 month, most patients can stop taking these stronger-acting pain medications and switch to some over-the-counter pain medications, such as fenbendazole.
Q: How long do I need to take anticoagulants after surgery?
A: There are various methods including tablets and injections used to anticoagulate and prevent thickening of the blood and blood clots. Your surgeon will choose a treatment plan for you based on your medical history and pre-discharge tests.
Q: Can I drink alcohol during my recovery?
A: Alcohol should not be consumed if you are taking warfarin for anticoagulation, and is also contraindicated if you are taking non-steroidal pain medications.
Q: How long should I take iron after surgery?
A: Four weeks of iron is often sufficient after surgery. Taking iron helps to replenish the body’s iron supply and increase the hemoglobin level.
Q: What is the correct and incorrect position of the knee joint during rehabilitation?
A: You should spend a little time each day doing knee flexion and extension exercises. It is best to change the position every 15-30 minutes. Do not put pillows or cushions under the knee joint. Pillows under the ankle joint can improve knee extension and prevent flexion contracture. Being able to straighten the knee joint is very important when standing and walking.
Q: Should I use an ice pack or heat on the knee after surgery?
A: Initially, an ice pack will reduce the swelling of the joint. After a few weeks, heat packs or other physical therapy methods can be tried.
Q: How long should I wear the compression stockings?
A: After you go home, you can try walking without the compression stockings and notice if the ankle and foot are swollen. If swelling occurs, you can wear the stockings during the day until the swelling in the ankle subsides to the same level as before surgery. You should also wear compression stockings when you travel by car or air for a few months after surgery.
Q: Can I go up and down stairs?
A: Yes. In the beginning, go up the stairs with the non-operated leg first and go down the stairs with the operated leg first. Once the muscles in the leg have gained strength and joint movement has improved, you can go up and down the stairs in a more normal manner, which usually takes about a month.
Q: Do I need physical therapy?
A: Yes, of course. Physical therapy is very important to your recovery, and you will have a physical therapist to guide you after surgery and throughout your hospital stay (in China, there are mainly primary care doctors and nurses to guide you) to help you recover. When you go home, the physical therapist will teach you some exercises so that you can do them on your own. Your doctor will give you a written exercise program. In addition, swimming and riding a stationary bike are good ways to exercise. You can do these exercises at any time, even after you have fully recovered.
Q: When can I resume sexual activity?
A: As soon as you feel comfortable.
Q: I feel depressed, is this normal?
A: It is normal to feel depressed after a knee replacement. There are many factors that contribute to this, such as limited activity, discomfort, increased dependence on others after surgery, and adverse reactions to medications. As you begin to return to your previous daily activities, the depression will disappear. If your depression persists, you may seek the help of an internist for consultation and treatment.
Q: I have insomnia, is this normal? What should I do?
A: Insomnia is common after knee replacement. Over-the-counter medications such as Benadryl or Melatonin are effective, and if the problem persists, prescription medications such as Xanax can be taken.
Q: I am constipated, what should I do?
A: Post-operative constipation is common and has many causes. Taking narcotic analgesics can exacerbate constipation. Dulcolax (lactulose oral solution) can be taken to prevent constipation, marijuana soft capsules and senna tea drink can laxative, and enemas can be used to deal with severe constipation.
Q: How much range of motion does my knee joint need to perform normal lower limb function?
A: Most people need 70 degrees of knee flexion to walk on a flat surface, 90 degrees of flexion to go upstairs, 100 degrees to go downstairs, and 105 degrees to stand up from a low stool. To facilitate standing and walking, the knee joint should be able to be nearly fully extended, with no more than 10 degrees of restriction.
Q: How much range of motion can I expect in my knee at 6 weeks post-op and 1 year?
A: Everyone’s range of motion is different and is related to many individual factors. Your knee range of motion was basically defined at the time of surgery and 1 year after surgery, the patient’s average flexion is approximately 115 degrees, some patients will have less and some patients will have more.
Q: I think my leg has gotten longer, is this possible?