In the past 20 years, through the tireless efforts of orthopedic surgeons, biomaterials scientists and metallurgists, artificial knee joints have reached a level of perfection where serious knee diseases that were previously untreatable can be replaced by artificial knee replacements to regain joint function. However, a successful operation requires active cooperation from the patient in addition to the hard work of the doctors, and one cannot be achieved without the other. The purpose of this booklet is to give patients who need artificial knee replacement a certain amount of knowledge about the surgery before the surgery, and a better understanding and mastery of post-operative points of attention and rehabilitation methods, so that they can easily cooperate with the surgeon’s post-operative treatment and functional exercises and obtain the desired surgical results.
The knee joint is one of the most important joints in the human body, and it is extremely important for walking, walking up and down stairs, and sitting. When standing, it carries the weight of the body. If you have knee pain or movement disorders, your doctor may initially give you oral medication, injection therapy, massage and physical therapy after examining and judging the knee joint. If, after all of these treatments, the results are not satisfactory, you should discuss with your orthopedic surgeon to see if you need an artificial knee replacement.
If your doctor decides that you need artificial knee surgery, this booklet will help you learn more about this valuable procedure.
What is Artificial Knee Replacement Surgery
When the normal anatomy of the knee is severely damaged and the knee is unable to function normally, i.e., it is painful to move, the surgeon surgically removes the damaged joint and replaces it with a precision designed and manufactured artificial knee, called an artificial knee replacement.
The normal human knee joint
The knee joint is made up of three bones. The lower part of the thigh bone (femur) forms the upper part of the knee joint; the upper part of the main bone of the lower leg (tibia) forms the lower part of the knee joint; and the other small, slightly flattened bone (patella) forms the front part of the knee joint. All the bones of the knee joint are covered with a layer of smooth, mirror-like, slightly elastic, painless cartilage (articular cartilage) a few millimeters thick, called the articular surface.
In the knee joint, the femur and tibia form a pair of joints, and between the femoral articular surface and the tibial articular surface, there is a half-moon shaped fibrocartilage tissue (meniscus) that acts as a cushion between the femur and tibia. The lower end of the femur is in front of the patella and forms a pair of joints. These bones are also surrounded by muscular ligaments. All of these structures together make up the knee joint. The normal knee joint, through the action of the muscular ligaments, allows for smooth, smooth, even, painless movement of the joint surfaces, while ensuring effective joint stability. If the joint surface is worn, deficient or damaged for various reasons, it often causes painful walking and dysfunction.
The most common factors leading to knee pain and limited motion are osteoarthritis, rheumatoid arthritis and traumatic arthritis.
Osteoarthritis: commonly occurs after the age of 50 and often has a family history of arthritis. In this type of arthritis, the articular cartilage and meniscus that serve as a cushion have often worn away and the joint space has become smaller, resulting in painful friction, joint deformity and stiffness.
Rheumatoid arthritis: It can lead to inflammation of the synovial lining of the joints, producing excessive joint fluid; inflammation can also erode and destroy joint cartilage, causing joint pain, deformity and stiffness.
Traumatic arthritis: intra-articular fractures can directly destroy joint cartilage.
Materials of the artificial knee joint
The artificial knee joint is designed on the basis of extremely advanced metallurgy, biomaterials, biomechanics and bone surgery. It consists of three components. One is the femoral prosthesis, which is made of a smooth, wear-resistant alloy that fits tightly and firmly into the lower end of the femur after a special osteotomy, forming the articular surface of the femur; the other is the tibial prosthesis, which consists of two parts, one is a very wear-resistant and smooth ultra-high polymer polyethylene articular surface, under which a precision metal disk with a stem holds it, and the stem of the metal tray can be inserted into the marrow cavity of the upper end of the lower leg bone (tibia) to fit tightly with the bone; and the other is the tibial prosthesis. The shank of the metal tray can be inserted into the bone marrow cavity of the upper end of the calf bone (tibia) and closely combined with the bone; then there is a patellar prosthesis, which is disc-shaped and composed of ultra-high polymer polyethylene, which has to replace the patellar articular surface and closely combined with the patella. There are two types of bonding methods generally used, one is to use bone cement (an organic compound) to bond the prosthesis to the bone tissue, and the other is a special treatment of the metal surface, the human bone will grow into it closely to fix it. Most doctors today usually choose cemented fixation.
Whether to have a total knee replacement
The decision must be made in consultation with you, your family and your orthopedic surgeon. Common situations that require knee replacement surgery are
Severe knee pain that limits your daily activities, such as walking, going up and down stairs, or walking a few blocks, and you need the help of a walker or cane;
Pain when you are resting during the day or at night;
Inflammation and edema in the knee that does not improve with rest or medication;
A deformity of the knee, such as an O-leg or X-leg;
The knee feels stiff and is difficult to extend and flex;
Ineffective with non-steroidal anti-inflammatory drugs, such as anti-inflammatory pain, ibuprofen, etc;
Pain medication has serious side effects;
Physical therapy, hormone injections and other surgical treatments are not effective.
Most people who need surgery are between 60 and 80 years old, but doctors make different decisions depending on the individual. The recommendation for surgery depends on the patient’s pain and pathology, not just on age, and a successful total knee replacement can be achieved in a young person such as 16 years old or an older person such as over 90 years old.
Necessary tests before deciding to have artificial joint replacement surgery
The orthopedic evaluation includes the following tens of thousands of aspects.
Medical history: The doctor gathers information from asking about your general health, the extent of your knee pain and how it affects your daily life, etc;
Physical examination to determine the mobility and alignment of your knee;
X-rays are taken to examine the extent of damage and deformity of your knee;
Sometimes blood tests or other tests such as MRI, bone scans, etc. are used to examine the bone structure and soft tissues of your knee;
Based on this information and evaluation, your orthopedic surgeon will discuss with you the need for an artificial knee replacement to eliminate pain and improve function, as well as other methods of treatment such as medication, physical therapy or other types of surgery;
Your orthopedic surgeon will also explain the possible complications and potential risk factors for total knee replacement surgery, which have a 1 percent chance of occurring and, although low, are difficult to eliminate. They will be mentioned later in this brochure.
What to expect from a total knee arthroplasty
The vast majority of patients will experience a significant reduction in knee pain, significant improvement in function, self-management of daily activities, and an improved quality of life after surgery, but the surgery will not result in better knee function than before.
After surgery, there are some things you will be prohibited from doing for the rest of your life, including jogging and high impact sports. The artificial knee will wear a little on its plastic pad even with regular activity; excessive activity and weight bearing will accelerate the wear and tear, resulting in knee pain as the prosthesis loosens; if used correctly, the artificial knee will last for many years, more than 90% of patients can keep it for more than 10 years.
Risky activities after surgery: including running or galloping, contact sports, jumping, strenuous aerobic exercise, etc.
How to choose an artificial joint
At present, there are many manufacturers of artificial joints, including famous foreign brands such as Depuy (Johnson & Johnson), Zimmer (Jimmer), Link (Link), Streyker (Stryker), etc., which have more than 20 years of application history; there are also several domestic manufacturers, mostly Chinese and foreign joint enterprises, whose products are mostly imitation, although the product quality is reliable, but the application time is short. Regardless of which company’s products, the design principles and materials are basically the same.
When choosing an artificial joint, the following points should be taken into consideration.
One’s own expectations of the reconstructed joint: ordinary artificial knee replacement surgery can significantly improve the pain and function of severe knee disease and restore basic self-care; some specially designed artificial prostheses can also meet certain special requirements of the patient such as kneeling and cross-legged;
Patient age: More than 90% of ordinary artificial prostheses can be used for about 15 years, which is sufficient for ages over 65; the latest designs and materials of artificial knee prostheses can withstand wear and tear for more than 30 years in vitro, which is suitable for younger patients;
The surgeon’s familiarity and experience with a particular brand of prosthesis: use the prosthesis that the surgeon is most familiar with and most used;
Financial ability to pay: the more requirements you have, the more you will have to pay, although some requirements are less necessary.
Estimated cost of surgery
The cost of an artificial knee replacement consists of the following components
1. Artificial joint cost: The current cost of a domestic prosthesis is between 15,000 and 20,000; the cost of an imported prosthesis is between 28,000 and 46,000. The reason for the price difference is as described above. According to the regulations of our region’s medical insurance bureau, regardless of the use of any prosthesis, employees’ medical insurance reimbursement 8,000 yuan, new agricultural cooperation and urban residents insured persons reimbursement will vary from county to county, but generally less than 5,000 yuan.
2, surgery cost: unilateral surgery cost 1.4 thousand yuan; if bilateral replacement, add 60%. Some local health insurance offices may only reimburse the prescribed cost of surgery on one side at a time, and require re-hospitalization for surgery on the other side.
3.Anesthesia fee: 700 RMB.
4.Medication fee.
5.Blood products fee.
6.Ward treatment fee, bed fee, and nursing fee, etc.
7.Other.
Attention.
In general, the full cost of surgery with a common imported prosthesis is approximately between 35,000-40,000 RMB (before medical insurance reimbursement).
Patients who need simultaneous treatment due to the combination of other diseases will increase the cost of treatment.
Some disposable supplies used during surgery and medications for post-surgical treatment are important for successful surgery and complication prevention, but are not yet included in medical insurance reimbursement due to approval procedures or policy, etc. You need to talk to your doctor.