In the modern world, arthritis of the knee joint is becoming more common. Surgical methods of treating this disease are constantly being improved. One of the most effective is knee joint replacement. At the moment, patients who have undergone knee joint replacement surgery in Germany, can actively engage in sports without any restrictions. At the same time, each variant of surgical intervention has its own peculiarities.
Anesthesia in orthopedic surgeries
Surgery can be performed under either general or local anesthesia. People who smoke, abuse alcohol, or have other medical conditions are at greater risk for anesthesia-related complications. Patients concerned about their individual risks should talk to their physician.
General anesthesia
Generally, general anesthesia drugs are injected through a needle into a vein in the patient’s arm. The patient is rendered unconscious and does not feel any pain. Patients under general anesthesia are carefully monitored by an anesthesiologist. Hemodynamics are measured and breathing is assessed. In some cases, the type of anesthesia can be chosen by the patient, but most often, the anesthesiologist sets the indications or contraindications to a particular type of anesthesia.
Local (or regional) anesthesia
This type of anesthesia can be used instead of or in combination with general anesthesia. There are two types of regional anesthesia. Spinal and epidural anesthesia methods anesthetize the entire lower half of the body. The anesthetic is injected between the vertebrae, allowing the necessary nerves to be blocked. The peripheral nerve block targets the specific limb in which the surgeon is working. This approach allows fewer nerves to be blocked, which promotes earlier rehabilitation after surgery. However, this approach requires more experience in the anesthesiologist. Peripheral nerve blocks have become a more common method of anesthesia in recent years as medical technology has made them more accurate and reliable.
Local anesthesia can be used for a short time after surgery. This allows the patient to come out of general anesthesia and regain consciousness without pain.
Patient-controlled intravenous analgesia
Pain needs to be controlled after surgery. Post-surgical pain differs from patient to patient. To explain these variations in pain, patients are sometimes given control over the administration of an anesthetic. The patient presses a button on a pump that injects the medication into a vein. The pump is programmed by the medical staff to administer a specific dose. Therefore, there is no risk of overdose in this case.
Cement or cementless knee prosthesis
If a patient suffering from chronic knee pain due to arthritis prefers joint replacement surgery, the orthopedic surgeon will replace the existing joint surfaces with artificial joint prostheses. These prostheses or prosthetic components must conform to the patient’s natural bone. How this adhesion is achieved depends on the type of prosthesis used.
Cemented dentures use a quick-drying bone cement to help attach the denture to the bone. A cementless prosthesis, sometimes called a press-on prosthesis, has a special agent applied to it so that the bone can grow into it over time. Before a knee replacement, the surgeon will talk to the patient and decide whether to use cemented prosthesis, cementless prosthesis, or a combination of the two. The type of component(s) used may depend on the patient’s physiology, the type of surgery being performed, and the surgeon’s preference.
Cement dentures: advantages and disadvantages
A cement prosthesis has a layer of bone cement, usually an acrylic polymer called polymethylmethacrylate (PMMA). There are several advantages to using bone cement in knee replacement. Bone cement allows the surgeon to attach the components of the prosthetic joint to bone that is slightly deteriorated due to osteoporosis. Sometimes an antibacterial agent is added to the cement to reduce the risks of infection. The bone cement dries within 10 minutes of application, so the surgeon and patient can be confident that the prosthesis is firmly attached.
The disadvantage of using bone cement is that it can break down over time and pieces of cement can cause problems. Cement breakdown can result in an artificial joint, which can trigger the need for another replacement surgery (revision surgery). Cement debris can irritate surrounding soft tissue and cause inflammation. In rare cases, cement can enter the bloodstream and travel to the lungs, which can be life-threatening. If cement debris appears, arthroscopic surgery is performed to remove them. In rare cases, patients have an allergic reaction to bone cement and must undergo a second surgery to remove the glue and dentures.
Cementless dentures: advantages and disadvantages.
A cementless denture, also called a press-fit denture, has a rough surface or porous coating that encourages natural bone growth into it. The new bone growth will only be 1 or 2 mm, so the surgeon must use special tools to shape the natural bone to fit snugly into the denture. Some prosthetic components have screws or pins to help hold the bone and prosthesis in place until it is fully ingrown. Many surgeons prefer cementless components because: they believe that cementless components provide a better long-term bond between the prosthesis and the bone. Cementless prostheses eliminate concerns about possible cement failure. The disadvantages of cementless dentures are as follows. Pressed dentures require healthy bones. Patients with low bone density due to osteoporosis may be contraindicated for this type of prosthesis. It can take up to three months for the bone material to turn into a new joint component.
Another very important aspect in the choice of prosthesis is early rehabilitation. With a cementless prosthesis, it is not always possible to fully load the joint immediately, which in turn leads to a delay in rehabilitation. In the case of elderly patients or patients with chronic diseases, this can lead to a worsening of the condition.
It is generally recommended that patients avoid full load on the joint with a cement prosthesis from 4 to 12 weeks after surgery for knee prosthetics. Limited partial loading is allowed. This cautious approach lengthens the patient’s rehabilitation schedule but protects against stress or loosening of the new joint, which can be painful and may require reoperation. Alternatively, other patients with cementless joints may be encouraged to load the joint fully as soon as a day or two after surgery. Studies of cementless prostheses support this approach, showing that well-supported cementless prostheses can handle pressure and loading. Full load during early recovery and rehabilitation promotes muscle and bone strength and reduces the risk of — pulmonary embolism and the development of pressure sores and hospital-acquired pneumonia. However, research in this area is still ongoing and only a physician can decide which load should be performed on a particular patient after analyzing all indications and contraindications.
In some cases, doctors use both prosthetic options. For example, some knee replacements use bone cement to attach the tibia and patella components, while using cementless components on the hip. Early research on this technique is promising, but more research is needed.
Patients with knee arthritis consider surgery when: quality of life is significantly affected by pain and functional limitations. Non-surgical solutions for pain control, such as drug therapy and physical therapy, have been tried for months or longer without satisfactory improvement. MRI confirms degeneration of the knee joint. Of course, each patient is different in how each assesses quality of life as well as pain tolerance. Some people consider knee arthritis a serious problem if it prevents them from participating in sports or taking long walks. Other people don’t consider knee arthritis a serious problem until the pain interrupts sleep or affects their ability to perform even simple activities, such as household chores. When a person is ready to consider knee surgery, his or her doctor may recommend several options. The most common surgeries to treat knee arthritis are:
1. Total knee replacement (total knee arthroplasty)
2. Partial knee joint replacement (one-piece knee arthroplasty)
3. knee osteotomy (tibial osteotomy or femoral osteotomy)
It is important to note that a surgery that works well for one patient with knee arthritis may not work for another patient. The anatomy of the knee joint and knee degeneration can vary greatly from person to person. The surgical intervention in this case is planned, so it can take place when it is convenient for the patient. Patients can plan for life events such as retirement, weddings, and vacations to make sure they can put 100% effort into rest and rehabilitation in the weeks following surgery.
Total knee replacement surgery (total knee arthroplasty) is considered for patients with moderate to severe knee arthritis in which non-surgical treatment options have been exhausted. The surgery involves cutting open the arthritically damaged ends of the tibia and femur and then closing them with prosthetic parts on both sides. The two prosthetic parts are made of metal or a strong plastic called polyethylene. These new surfaces move smoothly against each other to create a functional knee joint. A partial recovery usually takes 4 to 6 weeks, and a full recovery can take several months to a full year. Total knee replacement provides most patients with pain relief and improved knee function. However, a knee replacement is not as strong and durable as a healthy knee, and patients are strongly advised not to participate in high-impact activities (such as jogging) that can accelerate wear and tear on the new joint.
Partial knee replacement (one-piece knee arthroplasty)
A partial knee replacement, often called a one-piece knee replacement, involves replacing only one of the three «compartments» of the knee: the medial compartment refers to the inner knee (where a person’s knees touch when the legs are together). The lateral compartment refers to the outer knee. The patellofemoral compartment is at the front of the knee where the kneecap contacts the femur. Knee replacement surgery removes the arthritically damaged compartment of the knee (usually the lateral or medial compartment) while preserving healthy areas. This surgery is only suitable for a small number of people, and patients may be ineligible if their knees are severely stiff, have ligament damage, or if they suffer from inflammatory arthritis such as rheumatoid arthritis. Compared to total knee replacement, partial knee replacement is less invasive, so it is usually less painful and requires less recovery time. However, partial knee replacement is not as reliable as total knee replacement for pain relief.
Knee osteotomy (tibial osteotomy or femoral osteotomy). This surgery is suitable for a limited number of young (under 60 years of age), physically active people who have knee joint wear on only one side, a condition called unilateral knee arthritis or asymmetric knee arthritis. During a knee osteotomy, the surgeon reaches the femur or tibia and either: removes a small portion of bone or adds a small section of natural bone graft or artificial bone material. An osteotomy realigns the joint to shift more pressure to the «good» side of the knee joint and reduce wear and tear on the bad side. The goal is to reduce pain and possibly slow the progression of osteoarthritis of the knee joint. A successful knee osteotomy can delay the need for total knee replacement surgery for up to 10 years. Unlike total knee replacement, a knee osteotomy allows the patient to participate in high-impact sports.
Arthroscopic surgeries. Arthroscopic surgery requires only small incisions through which the surgeon inserts a very small video camera and surgical instruments. During knee arthroscopy, the surgeon can evaluate joint degeneration due to arthritis. The surgeon may also perform bone cleaning and lavage, which involves the following process: loose pieces of cartilage or bone (loose osteophytes) that are suspected of causing irritation are removed. In addition, the surgeon removes cartilage that has become heterogeneous and bumpy, repairs inflamed synovial tissue, and flushes the joint with saline solution. This is necessary to remove materials that are known to cause irritation and swelling. Expert opinions vary on whether knee arthroscopy is an appropriate treatment option for knee osteoarthritis. Some experts point to clinical studies that suggest knee arthroscopy offers no benefit to patients with knee osteoarthritis. Others believe that because knee arthroscopy is less invasive and carries fewer risks, it is worth trying before proceeding with more invasive surgery such as total surgery (most experts agree that arthroscopy is useful for treating other knee problems, such as meniscus ligament repair). Knee arthroscopy is an outpatient procedure, but it is still a surgical procedure, and rehabilitation can take 6 to 8 weeks for full recovery.
Damaged cartilage no longer heals well. Even if the joint is able to grow new cartilage, it tends to be rough and bumpy and therefore less able to facilitate smooth movement in the joint. There are several surgeries that attempt to restore or stimulate the growth of healthy cartilage: bone marrow stimulation, which stimulates cartilage growth by creating precise microfractures in the surrounding tissue; bone grafting techniques (OATS), also called «mosaicplasty,» which involves grafting cartilage from one area to another. Autologous chondrocyte implantation (ACI), which requires two operations. First, cartilage cells are harvested and then grown in the lab for several weeks. In the second surgery, the cartilage cells are re-implanted. These procedures may be appropriate for patients with a relatively small and very isolated area of articular cartilage damage. Typically, these patients are younger and have damaged cartilage due to trauma (e.g., sports injury) rather than many gradual wear and tear events. Thus, these surgeries are usually more appropriate for people who are trying to slow or prevent severe arthritis rather than relieve it.
New types of surgery, less invasive surgical techniques, and new implant designs and materials are the subject of ongoing research. People suffering from knee arthritis should make a concerted effort to relieve symptoms with nonsurgical treatments. If nonsurgical treatments do not provide satisfactory pain relief and improved knee function, an orthopedic surgeon who specializes in knee surgery can determine if surgery is an appropriate option. In addition to recommending a specific surgery or set of surgeries, the surgeon will explain the potential benefits of surgery, the expected recovery period, and possible risks and side effects, alternatives to surgery. Once fully informed, the patient can decide whether surgery is worthwhile.
Double knee replacement. Between 4% and 6% of knee replacement surgeries have double knee replacements, in which both of the patient’s knees are replaced. This procedure is sometimes referred to as a bilateral knee replacement. The goal of knee replacement surgery is to relieve knee pain and increase knee function. People considering bilateral knee replacement have moderate to severe arthritis in both knees. They may find it painful to walk or do other daily activities. Double knee replacements have similar short- and long-term results as single joint replacements. Most patients report decreased knee pain and improved function after both surgeries.
Pros and cons of double knee replacement.
Dual replacement is more efficient and convenient. For example, patients spend less time in the hospital, less time in rehabilitation, and less time in physical therapy. However, there are drawbacks, including an increased risk of blood loss and an increased risk of complications. (Although it’s worth noting that people who opt for double knee replacements are only exposed to these risks once.)
Eligibility. Because of the increased risks during and immediately following bilateral knee replacement surgery, most doctors recommend that patients be in good physical condition (except for their arthritic knees). There are no age requirements for bilateral knee replacements. When planning staged knee replacements, the patient and physician should consider the patient’s overall condition and ability to recover between surgeries. If a patient does not recover adequately from the first knee replacement surgery, he or she may be more prone to infection after the second surgery. People who have moderate to severe arthritis in both knees may consider performing a double replacement — replacing both knees during one surgery. The advantage of bilateral knee replacement is usually related to cost and convenience. Experts believe that a person can return to work 4-6 weeks after knee replacement surgery. A patient who has two separate knee replacements performed will take 4 to 6 weeks of work for each knee. Patients with double replacements typically spend at least half a day longer in the hospital than patients with a single knee replacement, but they only need to stay in the hospital once. In other words, a double knee replacement may require a one-day hospital stay, while two separate knee replacements may require two three-day stays (for a total of 6 days)
Time for physical therapy. People who undergo a single knee replacement should attend physical therapy 2-3 times a week for up to 8 weeks. For people who undergo a double knee replacement, these appointments are designed to rehabilitate both knees. People who undergo two separate knee replacement surgeries require two courses of physical therapy. The disadvantages of bilateral knee replacements are generally associated with increased medical risks, although researchers debate the exact nature and severity of these risks. Patients are advised to ask surgeons about their past experiences with bilateral knee replacements. Greater blood loss. Experts estimate that about 40 percent of people who undergo a double knee replacement require blood transfusions, compared to about 12 percent of people who undergo a single knee replacement.
Increased risk of complications. The risk of complications is higher in people who undergo bilateral knee replacements. For example, one study found that 3.8% of patients who underwent a double knee replacement experienced serious complications compared to 2.2% of patients who underwent a single knee replacement. Examples of complications include pulmonary embolism, wound infection, and the need for a second surgery. ⅔ of patients who have double knee replacements are admitted to a rehabilitation center, as opposed to ¼ of patients with a single knee replacement. The number of patients may vary by location. Not all people find staying in a rehab center a disadvantage — rehab centers offer 24-hour care, meals, physical therapy, and the opportunity to meet other people who have had similar surgeries. However, many people prefer to be at home. In addition, rehabilitation centers are associated with an increased risk of infection.
Duration of anesthesia. A double knee replacement requires more surgical time than a single knee replacement, which means the patient must spend more time under general anesthesia. More time under anesthesia increases the risk of complications. A person who has had both knees replaced does not have a supporting leg to stand on, making recovery more difficult. The person cannot rely on a stable leg to strengthen the body while standing, sitting, and using a walker or crutches. Because of the increased risk of complications, many surgeons will only perform bilateral knee replacements if patients are in good physical condition.
Thus, there are quite a large number of different options for knee replacement surgery. From this number, in each specific case, the doctor must choose the option that will be most effective according to the patient’s diagnosis. The choice of surgery option is a very important and responsible stage of treatment, which subsequently determines the result of treatment. Therefore, it is important to undergo treatment with an orthopedic surgeon of high specialization and qualification.
Our Munich clinics are staffed by orthopedic surgeons with the highest degree of qualification and extensive experience in knee surgery.