Knee replacement , also known as knee arthroplasty , is a surgical procedure for replacing the knee joints to reduce pain and disability. This is most often done for osteoarthritis, and also for other knee diseases such as rheumatoid arthritis and psoriatic arthritis. In patients with severe deformities due to advanced rheumatoid arthritis, trauma or osteoarthritis, surgery may be more complicated and at higher risk. Osteoporosis usually does not cause knee pain, deformity, or inflammation and is not a reason for knee replacement
Other major causes of a debilitating pain include meniscus tears, cartilage defects, and ligamentous tears. The debilitating pain of osteoarthritis is much more common in the elderly.
Knee replacement surgery can be performed as partial or total knee replacement. In general, surgery consists of replacing injured or damaged joint surfaces of the knee with metal and plastic components formed to allow continuous knee motion.
This surgery usually involves great postoperative pain, and includes strong physical rehabilitation. The recovery period can be 6 weeks or longer and may involve the use of mobility aids (for example, walking frames, sticks, crutches) to allow patients to return to preoperative mobility.
Video Knee replacement
Medical use
Knee replacement surgery is most often performed in people with advanced osteoarthritis and should be considered when conservative care has been exhausted. Total knee replacement is also an option to improve significant knee or bone joints in young patients. Similarly, total knee replacement may be performed to correct mild valgus or varus deformity. Serious valgus or varus deformity should be corrected with osteotomy. Physical therapy has been shown to improve function and can delay or prevent the need for knee replacement. Pain is often noted when performing physical activities that require various movements in the knee joint.
Maps Knee replacement
Risk
The risks and complications of knee replacement are similar to those associated with all joint replacements. The most serious complication is an infection of the joint, which occurs in & lt; 1% of patients. Risk factors for infection are related to patient factors and surgery. Deep venous thrombosis occurs in up to 15% of patients, and is symptomatic in 2-3%. Nerve injury occurs in 1-2% of patients. Persistent pain or stiffness occurs in 8-23% of patients. Prosthesis failure occurs in about 2% of patients at 5 years.
There is an increased risk of complications for obese people through total knee replacement. Morbid obesity should be advised to lose weight before surgery and, if medically eligible, may benefit from bariatric surgery.
Fractures or chipping of polyethylene platforms between the femoral and tibial components may be of concern. These fragments can get stuck in the knee and cause pain or can move to other parts of the body. Advances in implant design have greatly reduced this problem but potential worries still exist during the knee replacement period.
deep vein thrombosis
According to the American Academy of Orthopedic Surgeons (AAOS), deep vein thrombosis in the legs is "the most common complication of knee replacement surgery... prevention... may include periodic improvement of the patient's foot, lower leg workouts to improve circulation, support stockings and medicine to thin your blood. "
Fracture
Periprosthetic fractures become more common with an aging patient population and may occur intraoperatively or postoperatively.
Loss of motion
The knee at any given time can not restore its normal range of motion (usually 0-135 degrees) after total knee replacement. Much of this depends on the pre-operative function. Most patients may reach 0-110 degrees, but joint stiffness may occur. In some situations, knee manipulation under anesthesia is used to reduce postoperative stiffness. There are also many implants from manufacturers that are designed to be "high flexible knees", offering a greater range of motion.
Instability
In some patients, the kneecap can not be recovered postoperatively and dislocates to the outer side of the knee. This is painful and usually needs to be treated with surgery to realign the kneecap. But this is quite rare.
In the past, there was considerable risk of implant components loosening over time as a result of wear. However, as medical technology has improved, this risk has greatly declined.
Infection
The AAOS classification currently divides the prosthetic infection into four types.
- Type 1 (positive intraoperative culture): Two positive intraoperative cultures
- Type 2 (early postoperative infection): Infection occurs within the first month after surgery
- Type 3 (acute hematogen infection): Haematogenous spread from previously well functioning prosthesis
- Type 4 (advanced chronic infection): Chronic indolent clinical course; infections present for more than a month
Although relatively rare, periprosthetic infection remains one of the most challenging complications of joint arthroplasty. Detailed clinical and physical history remains the most reliable tool for recognizing potential periprosthetic infections. In some cases, classic signs of fever, chills, painful joints and flowing sinuses may be present, and diagnostic studies are only performed to confirm the diagnosis. But in reality, most patients do not present with clinical signs, and in fact clinical presentation may overlap with other complications such as loosening and aseptic pain. In such cases, diagnostic tests may be useful in confirming or excluding infections.
The modern diagnosis of infection around total knee replacement is based on the Musculoskeletal Infection Society (MSIS) criterion. They:
1. There is a sine channel that communicates with the prosthesis; or 2. The pathogen is isolated by culture of at least two separate tissue or liquid samples obtained from the affected prosthetic joint; or
Four of the following six criteria exist:
1. erythrocyte serum sedimentation rate (ESR & gt; 30mm/h) and serum concentrations of C-reactive protein (CRP & gt; 10 mg/L),
2. Calculate the number of synoval leukocytes,
3. Percentage of enhanced synovial neutrophils (PMN%),
4. Presence of purulence in affected joints,
5.Isolation of microorganisms in a culture of periprosthetic or fluid tissue, or
6. Greater than five neutrophils per high power field in the five high power fields observed from histologic analysis of periprosthetic tissue in ÃÆ'â € 400 enlargement.
None of the above laboratory tests had a 100% sensitivity or specificity for diagnosing the infection. The specificity increases when the tests are performed on patients suspected of clinical suspicion. ESR and CRP remain a good 1st line test for screening (high sensitivity, low specificity). The joint aspirate remains the test with the highest specificity to confirm the infection.
Treatment options depend on the type of prosthetic infection.
- Intraoperative culture positive: Antibiotic therapy alone
- Early postoperative infection: debridement, antibiotics, and prosthesis retention.
- Acute haematogenic infection: debridement, antibiotic therapy, prosthesis retention.
- Chronic end: delayed exchange arthroplasty. Surgical therapy and parenteral antibiotics alone in this group had limited success, and the standard of care involved the exchange of arthroplasty.
The right dose antibiotics can be found in the following instructional course by AAOS
Pre-operational preparation
To show knee replacement in the case of osteoarthritis, the radiographic classification and severity of both symptoms should be substantial. The radiography should consist of X-rays that weigh on both knees-AP, Lateral, and 30 degree flexion. AP and lateral views may not indicate constriction of joint space, but the 30 degree flexion view is most sensitive for narrowing. Full-length projection is also used to adjust the prosthesis to provide a neutral angle for the distal lower extremities. The two angles used for this purpose are:
- The angular-knee-axis angle (HKS), an angle formed between the lines through the longitudinal axis of the femoral shaft and its mechanical axis, which is the line from the center of the femoral head to the intercondylar notch of the distal femur.
- Hip-knee-ankle angle (HKA), which is the angle between the femoral mechanical axis and the center of the ankle joint.
Patients should perform various movement exercises and strengthening of the hips, knees and ankles as directed daily. Before surgery, preoperative tests are performed: usually complete blood count, electrolytes, APTT and PT to measure blood clotting, chest x-ray, ECG, and cross-linking for possible transfusions. About a month before surgery, patients can be given iron supplements to increase hemoglobin in their blood system. Accurate X-rays from the affected knee are required to measure the size of the components that will be required. Drugs like warfarin and aspirin will be stopped a few days before surgery to reduce the amount of bleeding. Patients can be treated on the day of surgery if pre-surgery is performed in a pre-anesthesia clinic or may come to the hospital one day or more before surgery. There is currently no evidence of sufficient quality to support the use of preoperative physiotherapy in older adults undergoing total knee arthroplasty.
Current preoperative education is an important part of patient care. There is some evidence that may slightly reduce anxiety before knee replacement surgery, with a low risk of adverse effects.
Surgical weight loss before knee replacement does not seem to change the results.
Technique
Surgery involves exposure of the front of the knee, with the release of part of the quadriceps muscle (vastus medialis) of the patella. Patella is transferred to one side of the joint, allowing exposure of the distal end of the femur and the proximal end of the tibia. The ends of this bone are then cut accurately into shape using a cutting guide oriented to the long axis of the bone. The cartilage and anterior cruciatum ligament are removed; the posterior cruciate ligament may also be removed but the tibial and fibular collateral ligaments are maintained. The metal component is then affected to the bone or fixed using a polymethylmethacrylate cement (PMMA). Alternate techniques exist that implant implants without cement. This cement-less technique may involve osseointegration, including porous metal prostheses.
Femoral replacement
A round implant is used for the femur, mimicking the natural form of the joint. In the tibia, the component is flat, although it sometimes has a stem that drops into the bone for further stability. A high or slightly inserted high density polyethylene surface is then inserted into the tibial component so that the weight is transferred metal to non-metallic plastic to metal. During operation, any abnormality should be corrected, and the ligaments are balanced so that the knee has a good and stable range of motion and is parallel. In some cases the patellar articular surface is also removed and replaced with polyethylene buttons cemented to the posterior surface of the patella. In other cases, the patella is changed unchanged.
Postoperative Pain Control
Regional analgesia techniques (Neuraxial anesthesia or continuous femoral nerve block or Adductor channel block) are most commonly used. Infiltration of local anesthesia in the pericapsular region using liposomal bupivacaine has been shown to provide good analgesia in the postoperative period without increasing the risk of instability or nerve injury. There are studies that use a combined approach of local infiltration analytia and femoral nerve block to achieve multimodal analaseia.
Variations
Different manufacturers of implants require slightly different instrumentation and techniques. There is no consensus about which is best. Clinical studies are very difficult to do, requiring many cases followed for years. The most significant variations are between cemented and non-cemented components and between patellar re-plating or not. Among those who do not coat the patella, there is also a variation between denervating patellas using electrocautery or not. In theory, this technique can disrupt the superficial pain receptors near the patella in the hope of eliminating anterior knee pain, a common postoperative complaint. There is no consensus, but recent randomized controlled trials show that while both methods provide assistance, patellar denervation yields modest benefits compared to no denervation in the short run. Patient satisfaction was higher with more patients assessing the procedure as excellent in the denervation group (74.6% vs. 50.8%). However, the benefits do not last long to long term postoperatively. The anterior knee pain component in the patellar score and Visual Analogic Scale for anterior knee pain were significantly better in the denatured group at 3 months (4.5 vs 5.1) but not at 12 months (4.4 vs 4.9) and 24 months ( 2.1 vs 2.2).
Some also studied patient-related satisfaction data with pain. Maintaining a posterior cruciate ligament (PCL) has proven beneficial to the patient. PCL removal has been shown to reduce the maximum strength that individuals can place on the knee. Usually individuals who have removed PCL will lean forward while climbing to maximize the strength of the quads.
Minimally invasive procedures have been developed in total knee replacements (TKRs) that do not cut the quadriceps tendons. There are different definitions of minimally invasive knee surgery, which may include a shorter incision length, a patellar retraction (kneecap) without eversion (spin out), and special instruments. There have been randomized trials, but studies have found less post-operative pain, shorter hospital stay, and shorter recovery. However, no studies have shown long-term benefits.
In 2015 the OGAAP Team from Sydney Australia led by Dr Al Muderis presented revolutionary technology for the first time allowing the use of knee replacement in combination with a percutaneous bone retractor that allows amputation sufferers with short residual tibiia and/or knee joint arthritis to mobilize easily. This technology provides a solution for individuals with amputations that can not use traditional socket prostheses.
Partial knee replacement
Unicompartmental arthroplasty (UKA), also called partial knee replacement, is an option for some patients. The knee is generally divided into three "compartments": medial (inner part of the knee), lateral (outer), and patellofemoral (joints between kneecap and femur). Most patients with arthritis are severe enough to consider knee replacement to have significant wear in two or more of the above compartments and is best treated with total knee replacement. A small percentage of patients (the exact percentage is debatable but probably between 10 and 30 percent) have limited wear mainly to one compartment, usually medial, and possibly candidates for unicompartmental knee replacement. UKA benefits compared to foreign workers include smaller incisions, easier post-operative rehabilitation, improved postoperative range, shorter hospital stay, less blood loss, infection risk, stiffness, and blood clots. lower, but a more difficult revision if needed. While recent data show that UKA in properly selected patients has a comparable level of survival to foreign workers, most surgeons believe that TKA is a more reliable long-term procedure. Persons with inflammatory inflammation or inflammation (Rheumatoid, Lupus, Psoriatic), or defects are marked not candidates for this procedure.
Post-operative evaluation
Knee replacements are routinely evaluated with X-rays, including the following steps:
- HKA: Angle-knee-ankle angle, ideally between 3Ã, Â ° varum to 3Ã, Â ° valgum from right angle.
- FFC: the angle of the frontal femoral component. This is usually considered optimal when it becomes 2-7 Â ° in valgus.
- FTC: the angle of the frontal tibial component, which is considered optimal when located at a right angle. The varus position of more than 3 Â ° has generally been found to increase the failure rate of the prosthesis.
- LFC: the lateral (or sagittal) angle of the femoral component
- LTC: a lateral (or sagittal) tibia angular component, ideally positioned so that the tibia is 0-7Ã, Â ° flexed compared with a right angle to the tibia plate.
The length of postoperative hospitalization is 5 days on average depending on the patient's health status and the amount of support available outside the hospital. Weight protected pads on crutches or walkers are required until determined by the surgeon because of weakness in the quadriceps muscle
To increase the likelihood of good results after surgery, several weeks of physical therapy is required. In these weeks, the therapist will help the patient return to normal activities, as well as prevent blood clots, improve circulation, increase range of motion, and ultimately strengthen the surrounding muscles through certain exercises. Treatment includes encouraging patients to move early after surgery. Often the range of motion (up to the limit of the prosthesis) recovers within the first two weeks (the sooner the better). Over time, patients can increase the number of heavy loads on the legs that are operated, and finally can tolerate the full load with the guidance of a physical therapist. After about ten months, the patient should be able to return to normal daily activities, although the operated feet may be much weaker than the legs that are not operated.
For post-operative knee replacement patients, immobility is a factor triggered by pain and other complications. Mobility is known as an important aspect of human biology which has many beneficial effects on the body system. It is well documented in the literature that physical immobility affects every system of the body and contributes to the prolonged functional complications of disease. In most hospital surgical hospital units performing knee replacements, ambulation is a key aspect of treatment being promoted to patients. Early ambulance may reduce the risk of complications associated with immobilization such as pressure ulcers, deep vein thrombosis (DVT), impaired lung function, and loss of functional mobility. Nurses promotion and implementation of early ambulation in patients have found that it greatly reduces the complications listed above, as well as reduces length of stay and costs associated with further hospitalization. Nurses can also work with teams such as physical therapy and occupational therapy to achieve ambulation goals and reduce complications.
Continuous Passive Motion (CPM) is a post-operative therapy approach that uses machines to move the knee continuously through certain movements, with the aim of preventing joint stiffness and improving recovery. There is no evidence that CPM therapy leads to a clinically significant increase in the range of motion, pain, knee function, or quality of life. CPM is not expensive, convenient, and helps patients in therapeutic compliance. However, CPM should be used in conjunction with traditional physical therapy. In an unusual case where the person has a problem that prevents standard mobilization maintenance, then the CPM might be useful.
Some doctors and patients may consider doing ultrasound for deep vein thrombosis after knee replacement. However, this kind of screening should be done only when indicated because to do so on a regular basis would be unnecessary health care. If there are medical conditions that can cause deep vein thrombosis, doctors may choose to treat patients with cryotherapy and intermittent pneumatic compression as a precaution.
Both gabapentin and pregabalin have been found to be beneficial for pain after knee replacement.
Epidemiology
With 718,000 hospitalizations, knee arthroplasty accounts for 4.6% of all US operating room procedures in 2011 - making it one of the most common procedures performed during hospital stay. The number of knee arthroplasty procedures performed in US hospitals increased 93% between 2001 and 2011. A United States community hospital study showed that in 2012, among hospitalizations involving OR procedures, knee arthroplasty was the OR procedure most frequently performed during hospital stay. paid by Medicare (10.8 percent fixed) and by private insurance (9.1 percent). Knee arthroplasty is not one of the five most frequently performed OR procedures to remain paid for by Medicaid or for uninsured stays.
By 2030, demand for primary total knee arthroplasty is projected to increase to 3.48 million operations performed annually in the US.
See also
- Automatic condominium implants
- Microfractor operation
- Knee osteoarthritis
- Osseointegration
- Meniscus transplant
References
External links
- New Knee Set Comes With Price: Much Pain By Jane E. Brody, The New York Times, February 8, 2005
- When Pain is Severe, Doctors Still Learn Lots by Jane E. Brody, The New York Times, February 15, 2005
- A Year With My New Knee: Much Sick But A Lot Of Profits By Jane E. Brody, The New York Times, December 20, 2005
- 3 Years Later, Knees Made for Dancing, By Jane E. Brody, The New York Times, June 3, 2008
- Aid for Armed Bloody Joints, By Jane E. Brody, The New York Times, July 9, 2012
Source of the article : Wikipedia
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