How long have knee replacements been performed?
Modern knee replacement surgery began in the early 1970s. Over the last 30 years, the procedure has been refined and improved, and is now one of the most successful surgical procedures for the treatment of knee arthritis. Assuming there are no breakthrough preventive treatments for the conditions that lead to total knee arthroplasty, by the year 2030 the American Academy of Orthopaedic Surgeons estimates that about 450,000 total knee arthroplasty procedures will be performed annually. This is a significant increase from 245,000 total knee replacements performed in 1996, and reflects the aging of our active and mobile culture.
Why is total knee replacement surgery performed?
Knee replacement surgery is performed to treat advanced or end-stage arthritis. When arthritis in the knee joint or joints had progressed to the point where medical management is not effective, or deformity has become severe and debilitating, knee replacement surgery might be indicated.
What is knee arthritis?
Arthritis is a general term that describes inflammation and deterioration in joints. In the knee it results from damage to the coating or gliding surface called the articular cartilage. Depending on the amount of damage, ordinary activities such as walking and climbing stairs might become difficult. Damage to the knee joint cartilage and underlying bone might also result in deformity. Knock-knee or bow-legged deformities and unusual knee sounds (crepitus) might become more obvious as the degeneration worsens.
What causes knee joint degeneration?
Mechanical "wear and tear" on a person's knees over a lifetime seems to be an obvious explanation for the increase of arthritis with age, but the answer is not that simple. The current view is that a number of factors interact to cause knee deterioration. Some of these factors include heredity, developmental abnormalities of knee formation, genetic predisposition to abnormal cartilage metabolism, major or minor repetitive injures, and certain occupations. While being overweight does not necessarily cause arthritis, it certainly contributes to early and more rapid progression of knee problems.
Who is a candidate for knee replacement surgery?
People with painful knee deformities, severe degenerative X-ray changes, or advanced symptoms of arthritis are candidates for knee replacement surgery. Symptoms of advanced end-stage knee arthritis include, pain, crepitus, stiffness, limping, muscle weakness, limitation of motion, and swelling. Family physicians, internists, rheumatologists, physiatrists, and orthopaedic surgeons are all trained to manage knee arthritis and can perform an initial evaluation. When medicines, diet, and physical therapy fail to manage these symptoms, evaluation for knee replacement surgery might be indicated and performed by an orthopaedic surgeon.
What is a knee replacement?
Knee replacement surgery is designed to replace the damaged articular cartilage or gliding surface and any associated loss of bone structure or ligament support. The procedure itself is a resurfacing of the damaged knee, and relies on the patient's muscles and ligaments for support and function. The prostheses (replacement knees) come in numerous configurations designed for replacement of specific patterns of advanced arthritis.
Are all knee replacements the same?
Knee replacements are not all the same. There are six different types of knee replacements:
- Uni-compartmental
- Posterior cruciate ligament (PCL) retaining
- Posterior cruciate ligament (PCL) substituting
- Rotating platform
- Stabilized
- Hinge
These different prostheses can be made of cobalt chrome, titanium, and polyethylene (plastic), and can be fixed to the bone with acrylic cement or can be press-fit, which allows bone to grow into the implant. Use of a particular implant design, material, and fixation method depends on many factors related to each individual patient. The orthopaedic surgeon selects the type of knee replacement that best suits each specific patient based on the amount of arthritis bone loss, and quality of the ligaments supporting the knee.
How long does it take to recover from knee replacement surgery?
The vast majority of patients who undergo total knee surgery have dramatic improvement within weeks of the surgery. The pain caused by the damaged knee is relieved when a new gliding surface is constructed. Patients who have knee replacement surgery are standing and moving the joint the day after surgery. After about six weeks most patients are walking comfortably with minimal support. After muscle strength is restored, patients who have knee replacement surgery can enjoy most activities (except running and jumping).
How long do total knee replacements last?
When knee replacement procedures were first performed in the early 1970s, it was thought that the average total knee implant would last approximately 10 years. We now know that approximately 85 percent of the knee implants will last 20 years. Improvements in surgical technique, prosthetic designs, bearing surfaces, and fixation methods might increase the survival rate of these implants even longer.
