Knee replacement or knee arthroplasty refers to a surgical procedure during which the damaged components of the knee joint are removed and then replaced with artificial components. The procedure can be beneficial for individuals who have had knees debilitated by degenerative joint disease, other forms of arthritis, deformity, infection, or as result of trauma. Knee replacement may be recommended in situations where conservative non-surgical therapy or other procedures have not provided relief from pain, stiffness, and loss of function.
The knee joint is a hinge joint connecting the thigh bone (femur) to the shin bone (tibia). It is protected in the front by the patella (kneecap), which is a small flat triangular bone that also plays a role in knee extension. There are four major ligaments in the knee. These ligaments, along with help from the quadriceps muscles in the front of the thighs and the hamstrings in the back of the thighs, act to stabilize the knee and keep it moving in the proper direction. Two concave pads of cartilage called menisci, which are located between the ends of the femur and tibia, minimize friction in the joint and act as shock absorbers.
The largest joint in the body, the knee coordinates with the pelvis, hip, upper leg, lower leg, ankle and foot to facilitate a complete range of lower body movements. It is a strong weight-bearing joint that allows the leg to flex, extend, and twist slightly from side to side. Having healthy knees is essential to perform many daily activities.
Knee replacement is a very common and effective joint replacement surgery that is typically performed after less invasive treatment options have failed. The most frequent reason for the procedure is severe osteoarthritis of the knees. The goal of a knee replacement is to alleviate symptoms and to restore normal function to the knee. The three main areas of the knee involved in the procedure are the lower end of the thigh bone (femur), the upper end of the shin bone (tibia), and the area behind the kneecap (patella).
In a total knee replacement, all of the joint surfaces in the knee are replaced with artificial materials. During a total knee replacement surgery, damaged cartilage and bone are removed from the joint ends of the thigh and shin bones, and as needed from the back of the kneecap. The removed cartilage and bones are then replaced with implants to recreate the joint surfaces. A plastic spacer is then placed between the new metal ends of the thigh bone and shin bone to create a smooth gliding joint surface. In patients with only limited arthritis or damage to the knee joint, a partial or unicompartmental knee replacement may be a suitable option.
A high percentage of individuals who have knee replacement surgery experience a significant relief of symptoms along with an improvement in mobility. Physical therapy begins a short time after the procedure with total rehabilitation taking up to several months. In order to achieve the maximum benefits of the procedure, it is important to adhere to the post-operative guidelines as well as a well-planned rehabilitation program.
Hip replacement, also known as total hip arthroplasty, refers to a surgical procedure during which the damaged bone and cartilage in the hip joint is removed and replaced with new artificial components. A hip replacement procedure may be considered when chronic hip pain and disability have not responded to conservative treatment and interfere with normal daily activities.
The hip joint is located at the meeting point of the rounded head of the femur and the cavity-shaped acetabulum of the pelvic bone. It is a ball and socket joint with the rounded head of the femur being the ball and the curved depression that is known as the acetabulum being the socket. The hip joint is one of the largest weight bearing joints in the body. It withstands the tremendous forces that activities such as walking, running and jumping generate. As one of the most flexible joints in the body, the hip allows a greater range of motion than all of the other joints with the exception of the shoulder.
There are a number of conditions that can damage the hip joint and lead to the need for a hip replacement procedure. The most common of these conditions is osteoarthritis, which is a form of arthritis that is associated wear and tear on the joints and is typically seen in individuals over the age of 50. In cases of osteoarthritis of the hip, the articular cartilage covering the surfaces of the ball and socket wears out leading to painful bone on bone contact. As the damage progresses symptoms of hip pain, inflammation, stiffness, and impaired mobility increase in severity. Other than as a result of osteoarthritis, reasons for hip replacement surgery can include injuries, fractures, bone tumors, rheumatoid arthritis, congenital hip dysplasia, and osteonecrosis.
Hip replacement surgery is a commonly performed safe and effective procedure that can relieve hip pain and restore mobility. It is considered when severe hip pain and stiffness interfere with the ability to carry out everyday activities and when conservative methods such as medication, physical therapy, and walking supports have not alleviated the symptoms.
Total hip replacement involves removing both the damaged head of the femur and the damaged cartilage surface of the socket (acetabulum) and then replacing them with prosthetic parts. The new top of the femur consists of metal stem that is press fit or cemented into the hollow of the bone with a metal or ceramic ball attached to the top of it. The new socket is also made of metal and has a liner made of plastic, ceramic, or metal to help promote smooth movement.
The majority of individuals who have had hip replacement surgery report a dramatic relief of symptoms as well as improved mobility. However, as with all surgical procedures there are risks and benefits. Additionally, a full recovery from the procedure can take several months. Among the variables that may influence recovery time are the type of surgical procedure performed, an individual’s overall health, their adherence to post-surgical guidelines, and the success of their rehabilitation program.
Alternatives to total hip replacement for treating hip joint dysfunction include an osteotomy, which involves cutting the bone to realign the joint, as well as hip resurfacing. However the type of hip surgery that is most suitable for a particular case depends upon an individual’s overall health, age, hip anatomy, joint damage, and the nature of the underlying condition.