Primary Knee & Hip Replacement - Know More About Them!

Total Hip Replacement is also known as Total Hip Arthroplasty, in which the damaged cartilage and bones in the hip area are removed and replaced with prosthetic components. On the other hand, Total Knee Replacement, also known as Total Knee Arthroplasty or resurfacing, involves replacing the bone surface of the knee area.

Causes of Hip and Knee Pain

Arthritis is the most common cause of chronic hip and knee pain or disability. Other causes include:

● Avascular necrosis or Osteonecrosis is a condition where there is an inadequate supply of blood to the femoral head due to a hip injury. The inadequate supply of blood may cause the bone surface to collapse and this can result in arthritis.

● Rheumatoid Arthritis is the most common inflammatory Arthritis. In this condition, the synovial membrane surrounding the joint begins to thicken and become inflamed. This results in cartilage loss, stiffness, and pain.

● Osteoarthritis is the type of arthritis, usually related to old age but can occur among young people too. The cartilage cushioning the hip and knee bones becomes soft and gradually wears off. The bones eventually start rubbing against each other which causes stiffness and pain in the knee and hip area.

● Post-Traumatic Arthritis can follow a severe hip and knee fracture or injury.

● Some children with hip disease or problem, even after treatment, can develop into arthritis later. This may be caused by uneven or unusual growth of hip which affects the joint surfaces.

Knee Replacement Procedure

● Bone Preparation: The surface of impaired cartilage at the end of the tibia and femur are separated besides a small extent of the underlying bone.

● Locating the Metal Implants: The removed bone and cartilage are substituted by metal implants creating the joint surface. These metal pieces may either be press-fit or cemented into the bone.

● Resurfacing the Patella: The undersurface of the kneecap or Patella is cropped and reformed with a plastic button. This process is variable depending upon the condition.

● Inserting a Spacer: To form a smooth gliding surface, a plastic spacer of medical-grade is positioned between the metal components.

Hip Replacement Procedure

● Metal stem replaces the damaged femoral head and positioned into the femur’s hollow center.

● On the upper portion of the stem, a ceramic or metal ball is planted. This ball acts as a substitute for the damaged/detached femoral head.

● The damaged Acetabulum or cartilage surface of the socket is discarded and supplanted by a metal socket. Cement or screws are used to sustain the socket in place.

● A spacer, either metallic, plastic or ceramic is placed between the socket and the new ball for a smooth gliding surface.

Take Away

Knee and Hip Replacement are taken as the last option for the patient. The surgery and its outcome vary depending upon various factors. One should consult the doctor before undergoing for the Hip and Knee Replacement Surgery.