Anatomy

The knee is the largest joint in the body.

Normal knee anatomy

The knee is made up of the lower end of the thighbone (femur), the upper end of the shinbone (tibia), and the kneecap (patella). The ends of these three bones are lined with articular cartilage, a smooth coat that covers the bones and enables them to move easily within the joint.

The menisci are located between the femur and tibia. These C-shaped wedges act as shock absorbers that cushion the joint.

Large ligaments hold the femur and tibia together and provide stability. The long thigh muscles give the knee strength.

All remaining surfaces of the knee are covered by a thin lining called the synovial membrane. This membrane produces synovial fluid that lubricates the cartilage, reducing frictional forces in a healthy knee.

Normally, all of these components work in tandem. But disease or injury can disrupt this harmony, resulting in pain, stiffness, and reduced walking ability.

Causes of knee pain:

The most common cause of chronic knee pain and disability is arthritis. Although there are many types of arthritis, most knee pain is caused by just three types: osteoarthritis, rheumatoid arthritis, and posttraumatic arthritis.

Osteoarthritis: This is an age-related wear and tear type of arthritis. It usually occurs in people 50 years of age and older, but may occur in younger people, too. The cartilage that cushions the bones of the knee softens and wears away. The bones then rub against one another, causing knee pain and stiffness.

Rheumatoid arthritis: This is a disease in which the synovial membrane that surrounds the joint becomes inflamed and thickened. This chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain, and stiffness. Rheumatoid arthritis is the most common form of a group of disorders termed "inflammatory arthritis.“

Posttraumatic arthritis: This can follow a serious knee injury. Fractures of the bones surrounding the knee or tears of the knee ligaments may damage the articular cartilage over time, causing knee pain and limiting knee function

What is TKR?

Total knee replacement is a surgery is done to remove damaged /worn out parts of your knee joint and replace them with metal and plastic components. This procedure is a boon for people suffering from various types of knee arthritis; who are troubled by the pain, stiffness and in some cases deformed /bent joints. The surgery helps restore the normal range of movement, corrects deformity and most importantly relieves the pain.

The correct artificial joint and preferred surgical techniques for you depend on your age, weight, activity level, knee size and shape, and overall health.

When should I opt for TKR?

Knee replacement surgery is a treatment for pain and disability in the knee when all other modalities have failed in achieving normal pain free active life. People with severe degenerative joint disease may be unable to do normal activities that involve bending at the knee, such as walking or climbing stairs, because they are painful. The knee may swell or "give-way" because the joint is not stable.

What are Implant Components of TKR?

• Femoral component: It covers the lower end of the thigh bone (femur). The metal femoral component curves around the end of the femur (thighbone). It is grooved so the kneecap can move up and down smoothly against the bone as the knee bends and straightens.
• Tibial Component: It covers the upper end of the leg bone (tibia). The tibial component is a flat metal platform with a stem which is fitted into the upper part of the tibia.
• Spacer : It is cushion of strong, durable plastic, called Highly Cross linked polyethylene fitted in between the femoral and tibial component.
• Patellar Component: Covers the back surface of the knee cap (patella). The patellar component is a dome-shaped piece of polyethylene that duplicates the shape of the patella. In some cases, the patella does not need to be resurfaced.

Risks:

As with any surgical procedure, complications can occur. Some possible complications may include, but are not limited to, the following:

• Bleeding
• Infection
• Blood clots in the legs or lungs
• Loosening or wearing out of the prosthesis
• Fracture
• Continued pain or stiffness