If your knee is severely damaged by arthritis or injury, it may be hard for you to perform simple activities, such as walking or climbing stairs. You may even begin to feel pain while you are sitting or lying down.
If non-surgical treatments like medications and using walking supports are no longer helpful, you may want to consider total knee replacement surgery. Joint replacement surgery is a safe and effective procedure to relieve pain, correct leg deformity, and help you resume normal activities.
Knee replacement surgery was first performed in 1968. Since then, improvements in surgical materials and techniques have greatly increased its effectiveness. Total knee replacements are one of the most successful procedures in all of medicine.
Whether you have just begun exploring treatment options or have already decided to have total knee replacement surgery, this article will help you understand more about this valuable procedure.
The knee is the largest joint in the body and having healthy knees is required to perform most everyday activities.
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 where they touch are covered with articular cartilage, a smooth substance that protects the bones and enables them to move easily.
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 releases a fluid that lubricates the cartilage, reducing friction to nearly zero in a healthy knee.
Normally, all of these components work in harmony. But disease or injury can disrupt this harmony, resulting in pain, muscle weakness, and reduced function.
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 post-traumatic arthritis.
- Rheumatoid arthritis
- Post-traumatic arthritis
A knee replacement (also called knee arthroplasty) might be more accurately termed a knee ‘resurfacing’ because only the surface of the bones are actually replaced.
There are four basic steps to a knee replacement procedure.
- Prepare the bone. The damaged cartilage surfaces at the ends of the femur and tibia are removed along with a small amount of underlying bone.
- Position the metal implants. The removed cartilage and bone is replaced with metal components that recreate the surface of the joint. These metal parts may be cemented or ‘press-fit’ into the bone.
- Resurface the patella. The undersurface of the patella (kneecap) is cut and resurfaced with a plastic button. Some surgeons do not resurface the patella, depending upon the case.
- Insert a spacer. A medical-grade plastic spacer is inserted between the metal components to create a smooth gliding surface.
Are there any risks?
Knee replacement surgery is a common operation and most people do not experience complications. However, as with any operation, there are risks as well as benefits.
Complications are rare but can include:
- stiffness of the knee
- infection of the wound
- deep infection of the joint replacement, needing further surgery
- unexpected bleeding into the knee joint
- ligament, artery or nerve damage in the area around the knee joint
- blood clots or deep vein thrombosis (DVT)
In some cases, the new knee joint may not be completely stable and further surgery may be needed to correct it.