What is a Knee Joint ?
The Knee is a complex joint made up of three bones in a hinge formation: the Patella (Kneecap), the end of the femur (Thigh Bone), and the top of the Tibia (Shin Bone). These bones articulate with each other forming the three compartments of the knee. In a healthy knee a highly specialised and naturally lubricated cartilage covers the surface of the bones in the joint and lets the joint surfaces glide smoothly over each other. This joint is controlled by groups of powerful muscles of the thigh and the leg.
What are the commonest causes of Knee Pain ?
A large number of diseases and injuries can damage the knee to the point where it becomes painful or will not function properly.
Although a large number of diseases can cause knee pain, the following are the most important ones: Osteoarthritis, Rheumatoid Arthritis and Post-Traumatic Arthritis.
- Osteoarthritis: This is an age-related wear and tear type of arthritis. It usually occurs in people 50 years of age and older.
- 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 bone leading to pain and deformities.
- Post-traumatic arthritis: This can follow major fractures of the bones surrounding the knee or tears of the knee.
In an arthritic knee the joint cartilage gets degenerated and the normally protected nerve endings in the bone gets exposed giving rise to severe pain. Also secondary effects like inflammation of synovium (soft tissue lining the joint), joint effusion, muscle spasm are present. Ultimately the joint end up in permanently deformed and a painful state restricting not only work and recreation, but also ordinary daily activities.
What is Total Knee Replacement ?
The surfaces forming the joint are removed and a highly polished metal prosthesis is inserted. The metal glides smoothly on a high grade plastic insert. The soft tissue imbalance is also corrected and any deformity is also corrected simultaneously.
What are the alternatives to TKR ?
Arthritis knee has four grades. In earlier grades non-surgical modalities are tried:
- You may benefit from some gentle exercise such as walking, swimming, cycling or other forms of physical therapy
- Weight loss can be very helpful in reducing pain from arthritic knees by reducing the stress
- Intra-articular PPRP / Sodium Hyaluronidase / Cortisone injection
- Knee braces
- Anti-inflammatory medications and pain medications that can help you live with arthritis.
- Some of the surgical options available are:
- Ostetotomy: By surgically changing the alignment of the leg, the axis of weight is shifted to the other compartment, thus slowing down the disease progression
- Unicompartmental Knee Arthroplasty: When the arthritic process is in the early stages and has involved only one of the three compartments in the knee, replacing only that compartment by this minimally invasive technique will address the goals of pain relief, quick clinical recovery and early return to daily activities
Unfortunately in spite of all these measures, the arthritis is progressive in most cases. In case of grade 4 arthritis, bone rubs against bone giving rise to severe pain, in which case, surgical management is the only option.
Why do i need a Knee Replacement?
As already pointed out, various modalities of managing the pain and preventing disease progression are available. But in advanced stages the joint worsens and no intervention is successful. Someone who is in constant pain, wheelchair bound, not able to walk without stick and not responding to non-surgical treatment should consider the option of replacement. The ultimate aim of Total Knee Replacement is complete pain relief and restoring joint movement.
What is the Prognosis?
In many ways, a total knee replacement is similar to changing a set of car tyres. How long the tyres lasts depends on how much the car is used, on what types of roads the car is driven, how heavy the car is, and whether or not the car is properly serviced and maintained. Similarly, how long a total knee lasts depends on how much it is used, what types of activities it is used for and whether you have regular follow-ups.
Average life of Total Knee Replacement is 15 – 20 years.