The knee is made up of three parts – the femur (thigh bone), tibia (shin bone) and patella (knee cap), which are covered by a substance called articular cartilage. The cartilage helps ensure that the bones do not rub against each other and are able to move easily and without friction or wear. The entire joint is held together by ligaments and is constantly lubricated with fluid.
What is knee replacement?
When a patient contracts arthritis, the articular cartilage is damaged and destroyed over time. This is a condition which cannot be reversed as cartilage cannot heal or be repaired. There is no single reason for the onset of arthritis and no specific timeframe either. What is common to all patients though is that they suffer from constant pain caused by the bones of the knee rubbing together (since the cartilage no longer separates them).
In this context, a total knee replacement is the recommended solution. The procedure involves ‘resurfacing’ the knee with artificial parts. A metal ‘shell’ is placed on the end of the femur and a metal and plastic trough on the tibia. If required, a plastic ‘button’ is used to resurface the rear of the kneecap.
Although the idea of having an ‘artificial knee’, can be scary, it is actually quite a common procedure these days. On occasion, only a part of the knee may need to be replaced and so a partial knee replacement is performed.
What can it do for a patient?
It is important to understand the objective of a knee replacement surgery and the limitations of your new knee. The knee replacement aims to
- alleviate pain
- improve flexibility
- allow resumption of normal, everyday functions
- allow a patient to walk reasonable distances
- correct deformities
It does not however mean that a patient can do anything he or she wants to. An artificial knee also has limitations and any activity which causes undue impact to it, such as running or martial arts, is better avoided.
Typically a patient is discharged from hospital within 3 to 5 days. It is important to then diligently follow the physiotherapy regimen recommended by your doctor. Timelines for complete recovery vary based on each individual’s fitness level, age, weight and so on, but is about six weeks.
Longevity of the implant
It is important to know that, like any mechanical device, the knee implant too has a finite life. Most implants should last a patient between 15 to 20 years. About 5% are known to require replacement within a decade. This replacement surgery is known as ‘revision’.