The worn surfaces at the end of the thigh bone are removed using special instruments during knee replacement surgery, and the damaged joint is resurfaced with metal and plastic implants. At first, the surgeon shapes the bone to prepare for this new covering.
The top of the shin bone (tibia) is prepared in a similar way. The worn surface is removed and a new tibial base is placed on top of the remaining bone. This tibial base holds a hard plastic spacer that will become the new shock absorber between the smooth metal coverings. The doctor may also replace the back of the kneecap with a new plastic surface. These components can be fixed to the bone by either using bone cement or a "press fit," allowing the bone to grow into the coating on the implant. The doctor will typically decide which type of fixation to use based on numerous factors including age, activity level, bone quality and other associated medical conditions.
Near the end of the surgery, the doctor will secure the new knee. When the implant is in position and all of the supporting muscles and ligaments are working well, the doctor closes the incision with stitches or staples.
When your surgery is over, you will be taken to the recovery room. Generally, you can expect to be moved to your regular room within one to three hours after surgery.
The difference between partial and total knee replacement
The knee is divided into three areas: medial and lateral (the sides of your knee) and patella (the kneecap). In partial knee replacement, the damage to the bone is isolated primarily to one of these three areas. The surgeon replaces the damaged area of the knee only, allowing patients to keep more of their natural bone, tissue and ligaments when compared to a total knee replacement. And because it’s less invasive, they have the potential for a faster recovery than with a total knee replacement.
On the other hand, if the damage has affected two or more areas, a total knee replacement may be the answer.
Knee replacement, in general, is a very successful operation. The success of your knee replacement is measured by whether or not you're satisfied with the decrease in your overall pain and the increase in your mobility, as well as the durability of your implant over time.
Once you have had knee replacement surgery, your surgeon will tell you when you can resume normal activities. Many patients are able to drive again in about four to six weeks, so long as you can tolerate it and are not taking narcotic medications. If your job is not physically demanding, you may be able to return to work after about a month.
The performance of knee replacements depends on age, weight, activity level and other factors. There are potential risks and recovery takes time. People with conditions limiting rehabilitation should not have this surgery. Only an orthopaedic surgeon can tell if knee replacement is right for you.