A Total knee replacement is when we replace the total knee, the medial compartment, lateral Compartment and the Patellofemoral compartment. If you have arthritis in all parts of your knee, replacing the knee with metal and plastic in all parts is the standard procedure.
The candidates for total knee replacement are people who have arthritis in the knee. You can have arthritis as you get older from wear and tear. You can be an ex-athlete and have just worn your knee out from playing your sport. Some people have fracture of the tibia or fracture of the femur and they have injured their knee along with those fractures. It's now 10 or 15 years later and those fractures have longed since healed, but now the arthritis is painful.
The purpose of replacing the knee, the entire knee, for total knee replacement is to cover all the parts of the knee. So when you have pain in all parts of the knee, replacing the entire knee is the way to go.
A typical total knee replacement, we will see him in the office, we will get weight bearing X-rays, discuss the findings with the patient and determine the activity level of the patient. If there's enough pain and deformity, we'll make arrangements for the surgery. Pre-operatively the patient needs to have a medical evaluation with their doctor, so there's is no question about any medical problem that we are unaware of.
The patient will come to the hospital few hours before surgery. We'll get some pre-medication. Then we take into the operating room. We usually do a spinal or epidural anesthetic, so they're numb from the waist down. They're given morphine in that injection, so that they have no pain usually for the first 24 hours. The advantage of the spinal or the epidural is that in recovery room, they don't feel nauseated or sick which is typical of a general anesthetic.
I also use a pain cocktail injection into the knee and they basically have no pain at all and we start physical therapy that same day. Physical therapist will see the patient daily, show the patient exercises to do. We ask them to do the exercises three times a day, even when the therapist is not there. We use CPM or a Continuous Passive Motion device to help with motion and the patient typically goes home on the fourth or fifth day. They then will have out-patient physical therapy for about two months.
They need to continue doing exercise for at least a year. The patients are walking the first day after surgery, and they usually are walking pretty close to normal by about eight weeks. For total knee replacements, we replace the entire knee. Here we have the femur and you can see that the femur has been cut in various angles, so that it matches the back of the implant and then we put this on and we impact it in place, so that it fits just like a normal knee.
On the tibia side, we cut the tibia and we put in a metal component and then we select the proper height of plastic, and then the whole knee moves smoothly with metal on plastic.
When you have arthritis in all the parts of your knee, you can see that we've replaced the whole knee, and everything has got metal on plastic. The plastic is an ultra high molecular weight polyethylene which has been improved over the last few years for much better wear capabilities.
Total knee replacement can be done using transfusion free techniques in two ways. One way is we can put a drain into the knee, the blood that comes out will then go into a reservoir and it's triple filtered and can be given back to the patient. That way you are less likely to require a bank blood transfusion and you have no exposure to any of the potential diseases that are there.
If an individual for religious reasons does not want to have a transfusion, what we do is we make sure you have homeostasis and the end of the procedure, we would not use a drain and we would use more compression devices in the knee.
Since the procedure is done under a tourniquet, there's no bleeding during the procedure at all. The only blood loss will be afterwards. Postoperative care for total knee replacement is the pain management which we discussed, the spinal or epidural with morphine; the PCA machine and the use of oral medications for pain. When the patient goes home, the oral medications are available and the patient should take those prior to doing their physical therapy that will get the patient moving better and will actually decrease the pain. The rehab protocol for total knee replacement includes motion exercise and strengthening exercises.
It's very important for the individual to contract their muscles both in extension and flexion and to push their knee into extension and flexion, especially early on. Sometimes we can use a muscles stimulation machine to get the muscles contracting, but it's up to the individual to do those exercises.
A lot of people think that just walking is a good exercise for the knee. In fact, it really isn't. I want them to walk obviously, but I want them more importantly to do the knee rehab exercises.
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