A Total Knee Replacement (TKR) or Total Knee Arthroplasty is a surgery that replaces an arthritic knee joint with artificial metal or plastic replacement parts called the ‘prostheses’.
The procedure is usually recommended for older patients who suffer from pain and loss of function from arthritis and have failed results from other conservative methods of therapy.
The typical knee replacement replaces the ends of the femur (thigh bone) and tibia (shin bone) with plastic inserted between them and usually the patella (knee cap).
Other causes include
In an Arthritic Knee
The combinations of these factors make the arthritic knee stiff and limit activities due to pain or fatigue.
The diagnosis of osteoarthritis is made on history, physical examination & X-rays.
There is no blood test to diagnose Osteoarthritis (wear & tear arthritis).
The decision to proceed with TKR surgery is a cooperative one between you, your surgeon, family and your local doctor.
The benefits following surgery are relief of symptoms of arthritis. These include
Prior to surgery you will usually have tried some conservative treatments such as simple analgesics, weight loss, anti-inflammatory medications, modification of your activities, canes, or physical therapy.
Once these have failed it is time to consider surgery. Most patients who have TKR are between 60 to 80 years, but each patient is assessed individually and patients as young as 20 or old as 90 are occasionally operated on with good results.
Each knee is individual and knee replacements take this into account by having different sizes for your knee. If there is more than the usual amount of bone loss, sometimes extra pieces of metal or bone are added.
Surgery is performed under sterile conditions in the operating room under spinal or general anesthesia. You will be on your back and a tourniquet applied to your upper thigh to reduce blood loss. Surgery takes approximately two hours.
The surgeon cuts down to the bone to expose the bones of the knee joint.
The damaged portions of the femur and tibia are then cut at the appropriate angles using specialized jigs. Trial components are then inserted to check the accuracy of these cuts and determine the thickness of plastic required to place in between these two components. The patella (knee cap) may be replaced depending on a number of factors and depending on the surgeon’s choice.
The real components are then inserted with or without cement and the knee is again checked to make sure things are working properly. The knee is then carefully closed and drains usually inserted, and the knee dressed and bandaged.
In anticipation of your surgery please review the links below for some helpful exercises to improve your sugical outcome.
When you wake, you will be in the recovery room with intravenous drips in your arm, a tube (catheter) in your bladder and a number of other monitors to check your vital observations. You will usually have a button to press for pain medication through a machine called a PCA machine (Patient Controlled Analgesia).
Once stable, you will be taken to the ward. The post-op protocol is surgeon dependant, but in general your drain will come out at 24 hours and you will sit out of bed and start moving you knee and walking on it within a day or two of surgery. The dressing will be reduced usually on the 2nd post op day to make movement easier. Your rehabilitation and mobilization will be supervised by a physical therapist.
To avoid lung congestion, it is important to breathe deeply and cough up any phlegm you may have.
Your Orthopaedic Surgeon will use one or more measures to minimize blood clots in your legs, such as inflatable leg coverings, stockings and injections into your abdomen to thin the blood clots or DVT’s, which will be discussed in detail in the complications section.
A lot of the long term results of knee replacements depend on how much work you put into it following your operation.
Usually, you will remain in the hospital for 5-7 days. Then, depending on your needs, either return home or proceed to a rehabilitation facility. You will need physical therapy on your knee following surgery.
You will be discharged on a walker or crutches and usually progress to a cane at six weeks.
Your sutures are sometimes dissolvable but if not, are removed at approximately 10 days.
Bending your knee is variable, but by 6 weeks should bend to 90 degrees. The goal is to obtain 110-115 degrees of movement.
Once the wound is healed, you may shower. You can drive at about 6 weeks, once you have regained control of your leg. You should be walking reasonably comfortably by 6 weeks.
More physical activities, such as sports previously discussed, may take 3 months to do comfortably.
When you go home you need to take special precautions around the house to make sure it is safe. You may need rails in your bathroom or to modify your sleeping arrangements, especially if they are up a lot of stairs.
You will usually have a 6 week check up with your surgeon who will assess your progress. You should continue to see your surgeon for the rest of your life to check your knee and take X-rays. This is important as sometimes your knee can feel excellent but there can be a problem only recognized on X-ray.
You are always at risk of infections especially with any dental work or other surgical procedures where germs (Bacteria) can get into the blood stream and find their way to your knee.
If you ever have any unexplained pain, swelling or redness or if you feel generally poor, you should see your doctor as soon as possible.
Complications can be medical (general) or local complications specific to the Knee
Medical complications include those of the anesthetic and your general well being. Almost any medical condition can occur so this list is not complete. Complications include:
Blood Clots (Deep Venous Thrombosis)
Stiffness in the Knee
Wound Irritation or Breakdown
Leg length inequality
Damage to Nerves and Blood Vessels
Surgery is not a pleasant prospect for anyone, but for some people with arthritis, it could mean the difference between leading a normal life or putting up with a debilitating condition. Surgery can be regarded as part of your treatment plan—it may help to restore function to your damaged joints as well as relieve pain.
TKR is one of the most successful operations available today. It is an excellent procedure to improve the quality of life, take away pain and improve function. In general 90-95% of knee replacements survive 15 years, depending on age and activity level.
Surgery is only offered once non-operative treatment has failed. It is an important decision to make and ultimately it is an informed decision between you, your surgeon, family and medical practitioner.
Although most people are extremely happy with their new knee, complications can occur and you must be aware of these prior to making a decision. If you are undecided, it is best to wait until you are sure this is the procedure for you.