Being told that you need a revision knee replacement can be incredibly difficult news to hear. After all that pain, physical therapy, recovery and those blessed years of relative comfort, your bionic parts appear to be failing you.
But don’t worry! Much like the ‘The Six Million Dollar Man‘ (remember when that seemed like an unfathomable amount of money?!), we can rebuild you. Only this time, with a much better state-of-the-art prosthetic knee!
What is a Revision Knee Replacement?
If you have had a knee replacement, and it is no longer functioning or alleviating your symptoms, you may require further surgery. This is called a revision knee replacement operation. All forms of knee replacement surgery have a finite lifespan. The chance that a total knee replacement lasts 15 years is 85% and a unicompartmental knee is 60 to 80%.
Revision Knee Replacement means that part or all of your previous knee replacement needs to be revised. This operation varies from very minor adjustments to massive operations replacing significant amounts of bone. 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).
Why does a Knee Replacement Needs to be Revised?
Pain is the primary reason for revision knee replacement. Usually the cause is clear but not always. Knees without an obvious cause for pain in general do not do as well after surgery.
- Plastic (polyethylene) wear – This is one of the easier revisions where only the plastic insert is changed.
- Instability – This means the knee is not stable and may be giving way or not feel safe when you walk.
- Loosening of either the femoral, tibial or patella component – This usually presents as pain but may be asymptomatic. It is for this reason why you must have your joint followed up for life as there can be changes on X-ray that indicate that the knee should be revised despite having no symptoms.
- Infection – usually presents as pain but may present as swelling or an acute fever.
- Osteolysis (bone loss) – This can occur due to particles being released into the knee joint that result in bone being destroyed.
- Stiffness – This is difficult to improve with revision but can help in the right indications.
What to expect before surgery
Undergoing a revision knee replacement is a major operation. You will require all routine investigations that were needed for total knee replacement surgery (blood tests, ECG and other x-rays), as well as specific investigations to establish the cause of failure of your knee replacement.
This may include blood tests to exclude infection (ESR, CRP), and possibly a knee aspiration procedure where a needle is introduced into the knee joint to withdraw fluid. There is also another test for infection. Additional specialized x-rays such as a CT scan or even an MRI scan may occasionally be used prior to your surgery.
All patients are reviewed by a physician prior to surgery to assess your general fitness for this operation. This is an excellent opportunity to have a full medical assessment and detect any medical issues that can be treated, hence reducing the risk of a medical complication during or after the operation.
What will happen on the day of your surgery?
You will usually be admitted to hospital the day of your operation, or sometimes the night before. Your surgeon will visit you to answer any questions you may have regarding surgery and will also mark the affected knee with an ink pen.
After your anesthetic has been administered, a tight band (tourniquet) will be applied to your upper thigh and your leg will be painted with an antiseptic solution. A routine draping will be performed with sterile sheets to allow exposure only of the knee.
A vertical incision is made at the front of your knee that usually includes the previous scar. If multiple scars are present on the front of the knee, the surgeon will choose the safest one to allow adequate exposure of the knee joint. Your surgeon will often send off fluid and tissue from within the knee joint which sometimes helps to establish a cause for failure of the prosthesis.
Usually all the failed implants are removed. New specialized knee prostheses are then inserted back onto the end of the femur and to the top of the tibia to recreate a new knee joint. These prostheses are often more sophisticated than those used for routine total knee replacement. This is because stems (rod extensions) that are inside the bone canal are sometimes added in order to allow additional stability of the metal femoral and tibial components.
Before completion of the revision knee replacement surgery, the knee is checked for stability, alignment and degree of motion. Often, a small drain will be left in the knee for 24 hours after the surgery to remove unwanted blood from the wound. Dissolving stitches are usually used to close the wound and the knee is then wrapped in a well padded sterile bandage.
After Revision Knee Replacement Surgery
You will wake up in the recovery ward where you will be closely monitored until you are ready to return to the orthopedic ward. Here you will continue to be observed until you are fully awake. Usually, you will spend the first postoperative day in bed.
A physical therapist will visit you to give you breathing exercises for your chest as well as exercises for your leg that can be performed while in bed. An x-ray of your knee will be taken to confirm optimal placement of the prosthesis.
Blood thinning medications will be administered daily to reduce the risk of blood clots (DVT) forming in your legs. In addition you will be given special stockings to wear on both of your legs. For the first 24 hours after your surgery, an inflatable sleeve will intermittently compress your calves to prevent stagnation of blood flow. You will receive intravenous antibiotics after your surgery for a designated period of time depending on the complexity of the operation. This will help to decrease the risk of infection.
Your bandages will be removed after 48 hours. A new dressing will be placed over the incision. Your knee will be quite swollen and usually has areas of bruising around it. This is normal.
You will be under the daily supervision of a physiotherapist until you are discharged from hospital. The aims of these visits are to optimize motion in the knee, regain the ability to walk, improve muscle strength and control knee swelling.
Once you can walk safely, have regained appropriate motion in your knee and your pain is controlled, you will be able to go home. Some patients require further inpatient care and are transferred to a rehabilitation unit for a short time.
What happens after you go home?
Your rehabilitation will continue after you leave hospital to initially maintain and improve on what you have already achieved. This will take the form of a home exercise program and outpatient physical therapy visits, which usually last 3-6 months.
An appointment will be made to see your surgeon six weeks after the operation. The goals of your revision knee replacement surgery are to be able to walk independently, to be able to bend your knee and to reduce the pain you were experiencing prior to your surgery. If you feel like you need to be seen sooner than 6 weeks, please don’t hesitate to call your orthopedic surgeon!
Return-to-activity timeline
Usually you will be in hospital for 3-5 days and then either go home or to a rehabilitation facility depending on your needs. 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 it should bend to 90 degrees. The goal is to get 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 be able 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.
If you ever have any unexplained pain, swelling, redness or if you feel unwell you should see your doctor as soon as possible.
Complications
Infection
Infection can occur with any surgery. In the hip this can be superficial or deep. Infection rates are approximately 1%. If it occurs it can be treated with antibiotics but may require further surgery. Very rarely your hip may need to be removed to eradicate infection.
Blood Clots (Deep Venous Thrombosis)
These can form in the calf muscles and can travel to the lung (Pulmonary embolism). These can occasionally be serious and even life threatening. If you get calf pain or shortness of breath at any stage, you should notify your surgeon.
Fractures or Breaks in the Bone
Can occur during surgery or afterwards if you fall. To repair these, you may require surgery.
Stiffness in the Knee
Ideally your knee should bend beyond 100 degrees but on occasion the knee may not bend as well as expected. Sometimes manipulations are required, this means going to the operating room where the knee is bent for you under anesthetic the knee.
Wear
The plastic liner eventually wears out over time, usually 10 to 15 years and may need to be changed.
Wound Irritation or Breakdown
Surgery will always cut some skin nerves, so you will inevitably have some numbness around the wound. This does not affect the function of your joint. You can also get some aching around the scar. Vitamin E cream and massaging can help reduce this.
Occasionally, you can get reactions to the sutures or a wound breakdown that may require antibiotics or rarely further surgery.
Cosmetic Appearance
The knee may look different than it was because it is put into the correct alignment to allow proper function.
Leg Length Inequality
This is also due to the fact that a corrected knee is more straight and is unavoidable.
Dislocation
An extremely rare condition where the ends of the knee joint lose contact with each other or the plastic insert can lose contact with the tibia (shinbone) or the femur (thigh bone).
Patella Problems
The Patella (knee cap) can dislocate. This means it moves out of place and it can break or loosen.
Ligament Injuries
There are a number of ligaments surrounding the knee. These ligaments can be torn during surgery or break or stretch out any time afterwards. Surgery may be required to correct this problem.
Damage to Nerves and Blood Vessels
Rarely these can be damaged at the time of surgery. If recognized they are repaired but a second operation may be required. Nerve damage can cause a loss of feeling or movement below the knee and can be permanent.
Discuss your concerns thoroughly with your Orthopedic Surgeon prior to surgery.
Summary
Surgery is not a pleasant prospect for anyone, but for some people with arthritis, revision knee replacement surgery 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.
Revision knee replacement 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.