Revision knee replacement

Introduction

A Revision Knee Replacement involves replacing part or all of a previous knee replacement. This operation may vary from very minor adjustments to massive operations replacing significant amounts of bone.

Why does a Knee need to be revised?

• Pain is the primary reason for revision. Usually the cause is clear but not always. Those 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 needs to be changed.
• Instability - Occasionally the knee is not stable and may be giving way or not feel safe when you are walking.
• Loosening - Either the femoral, tibial or patellar components may gradually become loose.. This usually presents as pain but may be asymptomatic. It is for this reason why you should 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 - This usually presents as pain but may present as swelling or an acute fever.
• Osteolysis (bone loss). - This can occur due to polyethylene wear particles being released into the knee joint which result in bone being destroyed

Before the operation

• You will need to attend a Pre-operative Assessment appointment, usually 2-3 weeks before your planned operation. - A series of routine investigations will be organised there. These usually include blood tests, X-rays, an ECG (heart tracing), urine tests and screening swabs for MRSA.
• Depending on your general medical history, you may be asked to undertake an assessment with one of the Anaesthetic Consultants, to ensure you are fit for the operation.
• If any changes to your usual medications are necessary before your operation, these will be explained to you.
• You will usually meet one of the Occupational Therapists who can discuss any necessary modifications around your home, which may help when you are discharged after your operation.
• You will have an opportunity to meet one of the Physiotherapists - An initial assessment is combined with advice on what to expect following surgery in terms of exercises etc.
• If you smoke, you should try to stop or cut down for as long as possible prior to surgery.
• When you are admitted for your operation, you should be fit for the surgery. - You should not have a cough or a cold, and there should be no sores, cuts or ulcers on your skin.
• You will be admitted in the afternoon before surgery if your operation is planned for a morning operation list. If your operation is planned in the afternoon or evening, you may be admitted early that morning.
• You should have nothing to eat for at least six hours before your operation. Clear fluids are generally allowed up to four hours beforehand. This will be discussed with you during your Pre-operative Assessment visit.

On the day of surgery

• You will meet the nurses and answer some questions for the hospital records.
• Further tests may be required on admission.
• You will meet your Anaesthetist - the type of anaesthetic best suited to you will be discussed and explained.
• You will be given a hospital gown to change into.
• Approximately 30 minutes prior to surgery, you will be transferred to the operating theatre.

Surgical procedure

Each knee is individual and the components take this into account by having different sizes available for your knee. If there is more than the usual amount of bone loss sometimes extra pieces of metal or bone are added.

There is no standard procedure in Revision Knee Replacement - Each operation is tailored specifically to the individual patient's need.

These procedures are often highly complex and they require careful planning by your Consultant. The exact procedure performed is often decided during the operation, so detailed explanation may not be possible pre-operatively.

After the operation

• 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.
• 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 your knee and walking on it within a day or two of surgery. The dressing will be reduced usually on the first post-operative day to make movement easier. A Physiotherapist will supervise your rehabilitation and mobilisation.
• To avoid lung congestion, it is important to breathe deeply and cough up any phlegm you may have.
• Your Consultant will use one or more measures to minimise the risk blood clots (DVT's) in your legs. - These may include stockings and injections to thin the blood
• Hospital stay is usually 5 - 7 days following surgery. You will need Physiotherapy on your knee following surgery.
• You will be mobilising with a walking aid - either a frame or crutches, and then progress to walking sticks.
• Your sutures maybe dissolvable but if not arrangements will be made for them to be removed at approx 15 days.
• Once the wound is healed, you can take a shower. You can drive at about 8 weeks, once you have regained control of your leg. You should be walking reasonably comfortably by 6 weeks. Advice and instructions on driving etc. will be provided by your Consultant.
• 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 if your bedroom is up a lot of stairs.
• You will usually have a 6 - 8 weeks check-up with your surgeon who will assess your progress.
• If you ever have any unexplained pain, swelling, redness or if you feel unwell you should see your doctor as soon as possible.
• Return to sedentary work is usually possible after 10 - 12 weeks.
• Return to light sport (e.g. Golf) is usually possible after 10 - 12 weeks but may take longer.

Risks and complications

As with any major surgery, there are potential risks involved. Your decision to proceed with the surgery should be made when you feel that the advantages of surgery outweigh the potential disadvantages.

It is important that you are informed of these risks before the surgery takes place. Complications can be medical (general) or local complications specific to the Knee.

Medical complications include those of the anaesthetic and your general well being. Almost any medical condition can occur so this list is not complete.

General complications include:

• Allergic reactions to medications
• Anaesthetic complications.
• Blood loss requiring transfusion with its low risk of disease transmission
• Heart attacks, strokes, kidney failure, pneumonia, bladder infections.
• Complications from nerve blocks such as infection or nerve damage.
• Serious medical problems can lead to ongoing health concerns, prolonged hospitalisation or rarely death.

Local complications include:

• Infection - Infection can occur with any operation. In the knee this can be superficial or deep. The infection rate after TKR is 2 - 3% approx - If it occurs it can be treated with antibiotics but may require further surgery.
• Blood clots (Deep Venous Thrombosis - DVT) - These can form in the calf muscles and can travel to the lung (Pulmonary embolism - PE). 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 doctor.
• Stiffness in the knee. - Ideally your knee should bend beyond 100° but rarely the knee may not bend as well as expected. Sometimes manipulation is required - This means going to theatre and under anaesthetic the knee is bent for you.
• Wear - The plastic liner eventually wears out over time and may need to be changed. If there is significant wear, the metal components may become loosened from the bones and revision surgery may be required.
• Dislocation - An extremely rare condition where the ends of the knee joint loose contact with each other or the plastic insert can lose contact with the tibia (shinbone) or the femur (thigh bone).
• Patellar problems - The Patella (knee cap) can dislocate that is, it moves out of place and it can break or loosen. This complication is extremely rare.
• Damage to nerves and Blood vessels - Rarely these can be damaged at the time of surgery. If recognised 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. This complication is extremely rare
• Fractures or breaks in the bone can occur during surgery or afterwards if you fall. To fix these, you may require further surgery.

Summary

Revision Knee Replacement is one of the more complex Orthopaedic operations available today.

The procedure is often complex, and more technically difficult than a primary Total Knee Replacement (TKR). Surgical outcome, though generally good, is difficult to predict.

Although most people are extremely happy with their new knee, complications can occur and you must be aware of there prior to making a decision. If you are undecided, it is best to wait until you are sure this is the procedure for you.

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