Why is revision knee surgery needed?
The majority of knee replacements are successful and last throughout a patient’s lifetime. However, sadly there are situations where revision of the original surgery becomes necessary.
Implants typically fail for one of a few reasons: loosening, infection, fracture, or mechanical failure of the implant.
The commonest reason to revise a knee replacement is loosening following years of function. All knee implants are subject to friction and wear as the joint surfaces rub against each other during motion. As they wear out they may loosen and cause pain. Younger and more active patients have a higher rate of revision due to the increased demands they place on their implants.
An implanted knee may become infected at the time of surgery or many years in the future. If a joint replacement is infected it will require further surgery to eradicate the infection. The type and number of surgeries is dependent on both patient and infection characteristics and will be tailored to suit each person.
Fracture may occur of the implant or bone surrounding the implant if a patient was to sustain a significant fall or trauma. In these cases the implant will need to be revised to restore mobility.
What does the surgery involve?
Any revision or re-do of a failed knee replacement requires a patient tailored and focused approached. The causes of failure and any other patient factors, individual circumstances are assessed and a surgical plan is made.
Typically, the majority of the original knee components may need to be removed and replaced by new implants.
Prior to surgery, your fitness to undertake the procedure will assessed. Screening blood tests are performed to help diagnose why the joint may have failed.
Revision knee surgery requires an anaesthetic. Antibiotics will be given prior to surgery to reduce the risk of infection.
During knee revision surgery, the artificial knee joint is removed and replaced with a new one through the old scar.
Surgery for infection often involves removing all the knee replacement and replacing it with a temporary knee joint made of cement – which can release antibiotics. A second operation is then required to restore the knee joint when the infection has been eradicated.
Each revision is unique and the advantages, disadvantages and surgical strategy are discussed with each individual patient.
Unlike a primary knee replacement the revision knee system used will have long stems to stabilise the new component in both the femur (thigh bone) and tibia (shin bone).
What happens after my surgery?
After surgery, you will be taken to the recovery room for a period of close observation. The staff will monitor you and will pay special attention to your circulation and sensation in your feet and legs. When you are fully awake and your condition is stable, you will be transferred to your hospital room.
You will notice that;
- An intravenous drip will continue post-operatively in order to provide adequate fluids and administer antibiotics and other medications.
- A catheter will be inserted into your bladder to allow for monitoring of your urine output and ease of nursing in the immediate post-operative period.
- A drain from the knee – which allows your own blood to be returned to you if correct parameters are met.
After a revision knee replacement the recovery is typically slower than the original knee replacement surgery.
After the operation you will need walking aids, such as walking sticks, for the first six weeks. Your rehab will be guided by the physiotherapy team. Physiotherapy will continue after your discharge from the hospital working on extension and flexion of the knee and muscle strengthening exercises.
Typically two weeks after surgery, two sutures and paper stitches are removed. This is an easy and painless procedure.
An anticoagulant will be prescribed for 14 days following the surgery to help decrease the risk of a deep vein thrombosis (Blood clot in the leg veins). During the inpatient stay, mechanical foot pumps will also be employed to help decrease this risk. Patients will wear ted stockings for six weeks following the operation.
Some patients experience swelling and bruising of the leg after undergoing knee and revision knee replacement surgery, this is normal. If you experience painful or worrying swelling, a scan maybe required to rule out a deep vein thrombosis.
It is important for the patient to keep in mind that knee revision surgery will require many months of recovery time before they will be able to walk without a limp or pain.