Patient Specific Knee Replacement
Standard and Custom-made Total Knee Replacements (TKR)
The knee joint is the largest joint in the body. It is formed by the top end of the tibia (shin bone), the far end of the femur (thigh bone) and the under surface of the patella (kneecap). The surfaces of the bone are lined with articular cartilage which is composed of type II collagen and proteoglycans. The collagen is different to that associated with collagen filler injections.
Osteoarthritis of the knee is a common condition where the articular cartilage becomes damaged and irregular due to breakdown of the collagen fibres. There are a number of reasons why this can happen. Examples include age related ‘wear and tear,’ chronic inflammatory disease, traumatic arthritis, and some birth defects.
TREATMENT OPTIONS
The treatment options for knee osteoarthritis depends on the severity of the osteoarthritis. Treatment options may include doing nothing, analgesia (pain relief), activity modification, using walking aids, injections, and a total knee replacement (TKR).
ABOUT KNEE REPLACEMENT SURGERY
A TKR is an operation performed to replace the damaged knee joint. The procedure involves cutting the skin and putting a ‘cap’ on the far end of the Femur (Thigh bone) and the top end of the Tibia (Shin bone). A polyethylene liner is put into the middle. The under surface of the kneecap is also replaced with a polyethylene liner.
The aim of surgery is to eliminate the pain and stiffness experienced with arthritis.
There are many different types of knee replacement designs. Some surgeons advocate the use of robotic knee surgery. This involves using a robot to help make cuts on the bone rather than using standard mechanical equipment. There is no evidence to suggest significant benefit at present.
Another technology is the use of custom-made total knee replacements. This involves obtaining a scan of the knee and then manufacturing a patient specific knee replacement. Companies that manufacture such implants include Conformis and Symbios. Patient specific knee replacements may provide superior outcomes compared to standard total knee replacements, although evidence is currently limited.
Find out more about Conformis total knee replacement’s here.
BEFORE SURGERY
‘Pre-rehabilitation’ before surgery to strengthen muscles and improve range of motion may help early recovery and improve the outcomes following surgery.
THE DAY OF SURGERY
On the day of surgery, you will see the surgeon and anaesthetist. The anaesthetist will discuss anaesthetic options. These may include general or regional anaesthetic. The nurses will prepare you for the operation.
The surgical procedure takes approximately two hours. Near the end of the operation, the knee will be injected with local anaesthetic to reduce the pain. Afterwards, you will go to recovery. When you have safely recovered from the anaesthetic, you will be sent to the ward.
You will be given antibiotics at the time of surgery to prevent infection. These may be continued afterwards for several doses. You will be given blood thinners following surgery which will need to be continued following discharge.
AFTER SURGERY
- You will be encouraged to mobilise as soon as it’s safe to do so. This is to improve the blood flow and give you confidence.
- As the local anaesthetic wears off, you will experience an increase in pain. It is important that you take your pain killers regularly and continue to work on your exercises.
- The pain will improve over time.
- Some patients may go home on the same day or the day after surgery if the operation is later in the day. Sometimes discharge from hospital can be after 2-3 days, for example for health reasons.
RISKS OF SURGERY
The knee replacement is a mechanical device. Approximately 80% of knee replacements are expected to survive 25 years; five percent may fail at 10 years. This means they require revision surgery, ‘re-doing the knee replacement.’ It is likely that this figure improves over time because implants continue to improve in design.
The risks associated with undergoing a total knee replacement include infection, deep vein thrombosis and pulmonary embolism (blood clots), pain, stiffness, damage to nerves (causing numbness or weakness which may be temporary or permanent) and blood vessels. Other risks include the fracture of bone and persisting pain which may take 2 years to settle. 15% of patients can remain unhappy beyond this time for reasons including pain, stiffness and instability. Death is a rare complication.
There are also other risks related to the anaesthetic. You will be asked to sign a consent form following a discussion of the risks.
PHYSIOTHERAPY
It is important to plan for physiotherapy after discharge. Physiotherapy will help with improving the range of motion and strengthening the muscles around the knee. It normally starts 2 weeks after surgery when swelling has settled. Recovery can be helped through the use of appropriate ice packs. This will be discussed with you during your appointments.
FOLLOW-UP APPOINTMENT
The wound will be reviewed two weeks after surgery to ensure that it has healed without complication. If there are any concerns, it is important that the wound is seen by the surgeon.
I would like to see you approximately six weeks following surgery to assess your progress. If you are doing well, you will be discharged.
Do not hesitate to contact me if you require any further information.
FAQs
A knee replacement can be painful and challenging after surgery. You will find it helpful to have the support of friends and family.
You need to keep the wound dry and protected using a dressing until it has healed (this will take about 2 weeks). Using a Tubigrip bandage and putting ice on it for 15 minutes every hour can help with the swelling. The Tubigrip should be taken off at night. Advice will be given to you before discharge from the hospital. You will be given exercises to do before you are discharged.
You will need strong pain killers after surgery. These will reduce over time, but you may need pain killers for several months.
It is important to avoid standing for long periods of time soon after surgery. Rest and an ice pack can help to reduce swelling. Do not sleep with a pillow under you knee as this could contribute to stiffness developing.
It is important to continue to take painkillers and gradually increase your exercises (which include walking and bending the knee) over time as the pain and swelling improve.
Acknowledgements | https://en.wikipedia.org/wiki/
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