What is Total Knee Replacement (TKR)?
Total Knee Replacement (TKR) surgery is commonly performed to relieve pain and improve movement for patients with worn-out and painful knee joints. This is carried out when patients do not respond adequately to conservative treatment (consisting of medication, physiotherapy and activity modification). It is an elective surgery that involves replacement of the worn-out joint surfaces with implants.
Stages of Knee Osteoarthritis
- Minimum disruption. There is already 10% cartilage loss.
- Narrowing. The cartilage to begin breaking down. Occurrence of osteophytes.
- Moderate joint-space reduction. Gaps in the cartilage can expand until they reach the bone.
- Joint-space greatly reduced. 60% of the cartilage is already lost. Large osteophytes.
- Joint-space
How will TKR help?
Going through a knee replacement will:
- Decrease pain
- Improve mobility
- Correct deformities of the lower limb
- Increase overall quality of life
After full recovery, you can enjoy low impact activities such as walking, swimming or cycling. However, sports that involve contact or jumping, as well as high impact activities like running or tennis are discouraged. You may not be able to squat after the operation.
Your surgeon will discuss the various techniques with you and recommend the best option for you.
In cases of severe alignment problems, or loose/unstable knees, a stemmed implant (or TKR with rod extensions) may be required to improve the stability of the knee.
Surgery can help to relieve pain and restore your mobility. Set an achievable goal with continued rehabilitation exercise in your journey of recovery.
TKR implants are made of surgical grade metal alloys and plastic components. They are joined to your bone by acrylic cement. Your surgeon will discuss with you the type of implant that best meets your needs.
What are the different types of knee replacement surgery?
TKR, where the whole knee joint is replaced, is the most common type of knee replacement surgery performed.
A unicompartmental knee replacement, or half knee replacement, is performed in selected patients where only one part of the knee is worn out.
How long can the implant last?
Typically, an implant can last up to 15 years but this varies from person to person. It is dependent on many factors, such as your physical condition, activity level, body weight and the surgical technique. There is no guarantee that a prosthetic joint will last the rest of your life.
There are various surgical techniques to conduct a knee replacement. Other than the standard traditional method of surgery, we also offer navigation or robotic-assisted surgery.
All prosthetic knees may need to be replaced at some point.
Possible Complications
As with any operation, TKR carries certain risks and benefits. Your surgeon and anaesthetist will answer any questions you may have about the surgery or the anaesthesia.
Surgical risks include:
- Surgical scar: The surgical scar will be in the centre of the knee and can vary based on the individual. Scar numbness and discolouration is common. The scar can sometimes be raised and thickened if you are prone to keloid formation. The scar usually becomes less prominent over a year.
- Pain: Pain will gradually ease after the first few months. However, few patients may continue to have moderate pain in the long term.
- Infection of the wound: Superficial skin infections are common and can usually be treated with antibiotics. However, deep infections (bacteria going into the joint and growing on the implant) can also occur. Though these occasions are rare, they may require multiple surgeries to clean the joint, and may sometimes involve removal of the implants.
- Blood clots or deep vein thrombosis (DVT): Blood clots may form in the leg veins in the first few weeks after surgery due to reduced movement in the leg. This can be prevented by using special support stockings/ leg pumps, early movement and walking soon after surgery, or by using blood thinning medications.
- Unexpected bleeding: This can happen inside or around the joint. Some bruising around the knee after surgery is expected. On rare occasions, the bleeding can become excessive and cause pain.
- Excessive scar tissue forming within the knee and restricting movement: Physiotherapy and exercise after surgery is crucial to recovery and ensuring improved range of movement of the knee. In rare cases, further surgery may be required to remove the scarring and restore movement.
- Damage to surrounding structures (ligaments, blood vessel or nerves) during surgery: Artery and nerve damage during surgery is an extremely rare but severe complication that can result in loss of the limb if repair cannot be adequately achieved. Ligament damage may result in a knee that feels loose after surgery and may require further corrective surgery.
How much will it cost? Surgery at Khoo Teck Puat Hospital (KTPH)
The cost will depend on the type of knee replacement chosen, the subsidies you are eligible for, as well as your personal insurance. Financial counselling will be provided prior to surgery.
Read more about our hospital charges here
Post-discharge Care
1. Going Home with Rehabilitation Appointments
After knee surgery, most patients stay at the hospital for 1-3 days to recover, before being discharged.
Anaesthesia risks include: With any anaesthesia choice - full or half body anaesthesia - there are risks involved. Serious complications include heart attack, stroke, lung infection, blood clots and allergic reactions during surgery. More common side effects include vomiting, giddiness and sore throat.
You will be given appointments to attend rehabilitation sessions to ensure the best outcomes after surgery. You may also be eligible to attend rehabilitation therapy at a Community Rehabilitation Centre near your home. Speak to your Physiotherapist or nurses for more information.
For subsidised wards, the amount of government subsidy given will be dependent on your Household Means Test Assessment. Please complete the declaration form and submit it to your financial care officer prior to your financial counselling appointment.
2. Intermediate Care
Some patients may be advised to transfer to a community hospital if they require more time to recuperate. Yishun Community Hospital (YCH) provides continual care such as rehabilitation services after discharge from an acute hospital. The cost will depend on the ward class and the subsidies you are eligible for.
You may discuss with us if you wish to transfer to other community hospitals.
Read more about our hospital charges here
Patient Reported Outcome Measures (PROMs)
What are PROMs?
Patient Reported Outcome Measures (PROMs) are questionnaires that help your doctor understand how your condition affects your daily life.
What will I need to complete?
You'll be asked to complete the Oxford Knee Score (OKS) before your surgery and at follow-up appointments at 3 months, 1 year, and 2 years after surgery. The OKS is specifically designed for knee replacement patients and takes about 5 minutes to complete, asking about your knee pain and daily activities.
Why are PROMs important?
- Share how you feel with your care team - PROMs help you communicate your health status so your care team can adjust your treatment to help you feel better.
- Track your health progress over time - PROMs capture important aspects of your condition between follow-ups and assist your clinician in selecting the best care for you.
- Take charge of your health - PROMs give you a voice in your care journey. Your answers help guide better treatment decisions.
Additional assessments
Your clinician will also work with you to complete the Knee Society Score, which evaluates your knee function and overall well-being. This assessment combines your input on functional activities with your clinician's evaluation of physical parameters such as range of motion and stability.
Next Chapter: Preparing For Your Surgery
