Sports Med - Total Knee Replacement Surgery

Total Knee
Replacement Surgery

Total Knee Replacement Surgery in Singapore

What is Osteoarthritis and how does it affect the knee?

Osteoarthritis describes the degeneration of cartilage in a joint. While it can affect any joint, the symptoms are most commonly felt in the knees, hips, and spine. The knee is the largest joint in the body and is made up of the femur (thigh bone), the upper end of the tibia (shin bone), and the patella (knee cap). The cartilage that covers the ends of our femur bone and tibia bone is like coconut flesh; white, thick and ultra-smooth. Arthritis occurs when the soft cartilage in our knee wears out due to various causes like degeneration, wear and tear, malalignment of the knee, trauma and infection. This previously intact cartilage starts to break down and offers less support and protection to our knees. Apart from the degenerative type of arthritis like osteoarthritis, there are also inflammatory types of arthritis such as rheumatoid arthritis or gout. In this article, the term “arthritis” may refer to either or both kinds of conditions.

Arthritis of the knee can be a debilitating condition affecting our basic quality of life, daily function and personal happiness. It affects millions of people around the world and is a major cause of lost work time and serious disability. The knee is the largest joint in the body and is made up of the femur (thigh bone), the upper end of the tibia (shin bone) and patella (knee cap). The cartilage that covers the ends of our femur bone and tibia bone is like the meat of a coconut; white, thick and ultra-smooth. Arthritis occurs when the soft cartilage in our knee wears out due to various causes like degeneration, wear and tear, malalignment of the knee, trauma and infection. This previously intact cartilage starts to break down and offer less support and protection to our knees. There are also two wedged-shaped pieces of cartilage called meniscus in our knees that act as shock absorbers and keep our knees stable. Degeneration of our cartilage and tears in our meniscus often occur together and contribute to the symptoms we experience. We start to feel pain, stiffness and even deformities in our knee. Arthritis creeps up on us ever so slowly. It starts with an intermittent pain that may progress into something more severe and debilitating.

What are the signs that I may have arthritis in the knee?

You may have knee arthritis if you experience:

– Pain and swelling in the knee. The pain in the knee joint can be sudden or progressive.
– Difficulty walking
– Clicking, creaking, grinding, or snapping sounds when you move your knee joints
– Severe joint stiffness
– Your knee suddenly buckling or giving out
– Locked knee (your knee cannot be bent or straightened)

When does it happen and does it get worse?

Osteoarthritis often develops after the age of 50-60 years old while inflammatory arthritis occurs earlier between 30 and 50 years of age. These conditions are worsened by obesity, malalignments of the legs or trauma.

There are two menisci in each knee which act as shock absorbers. They are crescent-shaped and help distribute weight in the knee as well as lubricate and stabilize the knee. Degeneration of our cartilage and tears in our meniscus often occur together and contribute to the symptoms of knee arthritis. Arthritis creeps up on us ever so slowly; it starts with intermittent pain but usually progresses into constant pain and stiffness which affects our daily functions. This condition actually affects millions of people around the world and is a major cause of lost work time and disability.

Can knee arthritis be prevented?

We can prevent arthritis by maintaining healthy body weight and participating in moderate amounts of aerobic exercise regularly. A healthy diet and lifestyle coupled with strong muscles help keep arthritis at bay

What about medication?

Glucosamine and chondroitin used to be regularly prescribed for the treatment or prevention of knee arthritis. The latest guidelines from the American Association of Orthopaedic Surgeons (AAOS) do not support the use of glucosamine or chondroitin for the treatment of arthritis. There are patients who feel these supplements significantly improve their symptoms. They may continue with them as long as they do not interfere with other medications or diabetic control.

Knee injections have been shown to help patients with knee arthritis. These include hyaluronic acid which lubricates the knee as well as newer injections that use patients’ own blood (autologous protein solution) to help reduce inflammatory cytokines in the knee. These cytokines or bad proteins are thought to compromise the integrity of cartilage and cause arthritis. While they are safe and have been shown to improve the symptoms of arthritis, current research is being done to determine the positive effects of these blood injections for knee arthritis.

Surgical Interventions

In the early stages of arthritis, much can be done to try and preserve the knee. Multiple surgeries have been done over the years to either replace the focal loss of cartilage or help to regenerate it. These include transplanting cartilage from other parts of the knee into the defect (OATS: osteochondral autograft transfer system) or harvesting and growing a small piece of cartilage in a lab before re-implanting it into the knee (ACI: Autologous chondrocyte implantation. A common procedure we have done for years and still continue to perform is the microfracture surgical technique. While the cartilage has no blood supply of its own and therefore cannot regenerate, the bone beneath it does. During a keyhole (arthroscopic) procedure, a long and fairly sharp instrument is used to penetrate the surface of the femur bone. This induces some bleeding from the bone itself. The blood supply coming out contains cells that have the ability to develop into cartilage (fibrocartilage) over time. This new fibrocartilage is not as robust as your native cartilage (Hyaline cartilage) but at least there is some cartilage to reduce the pressure and pain from arthritis. Where the cartilage loss is very diffuse and widespread, these knee preservation techniques do not work.

Partial Knee Replacement Surgery

There are three compartments to the knee; medial, lateral and anterior. Partial knee replacements are used to replace the knee compartments which are worn out while preserving the rest of the knee which are not affected. This procedure is often used for patients in their 40s or 50s who are still active and require more flexibility in their knees. There are some criteria that must be followed before offering patients a partial knee replacement; these include an intact anterior cruciate ligament, cartilage wear only affecting one or two parts of the knee and only a minor knee deformity. Those who have only part of their knee replaced may subsequently require a second operation later in life to replace their entire knee.

Total Knee Replacement Surgery

A total knee replacement (TKR) describes a procedure to remove the worn-out parts of the knee and replace them with implants. Healthy bones and ligaments are left behind to accommodate the metal femur and tibia implants as well as the plaster liner that sits in between the two metal pieces. Your orthopaedic surgeon may also replace your patella if there is significant wear and if your patella bone is large enough. A TKR is done to restore motion and function to the knee, enabling our patients to return to an active lifestyle.

Dr. Mizan has done hundreds of total knee replacements over the last decade. He is proficient with both conventional approaches as well as modern navigation techniques such as the MAKO robot-arm assisted arthroplasty. Navigated and robot-arm assisted techniques are employed to promote better positioning of implants in your knee and facilitate an optimal range of movement and flexibility after surgery. It is a fine balance between a stable and functional knee compared to a knee that is too tight or too unstable. Regardless of the technique, the total knee replacement surgery is able to correct both varus (bowing of your knees) or valgus (knock knees) deformities, improve your knee extension (straightening) and flexion (bending), and significantly improve your pain and function scores.

Knee Cap Replacement

If your knee pain centers around your kneecaps (patella), Dr. Mizan will determine if you are suited for patellofemoral joint replacement surgery, also known as knee cap replacement surgery. This may be done in isolation or as part of a total knee replacement. X-rays and MRI scans will be done to assess the cartilage damage in your knee before deciding which procedure is best suited for you. If the cartilage in other compartments of the knee is affected, a total knee replacement including resurfacing the patella might be more appropriate for you.

Robot arm assistant knee replacement (Mako)

The Makoplasty technique is a revolutionary tool for joint replacement surgery. It removes the guesswork out of a complex operation and patients benefit from well-placed implants with great knee function after surgery. This technique involves pre-operative planning with a CT scan and computer software. The CT scan provides a three-dimensional (3D) image of your knee which allows us to determine what size implants would be best suited for your knee and where to place them. During the surgery itself, Dr. Mizan will then make further assessments of your knee with navigational techniques to ensure that the CT scans are accurate. Even before a single bone cut is made, we can trial different-sized implants in different knee positions and make micro-adjustments along the way. The computer software advises on the most optimal implant position for you. The numbers on the screen reflect how well your knee moves and its stability with the virtual implants. We will only proceed to make the first bone cut and position the implants in your knee after we are satisfied with the data provided by computer software. The robot arm has been programmed to allow the surgeon to only cut the bone according to the surgical plan. If the bone cut deviates from the plan, the robot will freeze and the orthopaedic surgeon will have to withdraw and start again with the planned bone cut. This ensures the precision of the bone cuts and implant positioning, as well as prevents collateral injury to the adjacent soft tissues.

Comparison of a left knee before and after surgery. The bow-leggedness has been corrected with a total knee replacement using the robot-arm assisted technique.

This is a patient with arthritis in his left knee secondary to gout. The TKR allows all the worn out cartilage to be removed and enabled him to return to work with less pain and better function. His patella was also replaced to complete the TKR.

This patient had trauma to his left knee when he was a young adult. His left knee was severely bowed and he could barely walk 100m. He had to quit his job due to the severe pain from his post-traumatic arthritis. The total knee replacement not only corrected his bow-leggedness, it has significantly reduced his knee pain and he is now looking for new employment.

What to expect if I’m having a Mako robotic knee replacement?

Once a decision has been made to perform the MAKO robot-assisted knee replacement, Dr. Mizan will organize the CT scan of your knee as part of the pre-operative preparations. The surgery itself will take about 90 minutes or so. During surgery, most patients receive either a spinal anaesthetic or a general anaesthetic. You will be able to start walking the day after surgery with the help of a walking frame and physiotherapist.

Most patients stay in hospital for about 3 to 5 days, this depends on how well they walk and climb stairs. Patients are discharged with some oral medication and must continue their physiotherapy in the outpatient setting. Dr. Mizan will follow you up every week for about 3 weeks then this may be changed to once every few months.

Both knees are painfully affecgted by rheumatoid arthtitis, an inflammatory condition that frequently affects all compartments in both knees.

A bilateral total knee replacement is done to facilitate a meaningful rehab program and return the patient to gainful employment

Cost of knee replacement surgery in Singapore

Is Post-Surgery Scarring Normal?

There will be a 10 to 15cm scar in the front of your knee after the surgery. This surgical incision is needed to adequately expose the knee to remove all the worn-out parts as well as place the new implants in an optimal position. While keyhole surgery may be used in knee preservation techniques such as meniscus repairs, it cannot be used for a formal total knee replacement. Skin incisions that are too small may even compromise the surgery as the surgeon may not be able to have adequate visualization of critical areas and implants may not be placed optimally. The surgical incision takes two weeks to heal while swelling takes about a month or so to resolve. During this time, dressing changes are done to prevent infection and facilitate good healing.

How to reduce swelling

There are several techniques we employ to help reduce knee swelling. Immediately after surgery, your knee will be wrapped in wool and crepe dressing. This compression helps prevent bleeding into your knee after surgery. The day after surgery, this compression dressing is lightened and ice packs are applied to further reduce swelling. Finally, the elevation of the foot with pillows under the ankle helps reduce the swelling. Swelling around the knee may last for a month or two in some patients. This is completely normal and will improve from day to day.

Rehabilitation

Patients are encouraged to do as much walking and aerobic exercises as they wish. This helps to develop their general muscle strength and flexibility. Our patients usually report improved quality of life and physical function after their surgery. They also experience better knee extension and flexion. Squatting is something not everyone is able to achieve after a knee replacement. A lot of it depends on how much they were able to flex their knee before surgery; how large their thighs and calf muscles are and the strength in their legs to actually perform a squat and stand up after that.

Bilateral Knee Replacement

Some patients have returned to get the same operation performed on their other leg. After they have recovered from their first knee replacement and are satisfied with the results, they then want the same surgery on the opposite leg with confidence. A bilateral knee replacement is occasionally performed in patients who have severe symptoms in both knees and are very affected by them. In this group of patients, their rehabilitation will not be optimal if a total knee replacement surgery is only performed on one knee. At BFit Medical & Sports Clinic, we ensure that they are of the appropriate age and have minimal medical conditions so that they are suitable candidates for the procedure. Depending on individual patients, patients who have had a bilateral total knee replacement are only asked to walk 2 days after surgery instead than 1. This is to ensure their pain control is taken care of, they do not have any dizziness or vertigo and they have enough confidence to start their physiotherapy.

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