Robotic-Assisted
Total Knee Replacement

Dr. Chang performs the majority of total knee replacements with a robotic-assisted surgical system. Robotic-assisted total knee replacement is increasing in popularity due to improved accuracy of bone cuts and the ability to tailor implant positions to each individual patient. The robotic software provides the surgeon with valuable intra-operative data to help ensure that your new knee is well balanced and stable. There is also some evidence that robotic-assisted total knee replacement leads to an improvement in early functional outcomes.

You will require a special x-ray of your leg before surgery in order to develop a pre-operative plan using the robotic software. You will not require a CT scan (other robotic systems require it before surgery). Robotic-assisted total knee replacement typically adds an additional 10-15 minutes of operative time compared to a conventional total knee replacement.

It is important to note that research studies have not yet demonstrated any significant differences in long-term functional outcomes or implant survivorship between robotic-assisted total knee arthroplasty and conventional total knee arthroplasty. Surgeon experience and training is far more important than use of a specific technology.

Non-operative measures should be attempted prior to consideration of knee replacement. These measures are often helpful in the early stages of arthritis.

Pain medication: Tylenol is typically recommended as the first-line pain medication. Some patients with liver disease may not be able to tolerate regular Tylenol. Anti-inflammatory medications are also helpful but are not suitable for all patients. Patients with cardiac disease, high blood pressure, kidney disease, and/or stomach ulcers may not be able to take regular anti-inflammatory medications. Regular opioid medications are not recommended due to risk of addiction and development of chronic pain. Patients should consult with their family doctor prior to starting any new medication.

Physiotherapy: Physiotherapy exercises to improve strength to your core, buttocks, quadriceps, hamstrings, and abductors are often helpful for reducing symptoms in early arthritis.

Injections: Local knee injections can be helpful in the early stages of arthritis. They are less effective in end-stage disease. Consult your surgeon to determine if an injection would be indicated for you.

Bracing: Some patients with specific patterns of arthritis may benefit from bracing in order to “offload” the affected knee compartment. Consult your surgeon to determine if a custom knee brace would be indicated for you.

Weight loss: Weight loss helps reduce the pain associated with arthritis by taking pressure off your knee joint. It is appreciated that regular exercise can be challenging due to persistent and severe knee pain. Your family doctor can often help with diet resources.

Walking aids: A cane or walker may help improve your comfort, stability, and confidence with walking.

The decision to proceed with a knee replacement is an individual one. It is important to have a formal discussion with your surgeon to determine if you are a good candidate for a knee replacement.

A knee replacement can be considered in a patient with end-stage arthritis and knee pain that restricts walking ability and other day-to-day activities that impact quality of life. In addition, patients should have good baseline health and have attempted non-operative measures (see above).

In a knee replacement, the distal femur (bottom part of the thigh bone) and the proximal tibia (top part of the shin bone) are replaced with an artificial joint (prosthesis). In some cases, the undersurface of the patella (kneecap) is also replaced.

The femoral component is made out of metal (typically a cobalt-chromium alloy). The tibial component is made out of a metal baseplate (typically a titanium alloy) and plastic liner (typically polyethylene). The patellar component, when performed, is made out of plastic (typically polyethylene).

Many countries, including Canada, mandate data collection on certain medical devices such as joint replacements; these are called national joint registries. Recent evidence derived from pooled joint registry data from multiple countries estimate survivorship of a total knee replacement is 93.0% at 15 years, 90.1% at 20 years, and 82.3% at 25 years. It is important to remember that these are estimates of survivorship. There is optimism that the newer generation of implants used today will last longer than what is reported today in the literature.

The majority of total knee replacements done by Dr. Chang are performed as day surgery. After surgery you will be assessed by a physiotherapist to ensure that you can walk and climb the stairs safely. You will be given a prescription for pain medication and blood thinners prior to discharge.

Your first post-operative appointment will be approximately 2-weeks after surgery in the fracture clinic to check your wound and review your progress.

The second follow-up appointment will be approximately 6 weeks after surgery. A clinical review and x-ray will be performed at that time.

It is typical to require a walker or crutches for the first 2-4 weeks after surgery. It is often advisable to transition to a cane after you have stopped using a walker. Most patients are comfortable with normal day-to-day activities 6 weeks after surgery.

The average recovery time varies by patient but usually is 3-6 months. However, it can take up to 12-18 months after surgery to regain full strength.

All patients recover differently after surgery. The decision on when to return to work is variable and depends on you and your type of job. As a guide, most people with “desk” type jobs can resume work 6 weeks after surgery. People with more “physical” type jobs can resume work 12-16 weeks after surgery.

In general, you can drive once you regain full power and function in your leg to safely perform an emergency brake. In addition, you must have finished taking any opioid medication. This typically takes a minimum of 6 weeks after surgery.

One of the goals of a total knee replacement is to allow you to return to all the recreational activities that you enjoy. Many patients return to walking, hiking, cycling, skiing, skating, golf, tennis, and working out. Regular high impact activities, such as running and jumping, are generally not advised as they may lead to earlier implant failure. Kneeling can be uncomfortable for patients after a knee replacement but there are no specific restrictions against kneeling.

Travel should be delayed for 6 weeks after surgery. Long distance travel and flying increases the risk of developing a blood clot early in the post-operative period.

If flying is essential prior to 6 weeks, it is recommended that you get up and move every hour on the plane. You will also require a prescription blood thinner.

You do not require any antibiotics before a routine dental procedure.

The Canadian Orthopaedic Association (COA), Canadian Dental Association (CDA), and the Association of Medical Microbiology and Infectious Disease (AMMI) have reviewed the best available research and have provided clear guidance on this.

The risk of a (deep) prosthetic joint infection is approximately 1% following primary (first-time) total knee replacements and up to 5-10% of revision (re-do) knee replacements. You will receive a dose of IV antibiotics before and after surgery to decrease the risk of infection. Prolonged antibiotics after surgery have not been shown to provide additional benefit and are usually not required.

Symptoms of a prosthetic joint infection include swelling, redness, wound drainage and increasing pain. Patients can also experience systemic symptoms such as a fever. Please contact your surgeon and/or go to the emergency department if you believe you are developing an infection.

Deep prosthetic joint infections may require IV antibiotics and multiple operations in order to eradicate the infection. Some or all of the components may need to be removed or exchanged.

Superficial skin infections are more common and can be usually treated with a course of oral antibiotics.

After a total knee replacement, most patients experience significant pain relief and improvements in walking, sleeping, flexibility, and other daily activities. Approximately 85-90% of patients are satisfied after surgery even though the new knee may not feel completely “normal”. However, 10-15% of patients have residual pain after an otherwise uncomplicated total knee replacement.

Knee stiffness can be a problem after a knee replacement. It is normal for your knee to be stiff and painful immediately after surgery. However, it is very important to work on your knee range of motion after surgery to prevent permanent stiffness. Expected range of motion after a knee replacement is approximately from 0 (completely straight) to 120 degrees.

If you develop permanent stiffness, you may require surgery to manipulate the knee and break up the scar tissue (manipulation under anaesthesia). In some cases, a revision (re-do) total knee replacement may be necessary to improve flexibility.

Instability is another potential complication of a total knee replacement. Symptoms include the feeling of your knee “wobbling” or “giving way” while walking. Some patients also describe “lack of confidence” in their knee, particularly when going downstairs.

Instability can often be improved with physiotherapy to strengthen the quadriceps and hamstring muscles that support the knee. In some cases, patients may require bracing or revision (re-do) surgery.

Your extensor mechanism attaches your quadriceps muscle to the proximal tibia and allows you to straighten your knee when bent. It is made up of the patella tendon, patella, and quadriceps tendon and is essential for adequate function of your knee.

An extensor mechanism injury is a very rare complication of a total knee replacement. Treatment depends on severity but may involve immobilization in a knee brace or reconstructive surgery.

Robotic-assisted total knee replacement requires the insertion of pins into your thigh bone (femur) and shin bone (tibia) in order to secure optical trackers to the bones during surgery. These trackers communicate with the robot to ensure accuracy and precision during the surgery.

There is a <1% risk of a complication involving the pin sites. The most common complications are pin site infections or fractures. Pin site infections are typically treated with a course of oral antibiotics. Depending on the severity, pin site fractures may require further surgery to stabilize the fracture. Pin site complications are unique to computer-navigated and robotic-assisted total knee arthroplasty.

Most patients undergoing a total knee replacement develop numbness around the incision and directly outside (lateral) to it. This numbness tends to resolve slowly over time but may become permanent in some patients. Importantly, this has not been shown to affect the function or strength of your knee.

The most common indications for revision (re-do) surgery are infection, instability, stiffness, periprosthetic fracture, and loosening of the components. Implants can “wear” out and loosen over time and may require revision surgery to replace the old components.

Revision total knee replacement is associated with increased risk of complications and prolonged recovery compared to a primary (first-time) total knee replacement. However, patients typically do well after revision surgery.

A deep vein thrombosis (DVT) is a blood clot that can develop in the leg veins after surgery. DVTs that occur above the knee can be dangerous as they can dislodge and form a blood clot in the lungs called a pulmonary embolism (PE). This is a rare but serious condition which can be life threatening.

All patients receive medication to reduce the risk of a blood clot after surgery. The type of medication varies depending on the individual risk factors of each patient. If you have had a blood clot in the past it is important to inform your surgeon prior to surgery.

Damage to major nerves, such as the common peroneal nerve, is extremely rare following surgery. It is more common in patients with a severe knock knee (valgus) and flexion deformity (flexion contracture). This can lead to a partial paralysis such as a “foot drop” where there is inability to lift the front part of the foot. Recovery can be prolonged and incomplete.

Major blood vessel damage is also extremely rare but can necessitate emergency blood transfusion and vascular repair in some cases.