Total Knee Replacement has been shown to be both durable and reliable in relieving pain and improving function in patients with end stage knee arthrosis, allowing the patients to return to normal activities with improved quality of life. The number of knee replacements are increasing rapidly as the population lives longer.
The survival of a knee replacement depends on many factors:
Patients who are overweight or obese and have multiple medical problems may have reduced longevity of the knee replacement, and increased complications.
Prosthesis Factors: This depends on the design of the prosthesis. The more modern ones are more conforming to native kinetics and kinematics than older prostheses. The market includes standard knee replacement prostheses, medial pivot knee replacements, and many other designs.
Surgeon/Technique: Surgical techniques can vary from surgeon to surgeon. It is important the patient asks the surgeon for details of the surgery.
What does the robot really do in a knee replacement?
It positions the re-usable robotic arm over the knee so that the bone resections can be made appropriately, depending on the plans. In some instances, the robotic arm only positions the cutting guide into position, and the rest of the surgery is done manually by the surgeon.
Is the prosthesis different in robotic knee replacements?
The prostheses are not different, they are the same prostheses that have been used in standard knee replacements.
Does robotic-assisted knee replacement result in a better outcome or longer-term survivor-ship than conventional knee replacement?
Robotic-assisted knee replacement was introduced to enhance the precision of bone preparation and component positioning, with the goal of improving the clinical results and longevity of knee replacements.
Although numerous reports suggest that bone preparation and knee component alignment may be improved using robotic assistance, no long-term randomised trials of robotic-assisted knee replacements have shown whether they result in improved clinical function or survivorship of the knee replacement.
Almost 700+ robotic-assisted knee replacements and almost 700+ standard conventional/traditional knee replacements performed by one surgeon were compared. The patients were followed up for at least 10 years.
The study found there was no difference between robotic-assisted knee replacement and conventional knee replacement in terms of functional outcome scores, aseptic loosening, overall survivorship, and complications.
Considering the additional time and expense associated with robotic-assisted knee replacement, the study did not recommend its widespread use.
There is more marketing capital in the robotic joint replacement industry than there is scientific evidence of any advantages.
Does robotic joint replacement increase infection risk?
The robotic arm of the machine is usually re-used for all patients, however there are plastic sterile disposable drapes over the arm and console and they are usually sealed.
However the surgeon has to touch the console while operating many times in most cases during the surgery. This is a necessary prerequisite to getting the planning right to determine bone resections, alignment and component sizes as these are not planned before the actual procedure itself.
This means – in lay terms – the surgeon has touched other surfaces besides the patient.
It is a statistic that the higher the frequency of touching other surfaces the higher the risk of infection. This is a result of robotic-assisted joint surgery and could apply to any similar surgery, but if is the case it would need to be proven in a clinical trial.
What about pin track infections in robotic-assisted knee replacement?
In robotic-assisted joint replacements, 2 pins are usually inserted in the femur (thigh bone) and 2 pins in the upper tibia (above the shin). Some surgeons place these pins within the surgical wound but others don’t and have to make separate stab incisions to place them for attachment of trackers/sensors during the operation.
One of the disadvantages of these pins in robotic-assisted knee replacements is that there could be an increased risk of infection from pin tracking sites.
Could there be fractures associated with robotic-assisted knee replacements?
The other disadvantage of the pins used in robotic-assisted knee replacements (on the distal femur and proximal tibia a total of 4 pins) is that if the bone is soft, it acts as a stress riser increasing the risk of fracture in the femur or tibia after the knee replacement. Most surgeons usually try to avoid this, but it still remains a risk.
Disclaimer – Individual results can vary – patients are asked to discuss their specific restrictions with their surgeon after surgery.