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Robots in Orthopaedic Joint Replacement
Hundreds of thousands of joint replacements are performed worldwide every year to replace worn cartilage in knee and hips. Each implant is designed to replicate joint movement in a certain way, and need to be inserted in a certain alignment and rotation to make them function most efficiently.
Human beings, even orthopaedic surgeons, are prone to varying degrees of error, depending upon experience and skill levels. Robotic surgery aims to remove surgical errors by providing a higher degree of accuracy and reproducibility of results. Dr Alan Cheung is one of the few Surgeons in Asia to be an expert in the several robotic systems currently available for joint replacement:
1. Makoplasty System
Dr Alan Cheung was certified in the use of the Makoplasty robot at the Homer Stryker Centre in Mahwah, New Jersey, USA.
The Makoplasty system (Stryker) is used to perform total hip, partial and total knee replacements. Mako Technology was designed to help surgeons provide patients with a personalised surgical experience based on their specific diagnosis and anatomy.
It’s important to understand that the Mako system doesn’t actually perform the surgery. Surgery is performed by Dr Cheung, who uses the Mako System software to pre-plan your surgery.
The process begins with a CT scan of your joint that is used to generate a 3D virtual model of your unique anatomy. This virtual model is loaded into the Mako system software and is used to create your personalized pre-operative plan.
The implants can be positioned in any position that Dr Cheung thinks suits you best on the 3D map.1 He then uses a robotic arm to remove the exact amount of bone required. Haptic (tactile) feedback, as well as visual and auditory cues, are given to help prevent him from straying outside the preplanned area.
Early results so far are very promising.3 In a multicentre study, 909 knees underwent partial knee replacement using robotic-assisted surgery. There was a knee replacement survivorship of 98.8% at 2.5 years, with 92% of patients very satisfied or satisfied with their knee function.4
2. Navio System
Dr Alan Cheung underwent his training in the Navio system (Smith and Nephew) at the Scripps Mercy Hospital in San Diego, California USA.
The Navio system uses a robotic handheld burr to assist with partial and total knee replacements. The difference with this system is that there is no pre-operative CT scan. Instead, the surgeon registers a number of points on the bone of the joint surface to be operated on, creating an intraoperative 3D map of the knee joint. This enables ‘real time imaging’ during the surgery.
The Navio handpiece is used to burr away the desired bone according to a patient-specific plan. Although the Navio equipment is smaller and more portable than a Makoplasty machine, it does not provide haptic (tactile) feedback, and it is vital that the surgeon accurately registers the intraoperative points, as there is no CT-based 3D virtual model.
Early results from the Navio system are promising. A study in France looked at unicompartmental knee replacements (UKR) performed in 80 patients using the Navio system.5 These patients were matched with 80 patients undergoing UKR using the same prosthesis, implanted using a non-robotic technique. At around 2 years, the patients with Navio assisted surgery had better limb alignment and a lower revision rate. The accuracy of implant positioning is improved by the Navio robotic-assisted system.
3. Robodoc System
Dr Alan Cheung underwent his training in the Robodoc system at the Mirae Hospital in Busan, South Korea.
The Robodoc system was first used in 1992 to assist with a total hip replacement case in the United States. It relies on a preoperative CT scan of the limb to create a 3D plan, which the surgeon then uses to map regions of the joint during surgery. The difference between Robodoc and the other systems is that the robot is fully autonomous (i.e. self guided).
Once the Dr Cheung has guided the robot cutter arm to the bone surface, the Robodoc machine will automatically mill away the bone without any guidance. Dr Cheung is in control at all times and can stop the procedure at any point if required. He then manually implants the joint replacement as per usual.
There is evidence to suggest that the Robodoc system has some advantages in performing total knee replacement6 and total hip replacement7.
Although excellent results can be achieved using conventional joint replacement techniques, Dr Cheung believes that robotic surgery can give increased accuracy, better preoperative planning, and reliable, reproducible results particularly in technically challenging and revision cases.
Individual results of joint replacement vary. Implants are intended to relieve knee pain and improve function, but may not produce the same feel or function as your original knee. There are potential risks with joint replacement surgery such as loosening, wear and infection that may result in the need for additional surgery. Patients should not perform high impact activities such as running and jumping unless their surgeon tells them that the bone has healed and these activities are acceptable. Early device failure, breakage or loosening may occur if a surgeon's limitations on activity level are not followed.
Individual results may vary. There are risks associated with any surgical procedure. Joint replacement and robotic surgery is not for everyone. Children, pregnant women, patients who have mental or neuromuscular disorders that do not allow control of the knee joint, active infection, and morbidly obese patients should not undergo a joint replacement / robotic procedure. Please consult your surgeon for details to determine if surgery is right for you.
Dr Alan Cheung is a Consultant Orthopaedic Surgeon specialising in Sports Injuries such as torn ligaments and tendons, and cartilage injury in the knee, hip and shoulder, Adult Joint Reconstruction including total and partial Knee Replacement and Total Hip Replacement for osteoarthritis, and Robotic Surgery (Makoplasty, Navio and Robodoc systems). He has also received extensive training in trauma (fixing broken bones) and musculoskeletal tumour (bone cancer) surgery.