Trends in total knee replacement
Dr. Ramneek Mahajan
Knee Joint replacement is a very effective treatment for the management of arthritis. It involves the removal of the damaged joint and replacement with metal components thus allowing pain free movements.
With an active and longer living population and a trend for joint replacement earlier in life, there have been many natural movements. A few of these recent developments have been explained in this article.
1. Cementless knee total knee arthroplasty
Traditionally total knee arthroplasty prostheses have been implanted with bone cement to fix the implant to bone. The implant is designed in such a way that it does not require cement for fixation. It has the advantages of reducing rates of wear and loosening.
2. Implant surface modification
The surface of the implant is modified in such a way that it improves the strength of fixation and also has some antibiotic property. Titanium has been the focus for the advances in surface modification. Topographical modifications aim to improve fixation strength by encouraging growth or ingrowth of bone.
Modulation of a Titanium surface nanostructure has been demonstrated to reduce infection by several bacteria that are responsible for over 50 percent of joint infections. Thus, it maximizes the effectiveness of antibiotics given in the perioperative period. Addition of silver nanoparticles has demonstrated to be effective against few of the most common infection causing organisms.
3. 3-D Printing and custom implants
Newer technologies like 3-D printing have enabled doctors to get a patient specific implant i.e. a custom implant which is designed to match the anatomy of that patient. The customization of implants provides the opportunities to provide a personalized solution for knee joint construction. While the majority of arthroplasty cases probably do not require such a tailored approach. More complex revision surgery may benefit from such a strategy.
4. Computer navigation surgery
In this strategy the computer navigation is used to provide assistance to guide the positioning of instruments and implants. It enables the surgeons to improve the accuracy of implant positioning as well as improve the outcomes of surgery.
5. Robotic assisted surgery
One of the most exciting developments in joint arthroplasty is the use of robotic assistance to support the surgeon in these critical decisions. Robotic assisted joint replacement surgery has been around a while, with systems available in the 1980s. Robotic assisted surgery is an evolution of navigated joint replacement surgery. Robotic surgery takes this a step further with the robot helping to position instruments or controlling the function of tools to ensure that bone resection matches the planned operation.
There is good evidence that robotic assisted surgery can help to improve implant positioning accuracy compared to manual placement in both hip and knee arthroplasty surgery. Robotic surgeries are basically of two types – autonomous and semiautonomous. With the autonomous robotic-assisted system, the surgeon performs the surgical plan and the initial cut. Then the robotic system has the capability of completing the remaining surgery without surgeon input.
The semi autonomous robotic-assisted systems combine the benefits of a navigation system and of an autonomous robotic system. Semi Autonomous robots are controlled and manipulated by the surgeon. But the surgeon’s control is modulated by the robot to limit bone preparation to the surgical plan.
(The author is Senior Director (Orthopaedics) & Head Joint Reconstruction (Hip & Knee) Unit, Max SMart Super Specialty Hospital Saket)
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