Developing a prototype for a new total knee replacement concept

Developing a prototype for a new total knee replacement concept

OPN talks to Trevor Gascoyne, Director of Research Operations at the Orthopaedic Innovation Centre in Canada, about Surface-Guided Total Knee Replacement

The Orthopaedic Innovation Centre is a non-profit centre based in Winnipeg, Manitoba, specialising in medical device testing, research and development. Part of their research focuses on testing and clinical application of orthopaedic products – namely total joint replacements. In January of this year, they published a white paper, which describes the development, prototyping and validation of a new total knee replacement concept, which they have dubbed “surface-guided”. This new knee design has the potential to help reduce the 20 per cent of total knee patients that are dissatisfied with their surgery. The knee design is now a licensing opportunity for implant manufacturers, with patents granted in Canada, China, Japan, France, Germany, Great Britain, Italy, Sweden, Switzerland, and most recently the United States. 

OPN: Tell us a little about your background and education in the orthopaedic industry?

TG: I earned my bachelor’s and master’s degrees in Biomedical Engineering at the University of Manitoba and have been working with the Orthopaedic Innovation Centre since its formal inception in 2010, first as a student, then as a research manager, and recently as a director. Being immersed in the orthopaedics world, and being steps away from the offices of four high-volume hip and knee arthroplasty surgeons has helped me to build a well-structured understanding of joint replacement from a variety of different views. 

OPN: Could you explain more about your work in the area of total knee replacement and the recent developments outlined in the white paper?

TG: My clinical work in total knee replacement stems from assisting our surgical team with analysis of our local arthroplasty registry. The data demonstrated time and again shows that one in five total knee patients are dissatisfied after surgery. Further to this, our clinical team has studied numerous knee products using radiostereometric analysis (RSA) including, most recently, assessing polyethylene wear by means of model-based RSA. From the engineering side of things, our group has assessed the failure and success of current total knee systems in our retrieval laboratory. We have also tested the durability of many knee systems on our wear simulator machines. Putting all of this knowledge together, our team has gone from benchtop to bedside with total knee systems and I think this shows in our recent whitepaper – evaluating a novel design using simulation, finite element analysis, pressure mapping, and mechanical validation. 

OPN: How would the new concept of surface-guided surgery work?

TG: The surface-guided concept is actually in respect to the device design rather than the surgery itself. An important note is that the surgical method of total knee replacement is not being altered, and therefore requires no drastic change to current practice in order for this concept to be implemented. The surface-guided concept is unique in that it shifts the burden of replicating “natural kinematics” away from the soft tissues and surgical technique and places it on the implant design instead. In essence, the surface-guided design constrains the knee into a defined, or engineered, kinematic pattern – which can be tailored to the patient – without limiting range of motion. The constraint of this knee design comes in the form of highly congruent articular surfaces, thereby providing joint stability, even when ligaments are lacking.  

OPN: How will your device help surgeons and benefit patients?

TG: The surface-guided knee is designed to be inherently more robust, less sensitive to minute changes in implant positioning and ligament deficiencies. We therefore anticipate this design to be less taxing on the surgeon and more broadly indicated for patients in their surgical practice. From a patient standpoint, the obvious anticipated benefit is the more natural-feeling knee that allows a larger range of motion to suit a more active lifestyle. It is our goal, with this design, to create a knee replacement that patients forget they have. 

This design will also benefit orthopaedic device manufacturers. The surface-guided knee relates solely to the articulating surfaces – it is not a complete knee system. This means that any manufacturer can apply our patented design to their existing knee system(s) which may already have proprietary elements into which they’ve invested heavily (such as additive manufacturing, osseointegration surfaces, backside structure). 

OPN: What is the next stage for your development?

TG: Being a small, non-profit research centre, our next stage is to license this patented design to an orthopaedic device manufacturer, an OEM. As a research and testing centre, we are ideally suited to offer design and testing services to support the OEM in developing the knee system. This would be a symbiotic collaboration between the inventor and developer in which both benefit from a common goal.  There are few institutions that can offer this beneficial development model. 

OPN: What could your research mean for the future of orthopaedics?

TG: Orthopaedics is trending more and more towards personalised medicine, a trend to which I believe our surface-guided knee design aligns perfectly. Because this design uses patient anatomy to derive the articular surfaces, it is best-suited for patient-specific knee replacement systems. With the increasing use of additive manufacturing in orthopaedics, patient-specific implants are securing an expanding portion of the market share. I believe this surface-guided concept goes a step further than existing patient-specific systems. It doesn’t replicate the anatomy, but rather uses it to create a structured articulation that is engineered to return stability and function to a knee that is in a worsened condition due to arthritis pain and inflammation. 

OPN: What else are you currently working on at the Orthopaedic Innovation Centre?

TG: There are many new projects – medical innovation is always progressing. We are always testing new orthopaedic products on our mechanical test frames (hip, knee, shoulder and ankle replacements, spine and trauma devices) as well as facilitating clinical trials on these new products – often using RSA as a primary assessment tool. In terms of new research and development, we are in the midst of patenting a series of bioresorbable polymers pre-blended with antibiotics for use in additive manufacturing systems. The goal of this work is to develop a better product for treating infected joint replacements – a frontier of this field which, we believe, is underdeveloped given the catastrophic outcomes for these patients.  

To learn more about the Orthopaedic Innovation Centre and its work, please visit: http://www.orthoinno.com/

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