When the knee becomes significantly damaged from either arthritis or injury, and medication or walking supports become inadequate to help perform simple activities, knee replacement surgery is usually the next step to have a shot at improving quality of life.

First performed in 1968, knee replacement surgery is one of the most common orthopedic procedures. Since its inception, improvements in surgical material and techniques have made knee replacement much more effective. According to the American Academy of Orthopaedic Surgeons (AAOS) total knee replacement (TKR or TKA—total knee arthroplasty) is one of the most successful medical procedures.

The surgery takes place in four steps: removing damaged cartilage surfaces, positioning the metal implants (which can either be cemented or press-fit on the bone), resurfacing the patella with a plastic button (some surgeons don’t do this, depending on the case), and inserting a plastic spacer between the metal components. In unicompartmental knee replacement (also known as partial knee replacement—PKR) only a portion of the knee is resurfaced, which is used in cases when disease is limited to one area of the knee.

The most promising recent knee replacement innovations include robotics for accurate and reproducible bone preparation, surgical planning and navigation, sensors to provide objective ligament balancing data during surgery, and implants customized to reproduce the patient’s pre-arthritic anatomy with specialized instrumentation.

In order to gain insights into the knee replacement implant market and examine the latest knee arthroplasty technologies, ODT spoke with four significant players in the knee implant market.

Stryker Corp
ODT’s top 10 orthopedic device firms leader Stryker Corp. offers knee implants for partial and total knee replacements in both primary and revision procedures. The implants feature the company’s cemented and cementless TKA solution, the Triathlon Knee System. Triathlon’s single radius works with the body to promote natural, circular knee motion. Surgeries using Triathlon implants are bolstered by a number of supporting technologies in Stryker’s portfolio, including robotic and sensor technologies.

Edgar Gil, Stryker’s vice president of knee marketing, had the following to say regarding the company’s strategy for the knee implant market and its latest knee replacement innovations.

“Knee replacement is evolving rapidly and now includes robotics and smart sensor technologies. Our roots in innovation go back to Homer Stryker, who founded our company in 1941. We’re excited to continue his legacy of innovation with technologies like intraoperative sensors, wearables, and our Advanced Digital Healthcare portfolio for knee replacement.

Robotics has transformed joint replacement and Mako, the market leader in robotics, is the only robotic platform that offers 3D CT-based planning, Accustop haptic technology, and insightful data analytics that have been shown to deliver better outcomes for total hip, total knee, and partial knee patients.^1,2,3,4

Combined with Stryker’s clinically proven implants and legacy in robotics, we feel that no one has more expertise in this space. We’re extremely proud that over 500,000 Mako surgeries have been conducted worldwide—more than any other robotic-arm assisted surgery platform for joint replacement, with over 1,000 Mako systems installed across 33 countries.

Mako Total Knee is compatible with our cementless Triathlon Tritanium Total Knee System, which combines the kinematics of Triathlon, designed to work with the body, with the latest in highly porous biologic fixation technology. Tritanium’s tibial baseplate and metal-backed patella components are SOMA-designed with Stryker’s proprietary population-based orthopedic design and development system and enabled by our proprietary additive manufacturing technology.

We successfully built a robotics market in orthopedics with Mako SmartRobotics. Now we’re building a ’smart devices’ market in orthopedics. Our VeraSense for Triathlon sensor-assisted technology is a single-use sensor that delivers evidence-based data wirelessly to an intraoperative monitor, enabling surgeons to perform real-time, quantified soft tissue balancing and implant positioning during total knee arthroplasty through articular surface load sensors.

Another trend in the industry is the migration of surgeries to ambulatory surgery centers (ASCs), with Mako surgeries becoming more and more prevalent in that space. When it comes to technologies designed with ASCs in mind, we’re really excited about our newly launched Triathlon AS-1. Triathlon AS-1 is a CT-based patient-specific system designed to simplify the TKA procedure for a comprehensive ASC solution. Triathlon AS-1 delivers an easy-to-follow workflow through the use of step-by-step 3D printed cutting guides and trials. This system may reduce the number of reusable instrumentation cases by as much as 88 percent,⁵ which can help reduce ASC cleaning and sterilization needs, and, in most cases, requires 75 percent less storage space than traditional manual surgery,5 a key benefit for sites with limited available space. We couldn’t be more excited about the future of our robotics, sensor technology, and ASC solution platforms.”

DePuy Synthes
Johnson & Johnson company and ODT top 10 orthopedic device firms runner up DePuy Synthes offers several brands of knee replacement implant technologies, including ATTUNE, LCS COMPLETE, P.F.C. SIGMA and SIGMA, S-ROM NOILES, and TRUMATCH. The company also offers robotic-assisted technology to further support knee arthroplasty surgeries.

Andrew Ekdahl, DePuy Synthes’ worldwide president of joint reconstruction, had the following to say regarding the company’s strategy for the knee implant market and its latest knee replacement innovations.

“One of the most important trends we are addressing in our TKA approach is personalization. In every aspect of our lives, technology is customized for our experiences. When it comes to healthcare, our patients expect the same bespoke approach.

At the same time, knee reconstruction recipients are younger than in years past; they tend to be relatively active individuals who want to return quickly to everyday activities after knee reconstruction surgery. From 2000-2009, knee replacements among patients aged 45-64 increased by 188 percent. The majority of joint replacements, including knee replacements, can begin as early as age 55. Our cementless knee offerings, including our new ATTUNE Cementless Fixed Bearing Knee with AFFIXIUM 3DP Technology, help address this trend.

Another challenge that has informed our approach to TKA is up to 20 percent of TKA patients are unhappy with their knee replacement. Our goal is to change that by offering patients a tailored experience focused on working with a patient’s body to restore the knee, rather than replace it. We are committed to improving patient satisfaction through a combination of solutions that together are revolutionizing the traditional approach to TKA.

We designed our kinematically advanced and clinically proven ATTUNE Knee System for stability in motion and to more closely match the natural knee’s kinematics. The ATTUNE Knee is delivering significantly better patient satisfaction than the class of other knees. The VELYS Digital Surgery Platform is a platform of connected technologies powered by data insights, focusing on the pre-, intra-, and post-surgery patient experience, including our VELYS Robotic-Assisted Solution. Finally, patient-specific techniques help target restoration of an individual patient’ s knee function and helps preserve the knee’s soft tissue envelope.

We also consider it important to help meet the demands of surgeons who are under incredible pressure to be more efficient and deliver patient outcomes. The ATTUNE Cementless Fixed Bearing Knee with AFFIXIUM 3DP Technology offers flexibility and efficiency in the OR, and the ATTUNE Medial Stabilized Knee System delivers medial stability, function, and versatility, and is designed to restore natural knee kinematics for improved feel and function. Our VELYS Robotic-Assisted Solution merges insights, execution, and performance to help simplify knee replacement surgery. It requires no CT scan or added technician. The compact size and cost effectiveness of VELYS Robotic-Assisted Solution also suits it well for a high-efficiency outpatient environment.

The launch of the VELYS Robotic-Assisted Solution took place in 2021, as well as the start of early clinical use of our AFFIXIUM 3D tibial tray in the ATTUNE Cementless Fixed Bearing Knee with AFFIXIUM 3DP Technology, which we believe will change the direction of cementless knees. We are also starting early surgeon use of our ATTUNE Medial Stabilized Knee System.

In the VELYS Robotic-Assisted Solution—our next generation robotic solution—we are simplifying knee replacement surgery by providing valuable insights, versatile execution, and verified performance to deliver efficiency for surgeons and help optimize patient outcomes. At the same time, the 3D printing process in the ATTUNE Cementless Fixed Bearing Knee with AFFIXIUM 3DP Technology includes a more precise production method than traditional manufacturing, creating a similar shape to natural bone. This 3D porous structure is designed with macro and a diamond tread surface to increase the friction between the implant and the bone interface to provide greater initial stability (i.e.,create a stronger bond). The ATTUNE Medial Stabilized Knee System incorporates anatomic inserts with a raised medial lip to provide medial stability and a TruARC LateralPath for natural knee function and the versatility to address a range of surgical philosophies. We are pleased with the excellent feedback from surgeons who have begun using the AFFIXIUM 3DP Technology and the ATTUNE Medial Stabilized Knee System.

Our goal is to continually innovate with the patient at the center of all we do.”

Zimmer Biomet
Third on ODT’s top 10 orthopedic device firms is Warsaw, Ind.-based Zimmer Biomet, the result of a landmark 2015 $14 billion merger deal. The company’s knee replacement implant franchises include Persona/PersonaIQ, Oxford, Gender Solutions, NexGen, and Vanguard. Zimmer Biomet also bolsters knee replacement surgeries with robotic and digital health supportive technologies.

Liane Teplitsky, Zimmer Biomet’s president of global robotics and technology & data solutions, had the following to say regarding the company’s strategy for the knee implant market and its latest knee replacement innovations.

“The use of connected technology that provides data-powered clinical insights to care teams with the goal of improving patient outcomes is the gold standard in the orthopedics space. Zimmer Biomet is excited to be at the forefront of that innovation.

Earlier in 2021, the company introduced the ZBEdge Connected Intelligence Suite of digital and robotic technologies, advancing our vision of creating a seamlessly connected suite of digital health and robotic technologies to deliver objective data to clinicians throughout the surgical journey. Current ZBEdge technologies include:

• The ROSA Robotics Platform, including ROSA Knee, designed to support surgeons by delivering data-driven assistance, enhanced accuracy, and clinical insights throughout the episode of care
• Anatomical visualization and guidance solutions such as Signature ONE Surgical Planning, the Zimmer Biomet iAssist Knee Alignment System, and Optical Navigation tools, designed to deliver crucial patient insights
• Remote care and patient engagement management systems like mymobility with Apple Watch
• Data services and analytics including the OrthoIntel Orthopedic Intelligence Platform and the Omni Surgical Suite integrated operating room
• Persona IQ, combining the proven and trusted Persona The Personalized Knee implant with implantable sensor technology that measures range of motion, step count, walking speed, and other gait metrics

In August 2021, Zimmer Biomet introduced Persona IQ, the world’s first and only smart knee cleared by the FDA for total knee replacement surgery. Persona IQ combines the proven and trusted Persona The Personalized Knee implant with implantable sensor technology that measures range of motion, step count, walking speed, and other gait metrics.

Once placed in the knee, Persona IQ records and wirelessly transmits a wide range of gait data to a patient’s personal base station at home. The data are then securely delivered to a HIPAA compliant cloud-based platform, which can be accessed by the patient and the surgeon. Surgeons and their care teams can use Persona IQ data as an adjunct to other physiological parameter measurement tools during the course of patient monitoring and treatment post-surgery.”

Smith+Nephew
U.K.-based Smith+Nephew, holder of the fourth spot on ODT’s top 10 orthopedic device firms, also holds a number of knee replacement implant brands. These include JOURNEY II, GENESIS II, LEGION, VERILAST, STRIDE, and ZUK. Like its fellows, the company supports knee replacement surgeries with robotic-assisted and digital surgery technologies.

Nick Tolley, Smith+Nephew’s senior marketing manager—knees, had the following to say regarding the company’s strategy for the knee implant market and its latest knee replacement innovations.

“One major trend in the knee replacement market is the drive for increased efficiencies and improved patient outcomes and performance. A heightened awareness for operating room, hospital, and surgeon efficiency is being driven by an increasingly cost-conscious environment combined with the downstream effects of COVID-19. Smith+Nephew has addressed this market trend by steadily increasing the adoption of its CORI Surgical System—a next-generation handheld robotics platform—combined with new SYNC Performance Instruments. Together, these new technologies reduce the number of instruments and surgical steps required to complete a procedure, leading to less burden on the healthcare system. Smith+Nephew also recently launched the LEGION CONCELOC Cementless Total Knee System with proprietary 3D printed Advanced Porous Titanium technology—a 3D printed cementless knee system that removes the cost and time of cement from the knee procedure.

Patient performance in knee replacement has continued to be a focus of the industry as a result of knee outcomes not reaching the same satisfaction level as those of hip replacement. Smith+Nephew continues to address this concern with the JOURNEY II TKA System—which mimics normal patient anatomy and kinematics—resulting in more successful patient outcomes. The latest addition to this product family is the JOURNEY II Medial Dished (MD) System, which launched in late 2021. The JOURNEY II MD aims to better replicate normal kinematics in both cruciate-retaining and cruciate-sacrificing procedures, which has been shown to improve patient satisfaction and performance. The CORI Surgical System also helps address performance concerns by empowering surgeons to customize intraoperative decisions to most effectively match each individual patient’s needs.” 

Knee Support Knee implant makers looking to reduce speed to market, cut cost, and shorten their supply chain have the option to seek out specialty manufacturing partners for certain products. Knee replacement implants have evolved to become more complex, even personalized. These partners must also stay in tune with the knee replacement market to best serve their OEM partners. For insights on knee implant manufacturing, ODT turned to Viant, a Foxborough, Mass.-based end-to-end medical device manufacturing partner. Here’s what three members of the company had to offer on the subject. Sam Brusco: What recent technological/operational investments have been most beneficial to your knee implant/component manufacturing business? Dr. Andrew Thomas, senior director of operations: We recently made a big investment in supply chain capacity planning transformation by adding Kinaxis, a best-in-class forward planning software platform. It gives us an end-to-end view—we can aggregate data, look at historical forecasts, and model different scenarios to evaluate and update capacity issues. The end goal is to be a true partner to our customers with improved delivery, responsiveness, and transparency. We have rolled Kinaxis out at several of our facilities and have demonstrated industry-leading metrics. Our customers are extremely excited about it. When it comes down to it, you could make the best product in the world, but what good is that if you’re two months late getting it to the customer? We have also made investments in advanced machinery; for example, five-axis milling machines and mill and turn capabilities. Robotic instruments are pushing the boundaries of machine capabilities and inspection. We’ve standardized on vision systems for inspections, as well as a coordinated measuring machine (CMM). Our vision systems allow us to capture data to ensure our processes are stable. They help us achieve and maintain tight tolerances and reliably deliver assured quality. The system “guides” the operator to deliver nominal parts in a validated process. Sebastien Meunier, account manager—orthopedics, Europe: Surface is particularly critical for an implant, and we have made significant investments here. We have both robotic and automated polishing and recently invested in new in-house coating technology. By adding vacuum plasma spray (VPS) to our existing atmospheric plasma spray (APS) capabilities, we can coat hydroxyapatite (HA), titanium, or dual-layer materials (Ti + HA) in-house on parts made of cobalt-chrome alloys or titanium. This enhanced our Chaumont, France, facility’s vertically-integrated services, which include machining and milling, polishing, coating, assembly, and packaging. Brusco: What are the best practices for knee implant/component design and/or manufacturing partnerships? Dr. Thomas: It is good to get into design for manufacturability (DFM) as early as possible with a customer. That is imperative to ensure the process is as lean as possible and produces the original design intent. That doesn’t always happen—sometimes we have transfers or traditional knee replacement components that are mature products that can’t be modified. In either case, it’s important to have solid teams from both sides working together to maintain design intent and ensuring it can be manufactured as cost-effectively as possible. We’re currently working on a robotic platform for knee replacement that started with the customer approaching us to see if we could manufacture it because they had already had an unsuccessful manufacturing partnership. We were very frank and honest—we could not manufacture it as is and needed to remediate the drawings. We worked with them to refine the design and now we’re successfully making the robotic instruments for this knee platform. Frank Page, VP technical solutions: It’s also really important to consider the system holistically. The implant is only as good as how it’s implanted. Placement and alignment are absolutely critical to a successful outcome. With robotic systems, the instruments are far more complex with tighter tolerances than the general instruments used for traditional knee replacement. Instrument tolerances were already really tight, especially for those that were guiding or measuring for the implant. We worked on a measuring and sizing instrument that had 32 critical-to-quality characteristics that all had to have demonstrated statistical process capability. DFM becomes even more important when the instruments are so challenging to make. Robotic instruments are pushing the boundaries of machining and inspection capabilities. That’s where our investment in leading-edge machinery comes in. You need top-of-the-line equipment to hold those tighter tolerances and consistently manufacture products on time, at the right price, with the right quality. Meunier: Full integration with one partner simplifies and streamlines the process, giving the customer better visibility along with lower risk and faster speed to market. For example, our Orthoplastics brings together industry-leading UHMWPE, component machining, direct compression molding, and laboratory services to offer customers a complete solution in a leading implant material that integrates perfectly with the other capabilities in the overall Viant network.

References

1. Kayani B, Konan S, Tahmassebi J, Pietrzak JRT, Haddad FS. Robotic–arm assisted total knee arthroplasty is associated with improved early functional recovery and reduced time to hospital discharge compared with conventional jig-based total knee arthroplasty: A prospective cohort study. Bone Joint J. 2018;100-B(7):930-937. doi:10.1302/0301-620X.100B7.BJJ-2017-1449.R1
2. Mahoney O, Kinsey T, Mont M, Hozack W, Orozco F, Chen A. Can computer generated 3D bone models improve the accuracy of total knee component placement compared to manual instrumentation? A prospective multi-center evaluation. Poster presented at: 32nd Annual Congress of the International Society for Technology in Arthroplasty (ISTA); October 2-5, 2019; Toronto, Canada.
3. Illgen RL, Bukowski BR, Abiola R, et al. Robotic-assisted total hip arthroplasty: outcomes at minimum two year follow up. Surg Technol Int. 2017;30:365-372.
4. Kleeblad LJ, Borus T, Coon TM, Dounchis J, Nguyen JT, Pearle AD. Midterm survivorship and patient satisfaction of robotic-arm-assisted medial unicompartmental knee arthroplasty: a multicenter study. J Arthroplasty. 2018;33(6):1719-1726. doi:10.1016/j.arth.2018.01.036.
5. Stryker technical report. NPDP project number 301553. Triathlon AS-1 product data characterization. Windchill document number D0000078742; Study file number D0000079109.