In the early 1970s, the condylar knee was developed independently in both the U.S. and overseas.

Replacing the tibiofemoral condylar surfaces with cemented fixation, along with preserving cruciate ligaments, was then developed and refined. In order to correct severe knee deformities, the condylar knee with posterior cruciate-sacrificing design debuted, also in the early 1970s. By 1974, replacing the patellofemoral joint and either preserving or sacrificing the cruciate ligaments had become standard practice. After that, condylar knee designs were improved to include modularity and non-cemented fixation, with use of universal instrumentation.

Today, several orthopedic manufacturers make knee implants and there are over 150 designs on the market. This article will feature some of the major manufacturers of knee implants, as well as advancements in enabling technology to streamline knee replacement procedures. 

Zimmer Biomet

Warsaw, Ind.-based Zimmer Biomet has a rich history of knee replacement technology. The company began offering knee replacement products as early as 1974. As such, it’s quite aligned with the market trends for knee implants. 

“Cases of knee osteoarthritis, the leading cause of knee replacement, are projected to increase by nearly 75% by 2050,¹” said Joe Urban, president of Zimmer Biomet’s Knees business. “This, coupled with the significant trend of younger people seeking functionally restorative procedures, drives the demand for total knee replacements (TKR).²”

“Technological advances such as robotic surgical-assistants and navigation guides are continually making knee replacement more accurate and precise^3,4 with improved early outcomes,^5,6” said Urban. “As a result, we believe patients with joint pain will feel more comfortable seeking surgical treatment sooner.”

Zimmer Biomet obtained FDA approval for its Oxford cementless partial knee in November 2024, awarding it the title of the only FDA-approved cementless partial knee implant in the U.S.

The new Oxford knee features a mobile bearing that moves with the femoral component through the entire range of motion to mimic natural movement of the knee. The design, according to the company, provides better range of motion, a more natural feel, and more stable implant-to-bone fixation.

The system’s tibial and femoral components also have a titanium and hydroxyapatite coating to promote osseointegration.

“Unlike traditional partial knee replacements (PKRs) that use cement, the cementless design of the Oxford cementless partial knee allows for natural bone growth to secure the implant,” said Urban. “Surgeons are increasingly adopting cementless surgeries due to better operating room efficiency⁷ and promising clinical data. Although new to the U.S. market, the Oxford Cementless Partial Knee has a proven track record globally, in over 300,000 procedures in 50 countries over the last two decades.⁷ Similar to the cemented version of the Oxford Partial Knee, patients in the U.S. will be covered with a lifetime limited warranty that covers the cost of Zimmer Biomet replacement knee implants.”

As part of its nationwide U.S. launch in Q1 2025, the company will offer FDA-required training that focuses on the cementless surgical technique and proper patient selection.

December 2024 saw an FDA nod for the company’s Persona SoluTion porous plasma spray (PPS) femur. The total knee implant presents an alternative for patients who have sensitivities to bone cement and/or metal.

Hypersensitivity to metal is a challenge for certain patients related to a traditional cemented total knee replacement (TKR) with an implant made of cobalt-chrome (Co-Cr-Mo) alloy. When exposed to certain metals, people with these hypersensitivities can experience an inflammatory response, pain, and implant loosening that can require a revision TKR.

“The Persona SoluTion Porous Plasma Spray (PPS) Femur is a TKR femoral alternative designed to address sensitivities to metal and/or bone cement,” said Urban. “Patients with metal sensitivities who are treated with traditional cemented cobalt-chrome implants may experience inflammation, pain, and implant loosening, which can require a revision procedure. The Persona SoluTion PPS Femur features a porous coating for cementless fixation and leverages a proprietary surface treatment designed to enhance wear performance.^8,9 The implant is made of a proprietary Tivanium (Ti-6AI-4V) alloy that has been in clinical use for nearly 20 years.¹⁰”

Smith+Nephew

London, U.K.-based Smith+Nephew has also been involved in knee implant manufacturing for decades, since its 1986 acquisition of Memphis, Tenn.-based Richards Medical Company. Since then, the company has become a major player in the market with many insights to share.

“Adoption of technology for soft tissue balancing and surgical execution is increasing. We also see a trend toward cruciate retaining/sacrificing knee designs due to advances in both polyethylene shape and robotic execution,” said Mayank Shandil, senior vice president of global marketing, Reconstruction + Robotics, at Smith+Nephew. “Bone surfaces can now be cut or burred more precisely, which is one of the factors driving an increase in the use of cementless knee implants. Globally, we continue to see a shift towards outpatient care and we have established strategic partnerships to offer differentiated value in this site of care. Industry wide and macro-economic pressures on pricing, vendor consolidation, cost side inflation remain.”

In October 2024, Smith+Nephew began a co-marketing agreement with JointVue for its OrthoSonic 3D surgery planning technology. According to the company, OrthoSonic is the only ultrasound on the market that delivers 3D pre-operative planning.

Partnering with JointVue lets surgeons using Smith+ Nephew’s CORI surgical system for robotic-assisted knee replacement create a personalized surgical plan.

“CORI stands out in the market with its image-agnostic registration capabilities, offering both image-free and MRI-powered options for pre-operative planning,” said Shandil. “Now, with the exclusive adoption of JointVue’s OrthoSonic 3D Surgery Planning Technology for Smith+Nephew implants, surgeons have access to an additional procedural solution that utilizes ultrasound to generate a 3D plan within minutes. This radiation-free, automated planning tool guides surgeons to tailor the procedure uniquely to each patient. The combination of JointVue’s OrthoSonic technology with CORI, known for its small footprint and scalability, offers an ideal solution for Ambulatory Surgery Centers (ASCs) where OR space is limited.”

The company released its LEGION HK hinged knee (HK) system with proprietary OXINIUM (oxidized Zirconium) implant technology in the U.S. in October 2024.

Part of the LEGION total knee system, the LEGION HK system aims to provide a natural range of motion with medial pivot, lateral roll back, and screw home. Since 2011, the LEGION HK System has let surgeons transition intraoperatively from a constrained revision knee implant to a cobalt chrome-hinged assembly.

“Revision surgery can be a challenge for both the surgeon and the patient as the previous surgery has failed and there is increased bone and tissue loss with decreased function,” said Tim Bourne, Smith+Nephew’s vice president of global knee marketing. “The combination of our guided motion technology with LEGION HK allows patients to regain more normal knee function with the implant compensating for bone and ligament damage. With the launch of Legion HK with OXINIUM, it gives the only alternative option to CoCr on the market and allows for better biocompatibility for the patient. In revision surgery, and in cases where a hinge prosthesis is needed, you want the next surgery to be last. OXINIUM, with 25+ years of clinical success, is an ideal material to help minimize risks for the patients and allow them to regain mobility.”

Exactech

Gainesville, Fla.-based Exactech made its debut in the knee market in 1994 when it inked a deal to license and market the Optetrak knee implant based on designs by surgeons and engineers at the Hospital for Special Surgery. In the decades following, the company grabbed a considerable share of the market.

“Over the last decade, implant and procedural technologies have drastically improved the performance, understanding, and efficacy of total knee replacement surgery,” said Pete Cipoletti, senior director of knee marketing at Exactech. “The impact of these improvements can be seen in the shift to ‘same-day-surgery’ as the standard of care with cementless knees and advanced computer-aided planning enabling efficient, personalized procedures.”

Exactech earned FDA clearance for its Truliant porous tibial tray, a 3D-printed tibial knee implant, in October 2024.

The Truliant porous tibial tray leverages additive manufacturing technology for a porous structure that mimics that of cancellous bone. This design, according to the company, helps along both initial and biological fixation to accommodate active lifestyles.

The laser-printed 3D tibial tray features peripherally placed tibial pegs, a dual v-channeled keel, and optional cancellous bone screws to boost initial rotational stability and permit an increased bone-implant interface. The FDA clearance positions Exactech to continue to address the rising demand for cementless knee solutions.

“Coupled with ExactechGPS and Activit-E poly, the Truliant Porous tibial tray plays a critical role in completing our personalized surgical offering,” said Cipoletti. “By leveraging today’s advanced 3D printing technologies, we can mimic natural anatomy, encouraging bone to integrate directly with implants and eliminating the need for cement for long-term fixation.”

The company launched a new balancing technology for TKR patients that helps improve implant positioning and balancing in August 2024, as well. Harnessing the power of ExactechGPS computer-assisted technology, the Newton knee procedure provides surgeons visual guidance for personalized, balanced results.

The company’s new balancing technology let surgeons see patients’ joints in real-time to place the implant precisely. This is combined with the company’s knee implants, which feature advanced 3D printing technology and the latest generation polyethylene insert that incorporates vitamin E, a powerful antioxidant.

“The Newton Knee procedure gives surgeons access to personalized, ligament-driven planning for TKA in Exactech’s portable GPS platform, which is perfectly suited for the surgery center or ASC where space is limited,” said Cipoletti. “Our onboarding specialists expect new customers to be proficient with the system in six to eight procedures, which has contributed to the >60% adoption rate among our Knee GPS users.”

THINK Surgical

Fremont, Calif.-based THINK Surgical introduced a revolutionary idea for knee replacement. Instead of pairing a specific robotic assistance technology with a knee implant, the company’s solution is implant-agnostic so surgeons can have their choice of implant.

“Dominant market forces in the knee implant market include the ability to provide a combination of a desired robotic solution, in addition to having a robust implant portfolio offering choices in metal sensitive coatings, alternative alignment techniques, implant-specific designs/instrumentation to support those alignments and cemented or cementless fixation options,” said Nick Margree, chief growth officer at THINK Surgical.

The company’s Implant Data Hub (ID-HUB) is a proprietary data bank of partner implants designed to open access and choice for surgeons. Using ID-HUB, surgeons can readily connect their implant choice to a single robotic operating system.

“This model allows facilities that use a variety of different implant systems, as most hospitals do, to only have to adopt a single technology to achieve a successful robotic TKA program,” said Margree. “Surgeons can now select an implant from our ID-HUB Implant Databank to optimize treatment based on their patient’s unique needs, rather than being stuck with a single implant option as they are with existing robots. ID-HUB enables the most implant systems and design philosophies of any orthopedic robotic system currently available in the U.S. We believe in empowering surgeon choice.”

“We are a robotics company, not an implant company,” Margree went on. “We work with our implant partners to empower choice of implant designs to patients, surgeons, and administrators.”

The company’s TMINI miniature robotic system has earned FDA clearance for use with a variety of knee implants. In September 2024, it was cleared for use with Zimmer Biomet’s Persona knee system, making it the only company at present with a robotic system that has both an implant-exclusive option with the Persona knee and an open platform for implants from multiple other manufacturers for total knee replacement. 

November 2024 was quite the prolific month for the ID-HUB. Waldemar Link’s LinkSymphoKnee, Maxx Orthopedics’ Freedom total knee, Freedom Titan knee, and Freedom primary PCK systems, and b-ONE Ortho’s MOBIO knee all entered the databank within a week of each other. There are currently nine FDA-cleared implant partners from which to choose.

“With our library of compatible implants, we’ve unlocked the implant from the robot compared to the standard single-implant line, single-implant business models of other technologies on the market,” said Margree. “This allows surgeons, hospitals, and ASCs to choose an implant design philosophy based on each patient’s needs and their care setting.”

The TMINI surgical robot originally obtained FDA clearance in 2023 with a single implant partner. In January 2025, the company reported that it’s been used in over 500 TKA procedures in the U.S.

In July 2024, the company snagged FDA clearance for TMINI 1.1 system software, with new features to help surgeon choice in TKA. The new TMINI PRO allows positional refinement and optimization of the implant tailored to patient needs. Dynamic data capture and real-time feedback allow positional adjustments to be made to fine-tune implant positioning and stability.

The company said TMINI PRO is intuitive and customizable to surgeon preferences and implant philosophy choices. Adjustments to the surgical plan are transmitted wirelessly to the TMINI robot.

“In the TMINI system limited market release, the proficiency curve for TMINI was shown to be less than five cases¹¹ and by case, seven surgeons typically reach benchmark case skin-to-skin times,¹¹” said Margree. “TMINI was reported easy to learn by staff¹¹ who were able to perform 75% of cases independently after the 12th case¹¹ and had an average TMINI System set up time of six minutes.^11,12”

“This workflow efficiency combined with the sub-millimeter and sub-degree accuracy and precision of placing a cut guide compared to the planned placement¹³ demonstrates that a miniature, handheld robot like TMINI can reduce the size of technology in the OR without compromising on accuracy and precision,” Margree went on.

Supplier Spotlight

Mason, Mich.-based Orchid Orthopedic Solutions is one of the largest manufacturing partners to the orthopedic device industry. The company claims to touch 30% of the world’s knee implants.

Orchid offers a portfolio of knee manufacturing solutions, including instruments and implants for both total and partial knee replacement. As such, to gain further insights on the market, ODT spoke to Scott Reese, vice president of business development at Orchid Orthopedic Solutions.

Sam Brusco: From your perspective, what are the dominant market forces in the knee implant industry at present?

Scott Reese: There are five forces shaping the knee implant industry: patient expectations, the shift to ASCs, robotics, cementless options, and alternative materials to cobalt chrome.

The patient demographic for knee replacements is changing. The typical knee replacement recipient is no longer the advanced-age, low-demand patient. Today’s patients are younger, more active, and better informed compared to 10 years ago. Due to this, they seek out options that result in a better procedure experience, minimize surgical complications, and deliver a longer-lasting prosthesis to maintain active lifestyles. 

More and more knee replacement procedures are moving to the ASC environment, which drives the need for cost effective, innovative options.

OEMs no longer just sell total knee constructs—they sell complete knee platforms, and integrating robotics has become a driver of this strategy. Robotic platforms like Stryker’s Mako, J&J’s Velys, and Zimmer Biomet’s Rosa shape how surgeons approach knee replacements. It’s not just about the implant anymore; it’s about the technology ecosystem surrounding it.

ASCs and robotics are also driving adoption rates of cementless knee implants. While cementless is the standard for primary hip implants, only about 20% of primary knee replacements are cementless, and the adoption rate is growing rapidly—some OEMs predict cementless options could represent 50% of their knee implant sales within a few years. To compete in the market, having a cementless knee option is becoming more of a necessity for OEMs.

We see a strong push toward alternatives to cobalt chrome for patients with metal sensitivities. Titanium is more bio-compatible than CoCr and is emerging as the primary solution, but it introduces its own challenges, like the need for improved bearing surfaces. Legacy technologies like titanium nitride coatings and other surface-hardening innovations address these issues while companies are searching for new and more promising solutions to extend wear-properties and implant life.

We have developed a solution to the bearing surface challenges of titanium knee implants. Our ALTITUDE ceramic coating provides a thick, wear-resistant surface that outperforms anything on the market. 

Brusco: How has the shift toward cementless implants impacted your business?

Reese: The industry’s move toward cementless implants aligns with our expertise in bone in-growth surfaces, including sintered coatings and thick titanium plasma spray (TPS). Each OEM has unique product designs, which drive the choice of manufacturing methods and specifications.

What’s particularly exciting is how additive manufacturing (3D printing) simplifies the conventional manufacturing process. Traditional methods require more steps: forming (usually through casting), applying a bone in-growth coating, then finishing. With 3D printing, the forming and bone in-growth surface creation are combined into a single step, streamlining the supply chain and lowering costs for OEMs.

OEMs look to us to help reduce costs in their supply chain while they add new products to their portfolios. If 3D printing is supported through a robust and well-planned infrastructure, it’s a great option to reduce costs.
 
While some companies have used 3D printing to produce smaller volumes or patient-matched implants, we’ve built our platform to produce tibial baseplates and femoral components efficiently and at industrial scales, including machining and finishing operations. This allows us to meet the growing demand for cementless implants in a cost-effective and scalable way.

Using 3D printing, we can mimic the surface properties of market-leading bone in-growth designs—such as pore size, porosity, and strut size—to achieve structures that are clinically proven to be effective. 

Cementless titanium knee implants are the way of the future, and we believe 3D printing is the most economical and scalable way of delivering the next generation of knee implants.

Brusco: What manufacturing methods and strategies do you employ to enhance osseointegration properties?

Reese: Traditionally, we’ve offered sintered coatings—both spherical and asymmetrical—because they provide excellent bone in-growth properties. We also provide thick titanium plasma spray (TPS) coatings for our customers interested in on-growth properties. The cementless surfaces we’ve developed have evolved based on years of clinical success and have been adopted by many OEMs.

We’ve leveraged 3D printing to develop customizable lattice structures with exceptional porosity and strength. These mimic market-leading bone in-growth surfaces and let us collaborate closely with OEMs to tailor the design and material properties to their needs. It’s a blend of innovation and collaboration.

References

¹ bit.ly/odtknees01251
² bit.ly/odtknees01252
³ bit.ly/odtknees01253
⁴ bit.ly/odtknees01254
⁵ bit.ly/odtknees01255
⁶ bit.ly/odtknees01256
⁷ Internal Data on File: Sales Data November 2024
⁸ Improved Abrasion Resistance of Nitrogen-Hardened Titanium Alloy Surfaces. Current Topics in Orthopaedic Technology. Zimmer. Vol. 3, No. 6 (1991).
⁹ Zimmer ZRR_WA_2537_12
¹⁰ bit.ly/odtknees01257
¹¹ Data on File, TS-24-058 TMINI Limited Market Release Observational Study
¹² Data is based on average set-up time achieved by case 25 (excluding TMINI Miniature Robotic System warm up time)
¹³ Data on File, TS-24-017 TMINI Cut Block Placement Accuracy