It was a simple wish, really, rooted in despair.

Wesley Corbin wasn’t asking for the impossible. He just wanted his old self back—his old body back, actually—the body that permitted him to shoot a bow and arrow for hours, ride a bike for miles, or run amazingly long distances. 

That body. That self.

But wishing for that body—that self—back would be asking the impossible, thanks to Corbin’s ravaged inner chassis. 

Treatment for nearly a half-dozen bouts with cancer in as many years destroyed the teenager’s bone tissue. “Treatment gave me all sorts of other issues. I had a lot of steroids, mostly prednisone,” Corbin recalled in an online video. “What I found out from prednisone is that it can cause avascular necrosis, which cuts out the blood flow in certain parts of the body.”

Without blood flow, bone tissue cannot survive. Hence, bones and joint surfaces collapse, limiting flexibility and turning normal movements into execrable bouts of agony. 

“His joints had no cartilage left, they were just dead, basically. They were just bone rubbing on bone,” Corbin’s mother clarified in the same online video. “His knees and his hips…the ball actually collapsed. So there were just these collapsed joints in there. Any kind of mobility was just excruciating.”

That misery gifted Corbin with a one-way ticket to a sedentary lifestyle, forcing the once active teenager into dependent relationships with different mobility aids—a cane, crutches, and finally, a wheelchair.

Eventually, however, the pain became unbearable, even with the wheelchair for support. 

Corbin knew he had to do something but his options were limited. Advanced cases of avascular necrosis typically are treated either through joint replacement or core decompression (drilling small holes in the affected bone to improve blood flow; this procedure is sometimes combined with injections and bone grafts). 

Corbin chose the former option, trusting it would return his body to its former glory.

“Before he graduated from high school, he was not very mobile at that point,” Corbin’s mother said. “But he [Wesley] was very determined he was going to walk to get his diploma. He was not riding the wheelchair to get his diploma, so that was a huge motivation for him to start replacing joints.”

Indeed it was: Over 12 months, Corbin replaced both hollowed-out shoulders, both knees, and both hips, and recovered in time to walk in his high school graduation ceremony.

“I will never forget the look on his face [with] the first step he took on his new hip. His whole face just lit up and he just smiled,” Corbin’s mother reminisced. “And they were like, ‘how are you doing?’ And he was like, ‘the pain—it doesn’t hurt! Yeah, I feel incision pain but my joint doesn’t hurt anymore.’”

“It’s heartbreaking. There’s nothing more painful as a parent than watching your child in pain because you’d do anything to take it away,” she continued. “To me, having those joints replaced was just the best gift that my child could have ever gotten.”

Corbin received that gift from Zimmer Biomet Holdings Inc., a global medtech behemoth with a rich history in orthopedic implant design and manufacturing. The company’s musculoskeletal solutions aim to preserve soft tissue; restore natural anatomy, motion, and feel; and simplify surgical workflow. Its product portfolio comprises artificial joints, surgical instruments, biologics, restorative therapies, bone cements, sports medicine, CMF (craniomaxillofacial) repair, diagnostics, limb salvage, trauma devices, robotic-assisted surgery, digital technologies, anatomical visualization and guidance systems, and remote care and patient engagement management systems.

Zimmer Biomet’s hip lineup leverages innovations in biological fixation, advanced bearing materials, and infection diagnosis to meet patients’ and surgeons’ various needs. Its HAMMR Automated Hip Impaction System, for example, is designed to address surgeon strain, fatigue, and repetitive motion associated with the traditional mallet. The HAMMR System features three adjustable energy levels to address bone quality variation in both the femur and acetabulum. The ergonomic and balanced impaction device’s consistent and controlled energy helps minimize variability in both bone preparation and device implantation.

“Zimmer Biomet leads the global hip replacement market because we have curated a hip portfolio strategically designed to give surgeons the flexibility and choices to enhance efficiency, accuracy, and customization with the intent to deliver the best outcomes for patients,” said Louis Galrao, president, Hips, at Zimmer Biomet. “We’ve made tremendous advances in hip implant technology, surgical guidance, and assistive technology, which I believe are making THAs [total hip arthroplasties] more effective in terms of recovery time and implant survival.”

One of Zimmer Biomet’s more recent THA advancements is the Z1 Femoral Hip System, a triple-taper femoral solution unveiled last fall. The Z1 System pairs with the company’s modular G7 Acetabular System to provide surgeons with a versatile, streamlined, efficient THA solution.

Tapered in three planes, the Z1 System provides initial axial and rotational stability as well as long-term stability across various femoral anatomies. The system includes collared and collarless options for cementless applications and offers three distinct neck options to manage an array of patient anatomies. Offered with a single streamlined instrument tray, the Z1 System minimizes the instrument footprint and reduces processing and sterilization burden.

The Z1 System’s stem length is optimized to facilitate insertion through muscle-sparing surgical approaches, including the anterior approach, according to a product brochure. The stem length grows consistently by 2 mm increments (measured from the medial resection line) and ranges from 94 mm to 118 mm.

The Z1 Collared Stem is intended to enhance initial stability and transfer stress to the calcar region, thus reducing the possibility for subsidence and periprosthetic fracture. Its design incorporates a consistent length to minimize overhang potential, which could result in iliopsoas impingement, and includes a grit-blasted hydroxyapatite-coated underside that secures contact with the medial cortical calcar, product data indicates.

“Z1 was simple and intuitive to use and offers significant options and more versatility than earlier stems,” Dr. Jonathan Yerasimides of Louisville Hip & Knee Institute, who performed the first Z1 patient cases, said upon the System’s debut. 

Besides its 135-degree neck angle and 6 mm high-offset lateralization across all sizes, the Z1 System features Zimmer Biomet’s proprietary Porous Plasma Spray (PPS) coating to maximize fixation. Introduced 44 years ago, PPS helps maintain an implant’s inherent fatigue strength, according to the company, and has shown better biologic fixation than cobalt-chromium (CoCr), a common orthopedic implant material beloved for its high strength, temperature endurance, and wear resistance.

Implant longevity and toxicological concerns in the last two decades, however, have prompted orthopedic device manufacturers to develop non-CoCr alternatives such as titanium, ceramics, and enhanced polymer composites specifically engineered to mimic natural bone properties and promote better integration.

Zimmer Biomet offers several advanced material options for its hip implant portfolio. Its OsseoTi Porous Metal (alpha-beta titanium) boasts excellent corrosion resistance, clinical data show, while the company’s elemental tantalum (Trabecular Metal) features an open, engineered, interconnected pore structure that supports biological fixation and vascularization.

Zimmer Biomet’s polyethylene picks include Longevity Crosslinked polyethylene and Vivacit-E vitamin E highly crosslinked polyethylene. The former uses high-dose electron beam radiation to crosslink broken molecule chains, eliminating the free radicals that promote oxidation; Vivacit-E, on the other hand, employs vitamin E to stabilize the material and prevent oxidative degradation.

“Our proprietary Porous Plasma Spray coating is designed to support cementless fixation. Our newest hip implant solution, the Z1 Triple Taper Hip Stem System, features the PPS coating to provide initial stability through scratch-fit fixation, and is intended to maximize short- and long-term biologic fixation,” Galrao told ODT. “We’ve also tackled the challenge of conventional polyethylene oxidation, which can lead to eventual implant failure. We made a Highly Crosslinked Polyethylene (HXLPE) with Vivacit-E, a proprietary process that grafts (locks) vitamin E directly to the polyethylene chain and prevents oxidation of polyethylene. Bench testing of Vivacit-E HXLPE, which is used in our G7 Acetabular System, offers exceptional oxidative stability, reduced implant wear, and improved mechanical strength.¹”

Zimmer Biomet’s rivals cite those same clinical benefits in their own highly crosslinked polyethylene creations. Exactech’s XLE Vitamin E Liner is manufactured by blending ultra-high molecular weight polyethylene with vitamin E before consolidation and crosslinking; the process enables the vitamin E to be uniformly distributed and minimizes the elution effect found in diffused vitamin E liners, study data demonstrates.

A patented gamma irradiation and mechanical annealing process tailored to the vitamin E content is used to achieve the liners’ desired crosslink density.

“The advancements in polyethylene, specifically highly crosslinked polyethylene with vitamin E, are paving the way for greater performance and longevity when it comes to bearing solutions,” noted Adam Hayden, chief marketing officer and vice president of Large Joints at Exactech. “Exactech is proud to offer the Alteon XLE Liner which was developed by Massachusetts General Hospital in association with Cambridge Polymer Group, the foremost leaders in polyethylene technology. This material was engineered for improved wear properties, superior oxidation resistance, and optimized mechanical strength.”

Stryker Corp.’s X3 Highly Crosslinked Polyethylene was engineered with the same goals in mind. Introduced 20 years ago, X3’s patented process incorporates a crosslinking and stabilization method that involves three rounds of irradiating and annealing ultra-high molecular weight polyethylene (UHMWP). 

“Stryker is constantly advancing materials to enhance longevity and performance of total hip arthroplasty implants. As an example, our X3 polyethylene, produced using Stryker’s proprietary manufacturing technique, is an innovative sequentially annealed highly cross-linked polyethylene produced without the use of additives,” explained Sean Merrick, vice president and general manager, Hips, at Stryker. “This has allowed Stryker’s X3 polyethylene liners to perform well in the international registries; for example, the UNNJR registry data shows an 0.8% revision rate at 15 years for our thinnest polyethylene liners.²” 

Such positive long-term outcomes also are practicable with oxidized zirconium, a new study concluded. Led by the University of Bristol, the study analyzed National Joint Registry data from 1,026,481 hip replacement patients conducted in England’s and Wales’ public (National Health System) and private sectors for up to 15 years after initial hip replacement procedures (from 2003 to 2019).

The data showed hip implants with a delta ceramic or oxidized zirconium head and highly crosslinked polyethylene liner or cup had the lowest revision risk 15-years after surgery. However, the lower revision rate was limited to only the first two postoperative years when delta ceramic heads were paired with a delta ceramic or non-HXLPE liner, according to the study results.

Although revision risk rises with artificial hips using a cobalt-chrome head and HXLPE liner, it remains the same for implants combining either an oxidized zirconium or ceramic head and an HXLPE liner, researchers deduced. The analysis, they said, shows hip replacement revision risk is directly influenced by the type of material used in the bearing surface.

A new analysis from the Australian Orthopaedic Association’s National Joint Replacement Registry (AOANJRR) supports the Bristol study, released last fall. The AOANJRR’s latest annual report shows Smith+Nephew’s OXINIUM Technology (ceramicized metal on HXLPE) has the highest survivorship rate—94.1%—among all bearing combinations over a 20-year period for total hip arthroplasty.

“Our proprietary OXINIUM (Oxidized Zirconium) is the result of a manufacturing process that transforms the bearing surface, not just a coating,” said Ben Leathwood, global marketing director, Primary Hips, at Smith+Nephew. “This unique composition offers the wear resistance of ceramic, the durability of metal, and corrosion resistance better than ceramic and CoCr. When combined with highly cross-linked polyethylene, OXINIUM Technology has been shown to consistently deliver superior mid- to long-term survivorship and the lowest revision risk compared to all other modern bearing combinations in four arthroplasty registries. This powerful combination plays a pivotal role in extending the life of hip implants and improving patient outcomes.”

Buoyed by OXINIUM Technology’s success in improving patient outcomes, Smith+Nephew developed and launched a “diffusion hardened” version of the material that offers improved wear performance in a versatile, modular dual-mobility construct.

The company’s OR3O Dual Mobility System for primary and revision hip arthroplasty has a small diameter femoral head that locks onto a larger polyethylene insert, increasing its stability and offering a better range of motion compared with traditional solutions. The System incorporates OXINIUM DH in its liner and Smith+Nephew’s VERILAST Technology for the femoral head and polyethylene inserts.

“Smith+Nephew aimed to develop an advanced dual mobility solution that combines insights from the history of dual mobility, clinically successful technologies, and the incorporation of OXINIUM DH technology,” Leathwood stated. “OXINIUM DH underwent extensive testing, including two clinical studies and over 90 pre-clinical tests, resulting in more than 20 peer-reviewed abstracts and journal articles. The outcome is a device engineered for increased stability, featuring design elements with a proven clinical track record and simplifying the surgical process. The OR3O Dual Mobility System capitalizes on the growing popularity of modular dual mobility designs, with expanded market reach enhancing patient access to its benefits worldwide.”

Smith+Nephew’s competitors are capitalizing on the dual mobility design trend as well: DePuy Synthes (a Johnson & Johnson MedTech firm) markets the BI-MENTUM Dual Mobility System for hip revision procedures; which features four shell styles and a moderately cross-linked polyethylene liner that articulates within the shell’s inner surface to create natural movement and optimized range of motion. 

Comparably, Exactech’s Alteon Modular Dual Mobility System comprises CoCr liners and vitamin E-infused UHMWP inserts in seven configurations, with insert inner diameters (femoral head compatibility) of 22 mm or 28 mm, and liners fitting acetabular shells with 46 mm and 68 mm outer diameters. 

The G7 Acetabular System from Zimmer Biomet is also available in various sizes (limited hole: 42 mm to  68 mm, multi-hole: 42 mm to 80 mm; sizes increase in 2 mm increments), while Stryker’s recently-acquired Novae portfolio encompasses a wide range of cups and accessories. 

“We acquired SERF SAS, a France-based joint replacement company recognized by healthcare professionals worldwide for its innovations in hip implants, including the invention of the original Dual Mobility Cup, the Novae monobloc,” Merrick declared. “With this expanded portfolio, we now offer the industry’s first monoblock and modular dual mobility platforms. This acquisition emphasizes Stryker’s commitment to innovation within the hip arthroplasty market.”

That commitment is defined by the company’s investments in 3D printing, robotics, enabling technologies, and artificial intelligence (AI)—some of the main factors influencing hip implant design and innovation. 

3D printing (a.k.a., additive manufacturing) has enhanced hip implant technology by facilitating more precise designs, faster production, and customized implants. In addition, additive manufacturing (AM) can create complex shapes and structures that are not possible with traditional techniques, and it accelerates ideation evaluation via rapid prototyping. 

“Beyond manufacturing, 3D printing plays a crucial role in rapid iterative prototyping, allowing engineers to quickly refine and optimize implant designs before committing to full-scale production,” noted Scott Reese, vice president of Business Development at Orchid Orthopedic Solutions, a Holt, Mich.-based medical device outsourcing provider.

Stryker executes such swift concept analysis with the help of its AMagine Institute, which it touts as a “center of excellence for additive manufacturing.” Located at the firm’s 156,000 -square-foot AM facility in Anngrove (County Cork), Ireland, the Institute develops 3D printing technologies and deploys the solutions across Stryker’s product portfolio. The company’s 3D-printed solutions include the Trident II acetabular shell, which features a controlled network of pores designed to mimic cancellous bone and promote long-term biologic fixation.³ 

Zimmer Biomet and Smith+Nephew have chased the cancellous bone archetype through 3D printing as well—the former with its OsseoTi Porous Metal Technology, and the latter through the REDAPT Revision Acetabular Fully Porous Cup with CONCELOC technology. 

Despite its formidable cancellous bone impersonation talents, the hip implant sector has been slow to adopt 3D printing due to relatively fixed designs, regulatory constraints, and industrial-scale manufacturing limitations. However, the technology is gaining traction with cementless hip models.

“Newer supportless 3D printing technologies are changing the game. These innovations allow large-scale, high-density builds with minimal post-processing, significantly reducing the labor and time required to manufacture implants,” Reese remarked. “This is especially valuable for cementless hip implants, where 3D printing enables the direct fabrication of porous structures for bone in-growth, eliminating the need for secondary coatings or additional processing.”

3D printing creates porous structures by incorporating lattice-like patterns or interconnected “struts” in the implant’s shape; these cobweb-like patterns generate tiny spaces or pores that emulate bone’s natural porous structure, helping foster better bone ingrowth and improve tissue integration. Printing parameters such as layer thickness and infill density can customize pore size and distribution. 

“Porous structures can be created using multiple advanced manufacturing processes, including 3D printing, but also proprietary processes that involve creating a 3D structural lattice of irregularly shaped particles, which results in increased average pore size and greater porosity compared to traditional spherical beads,” Exactech’s Hayden said. “These proprietary porous processes are designed to strike an optimal balance between material strength, pore size, and porosity, providing excellent initial and biological fixation.”

Porous production prowess is just one of 3D printing’s many proficiencies, though. Its pairing with robotics has helped redefine hip surgeries over the last 15 years by creating patient-specific surgical planning tools and instruments that improve procedural outcomes.

Most major hip implant manufacturers use 3D-printed surgical guides to better visualize and plan procedures. These guides are usually included in the suite of enabling technologies offered with robotic-assisted surgeries. 

Enabling technologies embrace practically every solution within the digital healthcare realm, from robotics and telemedicine to artificial intelligence (AI)-enabled data analytics and risk assessment algorithms.

Zimmer Biomet’s enabling technologies suite incorporate AI, robotics, and mixed reality to provide surgical assistance, navigation, and guidance. Its cornerstone ROSA robotic system allows surgeons favoring the direct anterior approach to evaluate and execute a surgical plan based on real-time feedback and the patient’s unique anatomy.

The company’s other enabling technology components include:

• The HAMMR Automated Hip Surgical Impactor System, designed to address surgeon strain, fatigue, and repetitive motion associated with the traditional mallet, according to a product brochure. 
• The HipInsight System, touted as the first U.S. Food and Drug Administration-cleared mixed reality system that leverages the Microsoft HoloLens 2 to provide 3D holograms of patient-specific anatomy, instrumentation, and implants to help surgeons visualize accurate acetabular component placement and alignment in real-time.⁴
• OrthoGrid Hip AI, an AI-powered open platform that delivers intuitive and instantaneous intra-operative guidance to help surgeons achieve optimal outcomes in cup positioning, offset,  and leg length, product data indicates. The tool is a byproduct of Zimmer Biomet’s acquisition of OrthoGrid Systems last summer.

“Like many industries, AI is increasingly playing a critical role in the operating room by seamlessly integrating data into surgical planning and providing real-time guidance during procedures to help surgeons optimize precision and personalize care based on a patient’s specific needs,” Galrao said.

Certainly, AI has quickly become an essential part of orthopedic procedures nowadays. But the technology wears many masks, depending on its end user and intended purpose.

Mako SmartRobotics from Stryker, for instance, combines 3D computed tomography-based planning, AccuStop haptic technology, and insightful data analytics into one platform for optimal outcomes. Mako Total Hip enables surgeons to visualize potential impingement by looking at pelvic tilt changes, and its AccuStop feature allows for single stage reaming and guided cup impaction to help promote accurate implant placement, study data show.

Stryker also has developed an app for surgical plan viewing that is currently in limited market release. “We are excited to extend a surgeon’s Mako SmartRobotics experience in and beyond the operating room through the development of the myMako app, which is used on Apple Vision Pro and iPhone,” Merrick stated. “myMako on Apple Vision Pro allows surgeons to visualize and review patients’ Mako surgical plans anytime, anywhere in a brilliant, immersive visual experience.”

DePuy Synthes, conversely, is leveraging the powers of neural networks to deliver personalized functional hip cup positioning for every patient. Its CUPTIMIZE Advanced Hip-Spine Analysis & Guidance helps reduce edge loading and implant-implant impingement risk by providing clinicians with a target zone for optimal cup orientation.

Smith+Nephew’s approach to component alignment specificity is similar to its fellow implant makers. The company’s RI.HIP NAVIGATION solution helps surgeons take control of individual patient pelvic tilt, leg length, and offset measurement; it also assists with cup placement by giving clinicians a predicted view of the post-op AP X-ray in surgery. Similarly, the RI.HIP MODELER is used before surgery to evaluate cup placement based on a patient’s unique spinopelvic condition.

“Smith+Nephew’s RI.HIP MODELER provides the surgeon with a set of simulation-based motion patterns for activities of daily living, consistent with the spinopelvic condition of the patient,” Leathwood said. “Condition-specific motion of the implant during activities of daily living can therefore be used to identify an optimal cup placement and consequently reduce the risk of impingement.”

“Without a doubt, artificial intelligence has become a key area of focus for all companies across our industry,”  he continued. “…as we operate in an environment that is fast to adopt new technologies, it’s not only the design and material of the implant that can have a profound effect on the longevity of hip implants. Enhanced capabilities in pre-operative planning and improving outcomes through complimentary technologies continues to play a large part.”

A part that is only likely to grow with future advancements.

References

1. Vivacit-E Vitamin E Highly Crosslinked Polyethylene on ZimmerBiomet.com.
2. https://www.grandviewresearch.com/industry-analysis/hip-replacement-implants-market
3. Stryker R&D Technical Memo: Comparison of Tritanium Porous Surface to Cancellous Bone. A0027625
4. Sun D, Murphy W, Lane P, Murphy S. Accuracy of Acetabular Cup Positioning using Patient-Specific Augmented Reality Guidance. 33rd Annual Congress of International Society for Technology in Arthroplasty; 2022 Aug 31-Sept 3; Maui, Hawaii