Zimmer Launches New Knee System at AAOS

The whispers began well before any formal announcement was made. Something big was brewing at Zimmer Holdings Inc., the newsmongers said, and the company seemed truly excited about it.

The rumors appeared oddly accurate, judging by the grandiose booth Zimmer rented at the American Academy of Orthopaedic Surgeons (AAOS) annual meeting March 19-23 in Chicago, Ill., (the exhibit was outfitted with blue strobe lights, a movie theater-sized screen, plush carpeting and sleek counters for product displays) and a hard-to-spot door that opened only to invited guests (the door itself was partially concealed behind a larger-than-life model of a knee joint).

Then suddenly on March 20, the rumor became a reality. Something big was indeed brewing at Zimmer and that something big was called the Persona, a knee system that company executives called the “most comprehensive, anatomically accurate and highest fidelity” replacement product ever designed.

“Zimmer scientists and engineers and their designing surgeon partners pushed the boundaries of implant design, drawing upon advanced morphology, physiology, kinesiology and material sciences to develop a truly revolutionary system that allows surgeons to provide each patient with a personalized fit,” said Jeff McCaulley, president of Zimmer’s Global Reconstructive unit. “It’s the most anatomically accurate system ever seen and it’s the biggest launch the industry has ever seen.”

It certainly was one of the biggest launches at this year’s AAOS meeting, far surpassing the near non-existent publicity surrounding Smith & Nephew’s Journey II Bi-Cruciate Stabilized knee replacement, DJO Surgical’s Movation total knee replacement and the more understated (but nevertheless showy) debut of DePuy Orthopaedics Inc.’s Attune Knee System. Zimmer’s launch of the Persona Knee system included an informal press junket at the company’s booth, where in a similar fashion to DePuy, executives provided a guided tour through a multi-station display of the components that comprise the new knee. The invitation-only tour began with a 15-minute video that detailed the motivation for the Persona (to create a knee with “no compromises) and the efforts undertaken to create it.

The Persona system combines personalized implants with intelligent instruments to provide surgeons with better intraoperative precision to customize the best fit for patients. Among the technologies incorporated into the design of the new knee (on display in a hidden back room of Zimmer’s conference-floor booth) were:
• A Bone Resection Atlas, which allowed surgeon designers and engineers to study the morphology of hundreds of bones, representing a diverse global population, to precisely define anatomically accurate implant shapes and sizes.
• The company’s Virtual Biomechanical Knee, a kinematic computational analysis program that allowed rapid testing of hundreds of different design options to virtually assess their impact on soft tissues, motion and overall performance to optimize designs that more closely replicate natural feel and normal function.
• Zimmer’s Robotic Simulator, a six-axis, high-precision robot that replicated the kinematic patterns and biomechanical forces for various daily activities. The simulator was used to validate the design’s fidelity, precision and robustness.

The Persona knee contains trabecular metal and was infused with vitamin E for increased strength, ultra-low wear and oxidative stability for long-term performance. The company also introduced a range of patient-specific instruments with the new system, including the iAssist Knee, the Personalized Guidance System (a surgical guidance technology that provides simple, intuitive and accurate intraoperative feedback and alignment verification at the surgical site without the need for bulky capital equipment) and the eLibra Dynamic Knee Balancing System, which enables precise rotation of the femoral components to facilitate efficient and reliable soft tissue balancing (a top concern among joint replacement specialists). “Our whole focus was how do we eliminate the 25 percent of patients who are not satisfied with their knee replacement surgeries?” McCaulley noted. “That was the lens we took to every component, every instrument associated with the Persona knee.”

In addition to the instruments, Zimmer also designed modular trays for the Persona system that enable surgeons to select only the instruments and sizes needed to successfully complete the surgery. The tray design minimizes the total number of trays for each case; when used in conjunction with intelligent instruments, Persona procedures can be performed using only two to three trays, executives said.

“We designed the Persona system to meet the demands of today’s patients and provide surgical precision for surgeons, all in the context of concerns about the total cost of care,” McCaulley said. “The Persona system was designed to help hospitals deliver high quality, consistent outcomes while reducing total costs.”