Smith & Nephew Releases New Journey Knee Implant

Knees, knees and more knees. Among the predominant themes to emerge from this year’s installment of the American Academy of Orthopaedic Surgeons (AAOS) annual meeting (held March 19-23) in Chicago, Ill., was the rollout of several new total knee replacement implants.

Smith & Nephew’s offering is the Journey II Bi-Cruciate Stabilized (BCS) knee—the second generation of the Journey knee product. Other companies to introduce knees to the market were Zimmer and the DePuy/Synthes division of Johnson & Johnson.

“The Journey II BCS knee takes knee performance beyond the current standards for fit and alignment and gives patients the complex motion, strength and stability of a human knee,” said Gaurav Agarwal, president of Smith & Nephew’s joint reconstruction business. “You don’t have to ask patients if it feels like a normal knee—you can see it in their gait and in their post-op[eration] X-rays. We redefined knee implant function when we launched the original Journey knee in 2005, and with Journey II we have again outpaced traditional knee replacement technology.”

According to officials from Smith & Nephew, this most recent Journey knee is more than an iterative change to an existing product. It is, they claim, the result of “intense research and design,” and the development of what the company calls “Physiological Matching” technology. Using its LifeMOD human simulation software, Smith & Nephew engineers were able to conduct proprietary analysis of the bone, ligament and muscle forces that impact the knee, and then account for those forces within the design of an implant that restores anatomic shapes and normal motion.

“Unlike implants that create unnatural motion with a symmetric, circular design, or with a rotating platform, the Journey II BCS knee accommodates the swing-and-rotate of the knee with the same engineering principles the body naturally uses,” explained Steven Haas, M.D., chief of the Knee Service at Hospital for Special Surgery in New York, N.Y. “As a result, the muscles and ligaments around the new joint don’t have to work harder because the implant’s natural shape and resulting motion allow these soft tissues to move in familiar ways. This leads to higher patient satisfaction scores, more mechanical efficiency of the muscle, and a more natural feeling while walking or bending in the months after their procedure.”

The Journey II is made from Smith & Nephew’s Verilast material, which is the combination of two wear-reducing materials—the firm’s proprietary Oxinium alloy and a highly cross-linked plastic liner. Smith & Nephew claims that Verilast “significantly” reduces implant wear compared to traditional bearing couples on the market. According to the company, Oxinium is 4,900 times more abrasion resistant than cobalt chrome and reduces knee replacement wear on traditional liners by up to 85 percent compared to cobalt chrome components.

And every little bit helps for getting knee replacement patients back to normal activity, particularly for younger patients. According to one study presented during the AAOS meeting, total knee patients are back to work quickly following their procedures.

Adolf V. Lombardi Jr., M.D., from Joint Implant Surgeons Inc. in New Albany, Ohio, and colleagues conducted a multi-center study involving patients of working age (18 to 60 years old) who underwent total knee arthroplasty (TKA). The study results, presented during the meeting, followed patients one to three years from their procedure to examine the return to work. Complete data was collected for 661 patients (average age, 54.2 years) by an independent third-party survey center.

The researchers found that 74.6 percent of participants were employed in the three months before TKA. After surgery, 91.1 percent returned to work, 93.3 percent of whom returned to the same job. Based on the labor category of the patients jobs, return to work was 92.3 percent for sedentary jobs, 79.2 percent for light jobs, 89 percent for medium jobs, 87.8 percent for heavy jobs, and 78.2 percent for very heavy jobs. Compared with females, males were significantly more likely to return to work (82.3 versus 73.7 percent).

“In this group of young, active patients, most returned to work at their usual occupation,” study authors wrote. “While those with sedentary occupations had the highest return to work rate, even those with very heavy jobs returned to work almost 80 percent of the time.”

Smith & Nephew is headquartered in London, the United Kingdom. The company’s U.S. base is in Memphis, Tenn.