ConforMIS Improves its TKR Offering

It’s been a long time coming.

After 16 months of talks, tests, tweaks and touts, ConforMIS Inc. has commercially released an enhanced version of its patient-specific total knee replacement (TKR) system. Dubbed the iTotal G2, the new edition incorporates improvements to the implants, instruments and planning guides based on more than a year’s worth of recommendations from orthopedic surgeons.

The 8-year-old Burlington, Mass., firm updated the iTotal’s implant design to address a wider range of anatomies and revised the iView planning images to give surgeons more detailed data. The iView images—included with each implant—provide patient-specific tibial and femoral osteophyte information, the tibial slope cut, posterior femoral resection value, and final implant positioning.

The iTotal (the “i” stands for individualized) uses proprietary software that incorporates data from computed tomography scans to generate a 3-D model of a patient’s knee. That model then is used to design and manufacture an implant that closely matches a patient’s natural joint anatomy and curves, allowing for more natural knee motion and flexibility. ConforMIS uses computer-driven machining or prototyping tools to fabricate the artifi-cial joint, a process that takes four to six weeks, as well as customized surgical tools (called “iJig”) to accurately place the implant.

Designed as an alternative to traditional TKRs that come in limited sizes and shapes, ConforMIS’ customized approach precisely matches each implant to the shape and curvature of the individual joint. As a result, the iTotal system allows doctors to avoid many of the sizing and fit issues that can compromise surgical results.

“Other knee implants give you an engineered solution and the shape they use is the same for every patient,” noted Jong Lee, senior vice president of marketing and business strategy at ConforMIS. “Studies show that a lot of patients don’t feel like their knee is their own. A lot patients with a traditional knee replacement end up feeling like they have a knee that does not feel natural, which impacts their satisfaction with the surgery.”

Though it was cleared by the U.S. Food and Drug Administration in January 2011, ConforMIS did not immediately release the iTotal system to the market. Instead, the company distributed the implant system in May (2011) to a limited surgeon population for feedback, a practice that is common among device developers. Executives had hoped to officially debut the system sooner, but the volume of valuable advice prompted them to make “comprehensive enhancements” to the iTotal before its commercial launch.

“We received a lot of high quality feedback during our limited release,” Lee told Orthopedic Design & Technology. “The G2 system incorporates a comprehensive set of changes that provide surgeons with a more simplified technique and more options to accommodate surgeon preferences on technique approaches. We were able to incorporate this feedback into a second generation system in just over a year, something that is hard to imagine with an off-the-shelf, inventory based business model.”

To achieve such top-notch quality the second time around, ConforMIS engineers heeded physicians’ suggestions to simplify the surgical technique, which in many cases, required modifying instruments. For example, the original tibial jig (used on the bottom part of the knee) came in three separate pieces and required assembly before using; with the iTotal G2, that tibial jig is now one piece. Slight modifications also were made to the implant itself—Lee said engineers added a metal bar to the new system’s tibial component.

ConforMIS executives believe the iTotal G2 addresses the dissatisfaction experienced by many TKR recipients. The source of this discontent is varied, ranging from implant over-hang, component replacement errors, and mismatched anatomical shapes, according to industry studies.

“For the patient population that requires a total knee replacement, the physician’s ultimate goal is to give patients a long-lasting, more natural-feeling knee,” said Gregory Martin, M.D., medical director of the Orthopedic Institute at JFK Medical Center in Atlantis, Fla., who helped design the iTotal G2. “With the ConforMIS iTotal Knee System, I’m seeing in my early patient data that I’m resecting less bone, measuring less blood loss and that patients are having a quicker return to activities they enjoy. The patient response is noticeably different than what I’m used to seeing in my standard total knee patients.”