Medical Device Daily National Editor

The talk of late about "Gender knees" and the like being all the rage in the orthopedics industry is a little confusing to ConforMIS (Burlington, Massachusetts). That company is all over the "personalized fit" question when it comes to reconstructive implants.

The company's latest patient-specific implant, the iUni, is designed for patients whose arthritic damage is isolated to either the medial or lateral compartments of the knee, with little to no damage present in the other compartments. The use of such a unicompartmental implant often is referred to as "partial knee replacement."

The implant is available for either the medial or lateral compartments and is 510(k) cleared for marketing by the FDA and CE-marked for sale in Europe.

The new implant and its corresponding iJig disposable instrumentation were highlighted by the company at last month's American Academy of Orthopaedic Surgeons (AAOS; Rosemont, Illinois) annual meeting in San Francisco.

Speaking with Medical Device Daily at AAOS, CEO/chairman Philipp Lang, MD, hailed the bone-conserving nature of his company's products. "Our unicompartmental device is so bone-conserving," he said, adding that ConforMIS has "had this vision from the start."

The privately held company was started in 2004.

Rather than coming in a finite number of sizes that, despite clinician efforts to come up with the best possible fit, still are far from sized to fit, ConforMIS's implants are just that. They are patient-specific, with sizing done from measurements obtained in a preliminary CT scan.

Each iUni is designed from an individual patient's CT scan, using the company's iFit technology and made specifically for that patient.

In the early phase, it is taking up to six weeks between the time of the scan and getting the completed implant back into the surgeon's hands, but the company expects that turnaround time to dip into the three- to four-week range as the process evolves.

The company said the patient-specific iUni "allows for true resurfacing of the femur and complete coverage of the weight-bearing surfaces for each patient, a result not previously achievable with off-the-shelf implants."

With conventional implants, orthopedic surgeons generally must do a fair amount of what we'll term "manipulating" the bones at the implant site. The result is an implant shaped and sized specifically to that patient.

Lang said that conserving bone through the computer-generated model "means no revision problems." Complete cortical rim coverage on the tibia, for example, is expected to reduce the risk of implant subsidence and loosening, key failure mechanisms for standard unicompartmental replacements.

He added that the company's "image-to-implant technology" offers physicians a bone-preserving option for early intervention, "combined with a simplified and reproducible surgical technique."

Early intervention patients especially younger patients in the 45-to-60 age range are the "sweet spot" of the market for ConforMIS.

Lang cited a study headed by Wolfgang Fitz, MD, of Brigham & Women's Hospital and Harvard Medical School (both Boston), which showed that being able to utilize imaging data to develop patient-specific knee implants "provides a significant advantage over existing traditional knee-replacement techniques."

Fitz, who was part of the surgeon design team for the iUni, said, "the ... new and unique implant designs and improved surgical techniques" offered with the iUni package "should expand both the patients and surgeons who can successfully utilize a partial knee resurfacing product."

Jong Lee, senior VP, marketing for ConforMIS, told MDD the technology is built around the data gathered in the CT scan. "We harvest the data [and] use it to make patient-specific implants," he said.

Asked about response from AAOS members on the exhibit floor to the just-introduced iUni, Lee said, "We're getting fast uptake in terms of surgeon interest."

He added that clinicians see the product as offering an opportunity for early intervention in the osteoarthritic knee before reaching the point of total knee replacement. "Early intervention is a problem they don't really have an answer for at present."

Lee said the positive response from surgeons "was pretty broad-based," but noted in particular that "we've had surprisingly fast uptake from private-practice surgeons."

He told MDD he isn't truly surprised by the response. After all, said Lee, "The value proposition for patients is quite big."

And for the physician and hospital as well. For instance, the iJig cutting and placement guides eliminate manual sizing during surgery and provide tactile guidance to "precisely" place the instruments, ConforMIS said, simplifying the surgical technique.

The disposable iJigs replace multiple trays of traditional instrumentation and save the hospital hundreds of dollars in instrument handling, storage and sterilization costs, the company said.