ConforMIS (NSDQ:CFMS) said today a head-to-head study comparing its iTotal PS customized knee implant with the off-the-shelf NexGen PS implant made by Zimmer Biomet (NYSE:ZBH) showed that its device more closely replicated the natural motion of a human knee.
The 31-patient study, presented at the annual meeting of the British Assn. for Surgery of the Knee last month in Southport, U.K., compared the knee kinematics of 13 iTotal patients with 18 NexGen PS patients at least 6 months after implantation, using mobile X-ray imaging and 2D-3D registration. The iTotal arm showed a greater average range of motion, at 112° vs. 94°, and greater lateral femoral rollback (11.73mm vs. 4.69mm), medial translation (2.8mm vs. 1.0mm) and axial rotation (10.85° vs. 7.58°) during deep knee bends.
“All findings from this study suggest that the iTotal PS has the kinematic and functional benefits that have been demonstrated with iTotal CR compared with traditional, off-the-shelf implants,” study investigator Dr. William Kurtz, of Nashville’s St. Thomas Hospital, said in prepared remarks. “Patients want to return to everyday activities after their recovery and, in my experience, maintaining normal knee motion is critical to achieving those goals. I have found that when you alter patients’ normal kinematics, as happens with off-the-shelf implants, there’s a greater risk that the patient won’t be able to return to their regular activities.”
Bedford, Mass.-based ConforMIS said that a pair of other studies, also presented at BASK, showed that the variability in femoral and tibial anatomy can’t be reproduced by off-the-shelf implants.
In 1 review of 24,042 CT data sets used to design customized iTotal implants, 61% of knees showed a distal femoral offset of more than 1mm and 83% showed more than 2mm of posterior condylar offset. A 2nd review of tibial implants showed that only 12% of tibial trays were within 2mm or less of symmetrical and 22% showed asymmetry of more than 5mm.
“In its 1st year of release, iTotal PS has met our expectations in terms of surgeon adoption and patient outcomes,” president & CEO Mark Augusti said in prepared remarks. “Clinical research has demonstrated our implants offer superior clinical outcomes compared with off-the-shelf implants. We are committed to continuing investing in the clinical study of our implants to demonstrate their superior clinical and economic value for patients, surgeons, hospitals, and payers across the healthcare continuum.”
