Quieter, ACL/PCL Preserving, More Natural Knee! (Orthopedics This Week)
A team of joint preservation superstars have dusted off a concept that was waiting in the wings…and given it wings. Adolph V. Lombardi, Jr., M.D., F.A.C.S. is president of Joint Implant Surgeons, Inc. in New Albany, Ohio. Dr. Lombardi tells OTW, “Along with my colleagues—Keith Berend, Craig Della Valle, Jeff DeClaire, Chris Peters, Professor Thomas Andriacchi, and Jorge Galante—I have developed a new design of a knee that preserves the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL). With roughly 120 surgeons across the globe implanting them, the preliminary comments from patients are that the knee feels more normal than a standard knee. For the surgeon, it feels more stable during the procedure.”
“While the concept of an ACL/PCL preserving knee is not new, it didn’t gain traction because the instrumentation was archaic. The design involved putting in the femur and tibia and doing distraction in flexion and extension…it was cumbersome. The new instrumentation that we have developed is very streamlined; the most challenging part is cutting the tibia and preserving the central island of bone. We have also developed a new way of doing the procedure. The femoral and patella preparation is straightforward; on the tibial side we’ve been through a couple of iterations in making the jig, how to do the cutting, how to set the rotation of the island and how to set the depth of resection. All of these are critical…and we can finally say that this process is user friendly.”
“We have made a point to release this product slowly so as to ensure that surgeons grasp each aspect of the process…and so that we can catch any issues early on. The big difference is that this knee gives the patient added proprioception and enhanced stability. The knee does well on the Lachman’s Test and the Anterior/Posterior Drawer Test; patients report that there is less noise than a standard knee and that it has a better range of motion and good stability.”
“We are requiring that surgeons do cadaver training because we want to ensure that they are totally comfortable with the technique. We learned that we must be meticulous about the cementing technique because when you do a standard knee you can displace the tibia all the way forward and you have to pressurize the cement. When you keep the ACL you can only displace it partially forward.”
“Looking ahead to the next six months or so, with the purchase of Biomet by Zimmer I predict that we will see an explosion of this technology because they will probably try to adopt it to their Persona line as well. I see this technology as a new element in the continuum of constraint in total knee arthroplasty (TKA). You start with a patient who has one or two compartment disease and do a partial replacement…and depending on the enthusiasm for partial knee arthroplasty, this could represent 15-20% of someone’s practice. The next element we’d like to look at are knee replacements for those patients who are active and have intact ACLs, but who have more disease in the lateral compartment. In these cases you can’t do a uni so this new knee would be a good fit. The utilization of the knee will depend on the surgeon’s ‘appetite’ for doing partial knee replacement.”