Moderator Thornhill: Seth, this is great. On behalf of the 16,000 people you’ve trained over the years, and especially for me…I get to ask these 2 experts some things that I really want to know. Thanks!
Fares, you talked about…everybody’s talked about 15-20% of people are not fully satisfied. Do you think by driving the implant to reproduce the kinematics of the normal knee, you will be able to reduce that?
Mr. Haddad: I think that there are a number of factors that contribute to that 15-20% rate. Patient selection. Accuracy factors and surgical factors. And technology. I think the reality is we need to move from a world whereby there was one solution for everybody towards actually understanding everyone’s anatomy; understanding everyone’s gait and their pathology, and choosing the right solution for each patient.
Moderator Thornhill: Do you think that the knee should be driven by the soft tissues that were abnormal or be driven by the prosthesis?
Mr. Haddad: I think, in principle, the knee should be driven by the patient’s native anatomy when they functioned well, when they were younger. We need to unravel that and for many patients that is a ball and socket on the medial side.
Moderator Thornhill: Okay. Chit, Fares said that when he looked at the medial pivot knee compared to one that wasn’t, that there was a higher incidence of forgotten knees with the medial pivot design. What is your comment on that?
Dr. Ranawat: God made the knee with p-substance fibers on the front because most of the activities that we do, hardworking, living, sporting activities, kneeling, require flexion and load bearing on the knee and therefore it’s a protective phenomena that God has created. You can make the knee better, but you will not be able to eliminate anterior pain in about 11%.
Moderator Thornhill: So, Fares, Chit’s saying that none of this stuff that we’re talking about is really it. It’s literally the factors around the soft tissues and the anterior surfaces of the knee. Your comment?
Mr. Haddad: I don’t think so. I think we confuse a lot of anterior knee pain after knee surgery with the anterior knee structures and the patellofemoral joint, but in reality a lot of that pain may be about sagittal stability. If you’ve got good sagittal stability, that may be the difference when you try and load the knee in flexion, particularly in up or down slope, or when you try to kneel or put weight through the knee.
Moderator Thornhill: So Chit, what are your comments about maintaining or preserving sagittal stability?
Dr. Ranawat: I think stability in both planes is important, however, the artificial knee cannot provide range of motion beyond 125 degrees with stability in all planes.
Moderator Thornhill: I think ongoing, clinical studies are important. The difficulty is we really don’t have equipoise. We don’t necessarily have an equal position on one side or the other and there are so many confounding variables, including patient variables. But gentlemen, thank you so much. You did a great job, both of you.
Please visit www.CCJR.com to register for the 2018 CCJR Winter Meeting, – December 12 – 15 in Orlando.
