The current data (Christensen & Peters, CORR 2016) show that there is a higher frequency of reoperation with the new design—300 cruciate retaining versus 80 bi-cruciate. There was not better range of motion, patient-reported outcomes, or physical function.
In the big series that included Dr. Lombardi’s initial experience (Della Valle et al., AAOS 2015)—383 patients—there were some clear problems in the first group of 120 cases, including 9% incidence of bone island fracture.
To summarize in one line—BCR has overpromised and underdelivered to date. I think bi-cruciate is a step too far and yet not far enough. It’s technically demanding enough to cause a substantial learning curve. And further, there is no demonstrable clinical benefit in regard to range of motion, patient-reported outcomes, or physical function.
If you want to do a reliable bi-cruciate, do a uni-compartmental knee replacement. And if you want to do a better total knee replacement in 2017, you’d be better off to pick one of these different technologies (sensor technology for balancing or robotics).
Moderator Sculco: Adolph, tell us why we should go back to using bi-cruciate retaining knees.
Dr. Lombardi: As Mark has outlined, a uni is sometimes a better operation than a total knee and the reason for that is maintenance of the cruciate mechanism which sort of feels a little better. As we look at the literature, we find the ACL present in many of the knees that we do—papers have reported 61%, 78%, up to 82%.
We looked at a series of our patients, 2,317, and found the ACL normal in 53% and present but abnormal in 28%. One of the interesting things is when we looked at our clinical results, the range of motion improvement was better when it was absent than when it was intact.
The Knee Society pain was better when it was absent than when it was intact. The clinical improvement was better when it was absent than when it was present and intact. And the function was better. This was the impetus for relooking at the old types of designs and seeing if we could actually do something a little different.
To-date 5,000 Vanguard XP bi-cruciate-retaining devices have been implanted globally. It has done what we intended it to do. But with mixed results.
One new complication that I haven’t seen with a PS [posterior stabilizing] or CR [cruciate retaining] knee is this cyclops lesion that some people frequently see when they do ACL reconstruction. There have been a couple of cases reported.
But our biggest problem has been some tibial loosening and quite frankly it comes from very poor cementing technique and I have been a victim of that myself.
To date, 5,020 have been implanted; 91 revisions for a 1.8% overall revision rate. And there have been some reoperations to take care of the cyclops lesion, resurface the patella and arthroscopic lysis lesions as well as some others. As far as ACL rupture, only one of those. There has been some arthrofibrosis though, 11 of those, and our biggest has been tibial loosening, 46.
Clinical studies…an RSA/RCT [radiostereometric analysis/random controlled trial] by Professor Anders Troelsen comparing this Vanguard XP to a CR knee—25 in each group—and he does the fixation in two stages. He has had one revision for fracture. Two operations for re-manipulation for a patient who apparently felt his range of motion was unacceptable. Overall, his clinical results are equal to the CR. His outcomes database shows that they’re similar, both the Oxford score and the Forgotten Knee Score…they’re doing as well.
