August 14, 2018
Cementing Best Practices in Total Knee Arthroplasty – VuMedi Webinar – July 30, 2018, presented by DePuy Synthes
Presenters:
Dr. J Bohannon Mason (OrthoCarolina)
“Recent publications and findings on TKA Cementing techniques”
Dr. Douglas A. Dennis (Colorado Joint Replacement)
“Critical Steps of the TKA Cementing Process”
Professor David Barrett (University of Southampton, UK)
“Importance of Cementing on TKA Fixation, Evolution of TKA Bone Cementing Techniques”
Introduction
This VuMedi webinar was of particular interest to us because of its relevance to CarboJet® use in cemented TKA. As you know, very early loosening of tibial components can occur on occasion. This type of loosening has recently been associated with the DePuy Attune knee to a much greater extent [1]. DePuy has been very active in trying to counter the perception that the Attune knee has a problem with early loosening, and has come to blame “lipid intrusion” and “lipid contamination” as the main culprits. With DePuy’s marketing muscle, these efforts have really highlighted the issue of lipid contamination of the cement bonds in a way that plays into our hands as we market and sell CarboJet! This increased awareness of “lipid problems” in general also gets surgeons thinking about the possible effects of lipid contamination at the bone/bone cement interface, which can reduce the long-term survivorship of knees. More than 800 people signed up and watched this particular VuMedi presentation!
Notes on Each Presentation and Key Take-Aways
Dr. J Bohannon Mason, Talk and Slides: Recent publications and findings on TKA Cementing techniques
Dr. Mason discussed his cadaveric data and showed that lipid intrusion through the bone cement during impaction contaminated the bottom of tibial trays, causing them to lose significant bond strength. He used 9 commercially available TKA designs and tested them all in both “motion” and “no motion” surgical techniques. The no motion group was cemented and the limb was left in extension for 7 minutes while the cement cured, whereas in the motion group the knee was “tested” for ligament balance immediately after the cementation. All samples were tested for pullout strength and the amount of lipid contamination of the tibial base underside was quantified. And guess what? 100% of all the knee samples, both the motion and no motion groups, showed lipid contamination on the undersurface of the tibial component! The no motion group fared better in terms of both pullout strength and contamination, but these implants still had 55% of their tibial tray undersurface contaminated with lipids! Wow! Dr. Mason showed video of the test implantations and noted lipids flowing out of the cutting guide pin holes in the anterior tibia and adjacent to the finger-packed cement while the tibial component was being impacted. He also showed video of implanted mock tibial trays made of clear acrylic material in which fat globules could clearly be seen rolling around between the cement and the underside of the tray when digital pressure was used to slightly rock the tray. No mention of CarboJet was made by Dr. Mason during his talk and he did not cite any of the publications on CarboJet’s impact on removal of marrow elements from the bone bed.
Key Take-Aways
- If there ever was a presentation that screamed “use CarboJet to get some of those lipids out of the bone bed before cementing into it”, this was it. Mason only recently tried CarboJet and seemed duly impressed, but unfortunately he probably felt that it was too soon for him to talk about CarboJet in a public forum, and perhaps he felt it was inappropriate given that this was DePuy sponsored event.
- Lipids intrusion is a very real issue that surgeons are becoming more aware of and should be looking for solutions to address. Our messaging on CarboJet will be resonating more, with more surgeons than ever, going forward.
- Right now is a fantastic time to approach knee surgeons (particularly DePuy knee users) about CarboJet.
Dr. Douglas A. Dennis, Talk and Slides: Critical Steps of the TKA Cementing Process
Dr. Dennis’ talk was primarily a review of the traditional steps involved in achieving a good cement technique. He talked about things like the importance of pulsatile saline lavage use to clean lipids/fatty marrow elements from the cancellous bone bed and careful drying with sponges. In discussing these concepts, he went so far as to cite the “Wolf suction” technique in which suction catheters are attached to the anterior tibia to suction out lipids/marrow elements from the proximal tibia and improve cement penetration. He noted that 3 to 4 millimeters of cement intrusion is thought to be ideal but commented that 5 mm of intrusion was too much and could cause thermal necrosis.
He talked about the importance of finger packing the cement into the bone bed prior to introduction of the implant. More than once, he used the term “lipid volcano” to describe the fountain of lipids/marrow elements that are routinely seen emanating from various places around and through the bone cement while inserting the tibial component.
Dr. Dennis also noted that loosening of cemented TKA femoral components is thought to initiate from the cement interface at the posterior condylar cuts, since this interface is loaded in shear. He noted that this area is harder to get at to clean.
Key Take-Aways
- Given the nature of his presentation and it’s fairly exhaustive review of the literature related to cementing technique, along with his repeated discussion of the cancellous bone as a source for unwanted lipid intrusion and his repeated advisement to carefully clean and dry the cancellous bone as thoroughly as possible, the fact that he did not mention CarboJet and CarboJet related publications was striking. Thankfully, one of the webinar attendees did finally ask about CarboJet! Here is an excerpt from the live chat session between attendees and presenters that occurred during Dr. Dennis’ talk:
- We think most people were following these chat conversations as they were very active and prominently displayed during the webinar, so most of the 800+ viewers probably read these comments on CarboJet. It should be noted that Dr. Mason had only first trialed CarboJet a couple days prior to the webinar and may not yet have had a chance to review the publications and data on the system we had provided him.
- Dennis’ comment about the posterior condyles as an initiation point of femoral component loosening gives you a great talking point when detailing CarboJet to potential surgeon users: CarboJet is particularly effective at reaching and cleaning the posterior femoral cuts when using the 40° Angled Tip nozzle. This nozzle can be easily rotated in the handpiece to aim it at these posterior cuts for thorough cleaning in this area (see McGee Vignette, linked here).
Professor David Barrett, Talk and Slides:
“Importance of Cementing on TKA Fixation, Evolution of TKA Bone Cementing Techniques”
Prof. Barrett’s talk was a summary of the information provided in the first two talks and it again emphasized the need for careful cleaning of the lipids from the cancellous bone bed before application of cement.
To sum it all up, this VuMedi webinar, with its emphasis on lipid intrusion, should significantly increase the number of surgeons who are receptive to the value that CarboJet technology offers. With more than 800 surgeons viewing the webinar, now is the time to quickly get out there and approach all knee surgeons in your territory. The audience for this webinar was probably weighted towards DePuy knee users, so it makes particular sense to target DePuy users and also to talk to your local DePuy sales reps about collaborating with CarboJet. These reps are actively looking for better bone preparation solutions for their customers.
Finally, adding fuel to the fire of CarboJet opportunity is the increasing move to tourniquetless TKA. There never has been a better time to go out and grow your CarboJet sales! Once established, each new account you add to your portfolio provides you with an additional steady stream of recurring income, without the need to attend cases or schlep heavy trays of instruments!
Please contact me (rbruce@kinamed.com) if you have questions or want to discuss how to make the most of this opportunity.
Bob Bruce, VP, Global Marketing and Product Strategy
[1] Bonutti et al (2017) Unusually High Rate of Early Failure of Tibial Component in ATTUNE Total Knee Arthroplasty System at Implant–Cement Interface. J Knee Surg 30:435–439.
Click here to view the archived VuMedi webinar (note: the archive version was edited and condensed, so some of the content mentioned above, including the CarboJet commentary, is not shown)