And my job this morning is to talk to you about the microfracture all, these are my disclosures. So I wrote this article about three years ago, abandoning microfracture has the time come. And why would anyone say this? In actuality, I should have said, abandoning traditional microfracture of the knee has the time come. So I would agree with Dr. Cole, is marrow stimulation a bad operation? Absolutely not. Is it helpful to do marrow stimulation? Absolutely. It clearly forms fibrocartilage over grade four e-bernated bone. It also appears helpful repair augmentation for meniscal and possibly ACL repair to get blood supply to the repair site. But what I would like to propose to you is you have to think of doing marrow stimulation differently and it is probably not the way you were taught to do it in your residency or fellowship or the way it has been traditionally described. Now, why would I say this? Well, it's fiction that traditional microfracture provides good long-term results because the vast majority of articles confirm significant deterioration of results after two years and the only L1 study with 10-year follow-up confirms only 37% of athletes remain improved. And the reasons are subchondral awl penetration destroys the bony architecture and actually fractures the bone and causes subchondral cyst formation and osteophyte formation in both human and animal studies. Microfracture can worsen future cartilage resurfacing outcomes such as ACI and allograft, according to Bugbee. In a meta-analysis of over 44 studies, L1 to L3 all concluded that results were poor after two to five years. And if you even go to the Journal of Bone and Joint Surgery which was published two years ago in this meta-analysis, microfracture had acceptable short-term results but can be expected to decline over time. So there is a fact that if you use drilling or using a power pick to go deeper, it results in better progenitor cells to allow for improved surface cartilage formation. But why is going deeper better? Well, the truth is you need to go greater than six millimeters to broach the calcified cartilage layer because type two collagen fibers are found in the calcified cartilage layer and account for 95% of the collagen content in cartilage. The problem with the awl is it's only about four millimeters in depth. And if you look at the histological evaluation of changes in the osteochondral unit after microfracture, microfracture holes made with an awl undergo enlargement during their early healing phase. These larger diameter holes in subchondral bone lead to too much subchondral bone remodeling causing intra-regional osteophyte formation as noted by Hayashi just six months ago. And if you take this a step further and look at Min's study, when he used a cannulated howl awl when he was doing knee replacements in patients, he found that when he put the awl in greater than six to eight millimeters, he found increased number of mesenchymal stem cells in the blood clot, confirming that if you go deeper, you get better cells. This is from Jason Koh, and what he found was that when you used an awl, you get compaction when you put the awl in. On the other hand, if you do a nanofracture, use a small drill, you get openings to trabeculae to get at the progenitor cells that you need to make better cartilage. So if you use small drills, one millimeter or less, this results in no subchondral cysts in sheep and goats, compared to larger drill holes greater than 1.8 millimeter. The short awl holes in these studies form 23% intra-regional osteophytes, 63% bone cysts, and 26% osteophytes. Now this is a typical response to a traditional microfracture in a goat. Yeah, yeah, ah, yeah, okay. So anyway, this is a 30-year-old male, two years after microfracture, and here you can see the cyst in the femur. And here's another one, one year status post-microfracture, and you can again see the cyst in the femur, which I had to do an osteochondral allograft on. Here we are with 43 patients with a mean 3.5-year follow-up, level four study, graft survival of greater than 90%. Out of 14 patients after microfracture, and this was published in the JVJS in November of 2018, 59% of the microfracture patients in this series that had failed microfractures had significant subchondral changes consistent with cyst and osteophyte formation. So I asked Dr. Brian Cole, as you just heard, a nationally known, highly published expert in cartilage repair, what his technique of microfracture is. So hopefully there's audio with this, please. Oh my goodness gracious. I'm sorry, gang, we went through this this morning, and it worked fine. But what Brian's saying here is he's abandoned the awl, and he uses a drill, and so that is his current technique of, if you will, microfracture. It's interesting that Kai Mithofer, Andreas Grimald, Riley Williams, Tom Minus, and Brian Cole, who collectively have written more articles on microfracture than all other authors combined, have all converted to nanofracture drilling with a small K-wire. Neither technique results in subchondral cyst formation and or intralesional osteophyte formation. And this was written just two months ago by Bert Mettelbaum in the Journal of Arthroscopy, and pointing out the fact that first generation microfracture really should be abandoned. So I think the take home from this lecture is think drilling, in other words, second generation microfracture, and this is Kai Mithofer's comment after a debate in Sorrento, Italy. So you can see I'm using a small K-wire here, and it works very much just like microfracture, except it's a drill with a small K-wire. So this is Jason Cole, throwing away his awl, and I really think that's what you all need to do. There's some proprietary devices that are out now, exclusive to the ones that are already available that will be available in the near future. So if you want to call drilling microfracture, go ahead and call it that. It's the same codable event, and you'll be providing your patient a better long-term result with a more durable cartilage surface. Thank you very much. Thank you.

microfracture surgery

limitations

long-term complications

cartilage formation

second-generation technique