So we're going to start with Greg Miletus who's going to give us some of his results from his extensive registry experience. Thanks, Greg. Thank you. Hard to follow all of that, but I was fortunate enough to call Freddy a mentor as well. So I'd like to thank my co-authors. We have no disclosures for this talk. Patellar tendon and hamstring autografts have been the dominant grafts for ACL reconstruction for many years, but there's been increasing interest in the use of quadriceps tendons. We can see from the ACL study group over the past 20 years that there's been an increasing number of quadriceps tendons being used. So it's not a new graft. It was popularized by Stobley and Fulkerson back in the 90s, but it's increased a lot in the last 10 years probably because of improved fixation devices and minimally invasive harvesting techniques, and it seems to have good biomechanical properties with possibly less donor site morbidity. But the only large study comparing quadriceps tendons with patellar tendons was the Danish registry study that was published in 2020, and it showed a three times higher risk of revision with quadriceps tendons compared to patellar tendons, which is quite worrisome. They did a follow-up study where they removed the two lowest volume sites and their two lowest volume hospitals, and they recalculated the results, and they showed that it was a little bit more congruent. But I think there is still some concern. So the purpose of this study was to evaluate the risk of revision and reoperation in a large cohort of primary ACL reconstructions based on the autograft used. We also wanted to look at some different age ranges under 22 and over 22 years of age. So the study design, it was a retrospective cohort using the Kaiser Permanente ACL registry. There were about 22,000 patients with 290 different surgeons. We used active surveillance with validated screening tools, and all the outcomes are validated. There were about 1,100 quadriceps tendons, about 9,500 patellar tendons, and a little over 11,000 hamstring tendons. Our outcomes of interest, again, were graft revision and ipsilateral reoperation. We used the multivariable Cox regression models, and the models were adjusted for patient and surgical factors. We looked at hazard ratios, and we'll also look at the number needed to treat. So when we compared quadriceps versus patellar tendon, the four-year incidence of revision was quite similar, 2.7% and 3%. And we looked at the ipsilateral reoperation incidence, also quite similar. And so there were no significant differences between these two graphs. When we compared quadriceps tendon with hamstring tendon, we found the four-year incidence of revision to be 2.7% for quadriceps and 4.5% for hamstrings. Similar reoperation incidence. And although this was not statistically significant, if we were to take a look at the under 22 population and look at the numbers needed to treat, if you were to do 30 ACL reconstructions with a quadriceps tendon, you'd potentially save one revision as if those had been done with a hamstring tendon. When we look at hamstring tendon versus patellar tendon, here we do see significant differences. The nine-year incidence of revision is 4.5% for hamstrings, 3% for patellar tendons. Also a difference in the reoperation incidence, 7% versus 9.7%. And again, in this case, if we look at the under 22 population and we look at the numbers needed to treat here, if you were to do 36 reconstructions with the quadriceps as opposed, or sorry, with the patellar tendon as opposed to a hamstring, you potentially save one revision. So there are not a lot of large cohort studies looking at quadriceps tendons. There are some systematic reviews and meta-analysis and most show no significant differences with respect to revision or instability or patient reported outcomes and possibly less quadricep or less donor site morbidity with the quadriceps. But one of the problems is most of these studies have actually fairly short follow-up periods. There are some large studies when we look at hamstring versus patellar tendon. We published a study in a different cohort many years ago, which showed similar findings. All the large registries have found very similar findings when comparing hamstrings to patellar tendons. Danish registry, the Norwegian, a large Scandinavian study, and also recently the New Zealand group. So somewhere in the order of 1.4 to 2.5 times higher risk with hamstring compared to patellar tendon. So there are certainly limitations. We only looked at revision. So those patients who had failures that never came to a revision, we didn't identify. We did not standardize surgical technique or rehabilitation. Clinical exams and PROs were not evaluated and certainly observational studies can't determine causality. But it was a rather large study with over 20 or nearly 22,000 patients with high internal validity. There's fairly good generalizability, at least with the insured U.S. population. So in conclusion, we found no difference in hazard ratios when comparing quadriceps tendon to patellar tendon or hamstring tendon autograph with the current numbers available. We did find a 1.5 times higher risk of revision with hamstrings compared to patellar tendon. But when looking at the numbers needed to treat, if one were to do 36 cases with patellar tendon or 30 cases with a quadriceps tendon instead of a hamstring tendon, you could potentially save one revision. Thank you. Thank you very much.

Greg Miletus

autografts

ACL reconstruction

quadriceps tendons

patellar tendon