That title rolls right off the tongue. Thanks for the introduction. My name is Adam Yenke from Rush. Thanks for the opportunity to present. This was also funded by a grant from Anna, so thank you very much for that as well. In general, we know — I'm sorry, disclosures are listed on the app. In general, we know that NPFL outcomes are very promising and they are continuing to improve as we understand the role of returning to sport and clinical outcomes and lack of redislocation. However, we try to further refine the procedure by decreasing complications associated with it and one that can be fairly devastating is patella fractures. We do know that based on existing literature by Dr. Critch and others that if you avoid sockets you could probably still do osseous fixation while still having extremely low or potentially nonexistent fracture rate associated with this, but it's still a clinical concern. This has moved some authors to move to doing a soft tissue-based reconstruction so that you can try to avoid this risk and mitigate this. Work by Dr. Tanaka and others has also demonstrated that there's a natural attachment of the NPFL or the MPFC proximal to the patella. About 50% of it inserts near the quad tendon. And so that portion could be functionally relevant, which also could help you avoid the osseous insertion. This has really led to the development of the MQTFL reconstruction, which Dr. Fulkerson and others also perform as this is anatomically accurate for the proximal half. When we look at the length changes associated along the medial patellofemoral complex going from proximal to distal, what we see is that the most distal insertion on the patella, which is essentially at the 50-yard line, only changes about 2.5 millimeters with regards to length change, whereas the most proximal extent to this changes about 12 millimeters going from 0 to 90 degrees of flexion. And most of this change happens with early flexion angles. So the question is, how functionally relevant is the proximal aspect compared to the distal aspect when it has that differential loosening with flexion? And our goal of this study was to look at the biomechanical differences of the distal and proximal half of the medial patellofemoral complex to see which one's the primary restraint in this setting. You'll see that this method is very similar to the method that Jordan presented, so I won't get into some of the details of the setup, but we did use 12 knees. These were paired, so we could do sequential sectioning in a randomized fashion of either the proximal or the distal extent first. We tested intact. We then did our exposure. We then randomized to proximal or distal resection and then complete resection. This video demonstrates the distal aspect is on the lower half and the proximal aspect is on the upper half, the black lines, the superior pole, the patella. And you can see how we would commonly see a robust band that would develop under tension near the area of the osseous insertion that wasn't present on the quadriceps insertion. This is a similar setup again where we used a fixed force of 20 newtons to measure the displacement. We did load the quadriceps during this and testing was performed at the flexion angles listed below. When we look at our results and we simplify it to four separate groups, when we look at the percent change from intact averaging across all flexion angles, we saw that there was about an 80% increase in lateral translation with the approach alone. There was not a significant increase when we sectioned the proximal aspect to the MPFC. When we sectioned only the distal aspect of the MPFC, we saw a significant increase in lateral translation. And when we moved on to complete transection, we did not see a significant difference between distal release and complete transection, but we did see a significant difference between proximal release and complete transection. When we look at this in a more detailed fashion across range of motion, this is the amount of translation for each degree of flexion. When we add our exposure for the arthrotomy, we saw an increase throughout all ranges of motion. And when we added the transection of the proximal aspect to the medial patellofemoral complex, we did not see any difference compared to the arthrotomy alone. This is what it looks like when we section only the distal aspect in isolation. And there's a significant every degree of flexion that it was measured at. When we do the complete transection compared to this, there was also no difference at any individual flexion angle between a distal transection and the complete transection, whereas there was a difference in every flexion angle of proximal to complete. This is not power to necessarily see a difference that trended toward significance that there may have been a difference between complete transection and distal transection at the lower degrees of flexion, up to 20 degrees. I think that with this information, we just need to understand that as we further fine-tune techniques, we need to take several factors into account. One is anatomy, both what the anatomy looks like when we visualize it grossly, but also how does it function with regards to the length changes and the anatomimetricity associated with it. We also need to understand how this actually acts as a restraint, and I think this study helps us understand that the distal aspect is a primary restraint, and the proximal aspect may be a secondary restraint. We also want to try to improve our clinical outcomes while also decreasing complications associated with our procedures. So there's a chance that the procedures we're doing may not be in line with the biomechanics or anatomy completely, but maybe they're functionally good enough, so to speak, to have good outcomes, and we may be slightly overkill with all of our reconstruction techniques. Future directions may suggest that we should consider a soft tissue and osseous-based insertion, and potentially with patients that have higher risk factors associated with recurrent dislocation, these changes may be even more appropriate to get correct. Thank you.

NPFL procedure

patella fractures

biomechanical differences

restraint

surgical techniques