Thanks for the opportunity to present this morning. So I'd like to just go over today, remind folks about the role of implant-mediated guided growth and looking for valgus on kids who need an MPFL. Talk a little bit about MPFL in the zone of injury and how it's different in kids and adults, how we manage the MPFL around the growth plate, and talk about the variety of reconstruction options to replace the MPFL that we have in pediatrics. So remember to look carefully for malalignment when you're indicating a kid for patellar realignment surgery. Any asymmetric valgus or significant valgus really requires a workup with a long leg x-ray standing hip to ankle. And when I'm in the clinic, I'll have the kids stand up, put their knees together, and if there's more than 10 centimeters of space between the ankles, then I usually indicate them for a standing alignment x-ray. An implant-mediated guided growth is a very powerful tool. It necessitates one to two years of growth remaining. When these plates are on the medial side of the growth plate, they really have a dramatic – can lead to dramatic improvement of the child's valgus and hopefully keep them – improve their structural alignment for patellar stabilization. Here's a kid who had hypophosphatemic rickets and bilateral patellar instability, who had a stage procedure where we used the plates first to correct the structural valgus. The other thing is about the zone of injury. I just want to point out the zone of injury of the MPFL, I think data has accumulated over the years that really suggests that the younger kids behave a little bit differently than the adults. Here you can see on the younger cohorts, it was more likely to be torn. The MPFL was to be torn near the patella, where the older cohorts was more likely to be torn off the femur. And these are just striking examples from my clinic in this last year where the MRI just happened to really catch where the tear was. You can see a 12-year-old with a clear MPFL disruption off the patella, but it does also happen off the femoral insertion as well. So for the old advocates of repair, you really have to kind of take that into account, and that's led to our practice or my practice always performing an MPFL for patella instability instead of a repair. So what about the MPFL and growth plate? There's been some – a lot of work on this. In 2011, we reported an MRI study that we felt that the MPFL insertion average is about five millimeters distal to the physis. Littell Farrell reported in a cadaver study that it was eight millimeters distal to the physis. And there's been a bunch of great work by Shatel Parikh, Ted Ganley, and Kevin Shea at the Peds Anatomy Group demonstrating that the MPFL center point of insertion is just below the growth plate. But in this 2018 AJSM article by the same group, they really showed while the majority of the patients were below the growth plate, there was some fibers that approached the growth plate and a few cases where the fibers clearly went proximal. And there's been a – Kevin Shea and Seth Sherman recently did a 2020 review and found that on average they felt that the MPFL insertion was seven millimeters distal to the physis. So we know our technique. We really got to get this insertion close to the physis, but obviously just distal to it. And here's my preferred technique is to do a double limb technique where I really spend a lot of time trying to get that insertion point really close to the medial distal femoral physis. In my hands, a lot of times I still use a hamstring autograph with a posterior harvest. But here's where we take a lot of the time. I want to spend a little bit of discussion. So it really requires an AP x-ray. So this is the same patient, the same K wire, and you can't rely on the lateral x-ray alone. The lateral x-ray kind of makes you think you're touching the growth plate, but so you have to rely on the AP x-ray for your safety. And I try to get it pretty close there. In my hands, I've gone away from making a large epiphyseal socket, and I have to change my sequence in order of graph placement in order to get my distal femoral insertion really close to the growth plate here. So here's another case where the guide wire is placed just distal to the growth plate. And at this point, before reaming, I would check isometrics with a suture and bring the suture to the patella. And once that's confirmed, then we'll ream a short socket and place the double-ended graft into the distal femur. That requires me to adjust the length on the patella. This is just a reminder. This is a large, loose body from the lateral femoral condyle in a 13-year-old fencer, is that we are all joint preservation surgeons when we're dealing with the patella. And I think it's important to restore the cartilage. And if you're doing that, to perform the MPFL at the same time. And here's two-year follow-up, and you can see pretty close to the growth plate here. So is growth arrest possible after MPFL surgery in children? Unfortunately, it is. There's one case report out of Austria demonstrating a pretty significant deformity and need for reconstruction. But numerous studies have shown it could be done safely as long as you're using both the AP and lateral x-ray. And both these images show, again, that you can't rely on the lateral x-ray alone. In one of our studies from KSSDA in 2019, we had 35 consecutive cases with postoperative imaging without a growth arrest. And here's from that paper a number of the post-op MRIs showing how our distal femoral insertion was close and just distal to the growth plate. So there's other options. We've talked about this free hamstring option. Another option, especially in cases of small patellas or revisions, is to do an insertion into the distal quad tendon, the MQTFL option. In some syndromic kids and the younger kids with really small epiphysis or severe osteoporosis, I've used this technique where you attach the distal femoral insertion actually into the adductor tendon. So that's a good bailout technique, and some people are having good success using that as a primary technique. And Art had published in this previously. Another option that Petre Salimpa in Finland has done is he'll take a partial portion of the adductor tendon magnum, adductor magnus tendon, with an open technique and then reflect it back as an MPFL. And some have even used slivers of quad tendon and bring that back to the medial femur. So we have a lot of choices of where we get our collagen from. I think if you're following the principles of anatomy, isometrics, length, not tension, we're going to end up with a good result. So thank you very much.

implant-mediated guided growth

valgus in children

MPFL reconstruction

patellar realignment surgery

MPFL tears