So, my name's Noah Quinlan, I'm presenting this work for my mentor and colleagues at the University of Utah, Dr. Aoki. The title of our work is titled MPFL Reconstruction in the Pediatric Population, Does Skeletal Maturity Affect Outcomes in Surgical Success? Here are disclosures, none pertain to the work presented here. So as we're hearing about patellar instability is a common pediatric knee condition and can result in recurrent instability. The MPFL we've identified as one of the primary restraints to lateral translation and as such MPFL reconstruction has become a mainstay of treatment for patellar instability. Charlotte's point of what we've been talking about is just anterior to the posterior femoral cortex, just proximal to the Blumensatz line. The issue though in skeletally mature patients is that it's in close proximity to the distal femoral physis. And so there's been various techniques that have been described to minimize physial damage. All the results of this are unclear and whether or not it alters graft mechanics, there's issues with residual instability, or if there's an effect on growth. And so the objective of this study was to understand if skeletal maturity affects MPFL outcomes. So our hypothesis was that in pediatric patients undergoing an MPFL reconstruction, those that are skeletally immature experience worse outcomes and a higher rate of recurrent instability compared to those that are skeletally mature. This is a retrospective chart review. We looked at patients under the age of 18 who had a primary MPFL reconstruction with a single surgeon from 2013 to 2019. They had all had a primary MPFL reconstruction and they were contacted a minimum of one year follow-up after their surgery. The follow-up questionnaire included IKTC scores, satisfaction rates, and rates of subsequent injury to the ipsilateral as well as contralateral knee. Patients were grouped into one of two cohorts based on the surgical technique. This was the skeletally mature versus our immature technique. Both techniques entail allograft fixation in the patella and femoral bone tunnels with tenodesis interference screws. The difference occurs in the trajectory of the femoral bone tunnel. The skeletally mature technique entails metaphyseal drilling at Shattles Point while the immature patients underwent all epiphyseal drilling as you can see here. Mercilane tape augmentation is also performed based on the surgeon discretion of laxity and remaining growth and analysis basically entailed comparison between these two cohorts. We identified 120 patients of which 118 met our final inclusion criteria. Our response rate was 75%, so 88 patients. We had 66 patients in the skeletally mature group and 21 in our skeletally immature group. Looking at our demographics, the skeletally mature was older as expected at 15 compared to 13 years old. There were slightly fewer males in our skeletally mature group and they also had a higher BMI. There was no difference in the presence of trochlear dysplasia based on the crossing sign. There was a higher rate of mercilane tape augmentation in the skeletally mature group although this was expected as our senior surgeon tries to avoid mercilane tape in the skeletally immature due to concerns for over-constraining the patella and concern on residual growth. There was no difference in follow-up at 4.2 versus 3.5 years for each of the cohorts. And then looking at our outcomes, there was no difference in IKDC scores, no difference in perceived percent normalcy of the knee, no difference in sport participation or avoidance or stiffness that would be limiting any sort of activity. We then looked at VAS pain scores up to 10 with three different activities. So at rest, activities of daily living and with sport. On the blue you have skeletally mature and the black you have the skeletally immature. And on the left is rest, then the middle activities of daily living and then with sport. And so we considered VAS pain scores under three as minimal pain. And so here the percentage of patients presenting pain scores under three. And you can see they're very similar for all cohorts, for both cohorts and all activities. We then looked at rates of ipsilateral and contralateral knee injuries. The skeletally mature did have a higher rate of subjective reporting of ipsilateral knee injury but when you look at the actual rates of recurrent dislocation or revision instability procedures there is no difference between each of these cohorts. There's also no difference in the rate of contralateral knee injury. This is our rate of satisfaction on the left and then percentage of patients when asked if they would undergo the same care again that would say yes they would. Again blue is the skeletally mature, black is the skeletally immature. There is no difference in satisfaction although there was a higher rate of the skeletally mature group that would undergo the same care again if needed at 96 compared to 76%. So our conclusions are that skeletally mature and immature pediatric patients both have good and comparable outcomes following MPFL reconstruction. However the skeletally immature group did have a higher rate of subjective reporting of subsequent knee injury but there was no real difference in the rate of actual dislocations or need for revision instability procedures. Again the skeletally immature were less likely to report they would undergo the same care again and contributing factors to this could have been the fact that these skeletally mature are younger age which is a known risk factor for recurrent instability and the fact that these patients had a lower rate of mercilane tape augmentation which in theory will add extra stability to the repair. Thank you.

Noah Quinlan

University of Utah

MPFL Reconstruction

Pediatric Population

Skeletal Maturity