INCREASED INCIDENCE OF ACUTE PATELLAR INSTABILITY AND PATELLAR INSTABILITY SURGERY ACROSS THE UNITED STATES IN PEDIATRIC & ADOLESCENT PATIENTS

Background: Participation in organized sports has been increasing over the last several decades for pediatric and adolescent athletes in this country. It is hypothesized that the overall incidence of acute patellar dislocation in this population would increase with more sports participation. Newer surgical techniques for patellar stabilization have also become popular and have been adapted for younger populations. The purpose of the current study was to evaluate the trend in the frequency of patellar dislocations treated at pediatric hospitals in the U.S. versus patients receiving surgical intervention for patellar dislocation. Methods: The Pediatric Health Information System (PHIS) database was queried for all patients 18 years or younger who underwent orthopaedic surgery between 2004 and 2014. A cohort of patients treated surgically for patellar dislocation was compared to a cohort of patients seen in the Emergency Department for management of a patellar dislocation. Data sets from 25 of the 48 pediatric hospitals participating in the PHIS initiative reported data consistently for the study time period and were included in the analysis. The rate of patellar dislocation surgeries per 1,000 pediatric orthopedic surgeries was analyzed for the 11-year period. Linear modeling was used to assess sex-based and overall trends. Results: During the study period, there were 447,285 orthopaedic surgeries at 25 institutions, which included 3,481 patellar dislocation procedures, suggesting a rate of 7.8 per 1,000 orthopaedic surgeries. An additional 5,244 patellar dislocations treated in the emergency room were identified. Over the study period, the number of patellar dislocation procedures increased 2.1-fold (95% CI = 1.4-3.0), while all surgeries increased 1.7-fold (95% CI = 1.3-2.0). There was only a 1.2-fold increase in patellar dislocation procedures relative to total pediatric orthopedic procedures. Emergency Department treatment of patellar dislocation increased 2.8-fold. Females yielded similar trends between operative and Emergency Department treatment of patellar instability (2.2-fold and 2.3 –fold, respectively); while males experienced a higher trend in the need for Emergency Department treatment compared to operative treatment (3.0-fold versus 2.0-fold, respectively). Conclusion / Significance: This study shows a significant rise in the rate of acute patellar instability events in pediatric and adolescent patients across the country. Interestingly, surgery for patellar instability increased by only slightly more than the rate of all pediatric orthopaedic procedures. Further research is needed to evaluate the link between increased acute patellar instability and risk for chronic patellar instability along with the potential need for surgical intervention.