Increased incidence of acute patellar dislocations and patellar instability surgical procedures across the United States in paediatric and adolescent patients

PURPOSE: Patellofemoral instability is a common cause of knee pain and dysfunction in paediatric and adolescent patients. The purpose of the study was to evaluate the frequency of patellar dislocations seen in emergency departments (EDs) and the rates of surgical procedures for patellar instability at paediatric hospitals in the United States between 2004 and 2014. METHODS: The Pediatric Health Information System database was queried for all paediatric patients who underwent surgery for patellar instability or were seen in the ED for acute patellar dislocation between 2004 and 2014. This was compared with the annual numbers of overall orthopaedic surgical procedures. RESULTS: Between 2004 and 2014, there were 3481 patellar instability procedures and 447 285 overall orthopaedic surgical procedures performed at the included institutions, suggesting a rate of 7.8 per 1000 orthopaedic surgeries. An additional 5244 patellar dislocations treated in EDs were identified. Between 2004 and 2014, the number of patellar instability procedures increased 2.1-fold (95% confidence interval (CI) 1.4 to 3.0), while orthopaedic surgical procedures increased 1.7-fold (95% CI 1.3 to 2.0), suggesting a 1.2-fold relative increase in patellar instability procedures, compared with total paediatric orthopaedic surgeries. CONCLUSION: This study shows a significant rise in the rate of acute patellar instability treatment events in paediatric and adolescent patients across the country. Surgery for patellar instability also increased over the study period, though only slightly more than the rate of all paediatric orthopaedic surgical procedures. This may suggest that increasing youth sports participation may be leading to a spectrum of increasing injuries and associated surgeries in children. LEVEL OF EVIDENCE: IV