O2115: Impact of National Radiographic Hip Surveillance Guidelines in the United States: HCUP KID Analysis 1997-2019

Background: Hip surveillance guidelines have been introduced by both the Australian (AusACPDM, 2008) and American (AACPDM, 2016) Academy for Cerebral Palsy and Developmental Medicine to screen for hip displacement in children with cerebral palsy (CP), but whether these guidelines have facilitated early surgical intervention remains unknown. In this study, we compare national trends in osteotomy rates and hip dislocations among children with CP in the United States using an extensive national database to assess the impact of these guidelines on surgery rates and spastic joint complications in this population.

Methods: This retrospective analysis utilized ICD-9-CM and ICD-10-CM codes to identify hospital admissions for hip osteotomies and hip dislocations in children < 20 years old with CP from the Kids Inpatient Database (KID) from 1997-2019. All cases without an admission month were excluded. National estimates of hospital cases related to CP, osteotomy (acetabular, proximal femoral) surgical rates, and hip dislocations were calculated using weighted variables provided by HCUP. The average monthly osteotomy surgical rates and hip dislocations were calculated and compared using one-way factor ANOVA for the periods before and after the establishment of each guideline (January 1997- December 2006, January 2009-September 2016, October 2016-December 2019). Baseline patient characteristics were also reported for each period and analyzed by either chi squared tests or one-way factor ANOVA.

Results: From 1997-2019, there were 318,367 weighted CP admissions. The incidence of CP hospitalizations increased by 43.9%. When comparing baseline characteristics of patients between the periods January 1997- December 2006 (preAusACPDM), January 2009-September 2016 (post-AusAPCDM, pre-AACPDM), and October 2016-December 2019 (post-AACPDM), the mean age (p < 0.001) and length-of-stay (p < 0.01) were significantly higher from 2016-2019 (post-AACPDM) compared to the two prior time periods, though the gender distributions were similar. The average monthly osteotomy rate was the highest pre-AusACCPDM from January 1997-December 2006 at 43 surgeries per 1,000 CP cases, decreased to 32 per 1,000 from 2009-2012, and was the lowest from 2016-2019 at 7.4 surgeries per 1,000 CP cases post-AACPDM, and these changes were significant (p < 0.001). There were no significant differences in rates of hip dislocation between these three time periods (p=0.18).

Conclusion: The establishment of hip surveillance guidelines has not led to an increase in corrective surgery rates or a decrease in hip dislocations despite the increasing number of hospitalizations related to CP. The average annual and monthly surgical osteotomy rate declined significantly from 1997-2019. Additionally, the average age and length of stay for CP patients hospitalized for a corrective hip surgery have increased, potentially indicating possible sicker patients, or increasing surgeon preference for multilevel surgery. Future studies should focus on creating productive systems-level efforts to maintain adherence to radiographic hip surveillance guidelines.