Impact of Hip Versus Knee Pain as the Presenting Symptom of Slipped Capital Femoral Epiphysis on Time to Imaging, Surgery, and Complications

Background: Slipped capital femoral epiphysis (SCFE) is a pediatric hip disorder affecting roughly 1 in 10,000 children and adolescents, with delayed diagnosis and treatment leading to poor outcomes. This study compares the association between presenting hip or knee pain symptomatology and its effects on time to diagnosis and treatment of SCFE, mid- to long-term complications, and risk of requiring hip reconstructive surgeries. Methods: A retrospective cohort study was conducted comparing SCFE presentations with chief complaints of either hip or knee pain that led to SCFE surgery. Propensity score matching adjusting for demographic factors, was performed on these cohorts. Survival analysis was implemented on the matched cohorts to compare time to imaging, primary SCFE surgery, complications, and the need for additional interventions. Results: A total of 724 patients undergoing surgery for SCFE were identified, with either an initial presentation of hip or knee pain. After propensity score matching, 145 patients were included in each group. The average age of patients was 11.5 years old. Children in the knee pain cohort experienced a significantly longer delay of ∼92 days in obtaining hip/pelvis imaging [98.51 vs. 6.79 d, hazard ratio (HR) 1.62, 95% CI: 1.22-2.14; P=0.034] and an average delay of ∼82 days in undergoing surgery from presentation [106.38 vs. 24.34 d; HR 2.39, 95% CI: 1.83-3.14; P<0.0001] compared with the hip cohort. Furthermore, knee pain patients had an increased risk of chondrolysis and osteoarthritis [risk ratio (RR) 1.88, 95% CI: 1.10-3.24; P=0.019] and higher need for hip reconstruction (RR 1.68, 95% CI: 1.002-2.83; P=0.045). Conclusion: This study is the first report attributing increased risks of chondrolysis, osteoarthritis, and need for future hip reconstructive surgeries to the delay in diagnosis among SCFE patients presenting with knee pain. Maintaining a high index of suspicion for SCFE among children presenting with knee pain, particularly among overweight adolescents, is crucial. Level of Evidence: Level III - therapeutic studies - investigating the results of treatment.