O3251: What is the average length of follow-up for patients with SCFE?

Background: Slipped capital femoral epiphysis (SCFE) is a common adolescent hip disorder with a paucity of studies observing long-term outcomes. Many orthopedic journals require a minimum of 2 years of follow-up, potentially skewing the literature to observing certain types patients with SCFE. Our purpose was to understand follow-up characteristics of patients affected by SCFE.

Methods: Patients with SCFE that presented to a tertiary pediatric hospital between 9/2010 to 3/2021 were retrospectively reviewed. Exclusions included: previous treatment at an outside hospital or missing data. Follow-up time, complications, and slip severity were analyzed. Patients were considered lost to follow-up (LTFU) if they did not follow-up as recommended at their last visit.

Results: 269 patients (175 male) met inclusion with a mean age at presentation of 12.4 years old (SD +1.8). 234 patients with a unilateral SCFE (128 left, 106 right). Of the 65 patients that underwent bilateral surgery, 30 patients were prophylactically pinned.

82% of patients were considered LTFU. Only 41% of the overall cohort had at least 2 years of follow-up. Of those LTFU, 66% of patients were lost before 2 years, 54% were lost before 18 months, 42% before 1 year, and 28% before 6 months. Patients that were considered lost to follow up cohort were found to have shorter follow-up time (p < 0.001) (Figure 1). For patients that were instructed to return as needed (PRN), 42% were released before 2 years of follow-up. However, of those with less than 2 years of follow-up, only 12% of patients were recommended to follow-up as needed.

A sub-analysis comparing those with greater than 2 years follow up and those with less than 2 years follow up revealed that there was no significant differences in slip laterality (p=0.47), operative side (p=0.12), re-presentation with a second slip (p=0.34), or sex (p=0.47). Slip severity at presentation was also found not to be significantly different between the two groups (p=0.66). However, younger patients were more likely to have at least two years of follow up (p < 0.01). Patients with follow up ≥ 2 years were also more likely to follow-up as recommended (p=0.03). Patients with complications were also more likely to follow up for at least 2 years (p < 0.01).

Conclusion: While our study demonstrates 80% of SCFE patients were lost to follow up, slightly less than half of patients had a minimum of 2 years follow-up. We found that a minimum follow-up of two years may potentially perpetuate the limitations in accurately depicting patients affected by SCFE and instead may focus on patients that are younger and those with complications. This study highlights the inherent difficulty in accurate representation in longitudinal SCFE research.