The Atypical Patient With Slipped Capital Femoral Epiphyses May Be at Increased Risk for a Missed Contralateral Slip

Slipped capital femoral epiphysis (SCFE) is a commonly encountered hip disorder. The goal of this study was to describe the incidence of missed contra-lateral SCFE as well as to identify risk factors. The authors hypothesized that contralateral slips are more often missed in patients with severe involvement of the treated side. After institutional review board approval was obtained, a retrospective chart review was performed of all pediatric patients who were treated for sequential and bilateral SCFE at a single institution during an 18-year period. Medical records were reviewed for demographic features and attending surgeon. Radiographs were reviewed for skeletal maturity, Klein's line, and severity of the treated slip. All radiographs were reviewed by 3 pediatric orthopedists. Contralateral SCFE was deemed present when consensus was achieved. Comparisons were made with Fisher's exact test, and P<.05 was considered significant. Of the records that were reviewed, 56 patients met the study criteria. Of these, 19 patients had bilateral involvement and 5 missed slips were identified (8.9%). The patients with missed disease tended to be younger (mean age, 10.8 vs 11.4 years), with a lower body mass index. Fellowship-trained pediatric surgeons were more likely to identify bilateral disease compared with orthopedists without pediatric training (P=.0065). A contralateral slip was more likely to be present in patients who had a positive finding for Klein's line (P<.0001). Severity of the treated slip did not increase the likelihood of missing a contralateral slip. Although Klein's line is a useful tool in the diagnosis of SCFE, a false-negative rate of 40% was observed. The authors recommend increased vigilance when an "atypical" patient with SCFE presents with unilateral disease. [Orthopedics. 2020;43(2):e114-e118.].