CAN WE PREDICT GRADE OF CONTRALATERAL SLIPPED UPPER FEMORAL EPIPHYSIS BASED ON RADIOGRAPHIC PARAMETERS AT FIRST PRESENTATION

Purpose The decision to undertake prophylactic pinning to prevent contralateral slipped upper femoral epiphysis (SUFE) remains controversial; we hypothesised that the grade of initial SUFE could predict the grade of a second SUFE and risk of poor outcome. Method We retrospectively reviewed radiographs of all children who presented to Alder Hey with a new diagnosis of SUFE between 2007–2014. Of those who developed a contralateral SUFE, grade of first and second SUFE was determined radio-graphically using % slip and Southwick angle on frog lateral radiograph. Results 100 patients that presented with a new diagnosis of SUFE were identified. 73 had no contralateral surgery at first presentation. Of these, 56 reached skeletal maturity with no contralateral slip. 17 re-presented acutely with a contralateral slip requiring operative intervention. 4 presented with unilateral symptoms but radiographic evidence of bilateral slips and underwent bilateral surgery at time of first presentation. No cases of severe slip where seen in children with initial mild or moderate slips. 100% of children presented with a contralateral SUFE of the same or less severe grade. In cases of initial severe SUFE, grade of second SUFE was unpredictable; 3 pre-slip, 1 mild, 1 moderate, 2 severe. Conclusion Grade of initial SUFE may be a useful adjunct to decision making when considering risk- benefit of prophylactic contralateral surgery. In cases of initial mild slip re-presentation with a severe contralateral SUFE is unlikely and a higher threshold for prophylactic intervention may be appropriate.