Beyond the First Fix: Unraveling the Long-term Impact of Surgical Fixation for Early-onset Slipped Capital Femoral Epiphysis in Children Aged 10 and Younger.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is rare in children 10 years or younger, raising concerns about the development of proximal femoral deformity and contralateral SCFE, and indications for prophylactic pinning. This study examines the outcomes of SCFE in children 10 years or younger.

METHODS: This retrospective study included children who were 10 years or younger at the time of surgery for SCFE and had a minimum of 2 years of follow-up or until triradiate cartilage closure. We collected demographics, slip characteristics, surgical details, and subsequent procedures. We measured femoral neck length (FNL), articulotrochanteric distance (ATD), and α-angle. Radiographic outcomes were compared between affected and contralateral, prophylactically pinned hips using Wilcoxon rank-sum tests, and the mean cumulative function curve demonstrated reoperation events.

RESULTS: Eighty-two children (71% females, 27% obese) with SCFE presented at a median age of 10.2 years (range: 5.6 to 10.9). Five patients presented with bilateral SCFE. About 68% (n = 59) hips were chronic SCFE, and 68% (n = 59) were mild. Among 77 unilateral SCFEs, 23% (n = 18) underwent prophylactic pinning of the contralateral hip, and the remaining 59 patients were monitored. About 27% (n = 16) of monitored patients developed a subsequent SCFE, while 73% (n = 43) remained radiographically normal throughout follow-up. When compared with normal hips, SCFE hips showed shorter FNL (3.8 vs. 4.8 mm, P < 0.001), shorter ATD (1.8 vs. 2.6 mm, P < 0.001), and greater α-angle (66 vs. 53 degrees, P < 0.001). Prophylactically pinned hips showed a slight decrease in FNL (4.3 vs. 4.6 mm, P = 0.03) but similar ATD and α-angle compared with normal hips. 28% (n = 23) underwent at least one additional surgical procedure. About 17% (n = 3) of the 18 prophylactically pinned patients experienced an outgrown screw and required revision.

CONCLUSIONS: SCFE in children 10 years or younger results in proximal femur deformity of shortened femoral neck and abnormal head-neck offset. Contralateral hip morphology was generally maintained, irrespective of prophylactic fixation or monitoring, suggesting that femoral neck growth is not entirely restricted by standard screw fixation. As 73% of monitored hips remained radiographically normal throughout follow-up, prophylactic surgery may not be necessary in this younger age group, and careful consideration with shared decision making is critical.

LEVEL OF EVIDENCE: Level III.