Vascularized fibular grafts for avascular necrosis after slipped capital femoral epiphysis: is hip preservation possible?

BACKGROUND: Avascular necrosis (AVN) of the femoral head is a potential complication in patients with slipped capital femoral epiphysis (SCFE), radiographically occurring in 3-60%. This may lead to early hip fusion or hip arthroplasty. Free vascularized fibular grafting (FVFG) may provide a reasonable means to preserve the femoral head. QUESTIONS/PURPOSES: We asked: (1) What percentage of patients with AVN after SCFE treated with FVFG underwent subsequent THA or hip fusion and what was the lifespan of the FVFG? (2) Did the graft survival rate of FVFG for AVN after SCFE coincide with historically reported rates of FVFG for idiopathic AVN? And (3) did hip function improve after FVFG?
METHODS: We retrospectively reviewed 52 patients who underwent FVFG for SCFE. We calculated the longevity of the graft and factors associated with graft survival. Harris hip scores (HHS) were recorded pre- and postoperatively. Minimum followup was 1 month (median, 19 months; range, 1-136 months).
RESULTS: Five of the 52 patients (10%) underwent conversion to THA (four) or hip fusion (one). Mean age was greater in these patients than in those not requiring further procedures: 16 versus 13 years. Median graft survival time before arthroplasty/fusion was 12 years (range, 2-16 years) while it is currently 8 years (range, 2-16 years) in patients not undergoing subsequent procedures. HHSs improved 35 points on average (38 points preoperatively to 73 points postoperatively).
CONCLUSIONS: In patients undergoing FVFG for AVN secondary to SCFE, 90% have maintained their native hips for 8 years with improved hip function, similar to other published reports of FVFG. Further followup is needed of patients currently retaining their FVFGs as to eventual conversion to THA or fusion. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.