Postoperative improvement of femoroacetabular impingement after intertrochanteric flexion osteotomy for SCFE.

BACKGROUND: Patients with slipped capital femoral epiphysis (SCFE) may develop cam-type femoroacetabular impingement (FAI). Early management of FAI has been advocated for patients with symptomatic FAI. The various treatment options, including reorientation surgeries, realignment procedures, and osteoplasty, remain controversial.

QUESTIONS/PURPOSES: We asked whether an intertrochanteric flexion osteotomy improved the clinical symptoms of FAI in patients with SCFE and confirmed whether the radiographic signs were compatible with the clinical signs of FAI.

METHODS: We retrospectively reviewed 32 symptomatic patients who underwent 32 intertrochanteric flexion osteotomies for severe SCFE. FAI was diagnosed clinically with a positive impingement sign. The osteotomies were designed preoperatively using CT. Cam-type FAI was evaluated with the modified α angle (β angle) on a Lauenstein view, measured between the proximal femoral shaft axis and the line from the center of the femoral head to the anterior point where the distance of the head center exceeded the femoral head radius. The minimum followup was 2 years (mean, 5 years; range, 2-9 years).

RESULTS: At last followup, only two patients complained of pain or inconvenience in daily life; the impingement sign was negative in 24 hips (75%). The β angles at last followup were reduced on average by 39°. The postoperative β angle was higher in hips with positive clinical signs of FAI than in those with negative signs.

CONCLUSIONS: Intertrochanteric flexion osteotomy for SCFE improved the clinical and radiographic signs of FAI. The β angle and clinical findings showed compatible improvement. We believe our intertrochanteric flexion osteotomy is a viable option for treating severe SCFE.

LEVEL OF EVIDENCE: Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.