Postoperative Improvement of Femoroacetabular Impingement After Intertrochanteric Flexion Osteotomy for SCFE

Abstract

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 a angle (b 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 b angles at last followup were reduced on average by 39°. The postoperative b 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 b 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.

Twelve Percent of Hips With a Primary Cam Deformity Exhibit a Slip-like Morphology Resembling Sequelae of Slipped Capital Femoral Epiphysis

“…This morphological similarity indicates that there might have been prior SCFE and supports previous reports that have proposed SCFE as a risk factor for the development of cam-type FAI (Fig. 8) [2,18,24].…”

“…The four study groups differed in terms of age at the acquisition of the MRI, weight, and body mass index (BMI) ( Table 1). The normal group showed a decreased age (17 ± 2 [range, [15][16][17][18][19][20] years) compared with the other study groups (mean age ranging from 24 to 25 years; p ranging from \ 0.001 to 0.002). In the normal group, both weight (66 ± 14 [48-95] kg) and BMI (22 ± 3.4 [18][19][20][21][22][23][24][25][26][27][28] kg/m 2 ) were decreased compared with the idiopathic cam (p = 0.028 and p = 0.002, respectively) and slip-like group (both p = 0.001; Table 1).…”

“…However, the etiology of a cam-type deformity of the proximal femur is not yet fully understood. Although secondary cam deformities such as posttraumatic deformities [4], sequelae of Legg-Calvé-Perthes disease [1,23], or SCFE [2,18,24] have been identified, the majority of cam deformities are referred to as primary cam deformity. Based on our experience with surgical hip dislocation in open capital realignment for SCFE [25,26], a similar slip-like appearance of the proximal femur was intraoperatively observed in some cases that were treated for primary cam-type FAI.…”

“…On the posterior side, the slip leads to increased offset of the femoral head-neck junction. The anterior asphericity often leads to a cam-type femoroacetabular impingement (FAI) and substantial damage of the cartilage and labrum resulting in hip pain and, if left untreated, progression of osteoarthritis [2,5,10,18,24].…”

Subcapital osteotomy of the femoral neck for patients with healed slipped capital femoral epiphysis

“…The decision about whether surgical intervention should be considered in a patient with asymptomatic FAI remains controversial. 13 Most authors would prefer to treat symptomatic cam-type FAI from a healed SCFE to prevent subsequent osteoarthritis. 2,3,14,15 The choice of operation has principally been between open dislocation of the hip and osteochondroplasty, arthroscopic osteochondroplasty and intertrochanteric repositioning osteotomy.…”