An alternative fixation method for femoral varus derotational osteotomy in spastic cerebral palsy: the Rush rod

The objective of this study is to present the clinical and radiographic data collected from patients who were treated with a varus derotational osteotomy using Rush rod fixation and compare this to published norms of outcomes using blade plate fixation. A retrospective chart and radiograph review was conducted after identifying 44 patients with 61 hips who underwent varus derotational osteotomy with Rush rod fixation at our institution between 2006 and 2016. We identified 44 patients with 61 hips who underwent the procedure. Information from follow-up clinic visits was gathered and any complications were noted. The patients' radiographs were analyzed to measure neck-shaft angle, center-edge angle, and acetabular index. At the time of surgery, 44 patients (61 hips) also had soft tissue releases performed, 44 (61 hips) had an open reduction of the hip, and 39 (55 hips) had Dega acetabular osteotomies performed as well. The average pre-operative neck-shaft angle was measured at 163.0° (range 128-180) with average post-operative neck-shaft angles measuring 111.3° (range 85-167). The acetabular index improved from an average of 33.3° (range 16-60) to 16.4 (range 4-35). Post-operative Center-Edge Angle measured 29.7° (range 5-45). There were no infections or cases of avascular necrosis of the femoral head. We present an alternative fixation method for performing varus derotational osteotomy of the proximal femur in children with cerebral palsy using the Rush rod. In our retrospective analysis of 61 hips undergoing this procedure, we present comparable radiographic outcomes with decreased complication rates. Level of evidence: Retrospective comparative study to previously published results, Level III.