Surgical correction of coxa vara: Evaluation of neck shaft angle, Hilgenreiner-epiphyseal angle for indication of recurrence

Abstract

Background: Coxa vara is a hip deformity in which the femoral neck-shaft angle decreases below its normal value. Standard surgical treatment for this condition is corrective valgus osteotomy. Appropriate correction of the Hilgenreiner-epiphyseal angle is important to prevent recurrence. The purpose of this study is to: 1) evaluate the recurrence of the deformity at the latest follow up; and 2) find the appropriate angle of correction associated with the lowest recurrence.

Methods: 34 hips in 31 patients who underwent surgery for treatment of coxa vara from 2005 to 2014 were included. Patient-reported outcomes, Hilgenreiner-epiphyseal angle, and neck-shaft angle were assessed preoperatively, postoperatively, and at latest follow-up.

Results: The mean age at surgery was 10.99, with a range of 5-30, years. Preoperative neck-shaft angle ranged from 60 to 100 degrees, and Hilgenreiner-epiphyseal angle ranged from 60 to 90 degrees. At the latest follow up, the neck-shaft angle ranged from 120 to 135 degrees and the Hilgenreiner-epiphyseal angle ranged from 22 to 35 degrees (p < 0.001). The Harris hip score improved from 47.20 (34-66) to 79.68 (60-100) (p < 0.001). There was no recurrence of deformities at the mean follow up of 37.87 months.

Conclusion: Surgical correction of coxa vara in various pathologies can be done successfully with the Hilgenreiner-epiphyseal angle corrected to ≤ 35 degrees or the neck shaft angle corrected to > 120 degrees in order to prevent recurrence of the deformity. Majority of the patients were reported improvement of hip function. However, a longer-term follow up is required to determine further outcomes regarding to recurrence of the deformity.

Keywords: Coxa vara; Fibrous dysplasia; Intramedullary nail; Osteogenesis imperfecta; Osteotomy; Skeletal dysplasia.

Figures

Fig. 1

Radiographic characteristics of a 12-year-old female patient: (1A) Osteogenesis imperfecta proximal femoral fractures with severe coxa vara; (1B) After healing of the right proximal femur, the neck-shaft angle decreased to 60 degrees, but the left hip had delayed union; (1C) Valgus osteotomy combined with a Sofield-Millar operation using a pediatric dynamic hip screw and titanium elastic nail performed at the left hip, then at the right hip 3 months later. At the 2-year follow-up, the patient could walk independently without aid and had a neck-shaft angle of 130 degrees.

Fig. 2

Radiographic characteristics of a 30-year-old female: (2A) Monostotic fibrous dysplasia with coxa vara and femoral fracture; (2B) Valgus osteotomy combined with a Sofield-Millar operation using gamma nail with plate and screw augmentation was performed at the left hip. At 3-year follow-up, the patient could walk independently without aid and had a neck-shaft angle of 130 degrees.

Fig. 3

Radiographic characteristics of a 18-year-old female patient: (3A) Fibrous dysplasia withcoxa vara; valgus osteotomy using a gamma nail was performed at the right hip. At the 3-year follow-up, the patient could walk independent without aid and had a neck-shaft angle of 130 degees. (3B).