Treatment Outcomes After Open Reduction, Varus Derotational Osteotomy and Dega Acetabuloplasty in Children With Dislocated Dysplastic Hip: Retrospective Analysis

Background. Treatment of developmental dysplasia of the hip (DDH) poses a great challenge for pediatric orthopedists due to the high risk of complications, the most severe of which are avascular necrosis of the femoral head and recurrent dislocation. In the most severe form of dysplasia, hip dislocation, the surgery is indicated after 18 months of age. However, the issue of determining the exact surgical intervention remains controversial.The aim of the study was to provide our own midterm treatment outcomes of patients with DDH, who underwent open reduction for DDH through a modified Ganz digastric approach and varus derotational femur osteotomy combined with Dega acetabuloplasty.Methods. The treatment outcomes of 12 patients with DDH grade III-IV according to the IHDI classification at the age of 1.5 to 3.5 years were analyzed. Thirteen operations were performed: open reduction, derotational varus femur osteotomy combined with Dega acetabuloplasty. In one case, surgery was performed bilaterally in two stages. The average follow-up period was 31.9 +/- 4.9 months (from 12 to 66 months). To evaluate the correction performed, a comparative analysis of X-ray images (acetabular index (AI) and femoral neck-shaft angle (FNSA) and Reimers migration index (MI)) was performed before, after surgery and at the last follow-up. The incidence of complications was assessed: recurrent dislocation, avascular necrosis of the femoral head (AVN), nonunion, infection, and loss of correction. In 8 patients with a follow-up period of more than 2 years, the limb length discrapancy was assessed.Results. Dega acetabuloplasty allowed to reduce the AI value from 38.62(degrees) to 18.76(degrees) (p<0.05) after surgery and to 20.61(degrees) at the last follow-up. As a result of varus derotational femur osteotomy, a decrease in the FNSA value was noted from 143.62(degrees) to 110.53(degrees) (p<0.05). AVN was observed in 4 cases in 3 patients (25%) (including the patient who underwent bilateral surgery). At the last follow-up, the FNSA increased to 119.11(degrees) in 9 patients without AVN and decreased to 87.75(degrees) in patients with AVN. In one patient with AVN, the development of medial dislocation of the femoral head due to progressive varus deformity was noted (up to 41(degrees)). No nonunions or infectious complications were observed.Conclusion. The combination of open reduction, varus derotational femur osteotomy with Dega acetabuloplasty is an effective method for treatment of DDH in toddlers. The small sample size and the absence of a control group do not allow us to draw conclusions regarding the effectiveness of the modified Ganz digastric approach as a measure to prevent the development of avascular necrosis of the femoral head after surgery.