RESUMO
Objective To investigate the effect of cartilage acetabular ,glenoid labrum and acetabular tissue on closed reduction of developmental dysplasia of hip ( DDH ) by analyzing the outcomes of the ultrasound measurement on DDH before and after Pavik Harness treatment . Methods Graf method was used in ultrasound measurement before the treatment . Position of cartilaginous acetabulum and glenoid labrum and displacement direction of femoral head in 31 patients with hip dislocations ( type D ,type Ⅲ ,typeⅣ ,36 hips) were recorded . T he follow‐up testing with ultrasound measurement on the inside of the hip were performed after 1 －2 weeks of Pavik Harness treatment . M ediolateral dimension ,anteroposterior dimension and the area of maximum section of acetabular tissue were measured . Reduction effects were evaluated . Results T he success rate of reduction of dislocation hips with cartilaginous acetabulum on the head orientation was obviously higher than that on the foot orientation( P ＜0 .000 1) . T he success rate of reduction of dislocation hips with glenoid labrum on the head orientation was obviously higher than that on the foot orientation ( P ＝ 0 .001 6 ) . T here was a statistically significant difference in the success rate of different types of hip dislocation ( type D , type Ⅲ , type Ⅳ ) ( P＝ 0 .002 7 ) . T here were statistically significant differences in mediolateral dimension ,anteroposterior dimension and the area of maximum section of acetabular tissue between the reduction group and the group without dislocation ,the irreducible group and the group without dislocation ,the irreducible group and the reduction group ( P ＜ 0 .01) . Conclusions Ultrasonography is of great significance in the diagnosis and treatment of children with DDH . T he position of hip cartilaginous acetabulum and glenoid labrum ,types of hip dislocation and the volume of acetabular tissue have important effects on the success of the closed reduction .