Regarding developmental hip dislocation (formerly known as congenital hip dislocation) it is generally believed that conservative treatment can be used before 18 months of age, and previous domestic textbooks mentioned that closed reduction external fixation treatment modality can be used before 3 years of age. Opinions on the choice of treatment modality in the walking phase differ. Mardam-Bey found that 66% of children with DDH in the walking phase required further surgical treatment after closed reduction, strong traction, and prolonged fixation to increase AVN, with an AVN incidence of 28% compared to 8.4% for initial surgery (1). Some authors advocate one-stage surgery, believing that long-term external fixation is less traumatic than closed reduction, and the average age of closed reduction is 10 months, while the average age of incisional reduction is 13 months and the earliest is 7 months (2). Wang Kelai, Department of Pediatric Surgery, Qilu Hospital, Shandong University
It has been debated whether the pelvis is osteotomized before 18 months, but even in the youngest children with a high rate of reoperation after simple incisional repositioning, incisional repositioning with simultaneous bony surgery before 18 months increases stability and reduces the incidence of AVN (because the joint is more stable and fixation is relatively easy) (3). Intraoperative requirements for neutral stability and good femoral head inclusion, and placing the affected limb (hip) in the abducted and internally rotated position to test stability is incorrect. If the hip is unstable intraoperatively, pelvic osteotomy is performed; hip stability is retested after osteotomy; if the hip is still unstable in neutral position and the anterior femoral neck tilt angle is greater than 45°, subrotor rotation osteotomy is performed.
Salter (1961) believed that the main pathological change in the acetabulum of DDH was the increase in the anteversion of the acetabulum, so the pelvic osteotomy he created was aimed at correcting the excessive anteversion of the acetabulum without changing the volume and depth of the acetabulum. The Pemberton osteotomy changes the shape of the acetabulum by using the acetabular Y-shaped cartilage as a hinge, whereas the Dega osteotomy changes the shape and orientation of the acetabulum by using an incomplete fracture of the ilium above the Y-shaped cartilage as a hinge. Since the osteotomy is performed through the superior edge of the acetabulum, the distal flip of the osteotomy depends on the incomplete fracture of the ilium and is not affected by the closure of the Y-shaped cartilage.Dega osteotomy has the advantages of changing the direction and shape of the acetabulum, increasing the coverage of the acetabulum anteriorly, laterally and posteriorly, not requiring internal fixation at the osteotomy site, not damaging the Y-shaped cartilage of the acetabulum, etc. The indications are wide and the surgical trauma is relatively small.
From the intraoperative observation combined with the results of 3D reconstruction of the acetabulum spiral CT, there was no obvious defect on the upper edge of the acetabulum, and Salter’s osteotomy was performed. If there was a significant defect on the superior acetabular rim, Dega surgery was performed. An anterior femoral neck tilt angle >45 degrees is not an absolute indication for subrotor rotational osteotomy, but mainly depends on the stability of the hip joint after pelvic osteotomy. In our group, no subrotor rotation osteotomy was performed, and the anterior tilt of the femoral neck exceeded 45° in 6 hips in the postoperative follow-up, and the rest of the joints were stable except for 1 case with an enlarged hip gap.
The average length of stay in the hospital was 8 days, the external fixation time was 6 weeks, and the operation time was 60 minutes. Blood loss was 25 ml, complications: no incision infection, one case of postoperative removal of external fixation after the incision oozing, thread knot reaction, the incision healed after drug change. There was no dislocation, and there were 3 cases of joint movement limitation, mainly internal restriction. Therefore, we believe that due to the improvement of anesthesia technology, surgical operation, postoperative care level; the accelerated pace of life, increased work tension, and increased burden of caring for sick children, it is not necessary to overemphasize the conservative treatment of small-aged children with DDH, and it is practical to relax the indications for surgery and advance the surgical treatment.
References
1. Mardam-Bey TH, MacEwen GD Congenital hip dislocation after walking age J pediatr orthop 1982; 5: 478-486
2. Nicholas M.P. The Surgical Treatment of Established Congenital Dislocation of the Hip. Result of Surgery After Planned Delayed Intervention Following the Appearance of the Capital Femoral Ossific Nucleus. J Pediatric Orthop 2005; 4: 235-239
3. Grudziak JS, Ward WT. Dega osteotomy for the treatment of congenital dysplasia of the hip. J Bone Joint Surg AM 2001,83-A 845-854
.