The Analysis For Redislocation After Operative Reduction Of Developmental Dislocation Of The Hip In Children

Background:Developmental dislocation of the hip (DDH) is commonly encounterred and frequently occurring disease in pediatric orthopedics. The patients need to be operative reduction when their age above 18 months, the alteration of the pathology of the DDH is very disparity in different ages, the methods of operation are varied, at present, which we often used are Salter osteotomy, Pemberton operation, Shelf operation and Chiari pelvic osteotomy and so on. Every methods of operation have its indication, advantage and defect. The operative treatment can make the joint function well, but many of complications are happened, for instance, postoperative redislocation, hip joint anchylosis, avascular necrosis of femoral head, and so on. Redislocation is most one of complications in postoperative patients of DDH, most of them need to be second operation, not only it can bring the large disaster and economic loss to the patients meanwhile they will loss well joint function, but also it affects the surgeon's confidence.Objective:To explore the reasons of redislocation after operative reduction of DDH in children, sum up the experience and methods to prevent redislocation.Methods:Between January 2000 and December 2009, 177 patients (209 hips) of DDH were treated in China-Japan union hospital of Ji Lin university in total, 6 patients (6 hips) have been redislocation, 4 patients are female, 2 patients are male, 4 hips were affected on the left and 2 hips on the right, The average age of the 6 patients was 5.6 years (range 3.25~9 years). The time of the redislocation was from 2 month to 14 months, the average time was 4.5 months. We make comprehensive analysis for the information which we collect from the 6 patients about the appearance of the X-ray, the chance of the method of operation, the deal with intra-operation and post- operation, the correlated medical history, and so on.Results:The results showed: the acetabular index of 1 patient was above 30 degree post-operation, the acetabular index of 4 patients hare been upswing and above 30 degree, the compare of the acetabular index of preoperative and redislocation was not statistics difference (p=0.293 >0.05). The femoral neck anteversion were above 45 degree in 2 patients, and was less than 0 degree in 1 patient. The continuity of shenton's line were discontinue in 2 patients, the location of the shelf was exorbitancy in 1 patient. 1 patient have identify a history of trauma, 1 Patient have a history of prematurity weight-bearing. In the second operation, we discovered that all of the 6 patients had soft tissue contracture, and 2 patients were seriously. There is lots of fat and fibrous tissue in acetabulum, glenoid labrum was left over in 1 patient, ligamentum transversum of 1 patient was reserved completely in acetabulum.Conclusions:There are a lot of factors to cause redislocation after operative reduction of DDH, in which, the main reasons are the uncorrected acetabular index enough, or the upswing of acetabular index, the uncorrected justo major femoral neck anteversion, or femoral neck anteversion is too small, the residue of the pathologic tissues in the acetabulum, the existence of large pressure between acetabulum and femoral head. Most of the patients of redislocation need to be treatmented by the second operation. The sufficient preoperotive preparation, accurate position and orthopedic degree measure, enough soft tissues brisement, good postoperative fixation and scientific postoperative functional exercise can prevent the occurrence of postoperative dislocation.