Is there a need for conservative surgery in DDH adult patients? Lessons learned after 30 years experience.

The aim of the present study is to set out our thirty-year experience in conservative surgical management of developmental dysplasia of the hip (DDH) in the young adult, using either periacetabular or intertrochanteric osteotomies. All the patients have the same radiographic assessment which allows evaluating the lateral center edge angle, the obliquity of the acetabular roof by the HTE and the anterior centre edge angle. According to the Hip Study Group classification, hips were classified as average DDH when VCE and VCA are between 25 degrees and 21 degrees, severe between 20 degrees and 5 degrees and extreme below 5 degrees. The study of the articular congruency is conducted through the surgical profile evaluating the S/FH ratio (S=projected acetabulum surface, FH=1/2 projected femoral head surface) and recentring radiographs by abduction. The presence of osteoarthritis is evaluated according to Tonnis. An additional CT-scan with intraarticular injection may actually be realized. No hip arthroscopy was performed. Several original modifications have been realized, including a single intrapelvian approach allowing all the cuts and a modification of the ischial cut ("2/3 PAO") in order to leave the posterior horn attached to the ischium when the S/FH ratio is below 3/4. The femoral posterior head coverage is then not modified whereas the periacetabular fragment is moved anteriorly. In our experience, PAO is an effective procedure for patients under 30 years of age without intraarticular damage and with average or severe DDH, to avoid a total hip arthroplasty in the future. For patients over 30 years old with a beginning of osteoarthritis or extreme DDH, it seems reasonable to avoid a major operation and maybe to consider less invasive techniques to delay a total hip arthroplasty.