Abstract
Direct anterior approach (DAA) is one of the best way to the hip joint for prevention of post-operative dislocation. We have applied this method as minimum invasive surgery (MIS) to more than two hundred developmental dysplastic hip of Japanese patients in total hip arthroplasty (THA) and there is no post-operative dislocation within three years of last observation carried forward (LOCF). The reason of this benefit is derived from the accuracy of cup positioning and keeping good muscle balance. But the learning curve is very important and some technical pitfalls are there in this approach. We have chosen thirty four patients that the duration of operating time more than one and half hours and loss of blood more than five hundred gram in hour series. The most important factors of the difficulties are the combinations of shortening of femoral neck, especially Perthes like deformity of developmental deformities of the hip joint (DDH) and widening of pelvic bone for the reason of insufficiency working spaces and the difficulties of broaching insertion (8/34). The second factor is the contracture of hip and knee joints combinations for the difficulties of lift up the proximal femur as broaching stem (3/34). The obesity, Body Mass Index (BMI) above thirty is not the reason of difficulties of women in our series. DAA can be extended to Smith-Petersen approach and very useful technique for primary THA in Japanese dysplastic hip patients.
