THA WITH DEROTATIONAL/SHORTENING SUBTROCHANTERIC OSTEOTOMY USING MODULUSR - ITS THEORY, SURGICAL PLANNING AND IMPLANT DESIGN

IntroductionIn DDH cases often have high anteversion. They also often have high hip center. THA for those cases sometimes requires subtrochanteric derotational/shortening osteotomy. To achieve good results of the surgery, accurate preoperative planning based on biomechanics of the high anteversion cases, method for accurate application of the plan, and stable fixation are very important. At ISTA 2008, we have reported that the location of the anteversion exist several centimeters below the lesser trochanter. Independently from the extent of anteversion, femoral head, grater trochanter, and lesser trochanter are aligned in the same proportion. We have also reported in 2007, in improper high anteversion cases, many cases grow osteophytes posterior side of femoral head to reduce it functionally. In 2014, we reported about development of the stem for subtrochanteric osteotomy. (ModulusR)[Fig.1] In the present study, we established systematic planning way for estimate proper derotation and shortening and apply...