A Randomized Comparative Study to Evaluate the Performance and Confirm the Safety of the Diocom Hip Syhstem in Cementless Hip Arthroplasty

It is of great importance for the function of uncemented total hip arthroplasty that the anchorage of the prosthesis in the bone of the femur is sufficient. This is of great importance in the prevention of stress shielding of the bone and to insure tranfer of forces from the prosthesis to the femur. The symax hip stem is developed to optimize stress tranfer to bone and insure mechanical stability. In this study the symax hip stem is compared to the HA_Omnifit hip stem (a frequently used and long term evaluated uncemented hip prosthesis) During the fist two years of follow up DEXA mesurments of bone mineral density are performed. Also patient satisfaction, patient fuction score and radiological evaluation measurements are done during 5 years of follow up. Our primary objective is: comparison of the short term bone remodelling surrounding the Symax hip stem to the short term remodeling surrounding the Stryker Omnifit HA hip stem measured by bone densitometry, clinical and radiographic evaluation.