RCT Comparing the DEXA Results of the HA-Omnifit Versus the Symax Uncemented Hip Stem

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

Thr purpose of this study is to compare the clinical and radiological results, as well as the femur bone density measurements of two uncemented total hip prostheses during 5 years of follow up.

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.

Inclusion Criteria:Male or non pregnant female patients >18 years Patient with degenerative or traumatic changes to hip requiring hip replacement Patient with BMI<35 Patient signed informed consent Exclusion Criteria: chronic anti-inflammatory medication use> 3 months revision surgery to the affected femur Cancer therapy including immunosuppression, chemotherapy and radiation Pathological fractures, delayed ossification or non-union is likely to occur

ten Broeke RH, Tarala M, Arts JJ, Janssen DW, Verdonschot N, Geesink RG. Improving peri-prosthetic bone adaptation around cementless hip stems: a clinical and finite element study. Med Eng Phys. 2014 Mar;36(3):345-53. doi: 10.1016/j.medengphy.2013.12.006. Epub 2013 Dec 27.