Femorale Umbauprozesse nach totaler Hüftendoprothese 17,6 Jahre nach Implantation

The aim of the study is to acquire bone density data revealed by Hounsfield units (HU) with the aid of computerized tomography (CT). Therefore a collective of five postmenopausal female patients was chosen. On average the total hip arthroplasty was 17,6 years ago. For this study we made computerized tomographical radiograms of both femora of the five patients. The same precedure was made 12 years after implantation. We studied the changes of bone density of the operated femur and of the contralateral femur with a special software, which were specially programmed for this study. Then we checked up the bone density in the period of 12 years till 17,6 years after implantation. In addition to this we also compared the operated femur with the contralateral femur to clear up that the reduce of bone density is not a physiological process but is caused by the implantation of hip prosthesis. A new CT started before we made the 17,6 years study, therefore we had to make a calibration study. A loss of bone density was noticed on all patients. The reduction of bone density is significant by patient 11 and 20. The median data for the single zones: +54,7HU (Zone 1), -49,8HU (Zone 2), -120,4HU (Zone 3), -1,3HU (Zone 4) -60,1HU (Zone 5), -116,8HU (Zone 6), -22,7HU (Zone 7) In comparison to the contralateral femur we also noticed a reduction of bone density. It was significant by patient 12, 17 and 18. -370,7HU (Zone 1), -217HU (Zone 2), -191,4HU (Zone 3), -82,9HU (Zone 4) -157,3 HU (Zone 5), -394,5HU (Zone 6), -72,2HU (Zone 7) If you consider the pros and cons the acquired clinical and computerized tomographical data are ethical acceptable and scientifical very useful. With these data we can compare and prove theories of periprosthetical remodelling processes. The in vivo acquired data are very important for computersimulations who simulates bone remodelling processes.