Virtual simulation for optimizing the range of motion in hip alloarthroplasty using an adapted trust-plate prosthesis model

The purpose of the present study was to increase the free range of motion i n conventional trust-plate prosthesis design and to optimize the trust-plat e contact as well as the osteointegration area below the trust-plate. For the first part of the study, the two-dimensional geometry of the osteot omy plane was demonstrated in 25 CT-reconstructed femora after performing a virtual cut at a CCD angle of 135 degrees. In the second part, we construc ted a prototype of an anatomic adapted trust-plate prosthesis (A-TPP) with an optimized trust-plate and corpus geometry based on the three-dimensional data of three human cadaveric femurs (age 67-75 years). In the final step, we documented the range of motion with computer-aided movement-mapping and compared the conventional TPP with the A-TPP. The results showed a wide variance in osteotomy geometry in the 12 femurs. With the A-TPP, we were able to obtain a much better fit in the trust plate surface. The movement-mapping showed a much higher range of motion in the A-TPP implant. With the A-TPP, the implant surface area for osteointegratio n could also be significantly increased.