Jumbo Bionic Trabecular Metal Acetabular Cups Improve Cup Stability During Acetabular Bone Defect Reconstruction: A Finite Element Analysis Study

The biomechanical effects of acetabular revision with jumbo cups are unclear. This study aimed to compare the biomechanical effects of bionic trabecular metal vs. titanium jumbo cups for the revision of acetabular bone defects. We designed and reconstructed American Academy of Orthopaedic Surgeons (AAOS) type I-III acetabular bone defect models using computed tomography scans of a man without acetabular bone defects. The implantation of titanium and trabecular metal jumbo cups was simulated. Stress distribution and relative micromotion between the cup and host bone were assessed using finite element analysis. Contact stress on the screws fixing the cups was also analyzed. The contact stress analysis showed that the peak contact stress between the titanium jumbo cup and the host bone was 21.7, 20.1, and 23.8 MPa in the AAOS I-III models, respectively; the corresponding values for bionic tantalum jumbo cups decreased to 4.7, 6.7, and 11.1 MPa. Analysis of the relative micromotion showed that the peak relative micromotion between the host bone and the titanium metal cup was 10.2, 9.1, and 11.5 & mu;m in the AAOS I-III models, respectively; the corresponding values for bionic trabecular metal cups were 17.2, 18.2, and 31.3 & mu;m. The peak contact stress on the screws was similar for the 2 cup types, and was concentrated on the screw rods. Hence, acetabular reconstruction with jumbo cups is biomechanically feasible. We recommend trabecular metal cups due to their superior stress distribution and higher relative micromotion, which is within the threshold for adequate bone ingrowth.

Automated summary

This study compared the biomechanical effects of bionic trabecular metal and titanium jumbo cups for acetabular bone defect revision. Finite element analysis showed that bionic tantalum jumbo cups had superior stress distribution and higher relative micromotion compared to titanium jumbo cups. Therefore, we recommend the use of trabecular metal cups for acetabular reconstruction.