Finite element analysis of intraosseous distal radioulnar joint prosthesis

Background: Joint replacement is one of the options to retrieve the DRUJ function. Interosseous DRUJ prosthesis has recently been introduced clinically to treat DRUJ instability. The stability and biomechanical behavior of the prosthesis during different loadings have been analyzed by the finite element method in this article. Methods CT images of a healthy 33 years old man were used to construct the three-dimensional geometry of the forearm bone. Then two models, which include a healthy foreman (Model A) and a damaged model with an inserted interosseous prosthesis (Model B) constructed to analyze and compare the foreman's stability and biomechanical behavior under different loading conditions using the finite element method. Both models were examined during pronation and supination movements with 500, 1000, 2000, and 5000 N.mm values. Also, both models were subjected to volar and dorsal loads with values of 10, 30, and 50 N and traction force with 100, 150, and 200 N. Results Maximum and minimum principal stress in all conditions performed during movements was extracted for the bones, and Von Mises stress was considered for the prosthesis and its fixing screws. In supination, the maximum stress in Model A is significantly higher than the Model B. The maximum principal stress of both models is similar during volar and dorsal loading. In traction force, in Model A, the maximum principal stress is about 68 MPa, while in Model B, it is about 850 MPa. In Model B, the absolute value of minimum principal stress is in pronation, and supination is higher than Model A. the prostheses and screws are subjected to higher stresses during pronation than supination. Also, the amount of stress created in prostheses and screws during volar and dorsal loading is almost equal. In traction loading, screws are subjected to very high stresses. Conclusion In conclusion, our study indicated that the interosseous DRUJ prosthesis looks stable. This prosthesis provides the ability to function similarly to a normal hand. Differences from the normal state can be eliminated, if necessary, with minor modifications in the prosthesis geometry.