Abstract
BACKGROUND: Joint replacement is one of the options to retrieve the interosseous distal radioulnar joint (DRUJ) function. DRUJ prosthesis has recently been introduced clinically to treat DRUJ instability. This article analyzes the biomechanical behavior of the prosthesis during different loadings by the finite element method. 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, a healthy foreman (Model A) and a damaged model with an inserted interosseous prosthesis (Model B), were constructed to analyze and compare the foreman's biomechanical behavior under different loading conditions using the finite element method. Both models were examined during pronation and supination 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 stresses were evaluated for bones in all conditions, and von Mises stress was considered for the prosthesis and fixing screws. In supination, the maximum stress in Model A is significantly higher than the Model B. However, the maximum principal stress of both models is similar during volar and dorsal loading. In Model A, the maximum principal stress in traction is much smaller than in Model B. The absolute value of minimum principal stress in pronation and supination in Model B is higher than in 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 significantly high stresses. CONCLUSION: Our study indicates that the interosseous DRUJ prosthesis can perform the foreman's normal daily activities. This prosthesis provides the ability similar to a normal hand. LEVEL OF EVIDENCE: IV.