Introduction: Kienbock's disease is characterized by lunate osteonecrosis. The management of this disease poses a medical challenge, and the optimal surgical approach for its treatment has yet to be determined. Scaphocapitate fusion is one surgical option that can be considered for patients, as it has shown good functional outcomes. This study aimed to evaluate the most effective orthopedic devices for scaphocapitate fusion.
Methods: A wrist CT scan of a normal subject was used in this study to create a three-dimensional model using MIMICS, 3 Mat, Free CAD, and OpenSIM software. Scaphocapitate fusion was simulated in the model using one pin, one screw, two pins, two screws, and one pin and a screw. The displacement of the scaphoid bone, Von Mises stress of the scaphoid and capitate bones, and the orthopedic devices were calculated.
Results: The study revealed that the scaphoid bone could move 2.37 mm in the proximal direction in normal conditions. However, in scaphocapitate fusion, the bone only moved in the distal direction, with the least movement observed when using two pins (1.9 mm). The most effective control over mediolateral and vertical motions was achieved with two pins (2.38 mm vs. 1.35 mm) and one screw (5.60 mm vs. 3.13 mm), respectively. All methods significantly reduced the angular motion of the scaphoid bone.
Conclusion: While the various methods of scaphocapitate fusion show minimal differences, using one screw may be the most effective option for this operation.