Effects of different intercarpal arthrodesis techniques on wrist biomechanics after wrist SLAC and snac lesion: Finite element analysis study

In this study, we investigated whether there is a difference in ROM between limited carpal arthrodesis combinations applied after SLAC and SNAC lesion. At the same time, we planned to find the effect of the number of implants and the position of the implant in the wrist bones on the wrist ROM. We aimed to achieve the most stable wrist fusion providing the most ROM with the least amount of implants. Robust wrist modeling; Using the finite element analysis method, while the wrist is in pronation, we made reference to the carpal bone movements in the tillva studies. We created the modeling without including soft tissues. After SLAC and SNAC, the scaphoid is excised and primarily the lunate and capitatum fusion; We have created various fusion models fusion. We modeled a total of 8 limited wrist fusions by adding the fusion models in which the triquetrimum is removed, which we think will increase the ulnar deviation. While the wrist model with limited conditions is natural limiting, we evaluated these fusion models that we created. We found flexion 84o, extension 74o, ulnar deviation 35o, and radial deviation 25o in the limited conditional additional wrist model we created. Flexion- extension arc, ulnar-radil deviation arc in the models we have determined for the SNAC and SLAC lesion, respectively, Lunocapitate 58o-39o, Kapitolunate 59o-40o, Lunocapitate-Triquetrohamat 75o-39o, Kapitolunat-Lunotriquetral-Triquetrohamat 73o-29o, Lunocapitate-Hamatokapitat 70o-30o, as we found. In models without triquetrium, we found flexion-extension arc, ulnar-radial deviation arc, respectively, Lunocapitate 69o-43o, Capitolunate 72o-48o, Lunocapitate – Hamatocapitate 71o-33o. As a result, in the fusion models; The fusion between the lunate and capitatum, which is the key fusion, has an effect on the screw direction, the removal of the triqutrum does not increase the ulnar radial deviation arc, but increases the flexion extension arc. We have shown that it is a stable detection method that is easy to apply. With this three-corner fusion, we have achieved a sufficient ROM for daily activities.