Load transfer through the radiocarpal joint and the effects of partial wrist arthrodesis on carpal bone behaviour: a finite element study

A finite element model of the wrist was developed to simulate mechanical changes that occur after surgery of the wrist. After partial arthrodesis, the wrist will experience altered force transmission during loading. Three different types of partial arthrodesis were investigated: radiolunate, radioscaphoid and radioscapholunate fusions and compared to the healthy untreated wrist. The results showed that the compressive forces on the radiocarpal joint decreased compared to the untreated wrist with both radiolunate and radioscaphoid fusions. The load transmission through the mid carpal joints varied depending on arthrodesis type. The forces in the extrinsic ligaments decreased with the fusion, most noticeably in the dorsal radiotriquetral ligament, but increased in the dorsal scaphotriquetral ligament. From the results of the study it can be concluded that the radioscapholunate fusion shows the most biomechanically similar behaviour out of the three fusion types compared to the healthy wrist. The modelling described in this paper may be a useful approach to pre-operative planning in wrist surgery.