ABSTRACT
Three dimensional Rigid Body Spring Modeling was applied for stress analysis of multiarticular joints such as the wrist, elbow and ankle joint. Geometric bone models were constructed using normal CT data with a 1 to 2 mm slice interval. Articular surface mesh models were constructed automatically by calculating the mid-points between two articulating bone surfaces. In the wrist radio-carpal joint under neutral loading condition, stress was concentrated on the volar side of the joint. The force distribution of radio-ulno-carpal joint was consistent with previous experimental results. In the elbow joint, ulnar-radial loading ratio of seven to three seemed reasonable in order to get equal stress distribution in both radio-humeral and ulno-humeral joints.
This model has much promise in solving multi-articular joint problems. An easy modeling procedure, simple formulation, and short calculation time enable this model to be applied to very complex structures—structures for which even FEA cannot easily be applied. However, further experimental studies will need to be performed in order to achieve complete validation of this method.
