A stress distribution analysis of a ceramic lunate replacement for Kienbock's disease

To determine the usefulness of a ceramic lunate replacement for the wrist joint as a possible treatment for Kienböck's disease, stress distribution of five wrist joint models (a normal wrist, one with the lunate bone removed, one with a coiled tendon replacement, one with a coiled tendon replacement with a ceramic core, and one with a ceramic lunate replacement coated with sheets of tendon) were analysed by the finite element method. The results of finite element method analyses were compared with those of pressure distribution analyses on the wrist joint using pressure-sensitive film and measurement of pressure on the radio-lunate joint with a tactile sensor. Both the coiled tendon model and ceramic core model were unable to resist applied force. Stress and pressure were well-distributed in the wrist joint of the ceramic lunate implant model. These results indicate that the ceramic lunate implant could be expected to prevent carpal collapse.