RADIOLUCENT LINES IN TOTAL TRAPEZIOMETACARPAL JOINT REPLACEMENT - A MORPHOLOGICAL AND FUNCTIONAL-STUDY

The first metacarpal bone is stressed by a dorsopalmar bending, as proved by radiological studies. In case of a trapeziometacarpal arthrosis the subluxated metacarpal bone is subjected to an increased bending stress. Functional adaptation of the bone leads to an augmented cortical thickness. The dorsopalmar diameter of the medullary cavity decreases. After the implantation of the prosthesis the magnitude of bending stress again decreases and bony resorption occurs. This explains the radiolucent lines at the bone-cement interface of the metacarpal component.