Trapezo-metacarpal joint prosthesis has metacarpal cup made with external and internal sharp-edged projections to fix against trapezoid bone and insert

摘要

The prosthesis, having metacarpal and trapezoid components, with the latter comprising a cup (15) and liner, has the cup made with external (20) and internal (23) sharp-edged projections round its outer and inner rim to engage with the trapezoid bone and insert respectively. The cup's outer surface also has four evenly-spaced points (21) and a coating of a substance such as calcium hydroxyapatite to promote bone growth.