Improved techniques for measuring in vitro the geometry and pressure distribution in the human acetabulum. II Instrumented endoprosthesis measurement of articular surface pressure distribution.

Abstract A technique to measure in vitro the distribution of pressure on the cartilage surface of the human acetabulum using a modified endoprosthesis with fourteen integral pressure transducers is described. Under a constant load vector pressure contour maps are generated for times from shortly after loading until 20 min into cartilage consolidation. The peak pressure decreases with time as the area of contact increases. The pressure distribution is neither uniform nor even axisymmetric about the load vector. We believe that the highly irregular pressure profiles observed are due primarily to cartilage thickness distribution and irregularities at the calcified cartilage interface as described in Part I.