Transverse strength of human femoral bone loaded by internal pressure

摘要

Press-fit hip arthroplasty primarily loads the proximal femur by a force normal to the stem (radial) resulting in a circumferential (transverse) direction loading in the bone. The resulting stress is known as hoop stress and is typically a tensile stress for a press-fit prosthesis. Cementless femoral component insertion can produce substantial assembly strains in the femoral cortex which occur during implantation of the prosthesis and have been shown to be large enough to cause both longitudinalcracks and fractures [1,2]. One of the simplest quantitative methods that can be used to pre-operatively assess femoral structural bone quality prior to hip arthroplasty is the cortical index [3] which utilizes standard clinical radiographs. Corticalindex, however, has not been utilized as a diagnostic criteria in patient selection prior to hip arthroplasty. The objective of the current study was to relate the transverse fracture of femoral bone specimens under a simulated press-fit loading condition to cortical index measurements from corresponding radiographs of the proximal femur.