Cortical pelvic strains with varying size hemiarthroplasty in vitro.

Four human pelves were dissected of soft tissues and instrumented with rosette strain gages. The pelves were left intact (not separated at the pubic symphysis or sacroiliac joints) although each of the eight hemipelves was tested separately. The pelves were loaded to simulate single leg stance with use of a wire mesh cemented to the wing of the ilium, representing the abductor muscles. Loading was carried out with the intact hip joint and 1 mm undersized, correct sized, and 1 mm oversized hemiarthroplasty. The correct sized component produced a strain pattern closet to normal. The oversized component was associated with an increase in strain at the medial acetabular dome.