Pelvic stresses in vitro--II. A study of the efficacy of metal-backed acetabular prostheses.
Six embalmed human cadaveric hemi-pelves with their associated proximal femurs have been tested in vitro using 25 strain-gauge rosettes on each hemi-pelvis. Loads were applied up to 2.5 kN and principal stresses were computed from the principal strain data. Acetabular prostheses, cemented in place upon a cartilage-devoid but intact subchondral bone-plate, showed little change in stress-patterns when compared with the normal data, regardless of whether or not the component employed metal-backing. The use of 30 anchoring holes of 6.4 mm diameter, in the intact subchondral bone-plate, had little effect upon the stress-patterns, regardless of whether metal-backing was employed upon the prosthesis. When the subchondral bone-plate was removed, there were notable changes in the stress-pattern in the periacetabular region and on the medial wall of pelvis. The metal-backed prosthesis did not produce such notable changes as its plastic counterpart, when the subchondral bone-plate was removed. The use of a plastic prosthesis cemented in a Protrusio ring, in an acetabulum devoid of subchondral bone, produced notable changes in the stress-patterns in the whole periacetabular region and on the medial wall.
D000077:Acetabulum / Q000502:physiology*; D006622:Hip Prosthesis; D006801:Humans; D008670:Metals; D010384:Pelvic Bones / Q000502:physiology*; D010969:Plastics; D011474:Prosthesis Design; D013314:Stress, Mechanical
D008670:Metals; D010969:Plastics