A Serial Study Of Hip Surface Replacement

Objective (1) To explore the effect of the hip surface replacement on the mechanical characteristics of proximal femur. (2) To test whether the hip replacement is able to avoid stress shielding similar to THA. (3) To explore the effect of congruence between the prosthesis and the acetabulum on the loading area, contact compression and contact stress. (4) To evaluate the effect of hip surface replacement on bone mineral density of proximal femur compared with THA group. (5) To evaluate the clinical result of the hip surface replacement for osteonecrosis and osteoarthritis in young patients.Method (1) Eight cases young fresh normal femoral specimens were selected and one leg in standing position was used in the measurement .The biomechanical test was performed on the WD-5 type machine to detect the relation of loading and strain, distribution of stress ,rigidity, torsion of normal proximal femur and resurfaced proximal femur under the loading of 1000N.(2) Eight cases young fresh normal femoral specimens were selected and one leg in standing position model was used in the measurement. The stress of normal proximal femur , proximal femur with a surface replacement and a total replacement were measured respectively under the loading of 1000N.The rate of stress shielding was calculated according to the formula ofη=(1-δ全板/δ未板)×100%.(3) Six cases young fresh normal femoral specimens were selected and one leg in standing position was used in the measurement. All specimens were divided into normal group and simulative operation group (A, B). The average contact compression and contact stress, loading area were detected from the press film which was inserted in the bearing clearance. (4) The clinical evaluation of 17 patients treated with hip...