A comparison of various loading configurations of the proximal femur for the evaluation of reconstructive surgical procedures.
The study was designed to evaluate the effect of different loading configurations on stem and bone stresses in simulated total hip arthroplasty. The traditional experiment design of loading the model through the head of the prosthesis by the resultant joint force was compared with a more realistic model which included an abductor strap to simulate the abductor muscle force. In addition, an alternative experiment design was evaluated in which a loading arm was clamped directly on to the head of the prosthesis. The results show that loading the model by the resultant joint force not only changes the magnitude of the stresses but also the stress distribution compared to the abductor muscle model. The new experiment design closely approximates stresses seen in the abductor muscle model below the lesser trochanter. In the proximal region, the stresses are increased on the medial side and decreased on the lateral side. The advantages of the proposed loading model are: (a) easy and reproducible set-up and alignment is facilitated, (b) different positions of the femur (flexion, extension) can be simulated and (c) a more realistic stress distribution and magnitude is achieved.
Schmotzer
H
H
Orthopaedic Research Laboratory, Hospital of the Good Samaritan, Los Angeles, California.
Tchejeyan
G
G
Song
J
J
D001696:Biomechanical Phenomena; D005270:Femur Head / Q000502:physiology*; D006622:Hip Prosthesis; D008954:Models, Biological; D011474:Prosthesis Design; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D016474:Weight-Bearing / Q000502:physiology*