Journal of Bone Research
Open Access

Abstract

Stability Studies of Acetabular Cup in Artificial Hip Joint Models

J Płomiński and Z Watral

Purpose: The article presents the results of stress testing of an artificial cup fixed in a model containing a fragment of an animal hip. The main objective of the study was to determine the effect of the angle of cup fixing on its stability.

Methods: In the model investigated, a polyethylene acetabulum was cemented on a base made of impacted frozen bone grafts by experienced orthopedists. In this way, the test conditions were similar to those in clinical trials. The model prepared in this manner was subject to cyclic loading followed by a trial to tear off the cup, performed on an INSTRON machine.

Results: As a result, a set of characteristics was obtained which illustrate the dependency of acetabular cup displacement as a function of the shearing force for different inclination angles of cup fixing and varying thickness of graft layers.

Conclusion: One conclusion was that the fixing angle of 60 degrees in relation to the vertical axis Zm of the global coordinate system provided significantly better stability that the angle of 30 degrees. It was also noted that the layer thickness of frozen grafts was another factor influencing the value of the shearing force applied to the cup.