Abstract
Non-cemented components have traditionally employed several possible features, among them a stem and/or collar, to achieve proper alignment and initial implant stability within the proximal femoral cavity.
The advent of MIS has stimulated an interest in reducing the dimensions of implants, specifically stem length, in order to facilitate introduction and implantation of the component. The consequence of this trend appears to be an increase in early aseptic failure, of some components, due to loosening and migration. Several important questions have arisen.
What are the direction of the deforming forces about a hip during daily activities?
What design features should a short stem implant exhibit so as to provide optimum stability against these forces?
Is having a stem an absolute requirement of a femoral component?
What is the minimum “safe” length a stem must have?
How can proper short stem alignment be optimized? Is intra-operative x-ray exposure necessary?
This presentation will discuss the computer modeling, laboratory testing and clinical outcomes of various
component designs; and make suggestions concerning directions for future investigations.
