A major problem associated with orthopaedic implants is the occasional loss of fixation to the underlying bone. Chapter 1 discusses various theories on causes of the loss of fixation including recent models of fracture along the interface. Based on some of the important observations of previous investigators, several new models of failure are proposed and solved.

In Chapter 2, the general solution for the interaction of a dislocation and an elliptical void or rigid inclusion is found in closed form. From this solution a Green's function is formed to solve relavant crack problems.

The problem of cracks emanating from a fluid filled elliptical void loaded in compression is solved in Chapter 3. The results show the combinations of parameters for which crack growth under static loads is likely. In Chapter 4 the problem for a crack emanating from a circular void in a compressive field is solved. The angles for which the stress intensity is highest are found for various length cracks.

In Chapter 5, the results from the previous chapters are compared to each other and to results from previous investigators. Based on an approximate comparison, the likelihood of the various failure mechanisms is discussed.