Biomechanics of noncemented total hip arthroplasty

Biomechanical research on noncemented total hip arthroplasty has not kept pace with the rate with which new devices have been introduced and tested in the clinic. Although promising clinical results of noncemented total hip arthroplasty are published in the peer-reviewed literature, many problems have been reported as well and long-term follow-up studies are scarce. Due to the variety of fixation methods, component designs, surgical techniques, and indications applied, the problems reported are not easily related to generalized paradigms for failure mechanisms (described as failure scenarios). However, this information is required if general guidelines for prosthetic designs and preclinical tests are to be developed. The problems appear to be concentrated around issues of primary fixation, initial stability and bony incorporation, issues of bone adaptation and periprosthetic resorption, and issues of wear particle reactions and interface loosening. Biomechanical studies have mostly been concentrated on interface mechanics and bone mechanics, as related to problems of fixation and bone remodeling. Recent publications of studies in these areas are reviewed here.