Biomechanical considerations on some postoperative problems of directly anchored total hip replacements

Abstract

Uncemented total hip replacements have resulted in a higher incidence of postoperative complaints than cemented ones. The theoretical explanation of these not well defined discomforts is based on the differences of the stress and strain fields around the distal portions of the femoral components. While the noncemented stems are press-fitted and most of them tapered distally, thus creating hoop stresses and strains in the surrounding cortical bone, the shrinkage of the cement prevents these mechanical irritations. The relatively sudden disappearance of these discomforts within the first 2 postoperative years is attributed to the shift of the main zone of load transmission from the distal to the proximal portion of the stems following bone remodeling.

Risk Factors for Femoral Fracture after Canine Press-Fit Cementless Total Hip Arthroplasty

“…The BFX ™ cementless THR system is a commonly used cementless THA system that relies on initial press‐fit of components into precisely prepared recipient acetabular and femoral bone beds and subsequent osteointegration for long‐term stability. Femoral fracture after cementless THA is a potentially devastating complication that may be associated with different mechanisms and risk factors than those reported for cemented hip arthroplasty 18–27 . Our purpose was to review case records and radiographs of dogs treated with BFX ™ cementless THA to determine patient and operative factors that influenced occurrence of postoperative femoral fracture.…”