Mechanical properties of femoral cortical bone following cemented hip replacement

Abstract

Femoral bone remodeling following total hip replacement is a big concern and has never been examined mechanically. In this study, six goats underwent unilateral cemented hip hemiarthroplasty with polymethyl methacrylate (PMMA) bone cement. Nine months later animals were sacrificed, and the femoral cortical bone slices at different levels were analysed using microhardness testing and microcomputed tomography (micro-CT) scanning. Implanted femurs were compared to contralateral nonimplanted femurs. Extensive bone remodeling was demonstrated at both the proximal and middle levels, but not at the distal level. Compared with the nonimplanted side, significant decreases were found in the implanted femur in cortical bone area, bone mineral density, and cortical bone hardness at the proximal level, as well as in bone mineral density and bone hardness at the middle level. However, no significant difference was observed in either variable for the distal level. In addition, similar proximal-to-distal gradient changes were revealed both in cortical bone microhardness and bone mineral density. From the mechanical point of view, the results of the present study suggested that stress shielding is an important mechanical factor associated with bone adaptation following total hip replacement.

Effects of treadmill running with different intensity on rat subchondral bone

“…The hardness of a material has been defined as its resistance to penetration by an indenter 42 . Vickers microhardness test was performed using a HMV-2T microhardness test machine fitted with a pyramidal diamond indenter (Shimadzu, Japan).…”

“…Vickers microhardness test was performed using a HMV-2T microhardness test machine fitted with a pyramidal diamond indenter (Shimadzu, Japan). Method was described previously 42 . Briefly, a mass of 40 g was used throughout the test.…”

Intervention timing of strontium treatment on estrogen depletion-induced osteoporosis in rats: Bone microstructure and mechanics

“…The mechanical properties of the vertebrae (L5) were evaluated following our previously established protocols . Briefly, the compression test was performed using a servo‐hydraulic material testing machine (MTS System, Inc., Minneapolis, MN).…”

Bone Loss and Reduced Bone Quality of the Human Femur after Total Hip Arthroplasty under Stress-Shielding Effects by Titanium-Based Implant

“…The degree of preferential BAp orientation is related to bone mechanical function, and reduced orientation is an important contributor to reduced bone mechanical function. 7,22) In fact, Ni et al 23) reported that the micro-hardness in the region proximal to the artificial hip joint is 20% lower than that on the non-implanted side. This may suggest that the change in the degree of BAp orientation is involved in this phenomenon.…”