Dynamics of femoral bone remodelling in well fixed total hip arthroplasty. A 20-year follow-up of 20 hips (original) (raw)
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The Journal of Arthroplasty, 2012
We investigated the cortical bone changes in 35 patients with total hip arthroplasty operated on only for osteoarthritis with more than 10 years of follow-up and with nonrevised femoral components and without radiologic signs of loosening. The mean follow-up was 16 ± 5 years. The thicknesses of femoral cortices were measured medially and laterally at 6 levels from the first postoperative and the last follow-up x-rays. A comparison with 10 patients who had a nonoperated contralateral hip was performed. We found a significant decrease in cortical thicknesses in total hip arthroplasty. The cortical thinning was significant at all periprosthetic levels but less expressed distally. Prosthetic femora were associated with greater cortical thinning as compared with the contralateral nonoperated femora, exceeding that caused by natural aging.
Mechanical properties of femoral cortical bone following cemented hip replacement
Journal of Orthopaedic Research, 2007
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. ß
Changes in bone mineral density around a stable uncemented total hip arthroplasty
International Orthopaedics, 1997
Changes in bone mineral density (BMD) around the components of the Zweymueller total hip arthroplasty were measured, using dual energy X-ray absorptiometry, in 36 women who were operated on for primary osteoarthritis. Seven regions of interest were studied. No changes occurred around the screw socket and the greater trochanter, but there was a significant reduction of BMD, only when measured immediately after the operation at the lesser trochanter and at the distal femoral cortex lateral and medial to the tip of the stem. These changes were not related to the age of the patients. The reduction of BMD in the femur was mostly associated with areas where bone had been removed at operation. The press-fit fixation of the Zweymueller stem and the maintenance of its fixation with time did not induce further bone turnover around it. The absence of changes in bone mineral density was due to the relatively small amount of subchondral removed and to the continued stable fixation of the socket.
European Journal of Orthopaedic Surgery & Traumatology, 2019
Introduction In the context of total hip arthroplasty (THA), there are several reasons that have motivated the development of short stems. It has been postulated that short stems allow a better conservation of the bone stock if compared to conventional stems. As far as we have knowledge, the quantitative loss of diaphyseal bone stock in patients with standard femoral stems has not been fully described. The aim of this study was to provide evidences about the thickness of the cortical bone at the diaphysis in patients who have undergone unilateral THA with Furlong ® stems with a minimum follow-up of 18 years. Patients and methods A retrospective study of patients who underwent THA in a single hospital was performed. The inclusion criteria were patients who had undergone a non-cemented elective THA with a Furlong ® stem, minimum follow-up of 18 years, and contralateral femur and hip without history of previous surgical procedures. The follow-up analysis was performed by means of radiological examinations performed at the last follow-up visit. Data related to the sex, age at surgery and adverse events registered during the follow-up were gathered. The cortical thickness index (CTI) and cortical thickness (CT) assessed at the last follow-up visit in anteroposterior pelvic X-rays were analyzed, both in the operated hip and in the non-operated hip (which was used as control). Calibration of the measurements was done by means of using the circumference of the head of the THA. Results The total number of patients who met the inclusion criteria was 22. There were 14 women and eight men. There were 12 left hips. The mean age at the time of surgery was 59.32 ± 6.83 (range 50-70) years. The mean follow-up was 20.86 ± 1.90 (range 18-24) years. The CTI was found to be 11.93% greater in the non-operated hips. The CT measured at 3 cm and 6 cm from lesser trochanter, and at 9 cm from the greater trochanter, was found to be 21.64%, 15.33% and 18.73% greater in the non-operated hips, respectively. Conclusion After a minimum of 18 years from the implantation of a Furlong ® stem, the bone density that surrounds the implant seems to involve a cortical bone ten percent less thick than the cortical bone of the non-operated contralateral side. With this stem, the cortical zones with less CT seem to be the lateral cortex at 9 cm from the greater trochanter, and the medial cortex at 3 and 6 cm from the lesser trochanter. Level of evidence III, retrospective case-control study.
Maintenance of bone mineral density after implantation of a femoral neck hip prosthesis
BMC Musculoskeletal Disorders, 2008
Background: Stress shielding of the proximal femur has been observed in a number of conventional cementless implants used in total hip arthroplasty. Short femoral-neck implants are claiming less interference with the biomechanics of the proximal femur. The goal of this study was to investigate the changes of bone-mineral density in the proximal femur and the clinical outcome after implantation of a short femoral-neck prosthesis.
Journal of Biomechanics, 2007
A hip replacement with a cemented or cementless femoral stem produces an effect on the bone called adaptive remodelling, attributable to mechanical and biological factors. The objective of all of cementless prostheses designs has been to achieve a perfect transfer of loads in order to avoid stress-shielding, which produces an osteopenia. In order to quantify this, the long term and massproduced study with dual energy X-ray absorptiometry (DEXA) is necessary. Finite element (FE) simulation makes possible the explanation of the biomechanical changes which are produced in the femur after stem implantation. The good correlation obtained between the results of the FE simulation and the densitometric study allow, on one hand, to explain from the point of view of biomechanical performance the changes observed in bone density in the long-term, where it is clear that these are due to a different transfer of load in the implanted model compared to the healthy femur; on the other hand, it validates the simulation model, in a way that it can be used in different conditions and at different time periods, to carry out a sufficiently precise prediction of the evolution of the bone density from the biomechanical behaviour in the interaction between the prosthesis and femur.
Biomaterials, 2003
Measurements were made from annual follow-up radiographs, obtained over 27.6 years, of 860 cemented total hip arthroplasties implanted by one surgeon. Femoral components were made of stainless steel or titanium alloy, were non-modular, and were all fixed with cement, and acetabular cups were all-polyethylene and were fixed with cement. Radiographic outcome was correlated with the shape and material of the femoral component. Specifically, throughout the follow-up, stems made of titanium alloy were at greater risk of developing bone-cement radiolucent lines than those made of stainless steel, the difference ranging from approximately 10-50 percent at 2-10 years of follow-up. Similarly, titanium alloy stems were at greater risk of developing endosteal scalloping, indicating osteolytic lesions. Among the stainless steel Charnley cobra and straight-narrow Charnley stems, none developed cement fracture, only one became radiographically loose and one developed endosteal scalloping. The differences in the risk of developing radiolucent lines, cement fracture and progressive loosening among these stems were correlated with the relative rigidity of the femoral stems, and were generally consistent with the predictions made heretofore using finite element models, although differences in stem surface finish and femoral ball size and material could have also influenced the results. r
The Journal of arthroplasty, 2014
This five-year prospective study was designed to investigate periprosthetic bone remodeling associated with two cemented stem models, ABG-II (Stryker) and VerSys (Zimmer), randomly implanted in patients older than 75 years. The sample consisted of 64 cases (32, ABG-II; 32, VerSys). Inclusion criterion was diagnosis of osteoarthritis recommended for cemented total hip arthroplasty. Besides clinical study, Finite Element (FE) simulation was used to analyze biomechanical changes caused by hip arthroplasty. Bone Mineral Density (BMD) measurements showed a progressive increase in bone mass throughout the entire follow-up period for both stems, well correlated with FE results except in Gruen zones 4, 5, 6 for ABG-II and in zones 4, 5 for VerSys, denoting that remodeling in those zones does not depend on mechanical factors but rather on biological or physiological ones.
The effects of total hip arthroplasty on the structural and biomechanical properties of adult bone
American Journal of Physical …, 2009
The responsiveness of bone to mechanical stimuli changes throughout life, with adaptive potential generally declining after skeletal maturity is reached. This has led some to question the importance of bone functional adaptation in the determination of the structural and material properties of the adult skeleton. A better understanding of age-specific differences in bone response to mechanical loads is essential to interpretations of long bone adaptation. The purpose of this study is to examine how the altered mechanical loading environment and cortical bone loss associated with total hip arthroplasty affects the structural and biomechanical properties of adult bone at the mid-shaft femur. Femoral cross sections from seven individuals who had undergone unilateral total hip arthroplasty were analyzed, with intact, contralateral femora serving as an approximate internal control. A comparative sample of individuals without hip prostheses was also included in the analysis. Results showed a decrease in cortical area in femora with prostheses, primarily through bone loss at the endosteal envelope; however, an increase in total cross-sectional area and maintenance of the parameters of bone strength, I x , I y , and J, were observed. No detectable differences were found between femora of individuals without prostheses. We interpret these findings as an adaptive response to increased strains caused by loading a bone previously diminished in mass due to insertion of femoral prosthesis. These results suggest that bone accrued through periosteal apposition may serve as an important means by which adult bone can functional adapt to changes in mechanical loading despite limitations associated with senescence.