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Evolution of bone mass density for ABG I (bone mass group I) and ABG II (bone mass group II), corresponding to five years, in the Gruen zones.
Source publication
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. All of the cementless prostheses designs try to achieve an optimal load transfer in order to avoid stress-shielding, which produces an osteopenia.Long-term densitometric studies...
Contexts in source publication
Context 1
... bone density evolution in the operated and healthy hip is reported in [8]. Taking various studies as reference [23,24], a linear relationship between the bone mass values [8], which come from the medical study collected in [7], and the apparent density was established in addition to a cubic relationship between the latter and the elastic modulus, using a maximal Young's modulus of 20 GPa, thereby obtaining the cortical bone modu- lus of elasticity values for each one of the 7 Gruen zones (Figure 3). To carry out the anal- ysis of the results, the cortical bone of each model is divided into seven zones which coincide with the Gruen zones. ...Citations
... Using FEA, the correlation between stress distribution after THA and changes in BMD has been reported in several studies [6,10,11,23]. These studies that use patient-specific CT data and cadaver bones are very useful; however, their limitation is that they are only simulation studies. ...
Purpose
Thermoelastic stress analysis (TSA) was used to evaluate stress changes over the entire surface of a specimen. This study aimed to assess the relationship between femoral stress distribution, analysed using TSA and changes in bone mineral density (BMD) after total hip arthroplasty (THA).
Methods
Stress changes in the simulated bone before and after taper‐wedge stem insertion were measured using the TSA. Stress changes were compared with BMD changes around the stem 1 year after surgery in a THA patient (58 hips) with the same taper‐wedge stem. Subsequently, we compared the correlation between stress changes and BMD changes.
Results
TSA revealed significant stress changes before and after stem insertion, with prominent alterations in the proximal medial region. The BMD changes at 1 year post‐THA exhibited a 15%–25% decrease in the proximal zones, while Zones 2–6 showed a −6% to 3% change. Notably, a strong positive correlation (0.886) was found between the stress change rate and BMD change rate.
Conclusions
This study demonstrated a high correlation between femoral stress distribution assessed using TSA and subsequent BMD changes after THA. The TSA method offers the potential to predict stress distribution and BMD alterations postsurgery, aiding in implant development and clinical assessment. Combining TSA with finite element analysis could provide even more detailed insights into stress distribution.
Level of Evidence
Case series (with or without comparison).
... Proximal fixation is achieved by the hydroxyapatite coating on the proximal third of the femoral implant and by the proximal anatomic press-fit which lead to a close contact and fixation in the cancellous metaphyseal bone. The main difference between the ABG-I and II femoral implants is the reduction of the overall length by 8% and the reduction of 10% of the proximal and distal diameter of the ABG-II ( Figure 1 and Figure 2) 5,11 . There is no difference in the operation technique between both femoral implants. ...
There are many different types of cementless anatomically adapted Total Hip Arthroplasties (THAs) on the market, the Anatomic Benoist Gerard (ABG) I and II are such types of cementless THAs. In this retrospective single-centre study we evaluated the overall survival with revision for any reason and aseptic loosening as endpoint at more than 11 years follow-up. Between 2000 and 2004, 244 cementless THAs were performed in 230 patients in a primary care hospital. At a mean of 11.3 years follow-up (range 9.8 – 12.8 years) clinical examination, plain radiography and Patient Reported Outcome Measures (PROMs) were obtained and analysed. The PROMs consisted of the Oxford Hip Score (OHS) and the Western Ontario and McMaster University Index (WOMAC). At a mean of 11.3 years follow-up 32 patients (13.1%) had died of unrelated causes. Of the remaining cohort all 198 patients (212 THAs) have been reached for evaluation. There were no patients considered as lost to follow-up. At a mean of 11.3 years 11 patients (11 THAs) have had a revision of either the femoral implant or acetabular component resulting in an overall survival of 95.5%. There was no statistically significant difference (p=0.564) in survival between the ABG I and II THAs. Radiographic there were no changes between the ABG I and II last follow up. The ABG II performed statistically significant better in PROMs. We concluded that both anatomically adapted hydroxyapatite coated cementless THAs show excellent survival at more than 11 years follow-up.
... Moreover, based upon DEXA analyses, Kim et al. [29] did not find any influence of the bearing types (CoC vs. CoP) on the bone density of the proximal femoral shaft. In addition to finite element and DEXA studies, as reported by Gracia et al. [30], modifications featured to the ABG 2 stem allowed for decreasing the proximal stressshielding as compared to ABG 1. ...
Introduction:
The current study aimed as a primary goal is to assess the results of a ceramic-on-ceramic (CoC) bearing hip system matched with ABG (Anatomic Benoist Girard) 2 components in terms of survivorship. Secondary objectives addressed specifically ceramic-related complications as well as specific patterns at the bone-implant interface.
Material and methods:
This is a retrospective bicentric continuous series involving 147 patients (95 males vs. 52 females) who underwent ABG 2 arthroplasties with CoC bearings. One hundred and twenty-five hips were closely followed-up at a mean period of 11.3 years.
Results and discussion:
With a mean follow-up of 11.3 years, nine cases (5.7%) underwent revision surgery, four caused by acetabular aseptic loosening, three by deep infections, one ceramic head fracture, and one femoro-acetabular impingement. The global survivorship was 92.2% at 12.7 years. The Harris Hip Score (HHS) mean scores increased post-operatively from 50.1 up to 96.1 points (p < 0.001). All stems featured patterns of radiological osseous integration onto the hydroxyapatite (HA)-coated zones. No radiological wear or osteolysis of ceramic bearings was demonstrated however, five patients reported hip squeaking using this bearing. This study demonstrated excellent results at mid-term follow-up in patients younger than 70 years of age using cementless ABG 2 components coupled with CoC bearings with no increase in complication rate.
... Additionally, the bone loss at the greater trochanter (ROI-1) was more pronounced among patients of group A than group B. This could be explained by the different methods of preparation the femora before inserting the stems. The standard (group A) stem requires more bone removal from the metaphysis to provide a wellaligned stem, while the short-stem implantation does not need such removal owing to the curved geometry of its design [26][27][28]. ...
... However, in densitometric studies, this implant produced a 12% decrease in BMD in zone 1 and 27% in zone 7 at the end of the first postoperative year. The redesign of this implant (ABG-II; Stryker) in the late 1990s maintained good clinical and radiological results, improving the results of bone remodeling [11] but still showing a decrease in BMD of 7% in zone 1 and 16% in zone 7 [12]. ...
... When this new stem was used in our department, a pilot study was carried out with the first 37 patients who received this implant. The results showed a reduced decrease in bone mass at the proximal femur, particularly in area 7 [13], compared with the ABG-II stem [11,12]. ...
... In both stems, more pronounced losses were observed in areas 1 and 7, but more intense in the ABG-I stem. The design of the ABG-II stem, with a widening of the metaphyseal anteroposterior diameter and with a shorter and smaller tail than the ABG-I, improved the pattern of load transmission to metaphyseal zones, explaining a lower bone loss in proximal areas [12] that ranged from 7% to 16%. The results of these anatomic models coincide with those observed in other similar anatomic designs, which share the same proximal fixation philosophy. ...
Background
Periprosthetic bone remodeling, which is a phenomenon observed in all femoral stems, has a multifactorial origin as it depends on factors related to the patient, the surgical technique, and the design of the implant. To determine the pattern of remodeling produced by 2 models of anatomic cementless implants, we quantified the changes in bone mineral density (BMD) in the 7 areas of Gruen observed at different moments after surgery during the first postoperative year.
Methods
A prospective, comparative, controlled, 1-year follow-up densitometric study was carried out in 2 groups of patients suffering from primary unilateral hip osteoarthritis. In the first group, with 68 patients, an ABG-II stem was implanted. In the second, with 66 patients, the ANATO stem was used. The contralateral, healthy hip was taken as a control.
Results
Both groups showed a decrease in BMD at 3 months in all the areas, which recovered at the end of the study, except in zone 7: there was a 17.7% decrease in the ABG-II group and a 5.9% decrease in the ANATO group. In zones 2 and 6, where more loads are transmitted, conservation of BMD is observed in response to Wolff's law. The differences in the pattern of remodeling between groups were maintained despite the age, gender, and BMI of the patients or the size of the implants.
Conclusion
The ANATO stem achieved a more efficient transmission of loads at the metaphyseal level, which promotes bone preservation at the proximal femur, than the ABG-II stem.
... Additionally, the bone loss at the greater trochanter (ROI-1) was more pronounced among patients of group A than group B. This could be explained by the different methods of preparation the femora before inserting the stems. The standard (group A) stem requires more bone removal from the metaphysis to provide a wellaligned stem, while the short-stem implantation does not need such removal owing to the curved geometry of its design [26][27][28]. ...
Purpose
Stem design is usually accused for proximal femoral remodeling following total hip arthroplasty (THA). The aim of this prospective study was to compare the in vivo changes in bone mineral density (BMD) of the proximal femur after implantation of cementless THA with two length alternative stems.
Methods
Between May 2011 and March 2014, 50 patients, who met our selection criteria and received cementless THA, randomized into two groups. Group A received cementless standard femoral stems, while group B received short stems. Harris Hip Score (HHS) and visual analog scale (VAS) were used for clinical assessment. Stem and cup positions and stability were radiologically evaluated. Dual-energy X-ray absorptiometry was used to follow and compare changes in BMD in different zones of proximal femur between both groups.
Results
After a mean follow-up of 21.4 ± 3.53 months, there was a significant (p < 0.05) improvement in mean HHS and VAS with no significant differences (p > 0.05) between groups. There was no significant difference (p > 0.05) between groups regarding radiological results and rates of complications. The mean overall BMD was decreased by 11.26% for group A and 8.68% for group B at the final follow-up (p > 0.05). The greatest loss was found in greater trochanter region for group A and so for group B, but to a lesser extent (p < 0.05).
Conclusions
Cementless short stem was not able to hold back proximal femoral bone loss, but only can modify or decrease its incidence within limits.
... Several previous studies confirmed that implants with differing designs produce different patterns of periprosthetic bone remodeling. [9,34,35] Thus it has to be noticed that the most recent generation of SHA, not included in this study, might show a different pattern of periprosthetic bone remodeling. Furthermore, some SHA stems are only a short version of a standard THA stem and result in a similar periprosthetic bone remodeling pattern as the standard THA stem, and therefore have to be clearly distinguished. ...
Background
Short-stem total hip arthroplasty (SHA) has been increasingly used in the treatment of hip arthroplasty. However, it is unclear whether there is a superiority of SHA in periprosthetic bone remodeling over standard stem total hip arthroplasty (THA). This meta-analysis of randomized-controlled trials (RCTs) compared the periprosthetic bone remodeling after SHA and THA.
Methods
PubMed and Embase were screened for relevant publications up to May 2017. RCTs that compared periprosthetic bone remodeling with bone mineral density (BMD) changes between SHA and THA were included. Meta-analysis was conducted to calculate weighted mean differences (WMDs) and 95% confidence intervals (CIs) using Stata version 12.0. Quality appraisal was performed by 2 independent reviewers using RevMan 5.3 software and Grades of Recommendation Assessment, Development, and Evaluation criteria.
Results
Seven studies involving 910 patients and 5 SHA designs (Proxima, Fitmore, Microplasty short, Unique custom, and Omnifit-HA 1017) were included for meta-analysis. The pooled data showed no significant differences in the percentage BMD changes in all Gruen zones, with Gruen zone 1 [mean difference (MD) = 11.33, 95% CI, −1.67 to 24.33; P = .09] and Gruen zone 7 (MD = 8.46, 95% CI, −1.73 to 18.65; P = .10). Subgroup analysis of short SHA stems with lateral flare showed a significant less percentage BMD changes compared with standard THA in Gruen zone 1 (MD = 27.57, 95% CI, 18.03–37.12; P < .0001) and Gruen zone 7 (MD = 18.54, 95% CI, 8.27–28.81; P < .0001).
Conclusion
The study shows moderate-quality evidence that periprosthetic bone remodeling around the analyzed SHA stems was similar to standard THA stems. However, short SHA stems with lateral flare revealed a moderate- to low-quality evidence for superiority over the standard THA and highlighted the importance of the different SHA designs. Besides, it has to be noticed that despite a similar pattern of periprosthetic bone remodeling, the femoral length where periprosthetic bone remodeling occurs is clearly shorter in SHA. Due to the moderate- to low-quality evidence and the limited stem designs analyzed, the further large-scale multicenter RCTs including the most recent SHA designs are required. However, the current findings should be considered by surgeons for counseling patients regarding total hip replacement.
... 15 the Accolade tmZF stem was modeled as a homogeneous and isotropic element, with an elastic modulus of 79.5 Gpa and a poisson's ratio of 0.33. 16 to simulate the stem interface, which was successfully osteointegrated into the femur, we assumed that the stem was completely bonded to the bone in our FeA model. the loading condition simulating simplified single-leg stance was used 7,9,10 to evaluate the distribution of mechanical load. ...
... bone remodelling occurs as an adoptive response to mechanical stimulus, therefore, FeA has been used to estimate the magnitude and distribution of mechanical stimulus on the femur after tHA in a number of studies. [7][8][9][10]16,[17][18][19]21 the strain adoptive theory is a major theory of bone remodelling, 28 and it is assumed that SeD calculated in FeA can predict the magnitude of bone remodelling stimulus. 17,18 However, in several studies, the stress parameter could predict bone remodelling better than the strain parameters. ...
Objectives:
In total hip arthroplasty (THA), the cementless, tapered-wedge stem design contributes to achieving initial stability and providing optimal load transfer in the proximal femur. However, loading conditions on the femur following THA are also influenced by femoral structure. Therefore, we determined the effects of tapered-wedge stems on the load distribution of the femur using subject-specific finite element models of femurs with various canal shapes.
Patients and methods:
We studied 20 femurs, including seven champagne flute-type femurs, five stovepipe-type femurs, and eight intermediate-type femurs, in patients who had undergone cementless THA using the Accolade TMZF stem at our institution. Subject-specific finite element (FE) models of pre- and post-operative femurs with stems were constructed and used to perform FE analyses (FEAs) to simulate single-leg stance. FEA predictions were compared with changes in bone mineral density (BMD) measured for each patient during the first post-operative year.
Results:
Stovepipe models implanted with large-size stems had significantly lower equivalent stress on the proximal-medial area of the femur compared with champagne-flute and intermediate models, with a significant loss of BMD in the corresponding area at one year post-operatively.
Conclusions:
The stovepipe femurs required a large-size stem to obtain an optimal fit of the stem. The FEA result and post-operative BMD change of the femur suggest that the combination of a large-size Accolade TMZF stem and stovepipe femur may be associated with proximal stress shielding.Cite this article: M. Oba, Y. Inaba, N. Kobayashi, H. Ike, T. Tezuka, T. Saito. Effect of femoral canal shape on mechanical stress distribution and adaptive bone remodelling around a cementless tapered-wedge stem. Bone Joint Res 2016;5:362-369. DOI: 10.1302/2046-3758.59.2000525.
... Since 1997, there has been an adjustment of the femoral stem geometry because of the high failure rates of the uncemented version [9], which led to the introduction of the ABG II femoral stem for both the uncemented and cemented versions. The main differences between the ABG I and II femoral stems concern the overall length which has been reduced by 8% and the proximal and distal diameters which have been reduced by 10% [10]. The articulations used were cobalt/chromium on highly cross-linked nitrogen-irradiated polyethylene (PE) in 322 cases (99.7%) and aluminum oxide ceramic on highly cross-linked nitrogen-irradiated PE in only 1 case (0.3%). ...
This retrospective single-center study evaluated the >10-year follow-up (FU) and survival of 2 anatomically adapted cemented total hip arthroplasties (THAs) in a series of 308 patients (323 THAs) with a mean age of 76.2years at operation. At a mean of 11years of FU, patient-reported outcome measures, clinical examination, and plain radiography were analyzed. In 6 THAs, the femoral and/or acetabular component was revised. Reasons for revision were aseptic loosening and infection. At >10years of FU, there was an overall survival for both THAs of 98.1%. Radiographic radiolucent lines were seen in 15 THAs affecting Gruen zone 4 and Delee and Charnley zone II. We conclude that both anatomically adapted cemented THAs have an excellent survival at 11years of FU.
... Basic science research and clinical trials have indicated that hydroxyapatite (HA) coating on the implant surface can enhance both the bone ingrowth and bony apposition. [3][4][5][6][7][8][9][10][11][12] However, the nonphysiological surface of HA coating leads to the diminished initial osseointegration of implanted prostheses. 13,14 An additional limitation of HA coating includes its brittle nature. ...
... 21,22 We propose that PVA represents a promising scaffold coating material because of its biocompatibility, proven mechanical strength, and anabolic effect on bone formation. [21][22][23][24] In addition, PVA hydrogels have been used in a number of biomedical applications including soft contact lenses, 11 cartilage implants, 12 drug-delivery matrices, 13 temporary skin covers or burn dressings, 14 and artificial organs. 15 This is because of their inherent nontoxicity, noncarcinogenicity, good biocompatibility, and desirable physical properties such as rubbery or elastic nature and high degree of swelling in aqueous solutions. ...
