Aims. Despite the interest in the association of gut microbiota with bone health, limited population-based studies of gut microbiota and bone mineral density (BMD) have been made. Our aim is to explore the possible association between gut microbiota and BMD. Methods. A total of 3,321 independent loci of gut microbiota were used to calculate the individual polygenic risk score (PRS) for 114 gut microbiota-related traits. The individual genotype data were obtained from UK Biobank cohort. Linear regressions were then conducted to evaluate the possible association of gut microbiota with L1-L4 BMD (n = 4,070), total BMD (n = 4,056), and femur total BMD (n = 4,054), respectively. PLINK 2.0 was used to detect the single-nucleotide polymorphism (SNP) × gut microbiota interaction effect on the risks of L1-L4 BMD, total BMD, and femur total BMD, respectively. Results. We detected five, three, and seven candidate gut microbiota-related traits for L1-L4 BMD, total BMD, and femur BMD, respectively, such as genus Dialister (p = 0.004) for L1-L4 BMD, and genus Eisenbergiella (p = 0.046) for total BMD. We also detected two common gut microbiota-related traits shared by L1-L4 BMD, total BMD, and femur total BMD, including genus Escherichia Shigella and genus Lactococcus. Interaction analysis of BMD detected several genes that interacted with gut microbiota, such as phospholipase D1 (PLD1) and endomucin (EMCN) interacting with genus Dialister in total BMD, and COL12A1 and Discs Large MAGUK Scaffold Protein 2 (DLG2) interacting with genus Lactococcus in femur BMD. Conclusion. Our results suggest associations between gut microbiota and BMD, which will be helpful to further explore the regulation mechanism and intervention gut microbiota of BMD. Cite this article: Bone Joint Res 2021;10(11):734–741

Objectives. The goal of this study is to investigate the relation between indicators of osteoporosis (i.e., bone mineral density (BMD), and Cortical Index (CI)) and the complexity of a fracture of the proximal humerus as a result of a low-energy trauma. Methods. A retrospective chart review of 168 patients (mean age 67.2 years, range 51 to 88.7) with a fracture of the proximal humerus between 2007 and 2011, whose BMD was assessed at the Fracture Liaison Service with Dual Energy X-ray Absorptiometry (DXA) measurements of the hip, femoral neck (FN) and/or lumbar spine (LS), and whose CI and complexity of fracture were assessed on plain anteroposterior radiographs of the proximal humerus. Results. No significant differences were found between simple and complex fractures of the proximal humerus in the BMD of the hip, FN or LS (all p > 0.3) or in the CI (p = 0.14). Only the body mass index was significantly higher in patients with a complex fracture compared with those with a simple fracture (26.9 vs 25.2; p = 0.05). Conclusion. There was no difference in BMD of the hip, FN, LS or CI of the proximal humerus in simple compared with complex fractures of the proximal humerus after a low-energy trauma. Factors other than the BMD and CI, for example body mass index, may play a more important role in the complexity of this fracture. Cite this article: J.W.A.M. den Teuling, B.S. Pauwels, L. Janssen, C.E. Wyers, H. M. J. Janzing, J.P.W. van den Bergh, J. W. Morrenhof. The Influence of bone mineral density and cortical index on the complexity of fractures of the proximal humerus. Bone Joint Res 2017;6:584–589. DOI: 10.1302/2046-3758.610.BJR-2017-0080

Aims. Osteoporosis and abnormal bone metabolism may prove to be significant factors influencing the outcome of arthroplasty surgery, predisposing to complications of aseptic loosening and peri-prosthetic fracture. We aimed to investigate baseline bone mineral density (BMD) and bone turnover in patients about to undergo arthroplasty of the hip and knee. Methods. We prospectively measured bone mineral density of the hip and lumbar spine using dual-energy X-ray absorptiometry (DEXA) scans in a cohort of 194 patients awaiting hip or knee arthroplasty. We also assessed bone turnover using urinary deoxypyridinoline (DPD), a type I collagen crosslink, normalised to creatinine. Results. The prevalence of DEXA proven hip osteoporosis (T-score ≤ -2.5) among hip and knee arthroplasty patients was found to be low at 2.8% (4 of 143). Spinal osteoporosis prevalence was higher at 6.9% (12 of 175). Sixty patients (42% (60 of 143)) had osteopenia or osteoporosis of either the hip or spine. The mean T-score for the hip was -0.34 (. sd. 1.23), which is within normal limits, and the mean hip Z-score was positive at 0.87 (. sd. 1.17), signifying higher-than-average BMD for age. The median urinary DPD/creatinine was raised in both female patients at 8.1 (interquartile range (IQR) 6.6 to 9.9) and male patients at 6.2 (IQR 4.8 to 7.5). Conclusions. Our results indicate hip and knee arthroplasty patients have higher BMD of the hip and spine compared with an age-matched general population, and a lower prevalence of osteoporosis. However, untreated osteoporotic patients are undergoing arthroplasty, which may negatively impact their outcome. Raised DPD levels suggest abnormal bone turnover, requiring further investigation. Cite this article: Bone Joint Res 2014;3:14–19

Purpose. The purpose of this study was to evaluate periprosthetic bone mineral density (BMD) changes around a cementless short tapered-wedge stem and determine correlations between BMD changes and various clinical factors, including daily activity, after total hip arthroplasty (THA) with a short tapered-wedge stem. Methods. The study included 65 patients (65 joints) who underwent THA with a TriLock stem. At baseline, and 6, 12, and 24 months postoperatively, BMDs of the seven Gruen zones were evaluated using dual-energy X-ray absorptiometry. Correlations were determined between BMD changes and clinical factors, including the Harris hip score, body mass index, University of California at Los Angeles (UCLA) activity rating score, age at surgery, and initial lumbar BMD. Results. Minimal BMD changes were noted in the distal femur (Gruen zones 3, 4, and 5). However, significant BMD loss was noted in zone 7 at each time point. BMD loss was also noted in zone 1 at 6 and 12 months postoperatively, but BMD recovered after 18 months. Significant positive correlations were noted between BMD changes and the UCLA activity rating score in zones 1, 6, and 7. Additionally, negative correlations were noted between BMD changes and initial spine BMD in zones 2 and 3. Table legends. Table 1 Background of the patients. Table 2 Bone mineral density changes (%) at 6, 12, and 24 months postoperatively in the seven Gruen zones. Columns represent mean ± standard deviation. ※indicates P < 0.05 compared with baseline bone mineral density. Table 3 Correlations between periprosthetic bone mineral density changes and clinical factors (the Harris hip score, body mass index, University of California at Los Angeles activity rating score, age at surgery, and initial lumbar bone mineral density) in the seven Gruen zones at 24 months postoperatively. Correlation coefficients and P-values are presented. Boldface indicates P < 0.05. Conclusion. Periprosthetic BMD was maintained in the proximal femur, especially Gruen zone 1, with a short tapered stem. Daily activity may reflect improvements in periprosthetic bone quality after THA with a short tapered stem; however, this stem is not recommended in patients with low bone quality. To view tables, please contact authors directly

We studied the bone mineral density (BMD) and the bone mineral content (BMC) of the proximal tibia in patients with a well-functioning uncemented Oxford medial compartment arthroplasty using the Lunar iDXA bone densitometer. Our hypothesis was that there would be decreased BMD and BMC adjacent to the tibial base plate and increased BMD and BMC at the tip of the keel. There were 79 consecutive patients (33 men, 46 women) with a mean age of 65 years (44 to 84) with a minimum two-year follow-up (mean 2.6 years (2.0 to 5.0)) after unilateral arthroplasty, who were scanned using a validated standard protocol where seven regions of interest (ROI) were examined and compared with the contralateral normal knee. All had well-functioning knees with a mean Oxford knee score of 43 (14 to 48) and mean Knee Society function score of 90 (20 to 100), showing a correlation with the increasing scores and higher BMC and BMD values in ROI 2 in the non-implanted knee relative to the implanted knee (p = 0.013 and p = 0.015, respectively). The absolute and percentage changes in BMD and BMC were decreased in all ROIs in the implanted knee compared with the non-implanted knee, but this did not reach statistical significance. Bone loss was markedly less than reported losses with total knee replacement. There was no significant association with side, although there was a tendency for the BMC to decrease with age in men. The BMC was less in the implanted side relative to the non-implanted side in men compared with women in ROI 2 (p = 0.027), ROI 3 (p = 0.049) and ROI 4 (p = 0.029). The uncemented Oxford medial compartment arthroplasty appears to allow relative preservation of the BMC and BMD of the proximal tibia, suggesting that the implant acts more physiologically than total knee replacement. Peri-prosthetic bone loss is an important factor in assessing long-term implant stability and survival, and the results of this study are encouraging for the long-term outcome of this arthroplasty. Cite this article: Bone Joint J 2013;95-B:1480–3

In patients with osteoporosis there is always a strong possibility that pedicle screws will loosen. This makes it difficult to select the appropriate osteoporotic patient for a spinal fusion. The purpose of this study was to determine the correlation between bone mineral density (BMD) and the magnitude of torque required to insert a pedicle screw. To accomplish this, 181 patients with degenerative disease of the lumbar spine were studied prospectively. Each underwent dual-energy x-ray absorptiometry (DEXA) and intra-operative measurement of the torque required to insert each pedicle screw. The levels of torque generated in patients with osteoporosis and osteopenia were significantly lower than those achieved in normal patients. Positive correlations were observed between BMD and T-value at the instrumented lumbar vertebrae, mean BMD and mean T-value of the lumbar vertebrae, and mean BMD and mean T-value of the proximal femur. The predictive torque (Nm) generated during pedicle screw insertion was [-0.127 + 1.62 × (BMD at the corresponding lumbar vertebrae)], as measured by linear regression analysis. The positive correlation between BMD and the maximum torque required to insert a pedicle screw suggests that pre-operative assessment of BMD may be useful in determining the ultimate strength of fixation of a device, as well as the number of levels that need to be fixed with pedicle screws in patients who are suspected of having osteoporosis

We compared peri-prosthetic bone mineral density between identical cemented and cementless LCS rotating platform total knee arthroplasties. Two matched cohorts had dual energy x-ray absorptiometry scans two years post-operatively using a modified validated densitometric analysis protocol, to assess peri-prosthetic bone mineral density. The knee that was not operated on was also scanned to enable the calculation of a relative bone mineral density difference. Oxford Knee and American Knee Society scores were comparable in the two cohorts. Statistical analysis revealed no significant difference in absolute, or relative peri-prosthetic bone mineral density with respect to the method of fixation. However, the femoral peri-prosthetic bone mineral density and relative bone mineral density difference were significantly decreased, irrespective of the method of fixation, particularly in the anterior distal portion of the femur, with a mean reduction in relative bone mineral density difference of 27%. There was no difference in clinical outcome between the cemented and cementless LCS total knee arthroplasty. However, both produce stress-shielding around the femoral implants. This leads us to question the use of more expensive cementless total knee components

The major advantage of hip resurfacing is the decreased amount of bone resection compared with a standard total hip replacement. Fracture of the femoral neck is the most common early complication and poor bone quality is a major risk factor. We undertook a prospective consecutive case control study examining the effect of bone mineral density changes in patients undergoing hip resurfacing surgery. A total of 423 patients were recruited with a mean age of 54 years (24 to 87). Recruitment for this study was dependent on pre-operative bilateral femoral bone mineral density results not being osteoporotic. The operated and non-operated hips were assessed. Bone mineral density studies were repeated over a two-year period. The results showed no significant deterioration in the bone mineral density in the superolateral region in the femoral neck, during that period. These findings were in the presence of a markedly increased level of physical activity, as measured by the short-form 36 health survey physical function score

Low-energy fractures of the proximal humerus indicate osteoporosis and it is important to direct treatment to this group of patients who are at high risk of further fracture. Data were prospectively collected from 79 patients (11 men, 68 women) with a mean age of 69 years (55 to 86) with fractures of the proximal humerus in order to determine if current guidelines on the measurement of the bone mineral density at the hip and lumbar spine were adequate to stratify the risk and to guide the treatment of osteoporosis. Bone mineral density measurements were made by dual-energy x-ray absorptiometry at the proximal femur, lumbar spine (L2-4) and contralateral distal radius, and the T-scores were generated for comparison. Data were also collected on the use of steroids, smoking, the use of alcohol, hand dominance and comorbidity. The mean T-score for the distal radius was −2.97 (. sd. 1.56) compared with −1.61 (. sd. 1.62) for the lumbar spine and −1.78 (. sd. 1.33) for the femur. There was a significant difference between the mean lumbar and radial T scores (1.36 (1.03 to 1.68); p < 0.001) and between the mean femoral and radial T-scores (1.18 (0.92 to 1.44); p < 0.001). The inclusion of all three sites in the determination of the T-score increased the sensitivity to 66% compared with that of 46% when only the proximal femur and lumbar spine were used. This difference between measurements in the upper limb compared with the axial skeleton and lower limb suggests that basing risk assessment and treatment on only the bone mineral density taken at the hip or lumbar spine may misrepresent the extent of osteoporosis in the upper limb and the subsequent risk of fracture at this site. The assessment of osteoporosis must include measurement of the bone mineral density at the distal radius to avoid underestimation of osteoporosis in the upper limb

Low bone mass and osteopenia have been described in the axial and peripheral skeleton of patients with adolescent idiopathic scoliosis (AIS). Recently, many studies have shown that gene polymorphism is related to osteoporosis. However, no studies have linked the association between IL6 gene polymorphism and bone mass in AIS. This study examined the association between bone mass and IL6 gene polymorphism in 198 girls with AIS. The polymorphisms of IL6-597 G→A, IL6-572 G→C and IL6-174 G→A and the bone mineral density in the lumbar spine and femoral neck were analysed and compared with their levels in healthy controls. The mean bone mineral density at both sites in patients with AIS was decreased compared with controls (p = 0.0022 and p = 0.0013, respectively). Comparison of genotype frequencies between AIS and healthy controls revealed a statistically significant difference in IL6-572 G→C polymorphism (p = 0.0305). There was a significant association between the IL6-572 G→C polymorphism and bone mineral density in the lumbar spine, with the CC genotype significantly higher with the GC (p = 0.0124) or GG (p = 0.0066) genotypes. These results suggest that the IL6-572 G→C polymorphism is associated with bone mineral density in the lumbar spine in Korean girls with AIS

Transient osteoporosis of the hip is a disorder characterised by pain, and associated with temporary osteopaenia. Although osteopaenia is the essence of the condition, data do not exist about the local bone density of the femoral neck if no medication is administered. We describe three patients who were treated with limitation of weight-bearing only. Repeated bone mineral density measurements were obtained, and that at the femoral neck was lowest two months after the onset of the condition. The mean reduction in bone mineral density when compared with an age-matched control group was 13% (3% to 24%). Spontaneous recovery was observed in all patients

There is limited literature available looking into circumstances surrounding the development of stress fracture of the medial and lateral malleoli after ankle replacement. We present the preliminary results of a prospective study examining the effect of ankle replacement upon local bone mineral density and the phenomenon of stress shielding. We aimed to assess the effect of ankle replacement loading of the medial and lateral malleoli, by analysing the Bone Mineral Density (BMD) of the medial and lateral malleoli before and after Mobility total ankle replacement. Ten consecutive patients undergoing Mobility total ankle replacement for osteoarthritis had pre-operative bone densitometry scans of the ankle, repeated at 6 months after surgery. The bone mineral density of a 2 cm square area within the medial malleolus and lateral malleolus was measured. The pre-operative and postoperative bone densitometry scans were compared. The relation between the alignment of the tibial component and the bone mineral density of the malleoli was also analysed. The mean preoperative BMD within the medial malleolus improved from 0.57g/cm2 to mean 6 months postoperative BMD of 0.62g/cm2. The mean preoperative BMD within the lateral malleolus decreased from 0.39g/cm2 to a mean 6 months postoperative of 0.33g/cm2. The mean alignment of the tibial component was 88.50 varus (range 850 varus to 940 valgus). However, there was no correlation between the alignment of the tibial component and the bone mineral density on the medial malleolus (r = 0.09, p = 0.865). The absence of stress shielding around the medial malleolus indicates that ankle replacements implanted within the accepted limits for implant alignment, load the medial malleolus. However, there was stress shielding over the lateral malleolus resulting in decreased BMD in the lateral malleolus

Aims. The distal radius is a major site of osteoporotic bone loss resulting in a high risk of fragility fracture. This study evaluated the capability of a cortical index (CI) at the distal radius to predict the local bone mineral density (BMD). Methods. A total of 54 human cadaver forearms (ten singles, 22 pairs) (19 to 90 years) were systematically assessed by clinical radiograph (XR), dual-energy X-ray absorptiometry (DXA), CT, as well as high-resolution peripheral quantitative CT (HR-pQCT). Cortical bone thickness (CBT) of the distal radius was measured on XR and CT scans, and two cortical indices mean average (CBTavg) and gauge (CBTg) were determined. These cortical indices were compared to the BMD of the distal radius determined by DXA (areal BMD (aBMD)) and HR-pQCT (volumetric BMD (vBMD)). Pearson correlation coefficient (r) and intraclass correlation coefficient (ICC) were used to compare the results and degree of reliability. Results. The CBT could accurately be determined on XRs and highly correlated to those determined on CT scans (r = 0.87 to 0.93). The CBTavg index of the XRs significantly correlated with the BMD measured by DXA (r = 0.78) and HR-pQCT (r = 0.63), as did the CBTg index with the DXA (r = 0.55) and HR-pQCT (r = 0.64) (all p < 0.001). A high correlation of the BMD and CBT was observed between paired specimens (r = 0.79 to 0.96). The intra- and inter-rater reliability was excellent (ICC 0.79 to 0.92). Conclusion. The cortical index (CBTavg) at the distal radius shows a close correlation to the local BMD. It thus can serve as an initial screening tool to estimate the local bone quality if quantitative BMD measurements are unavailable, and enhance decision-making in acute settings on fracture management or further osteoporosis screening. Cite this article: Bone Joint Res 2021;10(12):820–829

Aims. Assessment of bone mineral density (BMD) with dual-energy X-ray absorptiometry (DXA) is a well-established clinical technique, but it is not available in the acute trauma setting. Thus, it cannot provide a preoperative estimation of BMD to help guide the technique of fracture fixation. Alternative methods that have been suggested for assessing BMD include: 1) cortical measures, such as cortical ratios and combined cortical scores; and 2) aluminium grading systems from preoperative digital radiographs. However, limited research has been performed in this area to validate the different methods. The aim of this study was to investigate the evaluation of BMD from digital radiographs by comparing various methods against DXA scanning. Methods. A total of 54 patients with distal radial fractures were included in the study. Each underwent posteroanterior (PA) and lateral radiographs of the injured wrist with an aluminium step wedge. Overall 27 patients underwent routine DXA scanning of the hip and lumbar spine, with 13 undergoing additional DXA scanning of the uninjured forearm. Analysis of radiographs was performed on ImageJ and Matlab with calculations of cortical measures, cortical indices, combined cortical scores, and aluminium equivalent grading. Results. Cortical measures showed varying correlations with the forearm DXA results (range: Pearson correlation coefficient (r) = 0.343 (p = 0.251) to r = 0.521 (p = 0.068)), with none showing statistically significant correlations. Aluminium equivalent grading showed statistically significant correlations with the forearm DXA of the corresponding region of interest (p < 0.017). Conclusion. Cortical measures, cortical indices, and combined cortical scores did not show a statistically significant correlation to forearm DXA measures. Aluminium-equivalent is an easily applicable method for estimation of BMD from digital radiographs in the preoperative setting. Cite this article: Bone Joint Res 2021;10(12):830–839

To analyze the effect of tooth extraction site preservation on bone mineral density 6 months after surgery. From 2020 to 2021, two adjacent teeth (37, 38) of the same patient were extracted at the same time, and then 37 were selected for site preservation, implanted with Bio-oss bone powder, covered with double Bio-gide membrane, reduce tension and sutured. After 6 months of self-healing, 38 was taken CBCT, and the gray value measurement tool in the software was used to measure the bone mineral density of 37 bone graft areas and 38 extraction sockets. Bone density was high in the center of the bone graft area after the extraction site, and the density decreased in the adjacent alveolar socket, but the gray value was still higher than 38 for natural healing. Extraction site surgery can improve bone mass and quality at the extraction site. It is good for implanting

Introduction: Osteoporosis is one of the major diseases worldwide, affecting millions of elderly people, with severe economical and medical consequences. The most commonly used method for the determination of decreased bone quality is the assessment of Bone Mineral Density, measured by dual X-ray absorptiometry (DXA). However DXA is quantitative and not qualitative index of the bone structure. The purpose of this study was to correlate the bone mineral density measured by DXA with the mechanical properties of the femoral neck. Materials and Methods: Bone mineral density of the proximal femur of 30 patients (27 women, 3 men) undergoing total hip displacement was estimated by DXA. The average age of these patients was 63.7 years. Patients with sort femoral neck or previous surgeries in proximal femur were excluded from the study. After hip replacement bone samples (femoral head and neck) were frozen and stored at −60 °C. A plane bone slice with 6mm thickness was sawed of femoral neck using a double cutting saw. The exact specimen dimensions were measured using a sliding calliper with high accuracy. All bone specimens were destructively tested on a material testing machine, in order to determine the material properties (Young’s modulus and yield stress) of the samples. The maximum available compression load was 100 kN with a load rate of 10 kN/min. The operational parameters and experimental data were fully controlled and handled by a graphical software package. Finally all data were evaluated and statistically analyzed. Results: A strong linear correlation of bone mineral density (T-score) with maximum failure load of samples was noted (R2=0.852). No significant differences in Young’s modulus values, was found between bone samples. Conclusions: Bone mineral density measured by DXA, although has limitations, remain a strong predictor of bone strength in the femoral neck region

Introduction: There is limited literature available looking into circumstances surrounding the development of stress fracture of the medial and lateral malleoli after ankle replacement. We present the preliminary results of a prospective study examining the effect of ankle replacement upon local bone mineral density and the phenomenon of stress shielding. Aim: To assess the effect of ankle replacement loading of the medial and lateral malleoli, by analysing the BMD of the medial and lateral malleoli before and after Mobility total ankle replacement. Methodology: Ten consecutive patients undergoing Mobility total ankle replacement for osteoarthritis had pre-operative bone densitometry scans of the ankle, repeated at 6 months after surgery. The bone mineral density of a 2 cm square area within the medial malleolus and lateral malleolus was measured. The pre-operative and post-operative bone densitometry scans were compared. The relation between the alignment of the tibial component and the bone mineral density of the malleoli was also analysed. Results: The mean preoperative BMD within the medial malleolus improved from 0.57g/cm2 to mean 6 months postoperative BMD of 0.62g/cm2. The mean preoperative BMD within the lateral malleolus decreased from 0.39g/cm2 to a mean 6 months postoperative BMD of 0.33g/cm2. The mean alignment of the tibial component was 88.50 varus (range 850 varus to 940 valgus). However, there was no correlation between the alignment of the tibial component and the bone mineral density on the medial malleolus (r = 0.09, p = 0.865). Conclusion: The absence of stress shielding around the medial malleolus indicates that ankle replacements implanted within the accepted limits for implant alignment, load the medial malleolus. However, there was stress shielding over the lateral malleolus resulting in decreased BMD in the lateral malleolus

Introduction: There is limited literature looking into the circumstances surrounding the development of stress fractures of the medial and lateral malleoli after ankle replacement. We present the preliminary results of a prospective study examining the effect of total ankle replacement (TAR) upon local bone mineral density (BMD) and the phenomenon of stress shielding. Aim: To assess the effect of TAR loading othe medial and lateral malleoli, by analysing the BMD of the medial and lateral malleoli before and after Mobility TAR. Methodology: Ten consecutive patients undergoing Mobility total ankle replacement for osteoarthritis had pre-operative bone densitometry scans of the ankle, repeated at 6 and 12 months after surgery. The bone mineral density of a 2 cm square area within the medial and lateral malleoli was measured. The pre-operative and post-operative bone densitometry scans were compared. The relation between the alignment of the tibial component and the bone mineral density of the malleoli was also analysed. Results: The mean preoperative BMD within the medial malleolus increased from a mean of 0.57g/cm2 to 0.58g/cm2 at six months and 0.60g/cm2 at 12 months postoperatively. The mean preoperative BMD within the lateral malleolus decreased from 0.39g/cm2 to 0.34g/cm2 at six months postoperatively. However the BMD over the lateral malleolus increased to 0.356g/cm2 at 12 months. The mean alignment of the tibial component was 88.50 varus (range 850 varus to 940 valgus). There was no correlation between the alignment of the tibial component and the bone mineral density on the medial malleolus (r = 0.09, p = 0.865). Conclusion: The absence of stress shielding around the medial malleolus indicates that ankle replacements implanted within the accepted limits for implant alignment, load the medial malleolus. However, there was stress shielding over the lateral malleolus resulting in decreased BMD in the lateral malleolus

Background. Reduced bone mineral density is recognised as a risk factor for hip fractures and fragility fractures in general. Vitamin D is important in maintaining healthy bone mineral levels and can therefore affect risk of hip fracture. We investigated the correlation between vitamin D levels and bone mineral density, as well as fracture type, in neck of femur fractures and also assessed the relationship of vitamin D and social deprivation. Method. We included all patients admitted to our department, with a neck of femur fracture over one year (October 2013 to October 2014). We analysed vitamin D levels for all patients during admission and compared these to bone mineral density scores, based on DEXA scan results; hip fracture type & comminution, based on admission radiographs; and levels of social deprivation, based on the patient's address. Results. In total 360 patients were admitted over the study period, with a neck of femur fracture, of which 298 had vitamin D assessed and 76 had DEXA scans. Of these cohorts, 71% were found to be vitamin D deficient and 7% had osteoporosis. No significant correlation was found between vitamin D scores and bone density, or with level of vitamin D deficiency and fracture type or comminution. A significant correlation was however identified, between low vitamin D levels and decreasing levels of social deprivation (R=0.11, p=0.04). Conclusion. No relationship was identified between vitamin D levels and hip fracture type, suggesting that vitamin D cannot be used to predict patients at risk of more comminuted fractures. Although no relationship was also identified for bone mineral density and vitamin D, this may be because the sample size of DEXA scans was relatively small. Interestingly the relationship between vitamin D and social deprivation was the reverse of what was expected and suggests that affluent individuals may be at greater risk of low vitamin D

Varus deformity is found in 90% of patients with knee OA. Axis deviation of lower extremity influences joint biomechanics and produce alteration in bone mineral density. Structure and density of subchondral bone of the knee was previously examined by X-ray. Densitometry gives us a new method of bone mineral content measurement in the interesting regions of the skeleton. The aim of this study was the assessment of effect of varus deformity on bone mineral density in tibial epiphysis. Bone mineral densities (BMD) were estimated in 46 patients at a mean age of 62 years (15 to 78) who were operated on in Department of Orthopaedics. All of them represented osteoarthritis of the knee with varus deviation. BMD of the proximal tibia was evaluated on the Lunar DPX-IQ densitometer and analyzed in three regions of interest: medial, lateral and central. Lower extremity axis deviation was measured using the Metrecom devise (Faro). Results were compared to a control group of 20 patients without osteoarthritis of the knee and without deviation of lower extremity axis. Increased BMD was found on the overweighed compartment of the knee in comparison to the underweight one. These differences were not observed in the control group. We developed a coefficient, which is the ratio of BMD in the overweighed compartment compared to BMD in underweight one. In our patients the mean value of this coefficient was 3.3, and it ranged from 1,2 to 24,5 (SD 5,7). Significant correlation between varus axis deviation of the lower extremity and increased BMD coefficient was found

Femoral stem design affects periprosthetic bone mineral density (BMD), which may impact long term survival of cementless implants in total hip arthroplasty (THA). The aim of this study was to examine proximal femoral BMD in three morphologically different uncemented femoral stems designs to investigate whether one particular design resulted in improved preservation of BMDMethods: 119 patients were randomised to receive either a proximally coated dual taper wedge stem, a proximally coated anatomic stem or a fully coated collarless triple tapered stem. All surgeries were performed via the posterior approach with mobilization on the day of surgery. Dual energy x-ray absorptiometry scans (Lunar iDXA, GE Healthcare, Madison, WI) assessed BMD across the seven Gruen zones pre-operatively, and post-operatively at 6-weeks, 1-year, and 2-years and compared to the unoperated contralateral femur as a control. Patient reported outcome measures of pain, function and health were also included at these corresponding follow-ups. BMD increased in zones one (2.5%), two (17.1%), three (13.0%), five (10%) and six (17.9%) for all stems. Greater preservation of BMD was measured on the lateral cortex (zone 2) for both the dual taper wedge and anatomic stems (p = 0.019). The dual taper wedge stem also demonstrated preservation of BMD in the medial calcar (zone 7) whilst the anatomic and triple taper stem declined in this region, however this was not statistically significant (p = 0.059). BMD decreased on average by 2.1% inthe mid-diaphysis region, distal to the stem tip (zone 4) for all implants. All stems performed equivalently at final follow-up in all patient reported outcome measures. This study demonstrated maintenance of femoral BMD in three different cementless femoral stem designs, with all achieving excellent improvements in patient reported outcomes. There was no significant stress shielding observed, however longer follow-up is required to elucidate the impact of this finding on implant survivorship

Aims. To examine the relationship of sex steroid hormones with osteopenia in a nationally representative sample of men in the USA. Methods. Data on bone mineral density (BMD), serum sex hormones, dairy consumption, smoking status, and body composition were available for 806 adult male participants of the cross-sectional National Health and Nutrition Examination Survey (NHANES, 1999-2004). We estimated associations between quartiles of total and estimated free oestradiol (E2) and testosterone (T) and osteopenia (defined as 1 to 2.5 SD below the mean BMD for healthy 20- to 29-year-old men) by applying sampling weights and using multivariate-adjusted logistic regression. We then estimated the association between serum hormone concentrations and osteopenia by percentage of body fat, frequency of dairy intake, cigarette smoking status, age, and race/ethnicity. Results. Men in the lowest quartile of total E2 concentrations (< 21.52 pg/ml) had greater odds of osteopenia compared with men in the highest quartile (odds ratio (OR) 2.29, 95% confidence interval (CI) 1.11 to 4.73; p-trend = 0.030). Total and free T were not associated with osteopenia. Low total E2 concentrations were associated with greater odds of osteopenia among non-daily dairy consumers (p-trend = 0.046), current or former smokers (p-trend = 0.032), and younger men (p-trend = 0.031). No differences were observed by race/ethnicity and obesity. Conclusion. In this nationally representative study of the USA, men with lower total E2 were more likely to have osteopenia, which was particularly evident among younger men, men with less-than-daily dairy consumption, and current or former smokers. Cite this article:Bone Joint Res. 2020;9(3):139–145

To ascertain whether patients with Colles’ fracture should be investigated for osteoporosis and the risk of future fractures, we measured the bone mineral density of the distal radius of the other arm in 31 women patients and compared the results with those of a control group of 289 normal women. We divided the patients into two groups, those younger than 66 years and those older. In 25 patients we found values for bone mineral density which were lower than one standard deviation below the mean value for their age. Younger patients had a deficit greater than that expected for their ages. We believe that women with Colles’ fracture should be evaluated routinely for osteoporosis, particularly if they are under 66 years of age

It is accepted that resurfacing hip replacement preserves the bone mineral density (BMD) of the femur better than total hip replacement (THR). However, no studies have investigated any possible difference on the acetabular side. Between April 2007 and March 2009, 39 patients were randomised into two groups to receive either a resurfacing or a THR and were followed for two years. One patient’s resurfacing subsequently failed, leaving 19 patients in each group. Resurfaced replacements maintained proximal femoral BMD and, compared with THR, had an increased bone mineral density in Gruen zones 2, 3, 6, and particularly zone 7, with a gain of 7.5% (95% confidence interval (CI) 2.6 to 12.5) compared with a loss of 14.6% (95% CI 7.6 to 21.6). Resurfacing replacements maintained the BMD of the medial femoral neck and increased that in the lateral zones between 12.8% (95% CI 4.3 to 21.4) and 25.9% (95% CI 7.1 to 44.6). On the acetabular side, BMD was similar in every zone at each point in time. The mean BMD of all acetabular regions in the resurfaced group was reduced to 96.2% (95% CI 93.7 to 98.6) and for the total hip replacement group to 97.6% (95% CI 93.7 to 101.5) (p = 0.4863). A mean total loss of 3.7% (95% CI 1.0 to 6.5) and 4.9% (95% CI 0.8 to 9.0) of BMD was found above the acetabular component in W1 and 10.2% (95% CI 0.9 to 19.4) and 9.1% (95% CI 3.8 to 14.4) medial to the implant in W2 for resurfaced replacements and THRs respectively. Resurfacing resulted in a mean loss of BMD of 6.7% (95% CI 0.7 to 12.7) in W3 but the BMD inferior to the acetabular component was maintained in both groups. These results suggest that the ability of a resurfacing hip replacement to preserve BMD only applies to the femoral side

Aims. The aim of this study was to compare the pattern of initial fixation and changes in periprosthetic bone mineral density (BMD) between patients who underwent total hip arthroplasty (THA) using a traditional fully hydroxyapatite (HA)-coated stem (T-HA group) and those with a newly introduced fully HA-coated stem (N-HA group). Methods. The study included 36 patients with T-HA stems and 30 with N-HA stems. Dual-energy X-ray absorptiometry was used to measure the change in periprosthetic BMD, one and two years postoperatively. The 3D contact between the stem and femoral cortical bone was evaluated using a density-mapping system, and clinical assessment, including patient-reported outcome measurements, was recorded. Results. There were significantly larger contact areas in Gruen zones 3, 5, and 6 in the N-HA group than in the T-HA group. At two years postoperatively, there was a significant decrease in BMD around the proximal-medial femur (zone 6) in the N-HA group and a significant increase in the T-HA group. BMD changes in both groups correlated with BMI or preoperative lumbar BMD rather than with the extent of contact with the femoral cortical bone. Conclusion. The N-HA-coated stem showed a significantly larger contact area, indicating a distal fixation pattern, compared with the traditional fully HA-coated stem. The T-HA-coated stem showed better preservation of periprosthetic BMD, two years postoperatively. Surgeons should consider these patterns of fixation and differences in BMD when selecting fully HA-coated stems for THA, to improve the long-term outcomes. Cite this article: Bone Joint J 2024;106-B(6):548–554

Femoral stem design affects periprosthetic bone mineral density (BMD), which may impact long term survival of cementless implants in total hip arthroplasty (THA). The aim of this study was to examine proximal femoral BMD in three morphologically different uncemented femoral stems designs to investigate whether one particular design resulted in improved preservation of BMD. 119 patients were randomized to receive either a proximally coated dual taper wedge stem, a proximally coated anatomic stem or a fully coated collarless triple tapered stem. Dual energy x-ray absorptiometry scans (Lunar iDXA, GE Healthcare, Madison, WI) assessed BMD across the seven Gruen zones pre-operatively, and post-operatively at 6-weeks, 1-year, and 2-years comparing the unoperated contralateral femur as a control. BMD increased in zones one (2.5%), two (17.1%), three (13.0%), five (10%) and six (17.9%) for all stems. Greater preservation of BMD was measured on the lateral cortex (zone 2) for both the dual taper wedge and anatomic stems (p = 0.019). The dual taper wedge stem also demonstrated preservation of BMD in the medial calcar (zone 7) whilst the anatomic and triple taper stem declined in this region, however this was not statistically significant (p = 0.059). BMD decreased on average by 2.1% in the mid-diaphysis region, distal to the stem tip (zone 4) for all implants. All stems performed equivalently at final follow-up in all patient reported outcome measures. Implant design was shown to impact BMD changes. All stems preserved bone at the metaphyseal level in early follow-up, which theoretically indicates favorable implant fixation. There was no significant stress shielding observed, however longer follow-up is required to elucidate the impact of this finding on implant survivorship

The measurement of bone mineral density in defined areas around metal implants has improved with the development of dual-energy X-ray absorptiometry. We used this technique to compare the bone mineral density adjacent to metal cementless femoral implants with that of identical regions of bone in normal proximal femora. We studied the anteroposterior views only of 72 femora which contained total hip implants and 34 non-operated femora. We compared the regional bone mineral density of bone adjacent to proximally porous-coated and distally porous-coated implants of one design, to measure the relative differences in the remodelling changes induced by different amounts of porous coating. We also measured differences in bone density with time and with variations in implant size (and therefore stiffness). The greatest decrease in bone mineral density (34.8%) occurred in the most proximal 1 cm of the medial femoral cortex around relatively stiff, extensively porous-coated implants. The next most severe decrease (20% to 25%) was in the next most proximal 6 cm of the medial femoral cortex. Small, progressive decreases in bone mineral density continued for five to seven years after implantation

Objectives. Several genome-wide association studies (GWAS) of bone mineral density (BMD) have successfully identified multiple susceptibility genes, yet isolated susceptibility genes are often difficult to interpret biologically. The aim of this study was to unravel the genetic background of BMD at pathway level, by integrating BMD GWAS data with genome-wide expression quantitative trait loci (eQTLs) and methylation quantitative trait loci (meQTLs) data. Method. We employed the GWAS datasets of BMD from the Genetic Factors for Osteoporosis Consortium (GEFOS), analysing patients’ BMD. The areas studied included 32 735 femoral necks, 28 498 lumbar spines, and 8143 forearms. Genome-wide eQTLs (containing 923 021 eQTLs) and meQTLs (containing 683 152 unique methylation sites with local meQTLs) data sets were collected from recently published studies. Gene scores were first calculated by summary data-based Mendelian randomisation (SMR) software and meQTL-aligned GWAS results. Gene set enrichment analysis (GSEA) was then applied to identify BMD-associated gene sets with a predefined significance level of 0.05. Results. We identified multiple gene sets associated with BMD in one or more regions, including relevant known biological gene sets such as the Reactome Circadian Clock (GSEA p-value = 1.0 × 10. -4. for LS and 2.7 × 10. -2. for femoral necks BMD in eQTLs-based GSEA) and insulin-like growth factor receptor binding (GSEA p-value = 5.0 × 10. -4. for femoral necks and 2.6 × 10. -2. for lumbar spines BMD in meQTLs-based GSEA). Conclusion. Our results provided novel clues for subsequent functional analysis of bone metabolism, and illustrated the benefit of integrating eQTLs and meQTLs data into pathway association analysis for genetic studies of complex human diseases. Cite this article: W. Wang, S. Huang, W. Hou, Y. Liu, Q. Fan, A. He, Y. Wen, J. Hao, X. Guo, F. Zhang. Integrative analysis of GWAS, eQTLs and meQTLs data suggests that multiple gene sets are associated with bone mineral density. Bone Joint Res 2017;6:572–576

To prevent bone loss, OPG/RANK/RANKL signalling pathway is a key in keeping the balance between the action of osteoblasts and osteoclasts. Aim of this study is to assess the influence of long-term nicotine exposure on bone mineral density (BMD) scores, RANKL and OPG levels of plasma and RANKL and OPG immunoreactivities of tissue in rats. In this study, totally 36 Swiss Albino rats (70±10 g) were used in three groups. Whereas normal drinking water was given for the control group (n:12), 0.4 mg/kg/day and 6.0 mg/kg/day nicotine was added to drinking water for low-dose nicotine (LDN) group (n:12) and high-dose nicotine (HDN) group (n:12), respectively for 12 months. At the end of 12. th. month, BMD scores were measured via X-ray absorptiometry and then bone turnover was assessed via measuring both RANKL, OPG levels in plasma and RANKL, OPG immunoreactivities in tail vertebrae of all rats. Lumbar spine and femoral regions BMD scores of the control group and the nicotine groups were not significantly difference. In HDN group, OPG levels of plasma were found significantly higher when compared with the control and LDN groups (p=0.001) unlike RANKL levels of plasma. RANKL and OPG immunoreactivities of tissue were found significantly lower in both LDN and HDN groups (p<0.001, p=0.004, respectively) in comparison to control group. No correlation was found between plasma levels and tissue immunoreactivities of RANKL and OPG. As a result, this study indicates that nicotine is not primarily responsible for the decline of BMD frequently seen in smokers

Introduction. There is no published series described change in bone mineral density (BMD) after ankle replacement. We present the results of a prospective study examining the effect of total ankle replacement (TAR) upon local bone mineral density (BMD). Aim. To design a method and assess the effect of TAR loading on local ankle bones, by analysing the BMD of different area around ankle before and after Mobility TAR. Methods. 23 patients undergoing Mobility ankle arthroplasty for osteoarthritis had preoperative bone densitometry scans of the ankle, repeated at 1 and 2 years after surgery. BMD of 2 cm. 2. areas around ankle were measured. Pre- and postoperative data were compared. Results: Mean BMD within the lateral malleolus decreased significantly from 0.5g/cm. 2. to 0.42g/cm. 2. (17%, P > 0.01), at 1 & 2 years postoperatively. Mean BMD within medial malleolus decreased slightly from 0.67g/cm. 2. to 0.64 g/cm. 2. at the same period. However BMD at medial side metaphysic of tibia increased by 7%. There was little increase in BMD in tibia just proximal to implant and at talus. Discussion and Conclusion. Absence of stress shielding around distal tibia, just proximal to tibial component and talus indicates that ankle replacements implanted within the accepted limits for implant alignment, load distal tibia and talus. However, there was stress shielding over the lateral malleolus resulting in decreased BMD in lateral malleolus. Increase BMD at tibial metaphysis, proximal to medial malleolus indicates an increase in mechanical stress which may explain occasional postoperative stress fracture of medial malleolus or medial side ankle pain

To investigate whether children with fractures have a low bone mineral density, 109 children (46 female and 63 male) aged 10.5 ± 2.9 years (range 5–16) sustaining either a single fracture (n=60 patients) or multiple fractures (n=49 patients) had Bone Mineral Density measurements [BMD] (Hologic QDR4500A) of L2 to L4. The Z score {(Patient’s BMD – mean aged related BMD)/ standard deviation of that age group)} was calculated using two previously published data from Shropshire children and American children. A z score of zero indicates that the patients’ BMD is exactly on the mean. The proportion above and below zero and was compared using the binomial theorem. Comparison of frequencies between the groups was undertaken using the Chi 2 test. In a scatter plot of z score against age, low z scores were frequent in girls under 8yrs using both reference data. In this group BMD z score was more likely to be below zero (p< 0.05). A low z score was more frequent in boys less than 8 years using American reference data but not Shropshire data. Girls and boys above 8 years did not show any evidence of low BMD. There was no difference in the frequency of low BMD in patients with multiple compared with single fracture. Girls and possibly boys below 8 years who have sustained a fracture show evidence of low BMD. Boys at any age and girls over 8 years did not show any evidence of having low bone density. Further work is needed to establish whether this risk continues into later life. Multiple fractures do not appear to confer additional risk of low bone density

We undertook a randomised prospective follow-up study of changes in peri-prosthetic bone mineral density (BMD) after hip resurfacing and compared them with the results after total hip replacement. A total of 59 patients were allocated to receive a hip resurfacing (n = 29) or an uncemented distally fixed total hip replacement (n = 30). The BMD was prospectively determined in four separate regions of interest of the femoral neck and in the calcar region corresponding to Gruen zone 7 for the hip resurfacing group and compared only to the calcar region in the total hip replacement group. Standardised measurements were performed pre-operatively and after three, six and 12 months. The groups were well matched in terms of gender distribution and mean age. The mean BMD in the calcar region increased after one year to 105.2% of baseline levels in the resurfaced group compared with a significant decrease to 82.1% in the total hip replacement group (p < 0.001) by 12 months. For the resurfaced group, there was a decrease in bone density in all four regions of the femoral neck at three months which did not reach statistical significance and was followed by recovery to baseline levels after 12 months. Hip resurfacing did indeed preserve BMD in the inferior femoral neck. In contrast, a decrease in the mean BMD in Gruen zone 7 followed uncemented distally fixed total hip replacement. Long term follow-up studies are necessary to see whether this benefit in preservation of BMD will be clinically relevant at future revision surgery

To evaluate the effects of 6 and 18 months of abaloparatide (ABL) compared with placebo (PBO) on bone mineral density (BMD) in the acetabular regions of postmenopausal women with osteoporosis (OP). Acetabular bone loss, as may occur in OP, increases risk of acetabular fragility fractures. a. In total hip arthroplasty (THA), low acetabular BMD adversely affects primary stability, osseointegration, and migration of acetabular cups. c. ABL is an osteoanabolic agent for the treatment of men and postmenopausal women with OP at high risk for fracture. Effects of ABL on acetabular BMD are unknown. Hip DXA scans were obtained at baseline, 6, and 18 months from a random subgroup of postmenopausal women (aged 49–86 y) from the phase 3 ACTIVE trial randomized to either ABL 80 µg/d or PBO (n=250/group). Anatomical landmarks were identified in each DXA scan to virtually place a hemispherical shell model of an acetabular cup and define regions of interest corresponding to DeLee & Charnley zones 1 (R1), 2 (R2), and 3 (R3). BMD changes compared to baseline were calculated for each zone. Statistical P values were based on a repeated mixed measures model. BMD in all zones were similar at baseline in the ABL and PBO groups. BMD significantly increased in the ABL group at 6 and 18 months compared with PBO (all P<0.0001 vs PBO). BMD in the PBO group was relatively stable over time. ABL treatment resulted in rapid and progressive increases in BMD of all 3 acetabular zones. Increasing acetabular BMD has the potential to improve acetabular strength, which may reduce risk of acetabular fragility fractures. In bone health optimization prior to THA, increased acetabular BMD via ABL may provide better primary stability and longevity of acetabular cups in postmenopausal women with OP

Our aim in this prospective study was to compare the bone mineral density (BMD) around cementless acetabular and femoral components which were identical in geometry and had the same alumina modular femoral head, but differed in regard to the material of the acetabular liners (alumina ceramic or polyethylene) in 50 patients (100 hips) who had undergone bilateral simultaneous primary total hip replacement. Dual energy X-ray absorptiometry scans of the pelvis and proximal femur were obtained at one week, at one year, and annually thereafter during the five-year period of the study. At the final follow-up, the mean BMD had increased significantly in each group in acetabular zone I of DeLee and Charnley (20% (15% to 26%), p = 0.003), but had decreased in acetabular zone II (24% (18% to 36%) in the alumina group and 25% (17% to 31%) in the polyethylene group, p = 0.001). There was an increase in the mean BMD in zone III of 2% (0.8% to 3.2%) in the alumina group and 1% (0.6% to 2.2%) in the polyethylene group (p = 0.315). There was a decrease in the mean BMD in the calcar region (femoral zone 7) of 15% (8% to 24%) in the alumina group and 14% (6% to 23%) in the polyethylene group (p < 0.001). The mean bone loss in femoral zone 1 of Gruen et al was 2% (1.1% to 3.1%) in the alumina group and 3% (1.3% to 4.3%) in the polyethylene group (p = 0.03), and in femoral zone 6, the mean bone loss was 15% (9% to 27%) in the alumina group and 14% (11% to 29%) in the polyethylene group compared with baseline values. There was an increase in the mean BMD on the final scans in femoral zones 2 (p = 0.04), 3 (p = 0.04), 4 (p = 0.12) and 5 (p = 0.049) in both groups. There was thus no significant difference in the bone remodelling of the acetabulum and femur five years after total hip replacement in those two groups where the only difference was in the acetabular liner

Bone mineral density (BMD) around the femoral component has been reported to decrease after total knee replacement (TKR) because of stress shielding. Our aim was to determine whether a cemented mobile-bearing component reduced the post-operative loss of BMD. In our study 28 knees receiving a cemented fixed-bearing TKR were matched with 28 receiving a cemented mobile-bearing TKR. They underwent dual-energy x-ray absorptiometry, pre-operatively and at three weeks and at three, six, 12, 18 and 24 months post-operatively. The patients were not taking medication to improve the BMD. The pre-operative differences in the BMD of the femoral neck, wrist, lumbar spine and knee in the two groups were not significant. The BMD of the femur decreased postoperatively in the fixed-bearing group, but not the mobile-bearing group. The difference in the post-operative change in the BMD in the two groups was statistically significant (p < 0.05) at 18 and 24 months. Our findings show that a cemented mobile-bearing TKR has a favourable effect on the BMD of the distal femur after TKR in the short term. Further study is required to determine the long-term effects

We used dual-energy X-ray absorptiometry (DEXA) to compare the bone mineral density (BMD) of nine children aged from 2 years 7 months to 13 years 5 months who had mild osteogenesis imperfecta with an age- and sex-matched control group. The patients had only mild clinical symptoms but DEXA detected highly significant differences in BMD between them and the controls. The mean BMD in the children with osteogenesis imperfecta was 76.7% of normal in the lumbar spine (p < 0.001) and 71.2% of normal in the femoral neck (p < 0.001). DEXA is an objective, reproducible and sensitive method of measurement of BMD in children. It may help to establish the diagnosis, to assess prognosis and possibly to monitor the response to different types of treatment

Introduction:. Significant proximal femoral remodeling occurs after total hip arthroplasty (THA), with regions of bone loss, and regions of hypertrophy. This study compared three implants for changes in femoral bone mineral density over 2 years following primary uncemented hip arthroplasty with a conventional stem (THA), a novel femoral neck-sparing short hip stem (NS-THA), and resurfacing hip arthroplasty (RHA). Methods:. Seventy-one patients participated in this non-randomized, prospective study. All patients had a diagnosis of osteoarthritis and underwent primary uncemented hip arthroplasty. Dual Energy XRay Absorptomitry (DXA) scans were performed at preoperative, 3–7 days post-op, 6 weeks, 6 months, one, and two years post-op. Using custom 2 cm zones, 19 zones were observed for percent changes in bone mineral density (BMD). Radiographs and Harris Hip scores were obtained at each visit. Results:. Age, gender, and BMI were found to be statistically different with fewer females and lower age in the RHA group, and a lower age in the NS-THA group. In all three groups, regions that were located proximally were shown to be the most susceptible to bone loss. Combined 2 cm zones 1C/7C, 2A/6A, and 2B/6B showed statistical significance (p < 0.05). Bone loss in the proximal regions was 8–10% lower with the femoral neck-sparing short stem, and least in the RHA group, causing little to no BMD loss in proximal regions. Radiographic outcomes and clinical results including Harris Hip scores were equal between the groups. Conclusion:. Consistent with our hypothesis, it was found that hip arthroplasty with a conventional stem resulted in the highest proximal femoral bone loss, and resurfacing arthroplasty was associated with the least bone loss. The femoral neck-sparing short stem ameliorated the bone loss seen with traditional hip arthroplasty, and approximated the bone preservation seen with hip resurfacing. The short stem neck-sparing device may provide some of the benefits of hip resurfacing, but could potentially have wider indications for use

Introduction: This study prospectively measured fifty consecutive patients who had the preoperative diagnosis of osteoarthritis undergoing total knee arthroplasty (TKA) to evaluate the change of the bone mineral density (BMD) of the calcaneus. Materials & Methods: Broadband ultrasound attenuation through the calcaneus was measured to assess the BMD of patients. The BMD was measured preoperatively and 1 month (M), 3M, 6M, 1 year, and 2 years after TKA. Results: The mean BUA at each stage was 47.1, 45.8, 46.7, 46.7, 47.8 and 53.1, respectively. During the first 6 months, the BUA declined inconsistently in most patients, but by 1 year, the BUA recovered to the initial BUA before surgery and by 2 years, the BUA increased than the initial BUA, although there ware not satisfactory different. Despite a predicted age-related loss of 4% during 2 years, 78% of the calcaneus on the operative side had BMD higher than preoperative levels and 85% had BMD that was within the expected 4% age-related loss. Discussion: These results indicated that TKA might contribute to decrease the age-related BMD loss. The increase with TKA in patient mobility and the increased heel loading may be a mechanism whereby the calcaneus BMD increases. Conclusion: It is very important for surgeons to recognize the objection beneficial effects of TKA in addition to pain relief

Purpose of study:. The purpose of the study is to evaluate the changes in peri-prosthetic bone mineral density following cemented and cementless total hip arthroplasty over a follow up period of 1 year. Description of methods:. Ethics approval was sought and granted by the South African Medical Association Research Ethics Committee (SAMAREC). Patient consent for participation was obtained. Recruitment of the cohort took place over 2 years. Patients received an uncemented (Synergy) or cemented (Spectron) prosthesis as clinically appropriate. Functional status according to the University of California Los Angeles activity scale (UCLA scale) and bone mineral density as measured by Dual Energy X-ray Absorptiometry (DEXA) was assessed pre-operatively and at 3 months, 6 months and 12 months post-operatively. An independent Contract Research Organisation was used to monitor the site. Summary of results:. As at August 2010, 59 unique patients had undergone 59 hip replacements, and 7 patients (8.5%) were still due their 12 month evaluation. The mean UCLA scored showed a marked and steady improvement post-operatively, with most of the gain demonstrated by 3 months. When evaluating all patients, the mean pre-operative values for Gruen Zones 2, 4, and Net were significantly lower than the mean 12 month values. When evaluating patients who received the uncemented prosthesis (n=40), the mean pre-operative values for Gruen Zones 2 and Net were significantly lower than the mean 12 month values, and the mean pre-operative values for Gruen Zones 1 and 3 were significantly higher than the mean 12 month values. When evaluating patients who received the cemented prosthesis (n=19), the median pre-operative values for Gruen Zones 1, 2, 3, 4, 7 and Net were significantly lower than the median 12 month values. Conclusion:. At 1 year post surgery overall bone density showed a significant increase in both the cemented and uncemented cohort

The shape of the vertebral bodies from L1 to L4 was assessed from lateral dual-energy x-ray absorptiometry (DXA) images using an active shape model. The output from the model was compared to measurements of areal bone mineral density in L1 to L4 (aBMD) using a stepwise linear regression model. A significant relationship was found between aBMD and vertebral shape that suggests that the method may be useful for correcting artefacts such as osteophytes

The bone mineral density (BMD) can be measured by dual energy X-ray absorptiometry (DEXA) accurately and precisely. BMD measurements of proximal tibia, where the structure is dominantly trabecular bone, were made on 45 normal women, aged 24–91 (52.0±14.2) years, and on 46 normal men, aged 20–71 (53.7±15.5) years. The precision of BMD measurements of proximal tibia, expressed as the coefficient of variation, was smaller than 4%. Throughout this cross-sectional study, the following results were acquired. The mean BMD in male is higher than that in female. The BMD show a decrease with age at different rates in women and men. The BMD in both genders is found to increase with body weight. A positive correlation is found between the BMD and body height in women, not in men. In right proximal tibia, the BMD of medial regions are higher than that of lateral regions significantly. Our study also demonstrates that the excellent symmetry of the BMD of the bilateral proximal tibias in both genders, but not in men with age less than 50 years old. Through the study of BMD in proximal tibias using the DEXA, it may reflect the bone reactions to many factors, such as age, sex, body weight & height, and weight bearing etc. Such a kind of study might be an useful adjuvant tool to assess the bone remodelling around the knee joint following the different surgical procedures such as total knee arthroplasty or high tibial osteotomy and might predict the future surgical outcomes

Total Hip Replacement (THR) is one of the most successful operations in all of medicine, however surgeons just rely on their experience and expertise when choosing between cemented or cementless stem, without having any quantitative guidelines. The aim of this project is to provide clinicians with some tools to support in their decision making. A novel method based on bone mineral density (BMD) measurements and assessments was developed 1) to estimate the periprosthetic fracture risk (FR) while press-fitting cementless stem; 2) to evaluate post-operative bone remodeling in terms of BMD changes after primary THR. Data for 5 out of over 70 patients (already involved in a previous study. 1. ) that underwent primary THA in Iceland were selected for developing novel methods to assess intra-operative FR and bone mineral density (BMD) changes after the operation. For each patient three CT images were acquired (Philips Brilliance 64 Spiral-CT, 120 kVp, slice thickness: 1 mm, slice increment: 0.5 mm): pre-op, 24 hours and 1 year post-operative. Pre-op CT scan was used to create 3D finite element model (Materialise Mimics) of the proximal femur. The material properties were assigned based on Hounsfield Units. Different strategies were analyzed for simulating the press-fitting operation, developing what has already been done in prior study. 1. In the finite element simulation (Ansys Workbench), a pressure (related to the implant hammering force of 9.25 kN. 2. ) was applied around the femur's hollow for the stem and the distribution of maximum principal elastic strain over the bone was calculated. Assuming a critical failure value. 3. of 7300 με, the percentage of fractured elements was calculated (i.e. FR). Post 24 hours and Post 1 year CT images were co-registrated and compared (Materialise Mimics) in order to assess BMD changes. Successively, volumes of bone lost and bone gained were calculated and represented in a 3D model. Age and gender should not be taken as unique indicators to choose between implants typologies, since also three dimensional BMD distribution along with volume of cortical bone influence the risk of periprosthetic fractures. Highest FR values were experienced in the calcar-femorale zone and in similar location on the posterior side. BMD loss volume fractions after 1 year were usually higher than BMD gain ones. Consistently with prior studies. 4. , BMD loss was mainly concentrated around the proximal end (lesser trochanter area, outer bone). If present, BMD gain occurred at the distal end (below stem's tip) or proximally (lesser trochanter area, interface contact with the stem). The use of clinical data for BMD assessments serves as an important tool to develop a quantitative method which will support surgeons in their decisions, guiding them to the optimal implant for the patient. Knowing the risk of fracture if choosing a cementless stem and being aware of how the bone will remodel around the stem in one year's time can eventually lead to reduction in revisions and increased quality of life for the patient. Further work will target analysis of a larger cohort of patients and validate FE models

Cementless implants have gained popularity in modern orthopaedic practice. The type implants and surface characteristics on fixation has been extensively investigated, however there is insufficient data on the effect of the host bone bed status on implant fixation. This study aims to determine if there is a correlation between the fixation strength of cementless press-fit implants and bone mineral density (BMD) of the host bone bed. Implants coated with pure titanium, Hydroxyapatite (HA) with or without Hyaluronic Acid (HY) and implants coated with bone growth factors – Bone Morphogenetic Protein 2 (BMP-2) were inserted into tibiae and femora of 32 skeletally mature ewes (109 implants) for a period of 1, 2 and 4 weeks. Mechanical pull-out testing was performed after each time interval to evaluate the ultimate load of failure (Nmm. −2. ). The BMD (gcm. −3. ) surrounding the implant site was measured using a CT scanner. The mean BMD (S.D.) was 1.515gcm. −3. (0.147gcm. −3. ). The mean (S.D.) mechanical pull-out strength at 1, 2 and 4 weeks was 0.37 (0.31), 3.14 (0.17) and 9.74 (2.31) Nmm. −2. respectively. The overall correlation co-efficient between BMD and pull out strength is 0.31. Early fixation strength of implants is independent of BMD, however, the strength of fixation increases with time in a ‘normal’ sheep population. This suggests that the fixation of implants is dependent on the type of implant and surface coating used rather than the density of the host bone bed

We investigated the effect of locally administered bisphosphonate on distraction osteogenesis in a rabbit model and evaluated its systemic effect. An osteotomy on the right tibia followed by distraction for four weeks was performed on 47 immature rabbits. They were divided into seven equal groups, with each group receiving a different treatment regime. Saline and three types of dosage of alendronate (low, 0.75 μg/kg; mid, 7.5 μg/kg and high 75 μg/kg) were given by systemic injection in four groups, and saline and two dosages (low and mild) were delivered by local injection to the distraction gap in the remaining three groups. The injections were performed five times weekly during the period of distraction. After nine weeks the animals were killed and image analysis and mechanical testing were performed on the distracted right tibiae and the left tibiae which served as a control group. The local low-dose alendronate group showed a mean increase in bone mineral density of 124.3 mg/cm. 3. over the local saline group (analysis of variance, p < 0.05) without any adverse effect on the left control tibiae. The findings indicate that the administration of local low-dose alendronate could be an effective pharmacological means of improving bone formation in distraction osteogenesis

Introduction: Selective COX-2 (Cyclooxygenase-2) inhibitors have been found to impede fracture healing. The effect of selective COX-2 inhibitors on tendon healing in a bone tunnel, however, is unknown. Methods: The authors performed bilateral anterior cruciate ligament reconstructions in 32 rabbits and used peripheral quantitative computed tomography (pQCT) to compare tendon-to-bone healing between tunnel aperture and midtunnel regarding bone mineral density (BMD) and ingrowth of new bone. Each animal was assigned to one of four groups. Two groups received selective COX-2 inhibitors orally for 3 weeks (Cele-coxib; 10 mg/kg/d), the two other groups received no COX-2 inhibitors (controls). The animals were sacrificed 3 and 6 weeks after surgery. In biomechanical testing maximum load to failure and stiffness of the tendon grafts were calculated from the load displacement curve and failure modes were recorded. To assess indirectly the effect on local COX-2 activity the synovial content of Prostaglandin E2 (PGE2), the major metabolite of arachnidonic acid metabolism and catalyzed by COX-2, was measured by Enzyme-linked Immunosorbent Assay (ELISA). Results: Animals treated with selective COX-2 inhibitors had significantly lower BMD at the tunnel aperture (P=.02). In all groups the BMD at the tunnel aperture was significantly higher in comparison with the midtunnel (P< .05). In the controls ingrowth of new bone was greater at the tunnel aperture at 3 weeks (P=.028). After 3 weeks of COX-2 inhibitor administration synovial fluid concentrations of PGE2 were significantly lowered (P=.018) and increased more than threefold by 6 weeks after surgery and 3 weeks after last drug administration (P=.022), while in the controls there was a decrease in PGE2 between week 3 and 6. At 6 weeks the controls exhibited a twofold increase in maximum load to failure (3 weeeks: 28.2±20.9 N; 6 weeks: 59.6±53.6 N; P=.394), whereas the COX-2 inhibitor treated specimens decreased 1.9fold (3 weeks: 69.3±50.5 N; 6 weeks: 37.4±16.8 N; P=.24). Maximum load to failure values correlated with PGE2 changes, but not statistically significant (r. 2. = −0,502; p=0,056). Failure modes at 3 and 6 weeks were rupture and degloving, respectively, of the tendon graft. Discussion: This study revealed decreased bone mineral density at the tunnel aperture at 3 weeks, an increase of the inflammatory mediator PGE2 and decreased graft stability with time after treatment with selective COX-2 inhibitors. Untreated controls appeared to have a more physiological healing course with a continuous decrease in PGE2 and an increase in graft stability. Our results suggest, that selective COX-2 inhibitors may delay tendon healing in a bone tunnel

To achieve desirable outcomes in cementless total knee replacement (TKR), sufficient primary stability is essential. The primary stability inhibits excessive motions at the bone-implant interface, hence providing the necessary condition for osseointegration [1]. Primary stability for cementless TKR is provided by press-fit forces between the bone and implant. The press-fit forces depend on several factors including interference fit, friction between bone and implant surface, and the bone material properties. It is expected that bone mineral density (BMD) will affect the stability of cementless TKR [2]. However, the effect of BMD on the primary stability of cementless femoral knee component has not been investigated in vitro. Phantom calibrated CT-scans of 9 distal femora were obtained after the surgical cuts were made by an experienced surgeon. Since the press-fit forces of the femoral component mainly occur in the Anteroposterior (AP) direction, the BMD was measured in the anterior and posterior faces for a depth of 5 mm; this depth was based on stress distributions from a Finite Element Analysis of the same implant design. In addition, four strain gauges were connected to different locations on the implant's outer surface and implant strain measured throughout as an indication of underlying bone strain. A cementless Sigma CR femoral component (DePuy Synthes Joint Reconstruction, Leeds, UK) was then implanted using an MTS machine. In order to simulate a ‘normal’ bone condition, the implanted bone was preconditioned for one hour at a cyclic load of 250–1500 N, and a rate of 1 Hz. Finally, the implants were pushed-off from the bone in a high-flex position. Forces and displacements were recorded both during insertion and push-off tests. Strong correlations were found for insertion and push-off forces with BMD, R. 2. = 0.88 and R. 2. = 0.88, respectively (p < 0.001), so although implantation may be harder in patients with higher BMD, initial stability is also improved. A correlation was also found between final strain and push-off forces (R. 2. = 0.89, p < 0.01) and BMD also showed a strong reverse correlation with total bone relaxation (R. 2. = 0.76, p = 0.023). These results indicate that higher BMD induces higher bone strain, which can lead to improved fixation strength. There is no consensus on the best fixation method for the TKR but some surgeons prefer a cementless design for young and active patients. The results of our study showed that the primary stability of a cementless femoral knee component is directly correlated with the bone mineral density. Therefore, patient selection based on bone quality may increase the likelihood of good osseointegration and adequate long-term fixation for cementless femoral knee components

Fractures of the distal forearm are widely regarded as the result of “fragility”. We have examined the extent to which patients with Colles’ fractures have osteopenia. We measured the bone mineral density (BMD) in the contralateral radius of 235 women presenting with Colles’ fractures over a period of two years. While women of all ages had low values for ultra-distal BMD, the values, in age-matched terms, were particularly low among premenopausal women aged less than 45 years. This result was not due to the presence of women with an early menopause. This large survey confirms and extends the findings from earlier small studies. We consider that it is particularly important to investigate young patients with fractures of the distal forearm to identify those with osteoporosis, to seek an underlying cause and to consider treatment

We studied the bone mineral density (BMD) of 48 long-term survivors of highly malignant osteosarcoma who had been treated according to the chemotherapy protocols of the German- Swiss-Austrian Co-operative Osteosarcoma Study Group which include high-dose methotrexate. The mean age of the patients was 31 ± 4.2 years and the mean follow-up 16 ± 2.2 years. The BMD of the lumbar spine and of the proximal femur of the non-operated side was measured by dual- energy x-ray absorptiometry. A questionnaire was given to determine life-style factors, medical history and medication. Ten patients were osteoporotic, 21 osteopenic and 17 normal according to the WHO definition. Eighteen patients suffered fractures after receiving chemotherapy and all had significantly lower levels of BMD for all the sites measured

Dual-energy X-ray absorptiometry (DEXA) is increasingly used to measure changes in bone mineral density (BMD) around femoral prostheses after total hip arthroplasty. We have studied the factors which affect the accuracy of these measurements. The coefficient of variation was < 2% using a hydroxyapatite phantom, 2.7% in an anthropomorphic phantom specimen, and < 1% in repeated measurements on implanted cadaver femora. The precision did not vary with different implant materials or designs. In patients we found a mean precision error of 2.7% to 3.4%. The most significant factor affecting reproducibility was rotation of the femur. We conclude that DEXA is a precise method of measurement for small changes in BMD around femoral implants, but that correct and careful positioning of patients is essential to obtain reliable results

We investigated prospectively the bone mineral density (BMD) of the proximal femur after implantation of a tapered rectangular cementless stem in 100 patients with a mean age of 60 years (16 to 87). It was determined using dual energy x-ray absorptiometry, performed one week after surgery and then every six months until the end-point of five years. The BMD increased significantly in Gruen zones 2, 4 and 5 by 11%, 3% and 11% respectively, and decreased significantly in Gruen zones 1, 6 and 7 by 3%, 6% and 14% respectively, over the five-year period. The net mean BMD did not change over this time period. The changes in the BMD were not confined to the first 12 months after surgery. This investigation revealed no change in the overall periprosthetic BMD, but demonstrated a regional redistribution of bone mass from the proximal to distal zones

Purpose: Insertion of the femoral stem during total hip arthroplasty provokes a bridge between the proximal femoral forces leading to well-documented bone resorption. A review of the literature concerning the behaviour of the contralateral femur and the spine reveals conflicting data. Some authors report variable bone mineral density of the lumbar spine while the contralateral neck, studied with non-cemented prostheseis in all cases, shows a significant fall in bone density. All patients in these studies needed an unloading period to achieve definitive fixation of the hip prosthesis. The purpose of this study was to assess bone behaviour in the contralateral femur and the lumbar spine after unilateral cemented total hip arthroplasty with immediate postoperative weight bearing. Material and methods: The study series included 52 patients who underwent unilateral cemented total hip arthroplasty for degenerative hip disease. All were followed with standard x-rays and DPX of the contra-lateral hip and the lumbar spine. These examinations were performed one month before surgery then on D8, M3, M6, one year and two years. Bone mineral density (BMD) was measured in the femoral neck cortical and the L2–L4 trabecularlar bone. Patients were verticalised and encouraged to walk with full weight bearing on the average on day 3 to 4 after surgery. Results: DPX did not demonstrate any significant decrease in BMD in any of the patients included in this study, neither in the lumbar spine nor in the contralat-eral femoral neck. Discussion: Several studies in the literature point out the difficulty in recovering bone mass lost after a period of immobilisation or unloading. This bone loss could reach 10% of the bone mass even for short periods of unloading. Furthermore, minimal bone loss, to the order of 2.5% could accelerate the transformation of osteopenia into osteoporosis and increase the risk of fractures. The importance of minimising periods of unloading in older patients is thus evident

Bone mineral density (BMD) and bone mineral content (BMC) have not been previously assessed in unicompartmental knee replacement (UKR). We studied the early bone changes beneath the uncemented Oxford medial UKR. Our hypothesis was that this implant should decrease the shear stresses across the bone-implant interface and result in improved BMD and BMC beneath the tibial component. Using the Lunar iDXA and knee specific software we developed 7 regions of interest (ROI) in the proximal tibia and assessed 38 patients with an uncemented Oxford UKR at 2 years. We measured the replaced knee and contralateral unreplaced knee using the same ROI and compared the BMD and BMC. The initial precision study in 20 patients demonstrated high precision in all areas. There were 12 males and 16 females with an average age of 65.8 years (46–84 years). ROI 1 and 2 were beneath the tibial tray and had significantly less BMC (p=0.023 and 0.001) and BMD (p=0.012 and 0.002). ROI 3 was the lateral tibial plateau and this area also had significantly less BMC (p=0.007) and BMD (p=0.0001). ROI 4 and 5 immediately below the tibial keel had no significant change. These changes were independent of gender and age. These results were surprising in that the universal loss of BMC and BMD suggested that bone loading of the proximal tibia was not improved even after a UKR. The better BMD and BMC adjacent to the keel confirms other studies that show improved bone in-growth around keels and pegs in the uncemented tibial component. A prospective longitudinal study has been developed to compare BMD and BMC changes over time to see whether these changes are dynamic

We investigated the effect of the Birmingham hip resurfacing (BHR) arthroplasty on the bone mineral density (BMD) of the femur. A comparative study was carried out on 26 hips in 25 patients. Group A consisted of 13 patients (13 hips) who had undergone resurfacing hip arthroplasty with the BHR system and group B of 12 patients (13 hips) who had had cementless total hip arthroplasty with a proximal circumferential plasma-spray titanium-coated anatomic Ti6A14V stem. Patients were matched for gender, state of disease and age at the time of surgery. The periprosthetic BMD of the femur was measured using dual-energy x-ray absorptiomentry of the Gruen zones at two years in patients in groups A and B. The median values of the BMD in zones 1 and 7 were 99% and 111%, respectively. The post-operative loss of the BMD in the proximal femur was significantly greater in group B than in group A. These findings show that the BHR system preserves the bone stock of the proximal femur after surgery

Aims. The aim of this study was to compare the mid-term patient-reported outcome, bone remodelling, and migration of a short stem (Collum Femoris Preserving; CFP) with a conventional uncemented stem (Corail). Methods. Of 81 patients who were initially enrolled, 71 were available at five years’ follow-up. The outcomes at two years have previously been reported. The primary outcome measure was the clinical result assessed using the Oxford Hip Score (OHS). Secondary outcomes were the migration of the stem, measured using radiostereometric analysis (RSA), change of bone mineral density (BMD) around the stem, the development of radiolucent lines, and additional patient-reported outcome measures (PROMs). Results. There were no statistically significant differences between the groups regarding PROMs (median OHS (CFP 45 (interquartile range (IQR) 35 to 48); Corail 45 (IQR 40 to 48); p = 0.568). RSA showed stable stems in both groups, with little or no further subsidence between two and five years. Resorption of the femoral neck was evident in nine patients in the CFP group and in none of the 15 Corail stems with a collar that could be studied. Dual X-ray absorbiometry showed a significantly higher loss of BMD in the proximal Gruen zones in the CFP group (mean changes in BMD: Gruen zone 1, CFP -9.5 (95% confidence interval (CI) -14.8 to -4.2), Corail 1.0 (95% CI 3.4 to 5.4); Gruen zone 7, CFP -23.0 (95% CI -29.4 to -16.6), Corail -7.2 (95% CI -15.9 to 1.4). Two CFP stems were revised before two years’ follow-up due to loosening, and one Corail stem was revised after two years due to chronic infection. Conclusion. The CFP stem has a similar clinical outcome and subsidence pattern when compared with the Corail stem. More pronounced proximal stress-shielding was seen with the CFP stem, suggesting diaphyseal fixation, and questioning its femoral neck-sparing properties in the long term. Cite this article: Bone Joint J 2022;104-B(5):581–588

The relationship between the bone mineral density (BMD) and Charcot arthropathy is unclear. Prospectively, 55 consecutive diabetic patients presenting with a Charcot arthropathy of the foot or ankle were classified as having a fracture, dislocation, or a combination fracture-dislocation pattern of initial destruction. In these groups we used dual-energy x-ray absorptiometry to compare the peripheral bone of the affected and unaffected limbs. The clinical data relating to diabetes and related major comorbidities and the site of the arthropathy (ankle, hindfoot, midfoot, forefoot) were also compared. There were 23 patients with a fracture pattern, 23 with a dislocation pattern, and nine with a combination. The age-adjusted odds ratio for developing a Charcot joint with a fracture pattern as opposed to a dislocation pattern in patients with osteopenia was 9.5 (95% confidence interval 2.4 to 37.4; p = 0.0014). Groups also differed as to the site of the arthropathy. Fracture patterns predominated at the ankle and forefoot whereas dislocations did so in the midfoot. Diabetic Charcot arthropathy of the foot and ankle differs according to the pattern of the initial destruction. The fracture pattern is associated with peripheral deficiency of BMD. The dislocation pattern is associated with a normal BMD

Fragility fractures are an increasing cause of morbidity and mortality in the elderly population. Their association with reduced bone mineral density (BMD) is well documented. It is a reasonable assumption that hip fracture severity is linked to the magnitude of bone loss, (the lower the BMD, the more severe the fracture), however it is not known whether this correlation exists. Our aim therefore was to investigate the relationship between BMD and hip fracture severity. We reviewed 142 patients, 96 females and 46 males, mean age 74 years (49-92), who had sustained a hip fracture following a simple ground level fall. All had subsequently undergone DEXA bone scanning of the contralateral hip and lumbar spine. Fractures were classified as intra-capsular, extra-capsular or subtrochanteric, then sub-classified using the Garden, Jensen and Seinsheimer classifications respectively. They were grouped into simple (stable) or comminuted (unstable) fracture patterns. Risk factors for osteoporosis were recorded. A low hip BMD (<2.5) was associated with an increased risk of extra-capsular fracture (p=0.025). However, no association with fracture type (extra vs. intra-capsular, p>0.05) was identified with the following variables; age, gender, BMI <25, smoking, and excess alcohol intake. We did not find any statistically significant associations between fracture severity and the nine principle variables tested for: age; gender; smoking; BMI < 25; alcohol excess and low hip or lumbar BMD T or Z score <-2.5. Although the association between BMD and risk of fragility fractures is well documented, the results of this study would suggest that severity of hip fractures does not follow this correlation. Therefore, no assumption can be made about BMD of the proximal femur based on the severity of fracture observed on plain radiographs alone

In conventional DXA (Dual-energy X-ray Absorptiometry) analysis, pixel bone mineral density (BMD) is often averaged at the femoral neck. Neck BMD constitutes the basis for osteoporosis diagnosis and fracture risk assessment. This data averaging, however, limits our understanding of localised spatial BMD patterns that could potentially enhance fracture prediction. DXA region free analysis (RFA) is a validated toolkit for pixel-level BMD analysis. We have previously deployed this toolkit to develop a spatio-temporal atlas of BMD ageing in the femur. This study aims first to introduce bone age to reflect the overall bone structural evolution with ageing, and second to quantify fracture-specific patterns in the femur. The study dataset comprised 4933 femoral DXA scans from White British women aged 75 years or older. The total number of fractures was 684, of which 178 were reported at the hip within a follow-up period of five years. BMD maps were computed using the RFA toolkit. For each BMD map, bone age was defined as the age for which the L2-norm between the map and the median atlas at that age is minimised. Next, bone maps were normalised for the estimated bone age. A t-test followed by false discovery rate (FDR) analysis was applied to compare between fracture and non-fracture groups. Excluding the ageing effect revealed subtle localised patterns of loss in BMD oriented in the same direction as principal tensile curves. A new score called f-score was defined by averaging the normalised pixel BMD values over the region with FDR q-value less than 1e–6. The area under the curve (AUC) was 0.731 (95% confidence interval (CI)=0.689–0.761) and 0.736 (95% CI=0.694–0.769) for neck BMD and f-score. Combining bone age and f-score improved the AUC significantly by 3% (AUC=0.761, 95% CI=0.756–0.768) over the neck BMD alone (AUC=0.731, 95% CI=0.726–0.737). This technique shows promise in characterizing spatially-complex BMD changes, for which the conventional region-based technique is insensitive. DXA RFA shows promise to further improve fracture prediction using spatial BMD distribution

Introduction Vertebral fractures in the elderly frequently involve the anterior and superior regions of the vertebral body. We hypothesise that vertebral fracture patterns reflect regional variations in bone mineral density (BMD). Methods Nineteen motion segments (aged 48–90 yrs) were obtained from thoracic and lumbar regions of cadaver spines. Specimens were compressed to failure while positioned in moderate flexion (to simulate someone lifting in a stooped posture). Superior and inferior vertebrae were dissected and the site of fracture identified by visual inspection. The volume of each vertebral body was measured by water immersion, and BMD was measured using dual X-ray absorptiometry (DXA). BMD was also calculated for the following regions: superior and inferior end-plates; upper, middle and lower thirds of the vertebral body between the end-plates; anterior, middle and posterior thirds of the vertebral body. Results In 16 of the 19 specimens, an obvious fracture was located in the anterior or central region of the superior end-plate of the inferior vertebral body, accompanied by collapse of supporting trabeculae. BMD of the superior end-plate was significantly lower than that of the inferior end-plate. Similarly, BMD of the upper third of the vertebral body was less than that of the lower third, and BMD increased significantly from anterior to posterior regions in the vertebral body. Discussion Low BMD in the superior and anterior regions of old vertebral bodies predisposes them to fracture. Altered load-sharing in old spines secondary to disc degeneration may explain these regions of low BMD

The rising incidence of atraumatic fractures in patients either with Ewing's sarcoma or osteosarcoma years after chemotherapy revealed a growing population of childhood cancer survivors with a decreased bone mineral density (BMD) possibly due to a long-term effect of the chemotherapy. Therefore we started to screen our patients below 50y of age who were treated for bone malignancies between 1994 and 2009. The first series of measurements included 15 patients – eight Ewing's sarcoma, three female and five male, with a mean age of 18y (±13SD), and seven osteosarcoma, two female and five male, with a mean age of 19y(±9SD). We screened the patients for deficits in their bone status using DEXA (dual-energy-x-ray-absorptiometry) to gain the T-and Z-Scores of the proximal femur and the lumbal spine. Additionally we took blood samples for endocrinological analysis and utilised a questionnaire to scan the patient's liefestyle. The mean time between diagnosis and investigation was 95months (±79SD) in Ewing's sarcoma and 105months (±54 SD) in osteosarcoma. The results of the age and gender matched lumbal measurement (Z-Score) of the Ewing's sarcoma patients showed a reduction of the BMD in six cases (6/8), including three times osteopenia (3/8) and two times osteoporosis (2/8). The osteosarcoma patients presented a BMD-decline in four cases (4/7) with two times osteopenia (2/7) and one osteoporosis (1/7). In the proximal femur six Ewing's sarcoma (6/8) and six osteosarcoma patients (6/7) showed a BMD-decrease including three osteopenic (3/8) and one osteoporotic (1/8) Ewing's sarcoma and four osteopenic osteosarcoma (4/7). We found two cases of pathologic fractures (2/15), one Ewing's sarcoma 29 months after diagnosis with a fracture of the distal femur and the proximal Tibia (1/8) and one osteosarcoma with a fractured distal femur after 72 months (1/7). As presented in our case series osteoporosis after chemotherapy is an underestimated long-term effect of the chemotherapeutic treatment. In our series BMD-reduction seems to be independent of tumour-type and chemotherapeutic agent like MTX

Objective. In ex vivo hip fracture studies femoral pairs are split to create two comparable test groups. When more than two groups are required, or if paired femurs cannot be obtained, group allocation according to bone mineral density (BMD) is sometimes performed. In this statistical experiment we explore how this affects experimental results and sample size considerations. Methods. In a hip fracture experiment, nine pairs of human cadaver femurs were tested in a paired study design. The femurs were then re-matched according to BMD, creating two new test groups. Intra-pair variance and paired correlations in fixation stability were calculated. A hypothetical power analysis was then performed to explore the required sample size for the two types of group allocation. . Results. The standard deviation (. sd. ) of the mean paired difference in fixation stability increased from 2 mm in donor pairs to 5 mm in BMD-matched pairs. Intra-pair correlation was 0.953 (Pearson’s r) in donor pairs and non-significant at -0.134 (Pearson’s r) in BMD-matched pairs. Required sample size to achieve a statistical power of 0.8 increased from ten pairs using donor pairs to 54 pairs using BMD-matched pairs. Conclusion. BMD cannot be used to create comparable test groups unless sample size is increased substantially and paired statistics are no longer valid. Cite this article: Bone Joint Res 2014;3:317–20

Introduction: Osteoporosis is diagnosed by measurement of bone mineral density (BMD), with techniques that include single and dual energy x-ray absorptiometry (SXA, DXA) and quantitative computed tomography (QCT), which have relatively high cost and limited availability. Radiographic absorptiometry (RA), the corresponding technique based on plain radiographs, has not been favoured clinically because it required complex devices to calibrate and difficult techniques to measure the optic densitometry of films. In this paper a newly developed computerised radiographic technique is described that gives results in actual BMD units and includes a correction for soft-tissues. The technique has been developed in conjunction with a new solid phantom to facilitate the use in fracture clinics, without the need for further patient exposure. It also has the advantage of measuring the ultradistal radius, a clinically useful cancellous rich site. The design of the phantom and initial calibration testing are described. M& M: The new phantom is constructed from a solid water equivalent material, removing the need for a soft-tissue equalising water bath. The necessary hydroxyapatite (HA) calibration wedge is built into the phantom to give results in actual BMD units. A high-density grid has been used to minimise the effects of scatter caused by soft tissues. The phantom was initially calibrated by comparing its results with those obtained from specially manufactured hydroxyapatite disks. The European Forearm Phantom (EFP) was used in studies of further calibration and testing of anatomical specimens, obtained with permission from the department of Anatomy at the University of St. Andrews. Results: The test comparing the BMD determined by the new phantom to the known density of specially manufactured HA discs yielded a very high correlation (R> 0.999) with an error < 2%. Further studies with the EFP as a reference standard confirmed a very high correlation (R> 0.999) with an error of < 5%. Finally a study was performed on 25 cadaver forearms that were available for imaging using DXA and the modified RA technique. BMD results showed good correlation (R=0.93, P< 0.001) with an error of less than 10%. The error is partly explained because during this part of the study a high-resolution anti-scatter grid was unavailable and a standard grid had to be used. Also some cadavers had previous fractures and dissection marks. Without these problems, it is expected that the error percentage would be significantly reduced. Discussion: The phantom is light, small and the patient can comfortably fit even if the limb is fractured. The results compare favourably with published data for existing techniques that also used the EFP as a reference standard. The described technique carries the promise of a simple, inexpensive system, which yields superior results and can be used seamlessly in a fracture clinic. A pilot clinical study is being planned, comparing the results of the modified RA technique with peripheral DXA. This system can be quickly made available at minimum cost utilizing existing equipment. All the other advantages of computerised x-rays including more precise measurements of deformity and central analysis from a distance for isolated practices apply

Locking plate fixation in proximal humeral fractures has demonstrated good results tempered by a significant rate of loss of fixation. Reported rates of failure are typically around 10% of cases but can be 20% or higher. In addition large series are often made up of a diverse patient population, so we have chosen to focus solely on patients confirmed to have significantly reduced BMD who can be considered a subset at high risk of fixation failure. Twenty-three patients (5 male, 18 female) with a proximal humeral fracture treated by locking plate fixation were confirmed on DEXA scanning to be osteopaenic (17), osteoporotic (4) or severely osteoporotic (2). Patients early in the series were reviewed retrospectively and recalled for an updated assessment where appropriate, and the remainder were followed prospectively. The average age was 66 years (range 49 to 82). Follow up was for an average of nine months following surgery (range 2 and a half to 28 months). 17 patients underwent surgery for acute injuries and 6 for established surgical neck non-unions. Seven injuries were 2-part fractures, 12 3-part, 3 were 4-part and one a 2-part surgical neck non-union.1 plate failed due to complete loss of fixation within 2 months in a patient with severe osteoporosis and was treated with removal of metalwork. This was the only injury that failed to unite. Avascular necrosis occurred in three patients with two revised to a hemiarthroplasty. 1 patient had ongoing pain and underwent removal of the plate. Our series demonstrated that locking plate fixation of proximal humeral fractures is associated with a low rate of fixation failure and satisfactory outcomes in patients with significantly reduced bone mineral density

Stand-alone anterior lumbar interbody fusion (ALIF) provides the opportunity to avoid supplemental posterior fixation. This may reduce morbidity and complication rate, which is of special interest in patients with reduced bone mineral density (BMD). This study aims to assess immediate biomechanical stability and radiographic outcome of a stand-alone ALIF device with integrated screws in specimens of low BMD. Eight human cadaveric spines (L4-sacrum) were instrumented with SynFix-LR™ (DePuy Synthes) at L5/S1. Quantitative computed tomography was used to measure BMD of L5 in AMIRA. Threshold values proposed by the American Society of Radiology 80 and 120 mg CaHa/mL were used to differentiate between Osteoporosis, Osteopenia, and normal BMD. Segmental lordosis, anterior and posterior disc height were analysed on pre- and postoperative radiographs (Fig 1). Specimens were tested intact and following instrumentation using a flexibility protocol consisting of three loading cycles to ±7.5 Nm in flexion-extension, lateral bending, and axial rotation. The ranges of motion (ROM) of the index level were assessed using an optoelectronic system. BMD ranged 58–181mg CaHA/mL. Comparison of pre- and postoperative radiographs revealed significant increase of L5/S1 segmental lordosis (mean 14.6°, SD 5.1, p < 0.001) and anterior disc height (mean 5.8mm, SD 1.8, p < 0.001), but not posterior disc height. ROM of 6 specimens was reduced compared to the intact state. Two specimens showed destructive failure in extension. Mean decrease was most distinct in axial rotation up to 83% followed by flexion-extension. ALIF device with integrated screws at L5/S1 significantly increases segmental lordosis and anterior disc height without correlation to BMD. Primary stability in the immediate postoperative situation is mostly warranted in axial rotation. The risk of failure might be increased in extension for some patients with reduced lumbar BMD, therefore additional posterior stabilization could be considered. For any figures or tables, please contact the authors directly

The introduction of porous tantalum metal (Trabecular Metal; Zimmer, Warsaw, IN) for acetabular component fixation in total hip arthroplasty has shown optimum fixation qualities and “gap filling” effect. Recently, trabecular metal was introduced in tibial component for total knee prosthesis, however its effect on the bone mineral density (BMD) was not reported. The purpose of this study was to compare the BMD of proximal part of the tibia between trabecular metal and another cemented tibial component. 31 knees receiving trabecular metal tibial component and 33 knees receiving cemented tibial component (PFC Sigma RP, Depuy, Warsaw, IN) had dual energy x-ray absorptiometry (DEXA) scans at preoperatively and 3 weeks, 3, 6, 12, 18, 24 months post-operatively. To assess peri-prosthetic BMD, three regions of interest (ROI) were measured for each case. They were medial aspect (ROI 1), center aspect (ROI 2) and lateral aspect (ROI 3) of tibia. Average follow up period was 1.8 (range: 1.5 to 2) years. In both groups, BMD in tibia decrease postoperatively. Comparing postoperative decrease of BMD in lateral aspect of tibia (ROI 3) between both groups, it was significantly less in trabecular metal component (−0.09 g/cm2 +/−0.27) than cemented tibial component (−0.31 g/cm2 +/− 0.21) (p=0.0007). We conclude that trabecular metal tibial component showed a favorable effect on BMD of proximal part of the tibia after total knee arthroplsaty

Purpose. Use of a large femoral head metal-on-metal bearing in total hip arthroplasty may offer an advantage in terms of dislocation rates and more natural joint kinematics. The acetabular component is more rigid however in these prostheses and if not placed accurately can lead to increased levels of metal ion release. A prospective randomized controlled trial was conducted to quantify bone mineral density on the acetabular side, as well as compare metal ion levels from a standard metal-on-polyethylene bearing to a large head metal-on-metal bearing in primary total hip arthroplasty. Method. Fifty patients were randomized to receive total hip arthroplasty with either the CONSERVE A-Class Total Hip with BFH femoral head or the Lineage acetabular component with polyethylene insert and cobalt chrome femoral head. There were 27 females (11 BFH) and 23 males (14 BFH), with a mean overall age of 61.6 (range 47.7–73.2). Serum levels of cobalt, chromium, and titanium were measured at regular intervals up to two years. Harris Hip Score, WOMAC, UCLA, and RAND-36 were completed at these same intervals. Standard radiographs as well as periprosthetic BMD were performed. Results. Bone mineral density in acetabular zones II, III, and IV was greater in the BFH group compared with the metal on poly group (p= 0.030, 0.046, and 0.019 respectively). Serum levels of cobalt (2.31 microg/mL vs 0.23 microg/mL, p=<0.001) and chromium (1.53 microg/mL vs 0.21 microg/mL, p=<0.001) were statistically higher in the BFH group compared with the metal-on-polyethylene group at one year post-op. There was no significant difference in serum titanium levels between groups. Conclusion. At short term follow up the load transfer to the acetabular bony bed differed between the two groups, with the more rigid shells demonstrating increased BMD in certain zones when compared with metal on poly. Serum levels of certain ions were 7–15 fold higher in the metal-on-metal large femoral head design compared with a standard metal-on-polyethylene. We await results on any clinical differences in performance and complications in this group of patients. Systemic implications of these ion levels are not known and further study is warranted

Objectives. Osteosynthesis of anterior pubic ramus fractures using one large-diameter screw can be challenging in terms of both surgical procedure and fixation stability. Small-fragment screws have the advantage of following the pelvic cortex and being more flexible. The aim of the present study was to biomechanically compare retrograde intramedullary fixation of the superior pubic ramus using either one large- or two small-diameter screws. Materials and Methods. A total of 12 human cadaveric hemipelvises were analysed in a matched pair study design. Bone mineral density of the specimens was 68 mgHA/cm. 3. (standard deviation (. sd). 52). The anterior pelvic ring fracture was fixed with either one 7.3 mm cannulated screw (Group 1) or two 3.5 mm pelvic cortex screws (Group 2). Progressively increasing cyclic axial loading was applied through the acetabulum. Relative movements in terms of interfragmentary displacement and gap angle at the fracture site were evaluated by means of optical movement tracking. The Wilcoxon signed-rank test was applied to identify significant differences between the groups. Results. Initial axial construct stiffness was not significantly different between the groups (p = 0.463). Interfragmentary displacement and gap angle at the fracture site were also not statistically significantly different between the groups throughout the evaluated cycles (p ⩾ 0.249). Similarly, cycles to failure were not statistically different between Group 1 (8438, . sd. 6968) and Group 2 (10 213, . sd. 10 334), p = 0.379. Failure mode in both groups was characterised by screw cutting through the cancellous bone. Conclusion. From a biomechanical point of view, pubic ramus stabilisation with either one large or two small fragment screw osteosynthesis is comparable in osteoporotic bone. However, the two-screw fixation technique is less demanding as the smaller screws deflect at the cortical margins. Cite this article: Y. P. Acklin, I. Zderic, S. Grechenig, R. G. Richards, P. Schmitz, B. Gueorguiev. Are two retrograde 3.5 mm screws superior to one 7.3 mm screw for anterior pelvic ring fixation in bones with low bone mineral density? Bone Joint Res 2017;6:8–13. DOI: 10.1302/2046-3758.61.BJR-2016-0261

We aimed to evaluate the precision and longitudinal sensitivity of measurement of bone mineral density (BMD) in the pelvis and to determine the effect of bone cement on the measurement of BMD in femoral regions of interest (ROI) after total hip arthroplasty (THA). A series of 29 patients had duplicate dual-energy x-ray absorptiometry (DXA) scans of the hip within 13 months of THA. Pelvic analyses using 3- and 4-ROI models gave a coefficient of variation (CV) of 2.5% to 3.6% and of 2.5% to 4.8%, respectively. Repeat scans in 17 subjects one year later showed a significant change in BMD in three regions using the 4-ROI model, compared with change in only one region with the 3-ROI model (p < 0.05). Manual exclusion of cement from femoral ROIs increased the net CV from 1.6% to 3.6% (p = 0.001), and decreased the measured BMD by 20% (t = 12.1, p < 0.001). Studies of two cement phantoms in vitro showed a small downward drift in bone cement BMD giving a measurement error of less than 0.03 g/cm. 2. /year associated with inclusion of cement in femoral ROIs. Changes in pelvic periprosthetic BMD are best detected using a 4-ROI model. Analysis of femoral ROI is more precise without exclusion of cement although an awareness of its effect on the measurement of the BMD is needed

To explore a novel machine learning model to evaluate the vertebral fracture risk using Decision Tree model and train the model by Bone Mineral Density (BMD) of different compartments of vertebral body. We collected a Computed Tomography image dataset, including 10 patients with osteoporotic fracture and 10 patients without osteoporotic fracture. 40 non-fracture Vertebral bodies from T11 to L5 were segmented from 10 patients with osteoporotic fracture in the CT database and 53 non-fracture Vertebral bodies from T11 to L5 were segmented from 10 patients without osteoporotic fracture in the CT database. Based on the biomechanical properties, 93 vertebral bodies were further segmented into 11 compartments: eight trabecular bone, cortical shell, top and bottom endplate. BMD of these 11 compartments was calculated based on the HU value in CT images. Decision tree model was used to build fracture prediction model, and Support Vector Machine was built as a compared model. All BMD data was shuffled to a random order. 70% of data was used as training data, and 30% left was used as test data. Then, training prediction accuracy and testing prediction accuracy were calculated separately in the two models. The training accuracy of Decision Tree model is 100% and testing accuracy is 92.14% after trained by BMD data of 11 compartments of the vertebral body. The type I error is 7.14% and type II error is 0%. The training accuracy of Support Vector Machine model is 100% and the testing accuracy is 78.57%. The type I error is 17.86% and type II error is 3.57%. The performance of vertebral body fracture prediction using Decision Tree is significantly higher than using Support Vector Machine. The Decision Tree model is a potential risk assessment method for clinical application. The pilot evidence showed that Decision Tree prediction model overcomes the overfitting drawback of Support Vector Machine Model. However, larger dataset and cohort study should be conducted for further evidence

INTRODUCTION. Loosening is a major cause for revision in uncemented hip prostheses due to insufficient primary stability. Primary stability after surgery is achieved through press-fit in an undersized cavity. Cavity preparation is performed either by extraction (removing bone) or compaction (crushing bone) broaching. Densification of trabecular bone has been shown to enhance primary stability in human femora; however, the effect of clinically used compaction and extraction broaches on human bone with varying bone mineral density (BMD) has not yet been quantified. The purpose of this study was to determine the influence of the broach design and BMD on the level of densification at the bone-cavity interface, stem seating, the bone-implant contact area and the press-fit achieved. METHODS. Paired human femora (m/f=11/12, age=60±18 y) were scanned with quantitative computed tomography (QCT, Philips Brilliance 16) before broaching, with the final broach, after its removal and after stem implantation. Compaction broaching (n=4) was compared in an in situ (cadaver) study against extraction broaching with blunt tooth types (n=3); in an ex situ (excised femora) study, compaction broaching was compared against extraction broaching with sharp tooth types (n=8 each). QCT data were resampled to voxel sizes of 1×1×1 mm (in situ) and 0.5×0.5×1 mm (ex situ). Mean trabecular BMD of the proximal femur was determined. The cavity volumes were segmented in the post-broach images (threshold: −250 mgHA/cm3, Avizo 9.2) and a volume of interest (VOI) of one-voxel thickness was added around the cavity to capture the interfacial bone. VOIs were transferred to the pre-broach image and bone densification was calculated within each VOI as the increase from pre- to post-broach image (MATLAB). Detailed surface data sets of broaches and stems were collected with a 3D laser-scanner (Creaform Handyscan 700) and aligned with the segmented components in the CT scans (Fig. 1). Stem seating was defined as the difference between the top edge of the stem coating and the final broach. Distance maps between the stem and cavity surface were generated to determine the bone-implant contact area and press-fit. All parameters were analysed between 5 mm distal to the coating and 1 cm distal to the lesser trochanter and analysed with related-samples Wilcoxon signed rank and Spearman's correlation tests (IBM SPSS Statistics 22). RESULTS. Trabecular BMD ranged from 81 to 221 mgHA/cm3. Densification was higher with compaction compared to sharp (p=0.034), but not blunt extraction broaching (p=1.000). Proximal bone-implant contact area, press-fit and stem seating did not differ between broaching methods. Bone-implant contact area and bone densification increased with trabecular BMD (rs=0.658, p=0.001 and rs=0.443, p=0.034), press-fit with stem seating (rs=0.746, p<0.001) and contact area with bone densification (rs=0.432, p=0.039). DISCUSSION. Sharp extraction broaching reduces densification at the bone-cavity interface, but does not affect the press-fit or contact area. Trabecular BMD was positively associated with contact area, and stem seating with press-fit. Future studies will aim to link these findings to primary stability and influence on periprosthetic fractures. For any figures or tables, please contact authors directly

Cementless total knee replacement (TKR) is at the present date a controversial topic. Aim of the study was to compare the effect on tibial periprosthetic bone mineral density (BMD) between different implant materials and designs. During the two-year period between January 2005 and December 2006, we analysed data of 45 patients who underwent consecutively cementless TKR (49 implants) at our Institution for primary osteoarthritis. Data was divided in 2 groups: A) 26 implants with tantalium tibial component (Zimmer NexGen Trabecular Metal. TM. Monoblock); B) 23 implants with porous titanium tibial component (Lima MultiGen. TM. ). Data was comparable per sex, age, BMI, post-op alignment, post-op KSS > 75, absence of major post-op complications. Standard AP x-rays were taken 4 months post-op and 8 years post-op. In order to quantify the reduction of BDM, we determined using ImageJ (an open source software) the Mean Grey Value (MGV) of a specific area on the 4 months- and 8 yrs-postop AP x-rays. Group A and Group B had an average MGV variation of, respectively, 11.79% and 10.51%; there was no statistically significant difference between the two groups. Reduction of BMD in a TKR is known to be a biomechanical response to load and it is conditioned by the alignment of the components and their design. Our study shows that the different materials (porous titanium vs. tantalium), in relation to the different implant design, have a similar effect on the surrounding bone. The overall results show a valid osseointegration in both group of patients

Vitamin D is vital for bone health because it assists in the absorption and utilisation of calcium. Vitamin D deficiency may predispose individuals to developing osteoporosis and subsequent osteoporotic fracture. There are various studies in elderly females with hip fractures correlating the low bone mineral density (BMD) with vitamin D levels. But very few studies have evaluated the influence on elderly males. Therefore this study was conducted. All male patients aged more than 50 years presenting to orthopaedic department, in JIPMER, Puducherry, with either fracture neck of femur or intertrochanteric fracture were included. Serum vitamin D level was assessed in them and BMD of both the hips was evaluated by DEXA scan. The vitamin D levels, T-scores, Z-scores were then analysed and correlated. Of the total 41 patients evaluated 21 (51%) had fracture neck of the femur and 20 (49%) patients had intertrochanteric fractures. We found that 11 (26.8%) patients had osteoporosis, 17 (41.5%) had osteopenia, and 13 (31.7%) had normal values. The mean value of total T-scores on fracture side was −1.55 and on no fracture side was −1.88. Among them 9 (22%) patients had vitamin D level <20 ng /mL, 15 (36%) had levels between 20ng–30ng/mL and 17 (41%) had >30ng/mL. Total T-score and Z-score on fracture side and no fracture side showed no correlation with vitamin D (p value >0.05) in these patients. We found significant osteoporosis in both neck and trochanteric regions on both fracture and no fracture sides, yet we had some patients with trochanteric fracture and some with neck fracture on only one side. In view of this other factors like mode of injury, velocity of injury, muscle wasting might have contributed significantly to the type of fracture and side involved. The BMD was found to be lower in patients with neck of femur fracture compared to intertrochanteric fracture, but no correlation was found between vitamin D and BMD scores at neck and trochanteric region. From this study it appears that there is no direct relationship between the vitamin D level and BMD in elderly males with hip fractures. It may emphasise that in male patients with hip fractures vitamin D may not have critical role in development of osteoporosis. The treatment of such patients with vitamin D supplements to prevent hip fractures is still debatable. However further studies in very large groups and controls may bring more light on this subject

Our aim was to determine the precision of the measurements of bone mineral density (BMD) by dual-energy x-ray absorptiometry in the proximal femur before and after implantation of an uncemented implant, with particular regard to the significance of retro- and prospective studies. We examined 60 patients to determine the difference in preoperative BMD between osteoarthritic and healthy hips. The results showed a preoperative BMD of the affected hip which was lower by a mean of 4% and by a maximum of 9% compared with the opposite side. In addition, measurements were made in the operated hip before and at ten days after operation to determine the effect of the implantation of an uncemented custom-made femoral stem. The mean increase in the BMD was 8% and the maximum was 24%. Previous retrospective studies have reported a marked loss of BMD on the operated side. The precision of double measurements using a special foot jig showed a modified coefficient of variation of 0.6% for the non-operated side in 15 patients and of 0.6% for the operated femur in 20 patients. The effect of rotation on the precision of the measurements after implantation of an uncemented femoral stem was determined in ten explanted femora and for the operated side in ten patients at 10° rotation and in 20 patients at 30° rotation. Rotation within 30° influenced the precision in studies in vivo and in vitro by a mean of 3% and in single cases in up to 60%. Precise prediction of the degree of loss of BMD is thus only possible in prospective cross-sectional measurements, since the effect of the difference in preoperative BMD, as well as the apparent increase in BMD after implantation of an uncemented stem, is not known from retrospective studies. The DEXA method is a reliable procedure for determining periprosthetic BMD when positioning and rotation are strictly controlled

The study was designed to determine the incidence and to quantify the risk factors of permanently decreased bone mineral density (BMD) of the Lumbar spine and Femoral neck following tibial shaft fractures. 42 consecutive adults treated for isolated tibial shaft fractures at our institution between January 1984 and June 1985 formed the subjects of this study. Mechanism and type of injury, method of treatment, length of immobilisation and weight bearing status and healing time were determined from the patient records. A questionnaire including history of smoking, alcohol consumption, medications, other fractures, medical conditions like thyroid/parathyroid disorders, convulsions, and renal disorders was administered. Bone mineral density of lumbar 1–4 vertebrae and both hips was assessed using DEXA scanning. T and Z scores were generated. Statistical analysis was performed using the Chi square test to test the significance of association of osteopenia/osteoporosis (Z score < -1) with a previous tibial shaft fracture and calculating the odds ratio (OR) and 95% confidence interval (CI) to quantify the suspected risk factors. The incidence of significant loss of BMD of the ipsilateral femur and/or lumbar spine was found to be 33%. A statistically significant association (p< 0.001) between a history of tibial shaft fracture and permanent loss of BMD was noted. The following risk factors were found to be statistically significant; Smoking (OR 22, 95% CI=4–> 40, p< 0.001), Alcohol more than 20 units/week (OR 11, 95% CI 2.2–54,p< 0.005), Open fracture (OR 17, 95% CI=2.9–> 40, p< 0.001), Non-weight bearing more than 12 weeks (OR 15, 95% CI 2.9–> 40, p< 0.005), and delayed union defined as healing time more than 6 months (OR 15, 95% CI 1.54–> 40, p < 0.05). Permanent regional osteopaenia/osteoporosis occurs in a significant proportion of tibial shaft fracture patients. Modern fracture management should include identifying ‘at risk’ patients and appropriate management to prevent fragility fractures

The operative treatment of fractures of the proximal humerus can be complicated by poor bone quality. Our aim was to evaluate a new method which allows prediction of the bone quality of the proximal humerus from radiographs. Anteroposterior radiographs were taken of 19 human cadaver humeri. The cortical thickness was measured at two levels of the proximal humeral diaphysis. The bone mineral density (BMD) was determined for the humeral head (HH), the surgical neck (SN), the greater tuberosity (GT) and lesser tuberosity (LT) using dual-energy x-ray absorptiometry. The mean cortical thickness was 4.4 ± 1.0 mm. Specimens aged 70 years or less had a significantly higher cortical thickness than those aged over 70 years. A significant positive correlation was found between cortical thickness and the BMD for each region of interest. The cortical thickness of the proximal diaphysis is a reliable predictor of the bone quality of the proximal humerus

Purpose: To examine whether neutral or valgus placement results in greater fracture strength ex vivo, when the femoral neck is notched superolaterally as sometimes occurs during hip resurfacing arthroplasty. Methods: We loaded 10 paired fresh-frozen notched proximal cadaveric femora (8F/2M, 66 to 80 years) to failure. In each case, the right femur was implanted, using bone cement, with a machined resurfacing component aligned neutrally with respect to the femoral neck whereas the left femur was implanted at 10° valgus. The superolateral notch was 3 mm wide by 2 mm deep directly beside the component. Potted femurs were loaded to failure using an Instron materials testing machine. All 20 femora were scanned using Dual-Energy X-Ray Absorptiometry. Results: The effect of neutral versus valgus placement was complex. (1) Two pairs slowly crushed; the remaining femurs exhibited a clear fracture. When only the fracture-type failures were analyzed, valgus placement resulted in fracture loads on average 22% higher than for neutral placement (paired t-test, p< 0.05). All femurs failed within the notch, as occurs clinically. (2) Femurs with high bone density (BMD> 0.65 g/cm2) showed a significant increase in fracture load (p< 0.05) whereas femurs with low BMD (< 0.65 g/cm2) were unaffected by component placement. BMD was highly correlated with fracture load (Pearson r=0.87, p=0.0003). (3) The greatest improvements occurred when the neck-shaft angle was relatively low, 128°–132°. (4) Two of ten femurs required larger head sizes at 10° valgus. Conclusions: (1) Fracture load was primarily controlled by bone quality (BMD); (2) nevertheless, varus/valgus placement did affect the fracture load; (3) the magnitude and direction of this effect depended on fracture type, bone mineral density and the original neck-shaft angle; (4) for the level of bone quality typical of patients undergoing hip resurfacing, and for low-to-average neck-shaft angles (up to 132°), the fracture load for 10° valgus placement was significantly higher than for neutral placement. Funding: Other Education Grant

A total of 63 women who had an operation for a fracture of the hip was randomly allocated to one year of treatment either with anabolic steroids, vitamin D and calcium (anabolic group) or with calcium only (control group). The thigh muscle volume was measured by quantitative CT. The bone mineral density of the hip, femur and tibia was assessed by quantitative CT and dual-energy x-ray absorptiometry and of the heel by quantitative ultrasound. Quantitative CT showed that the anabolic group did not lose muscle volume during the first 12 months whereas the control group did (p< 0.01). There was less bone loss in the proximal tibia in the anabolic group than in the control group. The speed of gait and the Harris hip score were significantly better in the anabolic group after six and 12 months. Anabolic steroids, even in this moderate dose, given in combination with vitamin D and calcium had a beneficial effect on muscle volume, bone mineral density and clinical function in this group of elderly women

Introduction. Resorptive bone remodeling secondary to stress shielding has been a concern associated with cementless total hip arthroplasty (THA). At present, various types of cementless implants are commercially available. The difference in femoral stem design may affect the degree of postoperative stress shielding. In the present study, we aimed to compare the difference in bone mineral density (BMD) change postoperatively in femurs after the use of 1 of the 3 types of cementless stems. Methods. Ninety hips of 90 patients who underwent primary cementless THA for the treatment of osteoarthritis were included in this study. A fit-and-fill type stem was used for 28 hips, a tapered-rectangular Zweymüller type stem was used for 32 hips, and a tapered-wedge type stem was used for 30 hips. The male/female ratio of the patients was 7/21 in the fit-and-fill type stem group, 6/26 in the tapered-rectangular Zweymüller type stem group, and 6/24 in the tapered-wedge type stem group. The mean age at surgery was 59.9 (39–80) in the fit-and-fill type stem group, 61.7 (48–84) in the tapered-rectangular Zweymüller type stem group and 59.6 (33–89) in the tapered-wedge type stem group. To assess BMD change after THA, we obtained dual-energy X-ray absorptiometry scans preoperatively and at 6, 12, 24, and 36 months postoperatively. Results. There were no differences in demographic data, such as gender, age at surgery, and body mass index, among the 3 groups (Table1). In terms of BMD change after THA, no differences were observed in Gruen zones 1–5 among the 3 groups during the 3-year follow-up. The BMD in Gruen zone 6 was maintained in the tapered-wedge type stem group, but decreased by 5% in the fit-and-fill type stem group and by 20% in the tapered-rectangular Zweymüller type stem group (p < 0.01). The BMD loss in Gruen zone 7 was observed in all stem types; however, the BMD loss at 36 months in the tapered-wedge type stem group (−15%) was significantly less than that of the other 2 groups (the fit-and-fill type stem group: −29%; the tapered-rectangular Zweymüller type stem group: −30%; p < 0.001 for both groups) (Figure). Discussion and Conclusion. A difference in postoperative BMD loss was observed among the 3 stem designs. This may be a result of the different fixation concept associated with each stem design. In the present study, we compared the postoperative BMD change after THA among a fit-and-fill type stem, a tapered-rectangular Zweymüller type stem, and a tapered-wedge type stem. BMD in the medial-proximal femur was maintained 3 years after THA in the group with the tapered-wedge type stem, which is fixed in a more proximal part of the femur compared to the other stems

Introduction: Several factors render plain X-ray radiographs of the hip unsuitable for bone mineral density measurements, mainly variability in X-ray exposure levels and soft tissue surrounding the bone. We present modification of proximal femur digital radiographs to compensate for these interfering factors. Methods: The study population consisted of 99 women, in three groups: 1 – elderly, sustaining a fracture of the neck of the femur. 2 – elderly, without a fracture. 3 – young. Each patient’s hip was radiographed with a brass step-wedge for standard reference. Dual-Energy X-ray Absorptiometry (DEXA) of the same hip was performed. On each radiograph, Regions Of Interest (ROIs) of the proximal femur were determined in concordance with ROI of the DEXA, together with three soft tissue regions surrounding the bone. Mean gray level was measured for each ROI. Results: The difference in gray level of the ROI within the proximal femur was not statistically significant between the groups. Correction of bone gray level to exposure level by dividing the gray level of the ROI to that of the step wedge, resulted in statistically significant difference between group 1 and either group 2 or group 3. Similar results were obtained by correction of bone gray level to soft tissue gray level. Using this method, multiple R. 2. of 0.62 was found predicting the DEXA value from the gray level of each ROI. Conclusions: After correction to the exposure level and to the soft tissue surrounding the bone, a plain digital radiograph of the pelvis can provide valuable information concerning the bone mineral content of the proximal femur. These preliminary results warrant further research aimed at exploring the potential value of this fast, accessible and relatively inexpensive technique to diagnose osteoporosis and the prediction of future fractures

Introduction. The influence of the bone mineral density (BMD) on the mechanical behavior of bones can be examined using computer tomography (CT) data and finite element (FE) simulations, because the BMD correlates with the Hounsfield scale (HU) of the CT data. Therefor the material mapping strategy, which is required to assign the HU values to the FE mesh, is of crucial importance. In this study a nodal mapping strategy was analyzed concerning its sensitivity towards FE mesh parameters and an averaging of HU values from the area around the respective nodes. Method. The FE simulation is based on CT data of a human proximal femur. Once the bone shape was reconstructed, the resulting model was meshed with quadratic tetrahedral elements in ABAQUS/CAE and all nodes were assigned an HU value from the CT data by using the respective node coordinates. In this process, the mesh density, the threshold, which could be used to exclude connective tissue and fat from the material mapping process, the considered volume around the nodes and the method of averaging were varied. The material assignment was realized by an HU value dependent, linear elastic material definition. The femur model was clamped at the level of the isthmus and a displacement of 0.5 mm was applied at the femoral head. The evaluation was based on the resulting reaction forces. Results. The sensitivity analysis demonstrated, that threshold and mesh density mainly influenced the reaction force [Fig. 1]. If a threshold was applied, the reaction force increased by about 20 % in average. A threefold increase of the mesh density led to an average gain of the results of about 24 %. For a specific mesh density the curve progressions of the respective results intersected, i.e. an alteration of the considered volume or the method of averaging barely affected the reaction force [Fig. 2, Fig. 3]. Apart from this intersection, the comparison of the small and the large average volume led to a deviation of up to 11 %. On the other hand, the examination of different methods of averaging revealed only a maximum deviation of 4 % between “mean” and “median”. Discussion. The present study indicates, that the material mapping strategy is an influential part of the modeling process, which should be validated to avoid misjudgments of the load situation. Accordingly, the use of a threshold to exclude non-bone tissue could be a helpful tool. But with the exclusion of lower HU values, the load-bearing structure gains stiffness and the reaction force in the femur rises. A finer mesh leads to a higher resolution of the bone structure and, therefore, to a higher accuracy of the results. The “equilibrium” between the different models at the intersection is caused by a more homogeneous distribution of the material property which is increased by a larger considered volume and the method “mean”

Surface replacement is widely used as a treatment for younger patients requiring hip replacement. However the long-term performance of such devices remains unknown. One area of concern is the viability of the bone in the proximal portion of the femur. These concerns are related to the trauma which the proximal femur is exposed to during the operative procedure and the level of vascularity which is subsequently attained. Previous studies have used a single time point and shown reduced loss in bone stock compared to total hip replacement and minimal difference with the contra-lateral unaffected hip. The aim of this study is to report the changes in bone mineral density (BMD) which take place at different time points in the same patients following implantation using DEXA scanning. The effect of component placement and metal ion levels will also be considered. A total of twenty-six patients were recruited (18 male, 5 female; 15 left hip 11 right, mean age at surgery 56 years, range 31–69) who had DEXA measurements at all three time points post-op, 120 and 420 days (4 and 14 months). Measurements were taken in the neck region and Gruen zones 6 and 7. Metal ion levels were measured in whole blood using the high resolution ICP-MS technique. The BMD in the neck region, zone 7 and 6 post-operatively were 0.945, 1.092 and 1.451g/cm2 respectively. In the neck region BMD reduces at 120 days (96.5%) and then increases to higher than the post-op level at 420 days (103.6%, differences between all three groups: p< 0.008). In zone 7, BMD drops at 120 days (98.2%, p=0.03) but recovers to higher than post-op levels after 420 days (101.65%)but not significantly so (p=0.13). In zone 6 there are no significant differences at any ime points. Despite the wide variation in the immediate postoperative bone density (0.70–1.25g/cm2), there is no obvious relationship between this value and the capacity of the bone to recover from the operative trauma. Twenty-three of these patients were also part of a metal ion study previously reported. There was no relationship between the combined metal ion levels (chromium+cobalt) at 12 months and the changes in BMD in the neck region at 4 or 14 months. There was no significant difference in the response of the male and female patients. There was no significant relationship between changes in BMD and cup abduction angles, femoral component inclination nor acetabular component diameter. This is a short-term study, however it is reassuring that whilst BMD reduces in the neck and Gruen zone 7, by 420 days (14 months) it has recovered to postop levels and in zone 7 has exceeded the post-op levels. Furthermore this response appears to be unrelated to patient factors and component position

We have used dual-energy X-ray absorptiometry to measure bone mineral density (BMD) in patients with ankylosing spondylitis comparing 41 healthy control subjects and 33 patients with either mild or advanced ankylosing spondylitis. A Norland XR-28 bone densitometer was used to measure the BMD of the lumbar spine and that of the head, trunk, arms, femoral neck, Ward's triangle, legs, pelvis, and total body. Mild ankylosing spondylitis was defined as that showing no or incipient syndesmophytes between L1 and L5 vertebrae: we studied 16 men of mean age 37 years and six women of mean age 37 years. Advanced ankylosing spondylitis, in 11 men of mean age 42 years, showed a bamboo spine with bridging syndesmophytes across all disc spaces between L1 and L5. The mean BMD of the lumbar spine was significantly different in the patients and control subjects of the same sex (0.01 < p < 0.05, analysis of variance), being significantly reduced compared with control subjects in mild disease (0.001 < p < 0.01, t-test) and significantly increased in advanced disease over control subjects (0.01 < p < 0.05; t-test) and over patients with mild disease (0.001 < p < 0.01; t-test). The relevance of these findings to the aetiology and pathogenesis of spinal deformities and other complications in ankylosing spondylitis is discussed

The long-term performance of surface replacement devices remains unknown. One area of concern is the viability of the bone in the proximal portion of the femur. Previous studies, using a single time point, have shown reduced loss in bone stock compared to total hip replacement and minimal difference with the contra-lateral, unaffected hip. The aim of this study is use DEXA scanning to report the changes in bone mineral density (BMD) which take place at different time points up to 5 years post-op in the same patients following implantation. The effect of component placement will also be considered. Thirty patients were recruited (24 male, 6 female; 16 left hip 14 right, mean age at surgery 53 years, range 28–65). DEXA measurements were taken post- operatively and at 3, 12, 24 and 60 months. During the study 2 patients were revised and 8 were lost to follow-up. Thus the number of patients available at each follow-up were 28, 29, 23 and 20 respectively. The regions of interest were R1 (neck region), R2 (Gruen zones 2,6) and R3 (Gruen zones 3,5). BMD in zones R1, R2 and R3 post-operatively were significantly different, 0.955, 1.114 and 1.457g/cm2 respectively (p< 0.0001). In the R1, BMD reduced at 3m to 95.0% (p=0.005) and then recovered to higher than the post-op level 102.2% (p=0.241) by 12m, and further increases to 103.5% (p=0.019) at 24m and 103.9% (p=0.057) at 60m. In zone R2, BMD reduced at 3m (97.4%, p=0.02) but recovered to post-op levels after 12m and is maintained thereafter. In zone R3 there were no significant differences from post-op. In zone R1 at 3m, 20/28 cases (71%) had a BMD that was less than the immediate post-operative value. At 12m only 12/29 cases (41%) had reduced BMD, the balance (59%) undergoing an increase. The comparable values at 60m follow-up were 43% and 57%. There was a trend for patients with higher post-op BMD to undergo a greater reduction at 3m whilst showing a greater level of recovery after 60m. However patients with higher post-op BMD had the highest 3m and 60m values. There was a trend for older patients to have a lower post-op BMD although this was not translated into greater reductions in BMD. There was no obvious correlation between femoral component angle and BMD. However there was a trend for components with a higher cup angle to undergo a greater reduction in BMD at both 3m and 60m. The current cohort was dominated by male patients and therefore comparison by gender was not possible. Changes in BMD were confined to the neck region (R1) and Gruen zones 2, 6 (R2). The finding that BMD reduces in R1 at 3m but by 12m has recovered to postop levels in R2 and in R1 has exceeded post-op levels, strongly suggests that whatever inter-operative trauma takes places is quickly repaired and changes beyond 12m are minimal out to 60m

Objective. To compare regional body composition, bone mineral density (BMD), and clinical outcome in patients with two different shoulder arthroplasty designs. Materials and Methods. This cross-sectional study included 54 patients with a total of 63 shoulder arthroplasties. There were 18 men and 45 women with a mean age of 68.9 years SD ± 10.5. Mean follow-up time was 39.2 months SD ± 14.4. The patients were divided into three groups according to their history: 22 patients were diagnosed with a proximal humeral fracture and treated with a stemmed hemi arthroplasty, 11 patients were diagnosed with osteoarthritis and treated with a stemmed hemi arthroplasty, and 30 patients were diagnosed with osteoarthritis and treated with a resurfacing arthroplasty. All patients underwent a one-day protocol: Regional Dual X-ray Absorptiometri (DXA) was used to measure BMD of the distal third of humerus and regional body composition of the upper arm. The clinical outcome was measured using Western Ontario Osteoarthritis of the Shoulder index (WOOS) and Constant-Murley score. Results. All three groups were comparable regarding demographic data. Mean BMD of the distal third of humerus was 1.029 g/cm2 SD ± 0.204, mean tissue mass of the upper arm was 2.6 kg SD ± 0.7 and mean muscle mass was 1.4 kg SD ± 0.6. BMD of the distal third of humerus, tissue mass and muscle mass were significantly higher in the group diagnosed with osteoarthritis and treated with a resurfacing arthroplasty compared to the group diagnosed with a proximal humeral fracture and treated with a stemmed hemi arthroplasty, P = 0.03, P = 0.01 and P = 0.02 respectively. Median Constant score was 45.0, range 6–89, median WOOS 633, range 28–1824, and median strength 7.0 units, range 0–25. There were no significant differences between the three groups. Nevertheless, there was a trend towards a higher Constant-Murley score and muscle strength in the group of patients diagnosed with osteoarthritis and treated with a resurfacing arthroplasty compared to the group of patients diagnosed with a proximal humeral fracture and treated with a stemmed hemi arthroplasty. Conclusion. After shoulder arthroplasty BMD of the distal third of humerus and body composition are apparently more dependent on diagnosis rather than arthroplasty design. However, a larger number of patients diagnosed with osteoarthritis and treated with a stemmed hemi arthroplasty are needed to support this

Introduction. Dual energy X-ray absorptiometry (DEXA) is the gold standard for assessing bone mineral density (BMD) and fracture risk in vivo. However, it has limitations in the spine because vertebrae show marked regional variations in BMD that are difficult to detect clinically. This study investigated whether micro-CT can provide improved estimates of BMD that better predict vertebral strength. Methods. Ten cadaveric vertebral bodies (mean age: 83.7 +/− 10.8 yrs) were scanned using lateral-projection DEXA and Micro-CT. Standardised protocols were used to determine BMD of the whole vertebral body and of anterior/posterior and superior/inferior regions. Vertebral body volume was assessed by water displacement after which specimens were compressed to failure to determine their compressive strength. Specimens were then ashed to determine their bone mineral content (BMC). Parameters were compared using ANOVA and linear regression. Results. Measures of volumetric BMD obtained from Micro-CT were significantly higher than those obtained by DEXA (P<0.001), and estimates using the two techniques were not significantly correlated. DEXA measurements were strongly predictive of compressive strength, with areal BMD of the anterior vertebral body being the best predictor (R. 2. = 0.722, P = 0.002). Micro-CT measurements did not predict strength. Vertebral body BMD (derived from ash weight) correlated more highly with volumetric BMD values obtained from DEXA (R = 0.88) than those obtained from micro-CT (R = 0.72). Conclusion. BMD assessed by lateral DEXA predicted strength and BMC of osteoporotic vertebrae more accurately than micro-CT measures. Poor correlation between BMD measurements from DEXA and micro-CT suggests that ‘phantoms’ used in Micro-CT may require fine-tuning in order to better represent osteoporotic vertebrae

Aims: evaluate the relationship between Singh index (SI), bone mineral density (BMD) examining bone mechanical properties from ex-vivo human femoral heads. Methods: we collected the femoral heads of 22 patients that underwent arthroplastic for fracture of femoral head under low energy trauma. 5 patients were male while 17 were female. In each patient a pelvis X-ray was performed to estimate Singh Index. From 2 to 3 bone cylinders of cancellous bone were obtained from each femoral head. 52 bone cylinders (7x10mm) were obtained. In each specimen densitometric scans were performed by means of a Hologic QDR 4500 X-ray densitometer, using a small animal software. The coefficient of variation (CV) was calculated by repositioning a sample for 5 scans by different operators. The data obtained were expressed as bone mineral content (BMC) and bone mineral density (BMD). Compression tests with a JJ Instruments T5K machine were conducted on 52 spongy bone cylinders. Each specimen was loaded in movement control; maximum failure load and Young modulus were recorded. Results The CV for the precision was 1.8% for BMC and 2.7% for BMD. There are no differences between males and females in age, BMC, BMD and Young modulus, while there is a significant difference in maximum load and SI. As regards SI values, there are significant differences among different categories of SI for age, sex, BMC, BMD, Young modulus and maximum failure load. Considering each sample position, namely 1, 2 or 3, there was no significant difference in densitometric parameters and in mechanical properties Statistical analyses of correlations by Pearson’s coefficient showed significant inverse correlations between age and mechanical bone properties (Young modulus and maximum failure load), while the correlations between BMC, BMD and biomechanical bone behaviour were strictly direct Linear regression model demonstrated only maximum load predictors are Young modulus and BMD. Conclusions The maximum failure load is lower in females than in males with similar BMD but lower SI for different SI categories there are significant differences both in biomechanical behaviour both in densitometric parameters.The age is inversely correlated with bone densitometric features and bone biomechanical behaviour, while bone density is directly correlated with bone strength and elastic modulus.The bone strength is predicted with 93% accuracy by Young modulus and BMD

Introduction: The most widely accepted method for measuring bone mineral density (BMD) is Dual-energy X-ray Absorptionmetry (DXA). However, the need for relatively expensive equipment and trained personnel lower the accessibility of DXA as a routine screening tool. Plain pelvic X-ray radiography is a simple and inexpensive examination. In principal, the gray level of the bone in the X-ray radiograph is related to BMD. However, several factors render plain X-ray radiographs of the hip unsuitable for BMD measurements, mainly the variability in X-ray exposure levels and the soft tissue surrounding the bone. In this study, we aimed to develop new modifications of plain X-ray radiography of the proximal femur. Patients and methods: The study population consisted of 18 women with an average age of 77 years (range 57–96 years) who were hospitalized due to a low-energy fracture of the neck of the femur. Each patient’s contralateral hip was radiographed with an aluminium step-wedge positioned near the hip as a standard reference, using a computerized radiography system. A DXA examination of the same hip followed the plain radiograph. On each radiograph, regions of interest (ROI) were determined in concordance with the ROI of the DXA examination. The mean gray level was measured for each ROI. The neck-shaft angle and the femoral head diameter were also measured. Results: Comparing the gray levels of the plain radiograph with the BMD levels obtained by the DXA revealed a coefficient ratio of R=0.499. Correction of the gray levels using the step wedge as a standard reference revealed a ratio of R=0.576. If further correction was made with measurement of the soft tissue gray levels, a ratio of R=0.708 was obtained. Using the anatomical measurements (neck-shaft angle and femoral head diameter), a ratio of R=0.948 was obtained. Conclusion: This study shows that a plain digital radiograph of the pelvis can provide valuable information concerning the bone mineral content of the proximal femur, which is comparable to the results of the DXA examination. Ultimately, the research can lead to the development of a fast, available and relatively inexpensive technique to diagnose osteoporosis

Aims: To evaluate whether the atlantoaxial disorders (anterior atlantoaxial subluxation and atlantoaxial impaction) associate with destruction of shoulder or peripheral joints, and bone mineral density (BMD) in patients with long-term rheumatoid arthritis (RA). Methods: An inception cohort 67 patients with seropositive and erosive RA were followed up for 20 years. Cervical spine, shoulder, hand and foot radiographs, and the BMD of the lumbar spine and femoral neck were evaluated. Results: A positive relationship was detected between the occurrence of atlantoaxial disorders and the destruction of both shoulder (p < 0.001) and peripheral (p = 0.001) joints. In addition, the severity of atlantoaxial disorders positively correlated with the grade of destruction in the evaluated joints. Furthermore, a positive relationship was found between the occurrence of the atlantoaxial disorders and a decrease in BMD of the femoral neck (p = 0.019). Conclusions: Patients with severe RA and osteoporosis have an increased risk for atlantoaxial disorders, therefore the cervical spine radiographs of these patients should be analysed before major surgery and also at regular intervals. The co-existence of shoulder and cervical spine disorders makes the differential diagnosis of shoulder and neck pain challenging

Purpose: The ABG Total Hip Joint Replacement is a cementless, hydroxyapatite coated prosthesis designed to be metaphyseal loading. The aim of our study was to analyze the changes in proximal femoral bone mineral density (BMD) following implantation of this prosthesis. Method: Dual energy x-ray absorptiometry (DEXA) scanning has been shown to be an accurate and reliable method of assessing BMD following total hip arthroplasty. 14 patients undergoing primary ABG Total Hip Joint Replacement were recruited into the study following informed consent. BMD was determined for each of the seven periprosthetic zones of Gruen from DEXA scans, which were performed serially at preoperative,, 3 months, 6 months, 1 year and 2 years. Results: 8 patients have now completed their scans. The most dramatic change in BMD was found in zone 7 which is the femoral calcar. In this region there was a progressive decrease in average BMD to 75% of the preoperative value at 2 years. In zones 2 and 3 representing the femoral cortex lateral to the prosthesis there was an increase in BMD to approximately 114.5% at 3 months and this was maintained at 2 years. In the remaining zones BMD was reasonably stable between 97.5 and 101%. Conclusion: We have found that in the 2 years following ABG hip arthroplasty there is a dramatic decrease in BMD to 75% within the region of the femoral calcar. Further scans are required to determine if this is progressive. In the remaining regions BMD is either increased or relatively well preserved

Periprosthetic bone loss is one of the major concerns in total hip arthroplasty (THA). Several studies have reported that bone mineral density (BMD) decreases after THA especially in the proximal femur. The phenomenon is explained as an adaptive remodeling response of bone tissue to a significant alteration of its stress environment. The purpose of this study was to evaluate the pattern of load transfer after stem implantation, and to compare the stress of finite element (FE) studies to BMD in the proximal femur after THA. Forty-eight consecutive patients who received a primary cementless THA with implantation of the same femoral prosthesis (VerSys, Zimmer Inc, Warsaw, Idaho) between January 2007 to December 2007 were identified. Twenty-nine patients were excluded for administration of alendronate or alfacalcidol, and four patients were lost to follow-up or had incomplete computed tomography (CT) or dual-energy X-ray absorptiometry (DEXA) data. The remaining 15 patients formed the basis of this study. The average age of the patients at the time of THA was 64 years (range, 44 to 82 years). BMD were measured with DEXA at 1 week and 12 months after THA. Regions of interest (ROIs) were defined according to Gruen’s system (ROIs 1–7). FE models of the femur and stem were obtained from pre-and postoperative CT data by “Mechanical Finder (Research Center of Computational Mechanics Inc.)” that was a software to make FE models considering individual bone shape and density distribution. FE model of the femur consisted of approximately 600,000 elements and that of the stem consisted of 200,000 elements. The shaft was restrained and force was applied to the femoral head and directed within the coronal plane at 20° to the shaft axis. Stress distribution and strain energy density were analyzed and compared to DEXA data. BMD maintained at 1 year after THA in ROI 3,4,5, and 6, where as BMD decreased in ROI 1,2, and 7 by 17%, 16%, and 26 %, respectively. This means that BMD decreased especially in the proximal femur at 1 year after THA. FE studies revealed that the stress and the strain energy density in ROI 3,4,5, and 6 were much higher than in ROI 1,2, and 7. It was suggested that high stress and strain energy density are contributed to maintenance of BMD in the femur at 1 year after THA

Dual energy X-ray absorptiometry (DXA) is a precise tool for measuring bone mineral density (BMD) around total joint prostheses. The Hologic ‘metal-removal hip’ analysis package (Hologic Inc, Waltham, Massachusetts) is a DOS-based analysis platform that has been previously validated for measurement of pelvic and proximal BMD after total hip arthroplasty (THA). This software has undergone a change in the operating platform to a Windows-based system that has also incorporated changes to DXA image manipulation on-screen. These changes may affect the magnitude of random error (precision) and systematic error (bias) when compared with measurements made using the previously validated DOS-based system. These factors could influence interpretation of longitudinal studies commenced using the DOS system and later completed using the Windows system. The aims of this study were to compare the precision and bias of pelvic and femoral periprosthetic BMD measurements made using the Windows versus the DOS analysis platform of the Hologic ‘metal-removal hip’ software. A total of 29 subjects (17 men and 12 women) with a mean age of 51years (SD±10), who had undergone hybrid THA using a cemented stem and uncemented cup. Subjects underwent duplicate DXA scans of the hemipelvis and proximal femur taken on the same day after a period for repositioning.. Scans were obtained with the patient lying supine in the scanner with the legs in extension and the foot in a neutral position. Scans were carried out using the same Hologic QDR 4500-A fan-beam densitometer in ‘metal-removal hip’ scanning mode. The DXA scan acquisitions were analysed using both the DOS and the Windows versions of the analysis software. The same observer made all analyses (NRS). Pelvic scans were analysed using a four region of interest model and femoral scans were analysed using a seven region of interest model. Precision was expressed as coefficient of variation (CV%) and compared between methods using the F-test. Systematic bias was examined using the Bland and Altman method and paired t-test. The CV% for the pelvic regions of interest (n=4) varied from 3.92 to 8.54 and from 2.36 to 5.96 for the Windows and DOS systems, respectively. The CV% for the net pelvic region was 3.04 and 2.36 for Windows versus DOS, respectively (F- test, p> 0.05). The CV% for the femoral regions of interest (n=7) varied from 1.58 to 4.14 and from 1.84 to 4.65 for the Windows and DOS systems, respectively. The CV% for the net femoral region was 1.75 and 1.51 for Windows versus DOS, respectively (F- test, p> 0.05). Absolute BMD values for the net pelvic region were similar (Bland-Altman, Windows minus DOS value mean = -1.0%, 95% CI −7.5 to 5.6; t-test p.0.05). Absolute BMD values for the net femoral region were also similar (Bland-Altman, Windows minus DOS value mean = 1.3%, 95% CI −8.3 to 10.8; t-test p.0.05). In summary precision of the measurements using the 2 operating systems was similar and there was no systematic bias between methods. These data suggest that scans analysed using each platform may be used interchangeably within the same study subjects, without the need of a calibration correction

Measurement of the rate of fracture healing is a major problem in fracture research. Bone mineral density (BMD) of fracture callus has been used as a measure of healing in diaphyseal fractures. However, metaphyseal fractures (especially in the elderly) are now the commonest type of fracture and are a significant public health problem. This study investigated whether measurement of BMD at the fracture site in the distal radius can be used as a measure of fracture healing. We recruited 28 patients who had sustained a dorsally displaced distal radial fracture which was deemed to require treatment by intrafocal wire fixation. All patients had acceptable correction of dorsal and radial angle at final x ray (3 months). Wrist function was measured using the Patient Rated Wrist Evaluation (PRWE – a validated outcome measure for use after distal radial fractures), grip strength,and range of motion. All measurements were made at 6, 12 and 26 weeks. BMD was measured at the fracture site (examining the BMD of the medullary bone at the fracture site after removal of wires), in the opposite wrist and the lumbar spine using QCT at 6 weeks after fracture. There was no correlation between fracture site BMD and BMD at the other wrist or the lumbar spine (r < 0.3). The BMD at the fracture site was higher than the BMD at the other wrist (mean 168 vs 70 HU; p< 0.001 paired T test). There was no relationship between fracture site BMD or the ratio of BMDs fracture site / normal wrist, and any of the functional assessments (proportion grip strength recovered, range of motion or PRWE (r < 0.3)). 15 of these patients underwent a second QCT at 12 weeks after fracture. There was no significant change in fracture site BMD between the first and second scan. These data indicate that fracture site BMD is unlikely to be a useful method of measuring metaphyseal bone healing. The increase in BMD at the fracture site was unexpected; possible explanations include impaction of bone or high BMD in woven bone (the relationship of which to bone stiffness is uncertain)

Introduction: Bone mineral density (BMD) is currently the gold standard in predicting osteoporotic fracture, but evidence suggests that over one third of such fractures occur in those with osteopenia or even normal BMD. The level of bone turnover may affect bone quality in these patients independently of BMD. Bone markers have evolved as tools in monitoring anti-resorptive treatment in osteoporosis. Aims: The aim of this study was to investigate if levels of bone markers in postmenopausal women could be used as an adjunct to BMD measurements in the assessment of fragility fracture risk. Patients and Methods: 60 postmenopausal women (30 osteoporotic, 30 with normal BDM) were studied. A single BMD measurement by dual energy x-ray absorptiometry (DEXA) enabled categorisation. Serum bone formation markers (bone specific alkaline phosphatase (BSAP) and osteocalcin (OC)), and resorption marker (C-telopetide of type 1 collagen (CTX)), were measured. History of low trauma fracture was documented for each woman. Results: 36% of the osteoporotic group had experienced at least one fragility fracture. However, the femoral neck and combined spinal BMD in these women was not significantly different from the 64% of osteoporotic women who had no prior fracture. There was also no significant difference in the age of women in both subgroups. Serum bone markers were significantly increased in the osteoporotic fracture subgroup when compared to the non-fracture subgroup and also to the non-osteoporotic controls. The largest increases were seen in the levels of CTX. Smaller increases in all markers were seen when the non-fracture subgroup was compared to the non-osteoporotic control group but these increases did not reach statistical significance. Conclusions: Bone turnover is significantly increased in postmenopausal osteoporotic women with previous fracture compared to both osteoporotic non-fracture counterparts and non-osteoporotic controls. This suggests higher bone turnover will increase fracture risk in osteoporotic women. It is possible that combining 2 or 3 markers to produce an “index of bone turnover” would be a useful tool when used in addition to BMD to identify those at greatest fracture risk

Aims: Hormone replacement therapy (HRT) reverses the menopausal decline in bone mineral density (BMD).We investigate if part of this response is through modulation of Interleukin-6 (IL-6) activity, which is known to be reduced by HRT. Methods: We have examined the association of the -174 G/C functional promoter polymorphism of the IL-6 gene with the BMD response to HRT (Prempak C: 0.625mg oestrogen per day and 0.15mg norgestrel). 65 women were genotyped for the IL-6 polymorphism, and differences in genotype related to changes in BMD over a one year follow up period. Results: Baseline BMD (0.75 g/cm. 2. ) was independent of IL-6 genotype. The rise in BMD with HRT (5% ± 3%, p < 0.00005 by paired t-test) was genotype-dependent, with BMD rising least amongst those of GG genotype (6% ± 3% for ≥1 C allele vs 4% ± 2% GG, p=0.03). In the HRT group, BMD rose most amongst those with the putatively ‘lowest IL-6’ genotype combination- namely ≥ 1 ACE I allele and ≥ 1 IL-6 C allele (n=14) (7% ± 3%), when compared with other genotype combinations (4% ± 2%) (n=16) (p=0.003). Conclusion: These are the first data to demonstrate an influence for IL-6 genotype in influencing response to oestrogen therapy, rather than its physiological withdrawal

Introduction. Several short femoral stems have been introduced in primary total hip arthroplasty, supposedly in order to save proximal bone stock. We intended to analyse primary stability, changes in periprosthetic bone mineral density (BMD), and clinical outcome after insertion of the uncemented collum femoris preserving (CFP)-femoral device. Methods. A prospective cohort study on 30 patients scheduled for receiving the CFP-stem combined with an uncemented cup was carried out. Stem migration was analysed by radiostereometry (RSA). Preoperative total hip BMD and postoperative periprosthetic BMD in Gruen zones 1–7 was investigated by DXA, and the Harris hips score (HHS) was determined. The patients were followed up to 12 months. Results. 2 patients were intraoperatively excluded because their proximal femur was found to be unsuitable for insertion of the studied implant, 1 patient was later revised due to a deep infection. This left 27 patients for final analysis. RSA showed that only very little migration of the implant occurred, with the largest amplitude found in rotation around the y-axis (1.8°, SD 0.6, after 12 mths), representing minimal stem retroversion. DXA after 12 mths demonstrated substantial BMD loss in Gruen zones 7 (−30.8%), 6 (−19.1%) and 2 (−13.3%, p-values for all described changes <0.001 when comparing with baseline BMD determined immediately postoperatively). There was a moderate correlation of low preoperative total hip BMD with a higher amount of bone loss in Gruen zones 2 (Pearson correlation coefficient r = 0.6, p = 0.001), 6 (r = 0.5, p = 0.005) and 7 (r = 0.6, p = 0.003). In contrast, we found no correlation of periprosthetic bone loss in any of the Gruen zones 1–7 with logarithmically transformed maximal total point translation (MTPT) of the stem (p > 0.05 for all regions), neither after 3 nor after 12 mths. The mean HHS increased from 49 (SD 15) preoperatively to 99 (SD 2) after 12 mths. Interpretation. Based on these short-term data, we conclude that i) the studied implant seems to be stable within the first year, ii) substantial loss in periprosthetic BMD - with a predominance in the calcar region - occurs, iii) low preoperative total hip BMD predisposes towards greater loss of periprosthetic BMD after 12 months, iv) postoperative loss in periprosthetic BMD does not correlate with increased stem migration. Clinical results are excellent so far. Continuing follow-up will reveal whether this novel stem remains stable in the medium and long term, and whether the loss in BMD in the regions mentioned above can be recovered with time or whether it continues

Weight-bearing is a known stimulus for bone remodelling and a reduction in weight-bearing is associated with reduced bone mineral density (BMD) in affected limbs post lower limb fracture. This study investigated short and long-term precision of a method for measuring relative left/right weight-bearing using two sets of identical calibrated scales. The effect of imbalance on BMD at the hip and on lower limb lean tissue mass (LLTM) was also assessed. 46 postmenopausal women, with no history of leg or ankle fracture, were measured three times whilst standing astride two scales (Seca, Germany). 34 of the participants were re-measured after 6 months by the same method. Bilateral hip and total body dual x-ray absorptiometry measurements were performed using a GE Lunar Prodigy (Bedford, MA). Precision errors in weight-bearing measures were calculated using the root mean square coefficient of variation (RMSCV%). The correlations at the first visit between left/right differences in weight-bearing and differences in BMD and LLTM were calculated. The short-term RMSCV% for left and right weights were 4.20% and 4.25% respectively and the long-term RMSCV% were 6.91% and 6.90%. Differences in left/right weight-bearing ranged from 0 to 24% (SD 8.63%) at visit 1 and 0 to 30% (SD 10.71%) at visit 2. Using data from visit 1, the relationship between hip BMD differences and left/right weight-bearing differences were investigated, with no significant correlations found. However, a weak, but statistically significant correlation of r=0.35 (p=0.02) was found for differences in LLTM and left/right weight-bearing differences. In conclusion, left/right weight-bearing measured using two scales is a precise method for evaluating differences in weight-bearing in the short and long-term. Differences in left/right weight-bearing in this population varied by up to 30%. Participants showed a high degree of consistency in their long-term balance in a natural standing posture. Inequalities in left/right weight-bearing did not correlate significantly with BMD at the hip, but demonstrated a weak but statistically significant correlation with lean tissue mass

Background/Objective: Since estrogen receptors (ERα/ERβ) were identified in human chondrocytes, animal-and experimental studies have demonstrated the importance of continued estrogen production for the integrity of articular cartilage. However, human epidemiological support of the hypothesis has been inconclusive. The present study investigated the relationship between reduced bone mineral densities (BMD), as a surrogate parameter of endogenous estrogen status – assessed by digital x-ray radiogrammetry (DXR), and reduced minimum hip joint space width (JSW). Methods: Standardised hand radiographs of the Copenhagen Osteoarthritis Study cohort of 3.913 adults (1.470M/2.443F) with a mean age of 60 years (range, 18–92), were analysed by the X-Posure. ™. digital software v. 2.0 (Sectra-Pronosco). The system is operator independent. From 1.200 individual measurements per radiograph mean BMD was calculated. Minimum hip joint JSW was assessed in standardized, pelvic radiographs. Results: DXR-BMD decreased in both men and women after the age of 45 years, progressively more so in women. While minimum hip JSW in men remained relatively unaltered throughout life, a marked decline in female minimum hip JSW after 45 years was observed. We found moderate, but highly significant relationships between reduced BMD and reduced hip JSW in women (p < 0.001), adjusted for age and dysplastic joint incongruity. Conclusion: We believe that the present study supports the hypothetical relationship between reduced estrogen levels and hip joint space width reduction in women

At present we conduct a clinical study on four bearing combinations in hip arthroplasty. Our main purpose is to assess changes in bone mineral density (BMD), function of the joint, and to monitor serum concentrations of prosthetic metals as well as plasma concentrations of a range of cytokines, chemokines, and related proteins during a ten-year follow-up. This is done in order to evaluate the potential role of these variables as predictors of dysfunction or loosening of the arthroplasty. A total of 300 patients were randomly allocated to four bearing combinations. Four years after surgery the following number of patients were available for follow-up: Type A: Zirconia ceramic head, polyethylene cup insert in the Universal RingLoc metal backed shell (n=50); Type B: Cobalt-Chrome-Molybdenum head and cup insert in the Universal RingLoc metal backed shell (n=57); Type C: Zirconia ceramic head, polyethylene moulded on the Titanium shell of the Asian cup (n=55); Type D: Alumina head and cup insert in the Universal RingLoc metal backed shell (n=45). A BiMetric Titanium-Aluminium-Vanadium (Ti6Al4V) stem was used with all four combinations (n=207). All patients, but two with rheumatoid arthritis, had primary osteoarthritis or avascular necrosis of the femoral head. Five patients had astma and eight had diabetes. At the time of surgery the groups were equal with regard to age, gender distribution, body height and weight, side of arthroplasty, and BMD in all seven Gruen zones. Harris Hip Score prior to arthroplasty was equally low in all groups (mean ± SD) (42 ± 17), and increased in all groups, with no significant differences between them (87 ± 10). At follow-up there was a significant decrease in BMD in all Gruen zones ranging from −1.9 % in zone 4 in group C to −21.7% in zone 7 in group D. However, there were no significant differences between groups. There were significantly higher blood concentrations of Chromium and Cobalt in group B patients compared to all other groups (p < 0.001). Plasma concentrations of cytokines IL-1β, IL-6, IL-8, IL-10, TNF-α, TNF-R1, VEGF, OPG, GM-CSF, or TGF-β. 1. did not differ significantly between groups. Instead, elevated levels of IL-1β, IL-10 and TNF-R1 were found in patients with asthma. IL-6, TNF-α and VEGF were elevated in patients with rheumatoid arthritis or asthma. IL-8 and TGF-β. 1. were higher in patients with osteoarthritis, whereas GM-CSF was high in patients with asthma or diabetes. CONCLUSION: The elevated serum concentrations of Chromium and Cobalt were seen in the group of patients using a bearing with these metals. It still remains to be elucidated, whether high serum concentrations of bearing surface metals signify a dysfunction of the prosthesis. Concentrations of plasma cytokines are mainly related to patient comorbidity when no sign of prosthetic loosening is present. Changes in BMD adjacent to the cemented femoral stem can not be attributed to any of the bearing materials used in this study

Aims: To determine the effect of fracture and immobilization on bone mineral density and mechanical parameters in postemenopausal women with a distal radius fracture. Methods: Seventeen postmenopausal women with a distal radius fracture with an indication for conservative treatment were included in the study. pQCT measurements of the fractured forearm were performed 2–3 days after the fracture, at 10 days after the fracture and at cast removal (35–45 days). All measurements were performed at a 10mm, 20mm and 40mm distance from a reference line set at the most proximal part of the distal radioulnar joint. Cortical, trabecular and total density and SSIx, SSIy and SSIpolar parameters were assessed. Results: At the fractured forearm, a high statistically signiþcant decrease of cortical density was observed only between second measurement and cast removal at 10 and 20mm (p< 0.01) Total density was not signiþcantly altered and trabecular density at 10mm was signiþcantly increased at cast removal compared to values at the time of the fracture (p< 0.01). Subcortical bone density at 10mm was also signiþcantly decreased at cast removal (p< 0.01). At cast removal, SSIx and SSI-polar parameters of the fractured forearm were also statistically signiþcantly decreased at distances of 10 and 20mm (p< 0.05). Conclusions: Distal radius fractures in postmenopausal women treated conservatively lead to a decrease of cortical density and an increase of trabecular density near the fracture site. They also aggravate bending and torsional mechanical properties. The shift from cortical bone to trabecular bone seems to be time-dependent and is signiþcant at cast removal

Introduction: Knotless Suture Anchors provide numerous advantages in arthroscopic rotator-cuff (RC) repair such as, reducing the difficulties of knot tying, reducing surgical exposure, thus decreasing morbidity. The purpose of this in-vitro study was to compare the pull-out strength of three new knotless suture anchors in correlation with bone quality using the following anchors: Opus Magnum 2 -ArthroCare Co., USA; Push Lock and Swivel Lock -Arthrex Inc., USA. Material & Methods: Ten healthy and ten osteopenic macroscopically intact humeri with an average age of 51.7 and 79.5 years, respectively, were loaded with the three knotless suture anchors according to the manufacturers’ description. The healthy humeri had a mean trabecular BMD of 152.77 mgCa-HA/ml. The osteopenic humeri had a mean trabecular bone mineral density of 54.02 mgCa-HA/ml. The humeri were positioned in a custom - engineered adjustable fixation device, stabilising the direction of the pull of the sutures at an angle of 135° to the axis of the humeral shaft (Universal testing device Z010/TN2A – Zwick GmbH, Ulm, Germany). The anchors were cyclically loaded to simulate postoperative conditions. The ultimate pull-out strenngth, the initial displacement in millimeters after the first pull with 75 N and the modes of failure were recorded. Results: The mean ultimate failure loads of the Opus Magnum 2, PushLock and SwiveLock anchors in osteopenic humeri were 135.0, 102.5 and 130.0 N (p> 0.05), respectively, and in healthy humeri 142.5 N, 182.5 N and 202.5 N (p> 0.05), respectively. The initial system displacement in osteopenic humeri of the Opus Magnum 2, PushLock and SwiveLock anchors were 3.53 mm, 16.11 mm and 3.23 mm (p< 0.01), respectively, and in healthy humeri 3.71 mm, 1.98 mm, and 1.96 mm (p> 0.05), respectively. Discussion: The results of this study show that in osteopenic humeri, the Opus Magnum 2 and SwiveLock anchors display significant superiority in system displacement with an initial pull of 75N compared to the PushLock anchor in osteopenic bone, but all three anchors fail to provide significance in the ultimate failure load. PushLock anchor might cause a greater gap formation between the RC-tendon and greater tubercle interface in osteopenic humeri due to inferior gripping and therefore should not be used solely for RC repair. Due to a manufacturing flaw the suture holding fixture of the Opus Magnum 2 anchor “breaks” when a mean force of 138.75 N is applied to the system, regardless of the bone quality, thus disabling the anchor to unfold it’s properties in healthy bone. Whereas the results in osteopenic bone are comparable to the other two anchors. SwiveLock provides the best support of all three anchors in healthy humeri