Intertrochanteric Region Research Articles

Influence of vitamin D levels on bone mineral density and osteoporosis

BACKGROUND AND OBJECTIVES:The effects of vitamin D on bone mass remain to be understood. This study was conducted with the objective of evaluating the influence of 25-hydroxyvitamin D (25OHD) levels on bone mineral density (BMD) among Saudi nationals.DESIGN AND SETTING:Cross-sectional study carried out at university hospital from 1 February 2008 to 31 May 2008.SUBJECTS AND METHODS:Healthy Saudi men and women in the peak bone mass (PBM) age group and those aged ≥50 years were recruited from the outpatient department of King Fahd University Hospital, Al Khobar, Saudi Arabia, between February 1, 2008, and May 31, 2008. Patient age and sex were documented, and body mass index was calculated. Hematological, biochemical, and serum 25OHD tests were performed. BMD was determined by dual-energy x-ray absorptiometry of the upper femur and lumbar spine. Patients were divided into three groups, based on their 25OHD level.RESULTS:Data from 400 patients were analyzed. Among individuals with a normal 25OHD level, 50% of women and 7% of men in the PBM age group and 26.4% of women and 49.2% of men aged ≥50 years had low bone mass. In patients with 25OHD insufficiency, 84.2% of women and 88.9% of men in the PBM age group and 83.3% of women and 80% of men aged ≥50 years had low bone mass. Results for patients with 25OHD deficiency revealed that none of the men and women in the PBM age group or ≥50 years old had normal BMD. Significant positive correlations between 25OHD level and BMD and significant negative correlations with parathyroid hormone were shown in most of the groups.CONCLUSIONS:This study showed that the vitamin D level significantly influences BMD reading among Saudi individuals. Evaluation and treatment of hypovitaminosis D should be considered during management of low bone mass.

A preliminary dual-energy X-ray absorptiometry-based finite element model for assessing osteoporotic hip fracture risk

To more accurately assess osteoporotic hip fracture risk in a specific patient, a dual-energy X-ray absorptiometry (DXA)-based finite element model was constructed from the patient's femur DXA image. The outermost contour of the femur bone segmented from the DXA image was used to generate a finite element mesh. Bone mechanical properties, such as Young's modulus, are correlated with areal bone mineral density (BMD) captured in the DXA image. A quasi-static loading condition representing a sideway fall was applied to the finite element model. Three fracture risk indices were introduced and expressed as ratios of internal forces caused by impact forces occurring in sideway fall to bone ultimate cross-section strength at the three critical locations, i.e. the femoral neck, the intertrochanteric region, and the subtrochanteric region. The proposed finite element modelling procedure was validated against six representative clinical cases extracted from the Manitoba BMD database, where initial and follow-up DXA images have been taken to monitor longitudinal variation of areal BMD in individual patients. It was found from the clinical validation that variations in the proposed fracture risk indices have the same trends as those indicated by the conventional areal BMD and T-score. In addition, by the three proposed fracture risk indices it is possible to further identify the specific fracture location. It was also found that for the same subject, the variations in the three fracture risk indices have quite different magnitudes, with intertrochanteric region the largest and subtrochanteric region the smallest, which is probably owing to the different content of trabecular and cortical bones in the three regions. With further development, it is promising that the proposed DXA-based finite element model will be a useful tool for accurate assessment of osteoporosis development and for treatment monitoring.

Rheumatoid Arthritis is Associated With Less Optimal Hip Structural Geometry

The overall goal of this study was to assess the longitudinal changes in bone strength in women reporting rheumatoid arthritis (RA; n=78) compared with nonarthritic control participants (n=4779) of the Women's Health Initiative bone mineral density (WHI-BMD) subcohort. Hip structural analysis program was applied to archived dual-energy X-ray absorptiometry scans (baseline, years 3, 6, and 9) to estimate bone mineral density (BMD) and hip structural geometry parameters in 3 femoral regions: narrow neck (NN), intertrochanteric (IT), and shaft (S). The association between RA and hip structural geometry was tested using linear regression and random coefficient models. Compared with the nonarthritic control, the RA group had a lower BMD (p=0.061) and significantly lower outer diameter (p=0.017), cross-sectional area (p=0.004), and section modulus (p=0.035) at the NN region in the longitudinal models. No significant associations were seen at the IT regions or S regions, and the association was not modified by age, ethnicity, glucocorticoid use, or time. Within the WHI-BMD, women with RA group had reduced BMD and structural geometry at baseline, and this reduction was seen at a fixed rate throughout the 9yr of study.

Clinical study of Pipkinfracture classification

：Objective To assessesthe value of the Pipkin fracture classification on the treatment and prognosis of Pipkinfracture. Methods A total of 71 patients with Pipkin fractures treated from January 2002to January 2007 were followed up and the detailed information of 63 patients wereobtained. The clinical and radiographic evaluation criteria of Thompson was employed toevaluate the outcome, analyze the results and discuss the correlation between Pipkinfracture type and prognosis and hence propose the significance of Pipkin classification onthe prognosis. Results There was no statistical difference in aspect of the outcomebetween type Pipkin Ⅰ , Ⅱ injury and type Pipkin Ⅳinjury (typesPipkin Ⅰ and Ⅱ injury combined with minimum fracture, with fragment ＜ 1 cm,P＞0. 05). There showedstatistical difference in outcome between types Pipkin Ⅰ , Ⅱ injury and type PipkinⅣ injury (types Pipkin Ⅰ and Ⅱ injury combined withacetabular rim fracture, P ＜0. 05). Conclusions Pipkinfracture classification system needs a further improvement. The type Pipkin Ⅳ injury that is combined with types Pipkin Ⅰ , Ⅱ , Ⅲ injuries with minimum fracture (fragment ＜ 1 cm) of the acetabular rim should be incorporated into typesPipkin Ⅰ ,Ⅱ , Ⅲ injury. Type Pipkin Ⅳinjury refers totypes Pipkin Ⅰ ,Ⅱ , Ⅲ injuries, with major fracture of the acetabular rim and the hipjoint instability. In addition, the Pipkin fracture type involving the fracture line,femoral neck and intertrochanteric region is hard to treat clinically and has poorprognosis, suggesting that this type of injury should be considered as special type PipkinⅢ injury. Key words: Fractures, femoral head; Dislocation, hip joint

Combination of texture analysis and bone mineral density improves the prediction of fracture load in human femurs

Twenty-one excised femurs were studied using (1) a high-resolution digital X-ray device to estimate three textural parameters, (2) dual-energy X-ray absorptiometry (DXA) to measure bone mineral density (BMD), and (3) mechanical tests to failure. Textural parameters significantly correlated with BMD (p < 0.05) and bone strength (p < 0.05). Combining texture parameters and BMD significantly improved the fracture load prediction from adjusted r(2) = 0.74 to adjusted r(2) =0.82 (p < 0.05). The purpose of this study is to determine if the combination of bone texture parameters using a new high-resolution X-ray device and BMD measurement by DXA provided a better prediction of femoral failure load than BMD evaluation alone. The proximal ends of 21 excised femurs were studied using (1) a high-resolution digital X-ray device (BMA, D3A Medical Systems) to estimate three textural parameters: fractal parameter Hmean, co-occurrence, and run-length matrices, (2) DXA to measure BMD, and (3) mechanical tests to failure in a side-impact configuration. Regions of interest in the femoral neck, intertrochanteric region, and greater trochanter were selected for DXA and bone texture analysis. Every specimen was scanned twice with repositioning before mechanical testing to assess reproducibility using intraclass correlation coefficient (ICC) with 95% confidence interval. The prediction of femoral failure load was evaluated using multiple regression analysis. Thirteen femoral neck and 8 intertrochanteric fractures were observed with a mean failure load of 2,612 N (SD, 1,382 N). Fractal parameter Hmean, co-occurrence, and run-length matrices each significantly correlated with site-matched BMD (p < 0.05) and bone strength (p < 0.05). The ICC of the textural parameters varied between 0.65 and 0.90. Combining bone texture parameters and BMD significantly improved the fracture load prediction from adjusted r(2) =0.74 to adjusted r(2) = 0.82 (p < 0.05). In these excised femurs, the combination of bone texture parameters with BMD demonstrated a better performance in the failure load prediction than that of BMD alone.

Cerclage cable in fracture: frustration or necessity?

Dear Editor, I have read the article “The benefit of wire cerclage stabilisation of the medial hinge in intramedullary nailing for the treatment of subtrochanteric femoral fractures: a biomechanical study” with the great interest [1]. In their article, the authors argue that osteosynthesis frequently fails and a higher rate of nonunion is found in the subtrochanteric region of the femur. As I understand from their article, this nonunion is due to fracture distraction (commonly seen after intramedullary nailing) in the subtrochanteric region, and they believe that supporting the medial column with cerclage wiring can resolve this problem [1]. They concluded that “a mini-open approach to difficult fractures could be helpful in reducing the fracture with a clamp and is sometimes essential. An additional cerclage in oblique subtrochanteric fractures is a good option to ensure the reposition and cortical medial support if appropriate and to decrease osteosynthesis failure and rates of non-unions”. We would like to thank the authors for their invaluable study but do not agree with them. Yes, subtrochanteric fracture of the femur is a very problematic region for orthopaedic surgeons due to the particular anatomical features including high Ratio of cortical bone and to cancellous bone compared to other skeletal regions. These features result in low blood supply which means low union rates compared to other parts of the body. But higher nonunion does not mean more than 10%, but rather means higher compared to the intertrochanteric region. We work at a university hospital and we have faced many nonunions in our clinic, which is why we want to share our experience with cables. Cerclage cable inhibits fracture union in two ways (Fig. 1): (1) it prevents formation of callus and (2) it inhibits local blood supply. Cable is not implantable for transverse fractures and comminuted fractures, as it can only be performed to oblique or spiral fractures. The authors stated that reduction is important and this can be achieved with cable. Most angulation is due to improper nail insertion, and if technical guidelines are followed this problem can be minimised. Intramedullary fixation has biological and biomechanical advantages, but the operation is technically demanding. Gradual learning and great patience is needed in order to make this method truly minimally invasive. Long PFN, long gamma nail or Russell Taylor nail are reliable implants for subtrochanteric fractures, leading to high rates of bone union and minimal soft tissue damage [2]. If angulation still persists, a simple AO screw will suffice. The authors state that if you use clamp for reduction, you can insert a cable [1]. Technically, if you use a clamp, you do not need to cut or devitalize the surrounding tissue. That is why blood supply is not damaged. But if you use cable you need to dissect more tissue. For simple, well-reduced fractures the choice of implant is not critical. If subtrochanteric fractures are unstable (e.g., comminution, segmental bone loss, long spiral), the choice of implant is critical and should be restricted to implants that allow minimal fracture site motion (long gamma and Russell-Taylor) instead of short PFN [3]. Fig. 1 Cable failure and subtrochanteric nonunion In conclusion, in our experience along with other authors, higher union in the subtrochanteric region can be achieved with the last generation intramedullary nail with good technique. Using cable may improve anatomical reduction, but one should not forget that an extra implant may increase operation time, cost, bleeding and nonunion.

In peripubertal girls, artistic gymnastics improves areal bone mineral density and femoral bone geometry without affecting serum OPG/RANKL levels

Peripubertal artistic gymnasts display elevated areal bone mineral density at various bone sites, despite delayed menarche and a high frequency of menstrual disorders, factors that may compromise bone health. The concomitant improvement in femoral bone geometry and strength suggested that this type of physical activity might have favourable clinical impact. The purpose of this study is to evaluate the effect of artistic gymnastics (GYM) on areal bone mineral density (aBMD), femoral bone geometry and bone markers and its relationship with the osteoprotegerin (OPG)/rank-ligand (RANKL) system in peripubertal girls. Forty-six girls (age 10-17.2 years) were recruited for this study: 23 elite athletes in the GYM group (training 12-30 h/week, age at start of training 5.3 years) and 23 age-matched (± 6 months; leisure physical activity ≤ 3 h/week) controls (CON). The aBMD at whole body, total proximal femur, lumbar spine, mid-radius and skull was determined using dual-X-ray absorptiometry. Hip structural analysis (HSA software) was applied at the femur to evaluate cross-sectional area (CSA, cm(2)), cross-sectional moment of inertia (CSMI, cm(4)), and the section modulus (Z, cm(3)) and buckling ratio at neck, intertrochanteric region and shaft. Markers of bone turnover and OPG/RANKL levels were also analysed. GYM had higher (5.5-16.4%) non-adjusted aBMD and adjusted aBMD for age, fat-free soft tissue and fat mass at all bone sites, skull excepted and the difference increased with age. In the three femoral regions adjusted for body weight and height, CSA (12.5-18%), CSMI (14-18%), Z (15.5-18.6%) and mean cortical thickness (13.6-21%) were higher in GYM than CON, while the buckling ratio (21-27.1%) was lower. Bone markers decreased with age in both groups and GYM presented higher values than CON only in the postmenarchal period. A similar increase in RANKL with age without OPG variation was observed for both groups. GYM is associated not only with an increase in aBMD but also an improvement in bone geometry associated with an increase in bone remodelling. These adaptations seem to be independent of the OPG/RANKL system.

Bisphosphonate Use and the Risk of Subtrochanteric or Femoral Shaft Fractures in Older Women

Osteoporosis is associated with significant morbidity and mortality. Oral bisphosphonates have become a mainstay of treatment, but concerns have emerged that long-term use of these drugs may suppress bone remodeling, leading to unusual fractures. To determine whether prolonged bisphosphonate therapy is associated with an increased risk of subtrochanteric or femoral shaft fracture. A population-based, nested case-control study to explore the association between bisphosphonate use and fractures in a cohort of women aged 68 years or older from Ontario, Canada, who initiated therapy with an oral bisphosphonate between April 1, 2002, and March 31, 2008. Cases were those hospitalized with a subtrochanteric or femoral shaft fracture and were matched to up to 5 controls with no such fracture. Study participants were followed up until March 31, 2009. The primary analysis examined the association between hospitalization for a subtrochanteric or femoral shaft fracture and duration of bisphosphonate exposure. To test the specificity of the findings, the association between bisphosphonate use and fractures of the femoral neck or intertrochanteric region, which are characteristic of osteoporotic fractures, was also examined. We identified 716 women who sustained a subtrochanteric or femoral shaft fracture following initiation of bisphosphonate therapy and 9723 women who sustained a typical osteoporotic fracture of the intertrochanteric region or femoral neck. Compared with transient bisphosphonate use, treatment for 5 years or longer was associated with an increased risk of subtrochanteric or femoral shaft fracture (adjusted odds ratio, 2.74; 95% confidence interval, 1.25-6.02). A reduced risk of typical osteoporotic fractures occurred among women with more than 5 years of bisphosphonate therapy (adjusted odds ratio, 0.76; 95% confidence interval, 0.63-0.93). Among 52,595 women with at least 5 years of bisphosphonate therapy, a subtrochanteric or femoral shaft fracture occurred in 71 (0.13%) during the subsequent year and 117 (0.22%) within 2 years. Among older women, treatment with a bisphosphonate for more than 5 years was associated with an increased risk of subtrochanteric or femoral shaft fractures; however, the absolute risk of these fractures is low.

Osteoporotic hip fracture costs in the elderly Turkish population.

This study was designed to determine the length of hospital stay and treatment costs of patients with osteoporotic hip fractures in Turkey. A total of 1,118 osteoporotic hip fractures taken from patient records in 35 hospitals connected to a Disease Related Group (DRG) network were included in the study. Inclusion criteria were patients over the age of fifty with a diagnosis of a single, low-energy fracture located at the neck, head, or intertrochanteric region of the femur treated with total/hemi-arthroplasty, screw or nail methods. We examined the demographics, location of fracture, treatment type, length of hospital stay (LOS), direct cost and cost extrapolation based on the numbers of hospitals, beds and patient by hospital. Of the 1,118 patients (mean age: 75.3 ± 9.9 years), 62.8% were female. The main fracture type was of the femur neck without precise localization. The average LOS was 11.0 ± 7.9 days. The total weighed cost of all 1,118 hip fractures was $2,249,885 per year, indicating an average direct medical cost of $3,119 per patient in the 35 DRG hospitals. Based on this sample, the estimated total number of patients is 15,602 by number of hospitals; 8,521 by number of hospital beds and 9,365 by number of hospitalization, costing $31,530 million; $14,793 million and $18,948 million, respectively. Diverse results in cost estimations of osteoporotic hip fractures reflect the incoherence of data as well as a lack of standardization of health care services. Therefore, ICD and DRG coding needs to be improved and a national database must be created at least for the invoices of importation of prostheses to fully be able to calculate the burden of osteoporosis across Turkey.

Inter-sex differences in structural properties of aging femora: implications on differential bone fragility: a cadaver study

In this paper we examined age-related and sex-specific deterioration in bone strength of the proximal femur reflected in mechanical properties from dual energy X-ray absorptiometry (DXA)-based hip structural analysis (HSA) on a cadaveric sample from the Balkans. Cadaveric studies permit more precise measurement of HSA parameters and allow further analyses by micromorphometric methods. DXA and HSA analysis was performed on a total of 138 cadaveric proximal femora (63 female, 75 male, age range 20-101years) from Belgrade. HSA parameters are reported for three standard regions of the proximal femur (narrow neck, intertrochanteric, and shaft). Major age-related findings include an increase in the radius of gyration (first reported in this study), a decline in the cross-sectional area (CSA), a shift in the centroid towards the medial cortex, higher buckling ratios and lower section moduli. Whereas age appears to affect mostly the neck region in men, weakening is also evident in the intertrochanteric region in women, particularly after the age of 80. Aging femoral neck declines in bending strength and increases in buckling susceptibility. The reduced bone mass tends to be distributed farther from the centroidal axis (increase in radius of gyration with decline in CSA). Bone mass is preferentially lost from the lateral part of the cross-section shifting the centroid towards the medial cortex which may increase fragility of the lateral part during fall impact. Results of this study contribute to the epidemiologic data on gender differences and age trends in aging male and female femora.

Proximal femoral fractures

Fractures of the proximal femur include fractures of the head, neck, intertrochanteric, and subtrochanteric regions. Head fractures commonly accompany dislocations. Neck fractures and intertrochanteric fractures occur with greatest frequency in elderly patients with a low bone mineral density and are produced by low-energy mechanisms. Subtrochanteric fractures occur in a predominantly strong cortical osseous region which is exposed to large compressive stresses. Implants used to address these fractures must be able to accommodate significant loads while the fractures consolidate. Complications secondary to these injuries produce significant morbidity and include infection, nonunion, malunion, decubitus ulcers, fat emboli, deep venous thrombosis, pulmonary embolus, pneumonia, myocardial infarction, stroke, and death.

Improvement of Femoral Bone Quality After Low-Magnitude, High-Frequency Mechanical Stimulation in the Ovariectomized Rat as an Osteopenia Model

The treatment and prevention of osteoporosis involve great challenges. Nonpharmacological and supportive therapy procedures, sport, and physical exercises seem to prevent bone loss and improve bone mass. In the present study, we examined the effect of whole-body vertical vibration (WBVV) on femoral intertrochanteric bone quality in the rat osteoporosis model. Sixty female Sprague–Dawley rats, 3-month old, were ovariectomized (OVX) or sham-operated. After 3 months, each group was divided into two subgroups. In one of the subgroups, rats were treated with WBVV at 90 Hz (3.9 g) for 35 days; the second subgroup remained untreated. After killing the animals, biomechanical strength and trabecular bone architecture of the proximal region of femurs were analyzed. New cortical bone appositions and mineral density of femurs were additionally measured. Treatment with WBVV resulted in improved biomechanical properties. Maximal load and stiffness of the intertrochanteric region of femurs after WBVV were significantly enhanced. Maximal load and stiffness in treated OVX animals reached the levels observed in untreated sham rats. WBVV significantly improved all measured histomorphometric parameters in the trabecular area. Treated rats showed significantly improved mineral content in ashed femurs compared to untreated animals. A comparison of widths of fluorescence bands in cortical bone of subtrochanteric cross sections did not show any significant differences between the groups after WBVV. Low-magnitude, high-frequency mechanical stimulation improves bone strength in the proximal femur and may be a possible nonpharmacologic treatment option for postmenopausal osteoporosis.

In vivo discrimination of hip fracture with quantitative computed tomography: Results from the prospective European Femur Fracture Study (EFFECT)

In assessing osteoporotic fractures of the proximal femur, the main objective of this in vivo case-control study was to evaluate the performance of quantitative computed tomography (QCT) and a dedicated 3D image analysis tool [Medical Image Analysis Framework--Femur option (MIAF-Femur)] in differentiating hip fracture and non-hip fracture subjects. One-hundred and seven women were recruited in the study, 47 women (mean age 81.6 years) with low-energy hip fractures and 60 female non-hip fracture control subjects (mean age 73.4 years). Bone mineral density (BMD) and geometric variables of cortical and trabecular bone in the femoral head and neck, trochanteric, and intertrochanteric regions and proximal shaft were assessed using QCT and MIAF-Femur. Areal BMD (aBMD) was assessed using dual-energy X-ray absorptiometry (DXA) in 96 (37 hip fracture and 59 non-hip fracture subjects) of the 107 patients. Logistic regressions were computed to extract the best discriminates of hip fracture, and area under the receiver characteristic operating curve (AUC) was calculated. Three logistic models that discriminated the occurrence of hip fracture with QCT variables were obtained (AUC = 0.84). All three models combined one densitometric variable--a trabecular BMD (measured in the femoral head or in the trochanteric region)--and one geometric variable--a cortical thickness value (measured in the femoral neck or proximal shaft). The best discriminant using DXA variables was obtained with total femur aBMD (AUC = 0.80, p = .003). Results highlight a synergistic contribution of trabecular and cortical components in hip fracture risk and the utility of assessing QCT BMD of the femoral head for improved understanding and possible insights into prevention of hip fractures.

Diagnosis and conservative treatment of transient osteoporosis of the hip

Objective To investigate clinical diagnosis and clinical outcome of conservative treatment for transient osteoporosis of the hip. Methods Between October 2006 and July 2009, 10 patients with transient osteoporosis of the hip were treated in out-patient clinic. The clinical and radiologic characteristics were studied retrospectively. There were 4 males and 6 females with an average age of 35 years (range, 22-43). All female patients were not in the period of pregnancy. The diagnosis was made based upon detailed X-ray and MRI evaluations. X-ray revealed osseous demineralization of the femoral head at 8 patients and showed normal at 2 patients. All patients showed the characteristic MRI pattern of transient osteoporosis of the hip. The involved hip had a diffuse and homogeneous area of low signal intensity on T1-weighted images and high signal intensity on T2-weighted images in the head, neck and the intertrochanteric region in 7 patients. Non-operative management, consisting of symptomatic therapy and reduction of weight bearing was performed in all patients. Symptomatic therapy included nonsteroidal anti-inflammatory drug and bisphosphonate administration. Verbal pain rating scale and Harris hip score were used to assess the results of the treatment. Results All 10 patients have been followed up at 3, 6 and 12 months interval after they received treatments. The last follow-up duration of all 10 patients was 2.5 years (range, 1.0-3.5). All patients had pain relief in varying degrees at 1 day after the therapy. The pain scale level had diminished in all patients, while the Harris hip score had increased from 74.5 pre-therapy to 96 post-therapy. X-ray and MRI showed complete recovery after 6 months. No complications were found among them. Conclusion Transient osteoporosis of the hip was considered to be a distinct, self-limiting, and transient disease, which had specific clinical and radiologic characters. Non-operative management should be the first choice to treat this disease. Key words: Osteoporosis; Bone marrow; Edema; Hip joint

Trends in incidence of subtrochanteric fragility fractures and bisphosphonate use among the US elderly, 1996-2007.

Increasing numbers of atypical hip fractures have been reported among patients with bisphosphonate use. However, the nature and extent of the problem are unknown despite recent investigations. To analyze national trends in hip fractures and medication use in the elderly US population, we respectively used the Nationwide Inpatient Sample (NIS) and the Medical Expenditure Panel Survey (MEPS) from 1996 to 2007. In NIS, subtrochanteric fragility fractures were compared with typical hip fractures in femoral neck and intertrochanteric regions. Between 1996 and 2007, age-adjusted rates for typical hip fractures decreased by 31.6% among women (from 1020.5 to 697.4 per 100,000 population) and 20.5% among men (from 424.9 to 337.6 per 100,000 population). In contrast, overall trends in age-adjusted rates for subtrochanteric fragility fractures remained unchanged among men (p = .34) but increased 20.4% among women from 28.4 (95% confidence interval [CI] 27.7–29.1) in 1999 to 34.2 (95% CI 33.4–34.9) per 100,000 population in 2007. The annual percentage increase was 2.1% (95% CI 1.3–2.8, p < .001) based on joinpoint regression analysis. In MEPS, bisphosphonate use increased predominantly in women (from 3.5% in 1996 to 16.6% in 2007) compared with men (2.3% in 2007). In the context of declining typical hip fractures among the US elderly, we observed small but significant increases in the incidence of subtrochanteric fragility fractures from 1999 among postmenopausal women. Using age-adjusted rates, we estimated that for every 100 or so reduction in typical femoral neck or intertrochanteric fractures, there was an increase of one subtrochanteric fragility fracture. © 2011 American Society for Bone and Mineral Research.

The Effect of Cement Placement on Augmentation of the Osteoporotic Proximal Femur

Femoroplasty, the augmentation of the proximal femur, has been shown in biomechanical studies to increase the energy required to produce a fracture and therefore may reduce the risk of such injuries. The purpose of our study was to test the hypotheses that: (1) 15 mL of cement was sufficient to mechanically augment the proximal femur, (2) there was no difference in augmentation effect between cement placement in the intertrochanteric region and in the femoral neck, and (3) cement placement in the femoral neck would predispose the proximal femur to an intertrochanteric fracture, whereas trochanteric placement would result in subtrochanteric fractures. In each of 18 pairs of osteoporotic human cadaveric femora, 15 mL of polymethylmethacrylate bone cement was injected into the trochanteric or femoral neck region of 1 femur, and the noninjected femur was used as the control. The augmentation effect of femoroplasty was evaluated under simulated fall conditions using a materials testing machine. Multiple linear regressions incorporating random effects were used to check for associations between covariates (bone mineral density, cement location, and treatment) and the parameters of interest (stiffness, yield energy, yield load, ultimate load, and ultimate energy). Significance was set at P < .05. It was found that femoroplasty with 15 mL of cement did not significantly increase stiffness, yield energy, yield load, ultimate load, or ultimate energy relative to paired controls. There were no significant differences in parameters of interest or fracture patterns in specimens augmented in the femoral neck versus the trochanter. It was concluded that 15 mL of cement was not sufficient to augment the proximal femur and that there was no biomechanical advantage to the placement of cement within the femoral neck versus the trochanter.

Comparison of Femoral Morphology and Bone Mineral Density between Femoral Neck Fractures and Trochanteric Fractures

Many studies that analyzed bone mineral density (BMD) and skeletal factors of hip fractures were based on uncalibrated radiographs or dual-energy xray absorptiometry (DXA). Spatial accuracy in measuring BMD and morphologic features of the femur with DXA is limited. This study investigated differences in BMD and morphologic features of the femur between two types of hip fractures using quantitative computed tomography (QCT). Forty patients with hip fractures with normal contralateral hips were selected for this study between 2003 and 2007 (trochanteric fracture, n=18; femoral neck fracture, n=22). Each patient underwent QCT of the bilateral femora using a calibration phantom. Using images of the intact contralateral femur, BMD measurements were made at the point of minimum femoral-neck cross-sectional area, middle of the intertrochanteric region, and center of the femoral head. QCT images also were used to measure morphologic features of the hip, including hip axis length, femoral neck axis length, neck-shaft angle, neck width, head offset, anteversion of the femoral neck, and cortical index at the femoral isthmus. No significant differences were found in trabecular BMD between groups in those three regions. Patients with trochanteric fractures showed a smaller neck shaft angle and smaller cortical index at the femoral canal isthmus compared with patients with femoral neck fractures. We conclude that severe osteoporosis with thinner cortical bone of the femoral diaphysis is seen more often in patients with trochanteric fracture than in patients with femoral neck fracture. Level IV, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Critical molecular regulators, histomorphometric indices and their correlations in the trabecular bone in primary hip osteoarthritis

This study examined differential gene expression, histomorphometric indices and relationships between these, in femoral trabecular bone from osteoarthritis (OA) patients and control (CTL) subjects, with the aim of identifying potential molecular drivers consistent with changes in structural and remodelling indices in the OA pathology. Bone samples from the intertrochanteric (IT) region were obtained from age and sex-matched cohorts of 23 primary hip OA patients and 21 CTL subjects. Real-time polymerase chain reaction (PCR) and histomorphometric analysis were performed on each sample and correlations between gene expression and histomorphometric variables determined. Alterations in gene expression, structural indices and correlations between these were found in OA bone compared to CTL. In OA bone, expression of critical regulators of osteoblast differentiation (TWIST1) and function (PTEN, TIMP4) were decreased, while genes associated with inflammation (SMAD3, CD14) were increased. Bone structural and formation indices (BV/TV, Tb.N, OS/BS) were increased, whereas resorption indices (ES/BS, ES/BV) were decreased. Importantly, significant correlations in CTL bone between CTNNB1 expression and formation indices (OS/BS, OS/BV, OV/BV) were absent in OA bone, indicating altered WNT/β-catenin signalling. TWIST1 expression and BV/TV were correlated in CTL bone, but not in OA bone, consistent with altered osteoblastogenesis in OA. Matrix metalloproteinase 25 (MMP25) expression and remodelling indices (ES/BS, ES/BV, ES/TV) were correlated only in OA pointing to aberrant bone remodelling in this pathology. These findings indicate an altered state of osteoblast differentiation and function in OA driven by several key molecular regulators. In association with this differential gene expression, an altered state of both trabecular bone remodelling and resulting microarchitecture were also observed, further characterising the pathogenesis of primary hip OA.

Dietary Equol and Bone Metabolism in Postmenopausal Japanese Women and Osteoporotic Mice

Equol binds to the estrogen receptor with greater affinity than its precursor, daidzein, an isoflavone found in soybeans. Inter-individual differences in the ability to produce equol may lead to differential effects of isoflavone intervention on human health. Here, we review previously published work from our laboratory on equol producer status and bone health in humans and in a mouse model of osteoporosis. We performed a 1-y, double-blind, randomized trial to compare the effects of isoflavone (75 mg of isoflavone conjugates/d; equivalent to 47 mg/d of the aglycone form) with those of placebo on bone mineral density (BMD), fat mass, and serum isoflavone concentrations in 54 early postmenopausal Japanese women classified by their equol-producer phenotype. Isoflavone intervention increased the serum equol concentration in equol producers but not in nonproducers (P < 0.04). The annualized changes in BMD in the total hip and intertrochanteric regions in the isoflavone-treated equol producers (−0.46 and −0.04%, respectively) were less than in the nonproducers (−2.28 and −2.61%, respectively). The annualized change in fat mass was lower in the equol producers compared with the nonproducers in the isoflavone group. The annualized changes in BMD and fat mass did not differ between the equol producers and nonproducers in the placebo group. Equol also inhibited bone loss and fat accumulation in estrogen-deficient osteoporotic mice. Our data suggest that prevention of bone loss and fat accumulation in early postmenopausal women by isoflavones may depend on an individual’s equol-producing capacity. J. Nutr. 140: 1373S–1376S, 2010.

Integrity of the osteocyte bone cell network in osteoporotic fracture: Implications for mechanical load adaptation

The human skeleton has the ability to modify its material composition and structure to accommodate loads through adaptive modelling and remodelling. The osteocyte cell network is now considered to be central to the regulation of skeletal homeostasis; however, very little is known of the integrity of the osteocyte cell network in osteoporotic fragility fracture. This study was designed to characterise osteocyte morphology, the extent of osteocyte cell apoptosis and expression of sclerostin protein (a negative regulator of bone formation) in trabecular bone from the intertrochanteric region of the proximal femur, for postmenopausal women with fragility hip fracture compared to age-matched women who had not sustained fragility fracture. Osteocyte morphology (osteocyte, empty lacunar, and total lacunar densities) and the degree of osteocyte apoptosis (percent caspase-3 positive osteocyte lacunae) were similar between the fracture patients and non-fracture women. The fragility hip fracture patients had a lower proportion of sclerostin-positive osteocyte lacunae in comparison to sclerostin-negative osteocyte lacunae, in contrast to similar percent sclerostin-positive/sclerostin-negative lacunae for non-fracture women. The unexpected finding of decreased sclerostin expression in trabecular bone osteocytes from fracture cases may be indicative of elevated bone turnover and under-mineralisation, characteristic of postmenopausal osteoporosis. Further, altered osteocytic expression of sclerostin may be involved in the mechano-responsiveness of bone. Optimal function of the osteocyte cell network is likely to be a critical determinant of bone strength, acting via mechanical load adaptation, and thus contributing to osteoporotic fracture risk.