Increased cortical porosity in type 2 diabetic postmenopausal women with fragility fractures

The primary goal of this study was to assess peripheral bone microarchitecture and strength in postmenopausal women with type 2 diabetes with fragility fractures (DMFx) and to compare them with postmenopausal women with type 2 diabetics without fractures (DM). Secondary goals were to assess differences in nondiabetic postmenopausal women with fragility fractures (Fx) and nondiabetic postmenopausal women without fragility fractures (Co), and in DM and Co women. Eighty women (mean age 61.3 ± 5.7 years) were recruited into these four groups (DMFx, DM, Fx, and Co; n = 20 per group). Participants underwent dual-energy X-ray absorptiometry (DXA) and high-resolution peripheral quantitative computed tomography (HR-pQCT) of the ultradistal and distal radius and tibia. In the HR-pQCT images volumetric bone mineral density and cortical and trabecular structure measures, including cortical porosity, were calculated. Bone strength was estimated using micro-finite element analysis (µFEA). Differential strength estimates were obtained with and without open cortical pores. At the ultradistal and distal tibia, DMFx had greater intracortical pore volume (+52.6%, p = 0.009; +95.4%, p = 0.020), relative porosity (+58.1%, p = 0.005; +87.9%, p = 0.011) and endocortical bone surface (+10.9%, p = 0.031; +11.5%, p = 0.019) than DM. At the distal radius DMFx had 4.7-fold greater relative porosity (p < 0.0001) than DM. At the ultradistal radius, intracortical pore volume was significantly higher in DMFx than DM (+67.8%, p = 0.018). DMFx also displayed larger trabecular heterogeneity (ultradistal radius: +36.8%, p = 0.035), and lower total and cortical BMD (ultradistal tibia: -12.6%, p = 0.031; -6.8%, p = 0.011) than DM. DMFx exhibited significantly higher pore-related deficits in stiffness, failure load, and cortical load fraction at the ultradistal and distal tibia, and the distal radius than DM. Comparing nondiabetic Fx and Co, we only found a nonsignificant trend with increase in pore volume (+38.9%, p = 0.060) at the ultradistal radius. The results of our study suggest that severe deficits in cortical bone quality are responsible for fragility fractures in postmenopausal diabetic women.

Clinical risk factors for osteoporosis are common among elderly people in Nuuk, Greenland

Background

Osteoporosis is a debilitating condition characterized by fractures, pain and premature death. Risk factors for osteoporosis predict the risk of fragility fractures.

Aim

To describe the occurrence of risk factors for osteoporosis among populations in Nuuk, the capital of Greenland.

Methods

A random sample of women born in 1934–42, 1945–47, 1956, and men born in 1956 were selected from the national civil registry. A questionnaire was sent out in Greenlandic and Danish on risk factors for osteoporosis: family history, smoking habits, alcohol intake, presence of disease, sun exposure, intake of dairy products, age at menopause (women) and number of falls. Additional questions included the frequency of back pain, previous fractures, intake of vitamin D and calcium supplements, use of anti-osteoporotic drugs, steroids and other drugs.

Results

The questionnaire was sent to 317 subjects confirmed to be living at an address in Nuuk and 181 (57.1%) responded. More young women than older women were smokers (60.6% vs. 35.0%; p=0.022) while limited sun exposure was reported by more of the old women (37.2% vs. 5.6%; p=0.003). Family history of osteoporosis was reported by 15.0%, without difference between groups. Alcohol and milk intake did not differ between groups. Premature menopause was reported by 17.9% of the women. Falls within the last year were reported by 42.4% with fewer falls in the oldest age group (21.9% vs. 50.0%; p=0.005). Frequency of fragility fractures increased with age (5.7% vs. 24.3% vs. 30.4%; p=0.02) and the risk of a fragility fracture increased with age (p=0.004; OR, 95% CI: 4.5, 1.6–12.2, reference: below 70 years), when adjusted for smoking, gender and falls. The use of anti-osteoporotic drugs was low (3.4%) while 28.8% took calcium and vitamin D supplements.

Conclusions

Age is a dominating risk factor for fragility fractures in Greenland. The use of anti-osteoporotic drugs is low in Greenland, even if osteoporotic fractures are common in old age.

Effects of bone matrix proteins on fracture and fragility in osteoporosis

Bone mineral density alone cannot reliably predict fracture risk in humans and laboratory animals. Therefore, other factors including the quality of organic bone matrix components and their interactions may be of crucial importance to understanding of fragility fractures. Emerging research evidence shows, that in addition to collagen, certain noncollagenous proteins (NCPs) play a significant role in the structural organization of bone and influence its mechanical properties. However, their contribution to bone strength still remains largely undefined. Collagen and NCPs undergo different post-translational modifications, which alter the quality of the extracellular matrix and the response of bone to mechanical load. The primary focus of this overview is on NCPs that, together with collagen, contribute to structural and mechanical properties of bone. Current information on several mechanisms through which some NCPs influence bone's resistance to fracture, including the role of nonenzymatic glycation, is also presented.

Evaluation of fracture risk and fracture prevention: an Italian picture

Italy has one of the longest life expectancies when compared to other countries in the world, with 20% of the entire population being over 65 years of age and about 6% of these being already 80 years and over. Increased life expectancy is associated with a greater frailty index, typical of the elderly population, with higher prevalence of chronic and degenerative disorders, including fragility fractures. Data have been accumulating about the incidence of fragility fractures in the Italian population, with numbers that are truly alarming for the future decades. In this scenario, the need for the use of antifracture agents becomes strategic in our Country. Therapeutic options currently available for fracture prevention include both antiresorptive and anabolic compounds. Despite the incorporation of this evidence from randomized trials into clinical practice guidelines, these interventions are considerably underutilized. Furthermore, adherence to these therapies is a critical parameter affecting the effectiveness of treatments. Results of institutional databases pose the problem of unsatisfactory outcomes of compliance to antifracture agents prescriptions recorded within regional pharmaceutical databases. These care gaps highlight the finding that additional effort is needed to optimize management of osteoporosis in patients at risk of fragility fractures. Given that there is evidence that appropriate management of osteoporosis decreases fractures, it is felt that the use of appropriate management as the primary outcome is per se relevant. Future efforts should consider treatment appropriateness, treatment sustainability and treatment adherence, as the needed parameters to be applied to programs of osteoporosis care in a community setting.

Individual trabecula segmentation (ITS)-based morphological analyses and microfinite element analysis of HR-pQCT images discriminate postmenopausal fragility fractures independent of DXA measurements

Osteoporosis is typically diagnosed by dual-energy X-ray absorptiometry (DXA) measurements of areal bone mineral density (aBMD). Emerging technologies, such as high-resolution peripheral quantitative computed tomography (HR-pQCT), may increase the diagnostic accuracy of DXA and enhance our mechanistic understanding of decreased bone strength in osteoporosis. Women with (n = 68) and without (n = 101) a history of postmenopausal fragility fracture had aBMD measured by DXA, trabecular plate and rod microarchitecture measured by HR-pQCT image-based individual trabecula segmentation (ITS) analysis, and whole bone and trabecular bone stiffness by microfinite element analysis (µFEA) of HR-pQCT images at the radius and tibia. DXA T-scores were similar in women with and without fractures at the spine, hip, and 1/3 radius, but lower in fracture subjects at the ultradistal radius. Trabecular microarchitecture of fracture subjects was characterized by preferential reductions in trabecular plate bone volume, number, and connectivity over rod trabecular parameters, loss of axially aligned trabeculae, and a more rod-like trabecular network. In addition, decreased thickness and size of trabecular plates were observed at the tibia. The differences between groups were greater at the radius than the tibia for plate number, rod bone volume fraction and number, and plate-rod and rod-rod junction densities. Most differences between groups remained after adjustment for T-score by DXA. At a fixed bone volume fraction, trabecular plate volume, number, and connectivity were directly associated with bone stiffness. In contrast, rod volume, number, and connectivity were inversely associated with bone stiffness. In summary, HR-pQCT-based ITS and µFEA measurements discriminate fracture status in postmenopausal women independent of DXA measurements. Moreover, these results suggest that preferential loss of plate-like trabeculae contribute to lower trabecular bone and whole bone stiffness in women with fractures. We conclude that HR-pQCT-based ITS and µFEA measurements increase our understanding of the microstructural pathogenesis of fragility fracture in postmenopausal women.

Reverse shoulder arthroplasty for acute proximal humeral fractures in the geriatric patient: a review of the literature

Proximal humeral fractures are frequently encountered in the elderly population. While the majority of these fractures can be managed nonoperatively, 2-, 3-, and 4-part fractures, head splitting, and complex fracture dislocations typically require operative management. Open reduction and internal fixation (ORIF) is a popular treatment option for displaced fractures. Advent of locking plates potentially imparts a better option for patients with osteoporotic bone. Hemiarthroplasty has traditionally been used in proximal humeral fractures not amendable to ORIF. While typically providing good pain control, results of hemiarthroplasty have demonstrated inconsistent shoulder motion. Tuberosity malposition or poor healing is a major culprit in unsatisfactory postoperative range of motion. Reverse shoulder arthroplasty has been used in the setting of rotator cuff arthropathy with successful results. Reverse shoulder arthroplasty has recently been used in the setting of acute proximal humeral fractures of the elderly individuals. This technology has shown promising results with mean active anterior elevation from 97° to 122° reported with complication rates of 15% to 28% in short-term studies. Long-term studies and higher level evidence studies with comparison to hemiarthroplasty and ORIF are needed.

Evidence for success with locking plates for fragility fractures

Fixation of fragility fractures with plates and screws often results in loss of fixation and need for revision surgery. Locking plates and screw were introduced to improve fixation of fragility fractures and have been in use for a decade. This review was conducted to compile evidence that locking plates and screws improve fixation of fragility fractures. A search of PubMed was performed to identify biomechanical studies as well as clinical series of fragility fractures treated with locking plates. Biomechanics papers had to use models of osteoporotic bone and had to directly compare locking plates with traditional plates. Clinical studies included case series in which locking plates were applied to elderly patients with fractures of the proximal humerus and periprosthetic distal femur fractures. Most studies are retrospective case series. Locking plates lead to greater stability and higher loads to failure than traditional plates. When applied to proximal humerus fractures, uncomplicated healing occurs in 85% of patients. Constant and Dash scores approach normal values. For distal femoral periprosthetic fractures, union rates of 75% are reported with a malunion rate of 10%. Early evidence suggests that locking plates improve results of treatment of proximal humerus fractures and distal femoral periprosthetic fractures in the elderly. Loss of fixation is associated with failure to achieve stability at the fracture site. Principles of fracture fixation in osteoporotic bone defined prior to the introduction of locking plates should still be applied.

Improving mobility and reducing disability in older people through early high-dose vitamin d replacement following hip fracture: a protocol for a randomized controlled trial and economic evaluation

Hypovitaminosis D is particularly common among older people with a proximal femoral (hip) fracture and has been linked with poorer lower extremity functioning, falls, and fractures. There is evidence that disability severity and fall rates may be reduced by adequate vitamin D replacement. However, the ideal regimen for vitamin D administration to have these benefits in older people who have been in the hospital has not been established. This randomized controlled trial will investigate the effects of an oral vitamin D loading dose with maintenance oral vitamin D and calcium on lower extremity function (gait velocity), correction of hypovitaminosis D, falls, and fractures among older people after hip fracture surgery. The cost-effectiveness of the REVITAHIP program from the health and community service provider's perspective will also be established, as will predictors of adherence with the treatment. A total of 450 older people who have recently had a hip fracture requiring surgical intervention will be screened to achieve 250 participants for the study. Participants will have no medical contraindications to vitamin D replacement. The primary outcome measure will be mobility-related disability as measured with the 2.4-m gait velocity test. Secondary measures will be 25-hydroxyvitamin D (25-OHD) levels at 2, 4, and 26 weeks, number of falls and fractures, and additional measures of mobility, disability, quality of life, health system and community-service contact, adherence to the intervention, and adverse events. After surgical fixation and being deemed medically stable, participants will be randomly allocated to an intervention or placebo-control group. Participants of the intervention group will receive initial oral 250 000 IU (5 × 50 000 IU) vitamin D3 tablets. Both groups will receive oral maintenance vitamin D3 and calcium and will follow the usual hip fracture rehabilitation pathway. The study will determine the impact of a vitamin D loading dose on mobility-related disability in older people following hip fracture and will discuss the efficacy and cost-effectiveness of a loading dose vitamin D replacement more generally. The results will have direct implications for future use of vitamin D therapy for this high-risk group.

Subtrochanteric insufficiency fractures associated with bisphosphonate use: 2 case reports and review

Insufficiency fractures are beginning to emerge in case reports of patients on long-term bisphosphonate therapy. The side effects associated with the long-term use of bisphosphonates were once thought to only involve renal and gastrointestinal (GI) toxicity and osteonecrosis of the jaw, but it is becoming clear that the very condition bisphosphonates were meant to treat could be causing another, trading insufficiency fractures for another type of insufficiency fracture. We review the literature concerning this surprising trend in addition to providing 2 case reports and conclude that these fractures do occur, that they can heal uneventfully, and that further research is needed to determine optimum treatment algorithms concerning duration of treatment and to weigh the potential benefits and morbidity of bisphosphonate treatment.

The 1-year mortality of patients treated in a hip fracture program for elders

Comanagement of geriatric hip fracture patients with standardized protocols has been shown to improve short-term outcomes after surgery. A standardized, patient-centered, comanaged Hip Fracture Program for Elders is examined for 1-year mortality. Patients ≥60 years of age who were treated in the Hip Fracture Program for Elders were comanaged by orthopaedic surgeons and geriatricians. Data including age, place of origin, procedure, length of stay, 1-year mortality, Charlson score, and activities of daily living (ADLs) were retrospectively collected. A total of 758 patients ≥60 years of age with hip fractures between April 15, 2005, and March 1, 2009, were included. Their data were analyzed, and the Social Security Death Index and the hospital data system were searched for mortality data. Seventy-eight percent were female, with a mean age of 84.8 years. The mean Charlson score was 3. Fifty percent were admitted from an institutional setting. The overall 1-year mortality was 21.2%. Age (odds ratio [OR] = 1.03, 95% confidence interval [CI] = 1.00-1.05; P = .02), male gender (OR = 1.55, 95% CI = 1.01-2.36; P = .04), low Parker mobility score (OR = 2.94, 95% CI = 1.31-6.57; P = .01), and a Charlson score of 4 or greater (OR = 2.15, 95% CI = 1.30-3.55; P = .002) were predictive of 1-year mortality. ADL dependence was a borderline predictor, as was medium Parker mobility score. Prefracture residence and moderate comorbidity (Charlson score of 2-3) were not independently predictive of mortality at 1 year after adjusting for other characteristics. A comprehensive comanaged hip fracture program for elders not only improves the short-term outcomes but also demonstrates a low 1-year mortality rate, particularly in patients from nursing facilities.

Systematic review of effectiveness of bisphosphonates in treatment of low bone mineral density and fragility fractures in juvenile idiopathic arthritis

AIMS

To evaluate the currently available evidence for the effectiveness of bisphosphonates in children with low bone mineral density (BMD) and fragility fractures associated with juvenile idiopathic arthritis (JIA), and the safety of bisphosphonates in JIA and other conditions.

METHODS

Literature databases were searched using a structured search strategy. The effectiveness review included any studies of children with JIA treated with bisphosphonates. The safety review also included studies of osteogenesis imperfecta. Quantitative data analysis was not undertaken because of the heterogeneity of the studies; findings were summarised using tables and narrative synthesis.

RESULTS

Ninety four studies were identified. Sixteen studies (78 JIA children) were included in the effectiveness review: one randomised controlled trial, three controlled cohort studies, 11 case series, and one case report. At baseline, children had low BMD below the expected values for age and sex matched children. In all studies, treatment with bisphosphonates increased BMD compared with baseline: the mean percentage increase in spine BMD ranged from 4.5% to 19.1%. Overall, studies were heterogeneous and of variable quality. A total of 59 papers were included in the safety review; treatment durations were up to three years. The most common side effect was a flu-like reaction with intravenous treatment. This occurred during the first infusion and was transient; the symptoms were managed with paracetamol and did not occur during subsequent cycles.

CONCLUSIONS

Bisphosphonates are a promising treatment for low BMD and fragility fractures in children with JIA. However, the quality of the current evidence is variable and better studies are needed to more clearly assess their role.

Visualisation of three-dimensional microcracks in compact bone

Microdamage in bone contributes to the loss of bone quality in osteoporosis and is thought to play a major role in both fragility and stress fractures (Schaffler et al. 1995). In this study, in vivo microcracks in human ribs were bulk-stained in basic fuchsin and viewed in longitudinal section and in 3 dimensions using 2 different computer-based methods of reconstruction: (1) serial sectioning of methylmethacrylate embedded sections using a sledge macrotome and identification of microcracks using UV epifluorescence followed by computerised reconstruction of microcracks using software and (2) laser scanning confocal microscopy of thick sections followed by reconstruction of microcracks into a 3-D image. The size and shape of microcracks were found to be similar using both techniques. Both techniques of reconstruction showed microcracks to be approximately elliptical in shape. From the serial sectioning reconstructions (n = 9), microcracks were found to have a mean length of 404 +/- 145 microm (mean +/- S.D.) (in the longitudinal direction) and mean width of 97 +/- 38 microm (in the transverse direction). Using epifluorescence microscopy, 92 microcracks were identified; mean microcrack length was 349 +/- 100 microm in the longitudinal direction. This was consistent with other results (Burr & Martin, 1993) and with the theoretical prediction of an elliptical crack shape with aspect ratio (longitudinal: transverse) of 5:1 deduced from analysis of random 2-D sections (Taylor & Lee, 1998). The results obtained provide new data on the nature of microcracks in bone and the method has the potential to become a useful tool in the calculation of stress intensity values which indicate the probability of an individual microcrack propagating to cause a stress or fragility fracture.