Alison Stewart

Quantitative Ultrasound in the Management of Osteoporosis: The 2007 ISCD Official Positions

Dual-energy X-ray absorptiometry (DXA) is commonly used in the care of patients for diagnostic classification of osteoporosis, low bone mass (osteopenia), or normal bone density; assessment of fracture risk; and monitoring changes in bone density over time. The development of other technologies for the evaluation of skeletal health has been associated with uncertainties regarding their applications in clinical practice. Quantitative ultrasound (QUS), a technology for measuring properties of bone at peripheral skeletal sites, is more portable and less expensive than DXA, without the use of ionizing radiation. The proliferation of QUS devices that are technologically diverse, measuring and reporting variable bone parameters in different ways, examining different skeletal sites, and having differing levels of validating data for association with DXA-measured bone density and fracture risk, has created many challenges in applying QUS for use in clinical practice. The International Society for Clinical Densitometry (ISCD) 2007 Position Development Conference (PDC) addressed clinical applications of QUS for fracture risk assessment, diagnosis of osteoporosis, treatment initiation, monitoring of treatment, and quality assurance/quality control. The ISCD Official Positions on QUS resulting from this PDC, the rationale for their establishment, and recommendations for further study are presented here.

Association of Five Quantitative Ultrasound Devices and Bone Densitometry With Osteoporotic Vertebral Fractures in a Population-Based Sample: The OPUS Study

We compared the performance of five QUS devices with DXA in a population‐based sample of 2837 women. All QUS approaches discriminated women with and without osteoporotic vertebral fractures. QUS of the calcaneus performed as well as central DXA.

EXercising with Computers in Later Life (EXCELL) : pilot and feasibility study of the acceptability of the Nintendo WiiFit in community-dwelling fallers

BackgroundFalls management programmes have been instituted to attempt to reduce falls. This pilot study was undertaken to determine whether the Nintendo® WiiFit was a feasible and acceptable intervention in community-dwelling older fallers.FindingsCommunity-dwelling fallers over 70 years were recruited and attended for computer-based exercises (n = 15) or standard care (n = 6). Balance and fear of falling were assessed at weeks 0, 4 and 12. Participants were interviewed on completion of the study to determine whether the intervention was acceptable.Eighty percent of participants attended 75% or more of the exercise sessions. An improvement in Berg Score was seen at four weeks (p = 0.02) and in Wii Age at 12 weeks (p = 0.03) in the intervention group. There was no improvement in balance scores in the standard care group.ConclusionWiiFit exercise is acceptable in self-referred older people with a history of falls. The WiiFit has the potential to improve balance but further work is required.Trial RegistrationClinicalTrials.gov - NCT01082042

Long‐Term Fracture Prediction by DXA and QUS: A 10‐Year Prospective Study

This study investigated the ability of DXA and QUS to predict fractures long term when measured around the time of the menopause. We found both DXA and QUS are able to predict both any fracture and “osteoporotic” fractures and that QUS can predict independently of BMD.

Large-Scale Population-Based Study Shows No Evidence of Association Between Common Polymorphism of the VDR Gene and BMD in British Women

The VDR is a candidate gene for osteoporosis. Here we studied five common polymorphisms of VDR in relation to calcium intake and vitamin D status in a population‐based cohort of 3100 British women, but found no significant association with bone mass, bone loss, or fracture.

Bone mineral density in osteoarthritis.

The inverse relation between osteoporosis and osteoarthritis has long been considered in the literature. This review looks at current evidence to support this relation, concentrating on studies published since 1998. The review also summarizes previous large studies investigating this relation. Recent studies indicate higher bone mineral density as measured by dual energy x-ray absorptiometry in subjects with osteoarthritis at a distant site, but suggest less association with hand osteoarthritis. Genetic work has sought to explain this association and this too is discussed. There is some indication that a higher bone density may not protect against fracture in these subjects, due to the increased risk of falls.

Identification of hip fracture patients from radiographs using Fourier analysis of the trabecular structure: a cross-sectional study

BackgroundThis study presents an analysis of trabecular bone structure in standard radiographs using Fourier transforms and principal components analysis (PCA) to identify contributions to hip fracture risk.MethodsRadiographs were obtained from 26 hip fracture patients and 24 controls. They were digitised and five regions of interest (ROI) were identified from the femoral head and neck for analysis. The power spectrum was obtained from the Fourier transform of each region and three profiles were produced; a circular profile and profiles parallel and perpendicular to the preferred orientation of the trabeculae. PCA was used to generate a score from each profile, which we hypothesised could be used to discriminate between the fracture and control groups. The fractal dimension was also calculated for comparison. The area under the receiver operating characteristic curve (Az) discriminating the hip fracture cases from controls was calculated for each analysis.ResultsTexture analysis of standard radiographs using the fast Fourier transform yielded variables that were significantly associated with fracture and not significantly correlated with age, body mass index or femoral neck bone mineral density. The anisotropy of the trabecular structure was important; both the perpendicular and circular profiles were significantly better than the parallel-profile (P < 0.05). No significant differences resulted from using the various ROI within the proximal femur. For the best three groupings of profile (circular, parallel or perpendicular), method (PCA or fractal) and ROI (Az= 0.84 – 0.93), there were no significant correlations with femoral neck bone mineral density, age, or body mass index. PCA analysis was found to perform better than fractal analysis (P = 0.019).ConclusionsBoth PCA and fractal analysis of the FFT data could discriminate successfully between the fracture and control groups, although PCA was significantly stronger than fractal dimension. This method appears to provide a powerful tool for the assessment of bone structure in vivo with advantages over standard fractal methods.

Predicting a second hip fracture

In an attempt to identify a high-risk cohort of patients, who could be offered preventive therapy, we assessed patients who had suffered one hip fracture. A total of 394 patients were prospectively followed to determine those who had suffered a second fracture. Entry bone mass of the unfractured hip and total body was examined by dual X-ray absorptiometry (DXA) and of the os calcis, by quantitative ultrasound (QUS), along with various clinical parameters. The relative risks in the QUS parameters did not reach significance, except for broadband ultrasound attentuation as measured by the McCue CUBA Clinical, whereas femoral neck and total body bone mineral density also reached significance. Lowest quartile body weight was also a significant risk factor as were occurrence of a new fall and poor mobility score. Using Receiver Operator Characteristic curves, we found no significant differences between DXA trochanter or for the Mini Mental State Examination score in predicting those who sustained a second hip fracture. In this elderly group risk factors are almost as good as bone mass at predicting those who will sustain a second hip fracture. Low body weight and poor mobility could be used as triggers for the use of preventive therapy without the use of bone mass measurements and to target expensive preventive therapy to reduce fracture risk.

Bone shape, structure, and density as determinants of osteoporotic hip fracture: a pilot study investigating the combination of risk factors.

Objectives:This article compares and combines methods for examining the external shape and the internal structure of the proximal femur with bone mineral density (BMD) to provide a classifier for hip fracture. Materials and Methods:Fifty standard pelvic radiographs were available from age-matched fracture and control groups of postmenopausal women. Femoral shape was measured using an active shape model, the trabecular structure by means of a Fourier transform. Results:Both the shape and various structure measures were independent of BMD (P = 0.16 and >0.50, respectively). Calculating the area under the receiver operator characteristic (ROC) curve (Az), each of shape (Az = 0.81), the best structure measure (Az = 0.79–0.93), and BMD (Az = 0.79), could partially classify the fracture and control groups. However, the combination achieved almost perfect separation (Az = 0.99). Conclusions:This pilot study shows how bone shape and structure can complement BMD measurements for investigations of fracture risk.

Use of digital x ray radiogrammetry in the assessment of joint damage in rheumatoid arthritis

Objective: To compare digital x ray radiogrammetry (DXR) with manual radiography for assessing bone loss in RA and examine the relationship of the scores obtained with other disease indices. Methods: 225 consecutive consenting subjects attending the RA clinic were enrolled. An x ray examination was carried out; demographic details recorded; a self assessment questionnaire completed; blood taken for ESR measurement; and an assessment made by a trained nurse. All x ray films were scored manually using the modified Sharp technique by a single observer; 20 films were rescored by three readers. Films were assessed with the Pronosco X-Posure system, version 2.0. Analysis included χ2 tests, independent t tests, multiple linear regression, and partial correlations, as appropriate. The smallest detectable difference (SDD), coefficient of variation (CV), and coefficient of repeatability (CR) were determined from Bland and Altman plots. Results: The DXR precision varied: SDD = 0.002–0.9; CV = 0.09–5.9%; CR = 0.002–0.792, but was better than that of the intra- and interobserver Sharp scores: SDD = 73.9; CV = 27.8%; CR = 33.0–47.6. The DXR measurements, bone mineral density (R2 = 0.210), metacarpal index (R2 = 0.222), and cortical thickness (R2 = 0.215), significantly predicted Sharp scores. In women, DXR measurements significantly correlated with modified HAQ scores but with no other disease indices. Sharp scores significantly correlated with assessor’s global assessment, swollen and tender joint counts, pain, HAQ, and DAS28. Conclusion: DXR measurements are more precise than Sharp scores; both are related to long term disease activity in RA. DXR is simple to use, does not require intensive training, and may identify subjects not responding to standard treatment.