Effect of tool speeds during friction stir lap welding on mode of fracture and fracture strength of Al 6060-T5 joints

Friction stir lap welding (FSLW) of an age hardened Al alloy and evaluations of how FS speeds affected hooking and how hooking and softening due to FS affected fracture strength of the lap welds have been conducted. It was found that increasing rotation speed and reducing welding speed (v) increased the stir zone size (AB-SZ) and also hook size (h), although a maximum value of h (hMax) reached. The features of hooks for the observed - AB-SZ-h relationships are presented and explained. It was found that when h increased to a value of ~ 0.9 mm (for the 3 mm alloy sheets), it started to invoke a significant effect on reducing fracture strength. Factors such as FS softening and insufficient joining, limited the fracture strength of the lap welds for small h values and these are presented and discussed.

Fracture strengths of Mg alloy AZ31B-H24 friction stir lap welds

The effects of selected friction stir lap welding parameters on fracture strength of Mg alloy AZ31B-H24 welds have been studied. Rotation speed has been found to affect significantly the flow related hook size formation. Furthermore, fracture strength decreased almost linearly with hook size. A small amount of softening was detected in fracture location that was outside the nugget zone and thus this softening may only adversely affect the fracture strength slightly. Finally, simulation results are presented to show the uneven stress distribution in a lap geometry which together with the relative brittleness of the stir material must be the cause to have significantly reduced the fracture strength.

Patterns of treatment in Australian men following fracture

Summary This study aimed to describe treatment initiation rates for men who had recently sustained a fracture. Most (75.9%) men potentially eligible for subsidised treatment at the time of fracture remained untreated even after a subsequent fracture.

Introduction This study aimed to describe treatment initiation rates for men who had recently sustained a fracture.

Methods The study was conducted as part of the Geelong Osteoporosis Study in south-eastern Australia. Men in the study area who had sustained an incident fracture in the period July 2006 to December 2007 were identified from hospital radiology reports. A self-report questionnaire was sent to eligible participants approximately 12 months after fracture. Respondents were asked for details of medications prescribed for ‘osteoporosis/fracture/low bone mass’ before and after fracture, and where applicable, reasons for cessation of treatment.We analysed the results for 109 men aged 50 years and older who had sustained fracture in the study period.

Results Most (75.9%) men potentially eligible for subsidised treatment at the time of fracture remained untreated. Of the 87 men who were untreated, nine had osteoporosis at the hip and/or spine and 29 (26.6%) reported having sustained a low trauma prior fracture.

Conclusions Our findings are consistent with previously published data showing low rates of treatment initiation in men eligible for osteoporosis treatment. There appear to be barriers involving participants’ and medical practitioners’ knowledge, beliefs and attitudes regarding osteoporosis and treatment, as well as in the doctor–patient partnership in osteoporosis management. Establishment of clinical pathways for fracture management beyond orthopaedic care may be one of a range of appropriate responses.

Methodological reflections on using pilot data from fracture patients to develop a qualitative study

Background: Qualitative studies are particularly valued for their exploratory nature but, like other research methods, they do require careful planning to ensure rigorous study design. Our objective was to undertake a pilot study to inform the development of a larger qualitative study.

Results: We conducted a series of brief interviews with out-patients in a hospital setting. The interviews were designed to elicit superficial information about whether (and how) post-fracture osteoporosis investigation and/or treatment were being initiated among patients receiving treatment or follow-up for a current or recent fracture. We used thematic analysis to identify key themes in the data that related to the broader research questions. We analysed data obtained from 11 out of a total of 12 interviews conducted. Participants were male and female, aged 19-83 years of age (median age 57 years). Participants attended 2-8 medical appointments to seek treatment and follow up for a current or recent fracture. The following four overarching themes emerged from thematic analysis of the data: fracture event, referral pathway, osteoporosis investigation and/or treatment, and communication by health practitioners and staff.

Conclusions: This pilot study was necessarily tentative and exploratory in nature, but provided a helpful snapshot of some typical experiences in the public health system following fracture. Several themes emerged for consideration in the design of the main study. Despite its critics, theoretical sampling and saturation continue to provide sustainable methods for ensuring that relevant themes and categories are covered in sufficient depth and breadth, appropriate to the needs of the study.

The association between socioeconomic status and osteoporotic fracture in population-based adults : a systematic review

Summary : Although socioeconomic status (SES) is inversely related to most diseases, this systematic review showed a paucity of good quality data examining influences of SES on osteoporotic fracture to confirm this relationship. Further research is required to elucidate the issue and any underlying mechanisms as a necessary precursor to considering intervention implications.

Introduction : The association between socioeconomic status (SES) and musculoskeletal disease is little understood, despite there being an inverse relationship between SES and most causes of morbidity. We evaluated evidence of SES as a risk factor for osteoporotic fracture in population-based adults.

Methods : Computer-aided search of Medline, EMBASE, CINAHL, and PsychINFO from January 1966 until November 2007 was conducted. Identified studies investigated the relationship between SES parameters of income, education, occupation, type of residence and marital status, and occurrence of osteoporotic fracture. A best-evidence synthesis was used to summarize the results.

Results : Eleven studies were identified for inclusion, which suggested a lack of literature in the field. Best evidence analysis identified strong evidence for an association between being married/living with someone and reduced risk of osteoporotic fracture. Limited evidence exists of the relationship between occupation type or employment status and fracture, or for type of residence and fracture. Conflicting evidence exists for the relationship between osteoporotic fracture and level of income and education.

Conclusion : Limited good quality evidence exists of the role SES might play in osteoporotic fracture. Further research is required to identify whether a relationship exists, and to elucidate underlying mechanisms, as a necessary precursor to considering intervention implications.

The association between urban or rural locality and hip fracture in community-based adults : a systematic review

Urban or rural locality has been suggested to influence musculoskeletal health, with lower bone mineral density (BMD) and greater prevalence of fracture identified in urban residents. A computer-aided search of Medline, EMBASE, CINAHL and PsychINFO, January 1966 to November 2007 was conducted to identify studies investigating the relationship between urban or rural locality and the occurrence of hip fracture. The methodological quality of studies was assessed, and a best-evidence synthesis was used to summarise the results. Fourteen cohort studies and one case-control study were identified for inclusion in this review, indicating a lack of literature in the field. Best-evidence analysis identified moderate evidence for residents of rural regions to have lower risk of hip fracture compared to urban residents. Examining principal mechanisms for the observed relationship between urban/rural locality and hip fracture, such as factors at the person or area level, may help to identify modifiable risk factors and inform appropriate prevention strategies.

Femoral neck geometry and hip fracture risk : the Geelong Osteoporosis Study

To determine the relationship between femoral neck geometry and the risk of hip fracture in post-menopausal Caucasian women, we conducted a retrospective study comparing the femoral neck dimensions of 62 hip fracture cases to those of 608 randomly selected controls. Measurements were made from dual-energy X-ray absorptiometry scans (Lunar DPX-L), using the manufacturers ruler function, and included: hip axis length (HAL), femoral neck axis length (FNAL), femoral neck width (FNW), femoral shaft width (FSW), medial femoral shaft cortical thickness (FSCT_med), and lateral femoral shaft cortical thickness (FSCT_lat). The fracture group was older (median age 78.3 years vs 73.8 years), lighter (median weight 59.9 kg vs 64.5 kg), and, after adjustment for age, taller (mean height 158.7±0.8 cm vs 156.7±0.2 cm) than the controls. Furthermore, bone mineral density was lower in this group (0.682±0.016 g/cm² vs 0.791±0.006 g/cm²). After adjustment for age, bone mineral content (BMC) or height, hip fracture patients had greater FNW (up to 6.6%) and FSW (up to 6.3%) than did the controls. Each standard deviation increase in FNW and FSW was associated with a 1.7-fold (95% CI 1.3–2.3) and a 2.4-fold (95% CI 1.8–3.2) increase in the fracture risk, respectively. BMC-adjusted FNAL was greater in the fracture group (+2.1%) than in the controls, while the age-adjusted FSCT_med was reduced (–7.2%). There was a trend towards longer HAL (up to 2.1%) after adjustment for age or BMC, and thinner age-adjusted FSCT_lat (–1.7%) in fracture patients that did not reach statistical significance. In multivariate analysis, the risk of hip fracture was predicted by the combination of age, FNW, FSW, BMC and FSCT_med. HAL was not analyzed because of the small number of HAL measurements among fracture cases. We conclude that post-menopausal women with hip fractures have wider femoral necks and shafts, thinner femoral cortices and longer femoral neck axis lengths than do women with no fractures. Alteration in hip geometry is associated with the risk of hip fracture.