Protocol for constructing subject-specific biomechanical models of knee joint.

A robust protocol for building subject-specific biomechanical models of the human knee joint is proposed which uses magnetic resonance imaging, motion analysis and force platform data in conjunction with detailed 3D finite element models. The proposed protocol can be used for determining stress and strain distributions and contact kinetics in different knee elements at different body postures during various physical activities. Several examples are provided to highlight the capabilities and potential applications of the proposed protocol. This includes preliminary results on the role of body weight on the stresses and strains induced in the knee articular cartilages and meniscus during single-leg stance and calculations of the induced stresses and ligament forces during the gait cycle.

Current issues in care and support for HIV-positive gay men in Sydney.

We explored current access to care among HIV-positive people in Australia. In 2006, 270 HIV-positive gay men from a community-based Positive Health cohort in Sydney were asked about their health (including medical and social) service needs and, subsequently, about difficulty in accessing services. We report the prevalence of specific needs, barriers and associated factors. Participants most commonly used general practitioners (64%) for HIV management and needed at least one HIV-related medical service (usually several: doctors experienced in HIV management, dentists and hospital pharmacies). Most participants were able to access them. Barriers in accessing services were related to their convenience rather than lack or quality. Cost emerged as a substantial barrier to dental care and psychological counselling (91% and 48% respectively of those in need). Need for an HIV-related social service was reported by 46% of respondents. Difficulties in accessing these related to poor services and staff attitudes. Income was associated with limited access to multiple services. In Australia, HIV-related medical service needs outweigh those for social services. Complex health services remain essential to HIV-positive people, but some services are currently not meeting their needs. To remain adequate, services need to understand and constantly adapt to the changing needs of HIV-positive people.

Plantar pressure reduction in an incremental weight-bearing system.

BACKGROUND AND PURPOSE: Harness-supported treadmill ambulation has been advocated for patients to provide reduction in weight bearing to healing tissues and to reduce the energy cost of treadmill ambulation. The purposes of this technical report are to analyze the ability of one of these devices (Zuni Exercise System) to support a specific percentage of a subject's body weight during walking and running and to explore the relationship of unloading to pressure reduction in selected plantar surface regions of the foot. SUBJECTS: Ten male volunteers with no known foot pathology participated. METHODS: In-shoe plantar pressure and vertical ground reaction forces (GRFs) were measured during walking and running at full body weight and at 20% of body weight supported. RESULTS: Walking at a setting of 20% of body weight supported resulted in a reduction of the first and second vertical force peaks of 23.8% (SD = 7.3%) and 27.2% (SD = 4.1%), respectively. The total force-time integral during walking unloaded was 22.8% (SD = 3.3%). During running, the active vertical force peak and total force-time integral were reduced by 19.9% (SD = 6.0%) and 20.0% (SD = 3.3%), respectively, in the unloaded condition. Plantar pressures were reduced from 6.8% to 27.8% in the body weight-supported conditions. The reduction was variable across different regions of the foot. CONCLUSION AND DISCUSSION: The Zuni Exercise System appears to reduce the vertical component of the GRF during walking and running with 20% of body weight supported. Plantar pressures were reduced during body weight-supported conditions, but the reduction varied at different regions of the foot.

The torque test as a measure of lateral dominance.

The present study was designed to assess the validity of the Torque Test as a measure of functional lateral dominance in children. One hundred forty-nine children were administered the Torque Test and The Harris Test of Lateral Dominance. A low but statistically significant correlation was found between torque and total lateral dominance.

The cervical cap: an alternative contraceptive.

The cervical cap is a convenient, inexpensive, nonhormonal and non-invasive contraceptive method. This method has potential for better effectiveness if custom-fit caps are manufactured. As more health care providers become knowledgeable in the use of the cap, more women will become aware of this contraceptive method as an alternative to oral contraceptives and intrauterine devices. Research is needed to document the most accurate method of cervical cap fitting and the effectiveness rate of the cervical cap. Nurse practitioners who counsel patients and fit them for caps are in the perfect position to start doing this research.

PIP: Users have frequently complained about the inherent disruptiveness, expense, and messiness of barrier methods of contraception. The cervical cap seems to eliminate many of the previously cited disadvantages of barrier contraception. The cap does not interfere with intercourse, does not require daily client involvement, and is nonhormonal and noninvasive. The disadvantages connected with its use are that it requires precise individual fitting, it is not yet manufactured in the U.S., it takes time to learn proper placement, and it depends on the individual female anatomy. Despite wide use in Europe since the 19th century, the cervical cap is rarely used or discussed as a contraceptive in the U.S. Statistics cited from various studies of barrier methods in general give the cap an effectiveness range from 85-98%; these effectiveness ratings are for all vaginal barrier devices together so it is difficult to judge the cervical cap specifically. The device's effectiveness will vary according to various psychological and physiological user characteristics. Each of the following 3 types of cervical cap is described and diagrammed: 1) Dumas cap; 2) cavity-rim cap; and 3) Vimule cap. There is a need for health care providers and contraceptive counselors to better acquaint themselves with the cervical cap. Evaluation research on its effectiveness is needed.