Open‐MRI measures of cam intrusion for hips in an anterior impingement position relate to acetabular contact force

Open MRI in functional positions has potential to directly and non‐invasively assess cam femoroacetabular impingement (FAI). Our objective was to investigate whether open MRI can depict intrusion of the cam deformity into the intra‐articular joint space, and whether intrusion is associated with elevated acetabular contact force. Cadaver hips (9 cam; 3 controls) were positioned in an anterior impingement posture and imaged using open MRI with multi‐planar reformatting. The β‐angle (describing clearance between the femoral neck and acetabulum) was measured around the entire circumference of the femoral neck. We defined a binary “MRI cam‐intrusion sign” (positive if β < 0°). We then instrumented each hip with a piezoresistive sensor and conducted six repeated positioning trials, measuring acetabular contact force (F). We defined a binary “contact‐force sign” (positive if F > 20N). Cam hips were more likely than controls to have both a positive MRI cam‐intrusion sign (p = 0.0182, Fisher's exact test) and positive contact‐force sign (p = 0.0083), which represents direct experimental evidence for cam intrusion. There was also a relationship between the MRI cam‐intrusion sign and contact‐force sign (p = 0.033), representing a link between imaging and mechanics. Our findings indicate that open MRI has significant potential for in vivo investigation of the cam FAI mechanism. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:205–216, 2016.     

Novel taste test for nasolacrimal duct obstruction using denatonium benzoate: a randomized controlled pilot study

Objective

To evaluate a novel, simple, noninvasive method (known as the “bitter taste test”) of establishing nasolacrimal duct patency in healthy asymptomatic eyes.

Evaluating the efficacy of an educational ergonomics module for improving slit lamp positioning in ophthalmology residents

Objective

To characterize changes in body positioning while performing a standardized slit lamp examination after exposure to an educational module on ergonomics.

A workstation interface for measuring interspike intervals

A method is presented for collecting and storing, singly or in parallel, interspike intervals to a DOS-based workstation as a background process. The method comprises digital electronics and low-level software effecting an interface mechanism from the receipt of digital spike pulses to the recording of user-accessible data arrays readily manipulable by high-level software. Functional details, requirements, and application to parital cortex single unit physiology are discussed.     

Lifetime trajectory of physical activity according to energy expenditure and joint force

Objective

To develop and demonstrate the feasibility of a method for estimating lifetime hip and knee cumulative joint force using survey data on physical activity, and to construct and describe lifetime trajectories of energy expenditure and hip and knee joint force.

Methods

Exposure data on lifetime physical activity, including type (occupational, household, and recreation) and dose (frequency, intensity, and duration), were collected from a Canada‐wide population study of adults ages ≥45 years. Subjects were ranked in 2 ways: in terms of physical activity–related energy expenditure and in terms of a cumulative peak force index (CPFI) for the hip and knee, which is a measure of lifetime exposure and is a time/joint force product involving years of force and subject bodyweight. A relative joint loading index was calculated as the ratio of joint force (CPFI score) to energy expenditure.

Results

A total of 4,269 subjects completed the baseline measurements. Lifetime energy expenditure and hip and knee CPFI scores were higher for occupational and household activity than sport. The mean lifetime energy expenditure from total physical activity in the study sample was 119.1 metabolic equivalent‐hours/week. Women had slightly higher total lifetime energy expenditure and CPFI scores than men. The relative joint loading index was highest for male household and sport activity and lowest for female occupational activity.

Conclusion

Lifetime cumulative hip/knee joint force trajectories were successfully constructed from survey data and followed expected trends. Comparing energy expenditure with joint force revealed variation by age, sex, and activity type, indicating these measures may help distinguish the numerous benefits of physical activity from possible risks.     

Work‐related repetitive strain injury and leisure‐time physical activity

Objective

To investigate the relationship between leisure‐time physical activity and work‐related repetitive strain injury (RSI), adjusted for sociodemographic characteristics and work‐related physical and stress factors.

Methods

The data source was the 2003 Canadian Community Health Survey, a national cross‐sectional survey of 134,072 respondents. The analysis was limited to a sample of the survey population reporting full‐time work during the past 12 months (n = 58,622). The outcome of interest was work‐related RSI of the upper body. Multiple logistic regression was used to examine the relationship between the outcome and leisure‐time physical activity level, adjusted for sociodemographic, health, and occupational characteristics. The potential effect of leisure‐time physical activity with a high upper‐body load was investigated in a secondary analysis.

Results

The prevalence of upper‐body work‐related RSI was 5.9% in the Canadian population in 2003. An active lifestyle during leisure time was associated with a lower prevalence of work‐related upper‐body RSI (odds ratio 0.84, 99% confidence interval 0.75–0.95), after adjustment for work physical demands and other covariates. Female sex, obesity, smoking, age, work‐related stress, and work physical demands were associated with RSI. In the secondary analysis, we did not find that participating in leisure‐time activities with a high upper‐body load was a risk factor for RSI.

Conclusion

Our study results indicate that being physically active during leisure time is associated with a decreased risk of upper‐body occupational RSI, adding another potential health benefit to participation in leisure‐time physical activity.     

Work-related repetitive strain injury and leisure-time physical activity

OBJECTIVE: To investigate the relationship between leisure-time physical activity and work-related repetitive strain injury (RSI), adjusted for sociodemographic characteristics and work-related physical and stress factors. METHODS: The data source was the 2003 Canadian Community Health Survey, a national cross-sectional survey of 134,072 respondents. The analysis was limited to a sample of the survey population reporting full-time work during the past 12 months (n = 58,622). The outcome of interest was work-related RSI of the upper body. Multiple logistic regression was used to examine the relationship between the outcome and leisure-time physical activity level, adjusted for sociodemographic, health, and occupational characteristics. The potential effect of leisure-time physical activity with a high upper-body load was investigated in a secondary analysis. RESULTS: The prevalence of upper-body work-related RSI was 5.9% in the Canadian population in 2003. An active lifestyle during leisure time was associated with a lower prevalence of work-related upper-body RSI (odds ratio 0.84, 99% confidence interval 0.75-0.95), after adjustment for work physical demands and other covariates. Female sex, obesity, smoking, age, work-related stress, and work physical demands were associated with RSI. In the secondary analysis, we did not find that participating in leisure-time activities with a high upper-body load was a risk factor for RSI. CONCLUSION: Our study results indicate that being physically active during leisure time is associated with a decreased risk of upper-body occupational RSI, adding another potential health benefit to participation in leisure-time physical activity.     

Hypothermic and antipyretic effects of 3-methyl- and 3-phenyl-5-hydroxy-5-trichloromethyl-4,5-dihydro-1H-pyrazole-1-carboxyamides in mice

The effect of novel pyrazolines, 3-methyl-5-hydroxy-5-trichloromethyl-4,5-dihydro-1H-pyrazole-1-carboxyamide (MPCA) and 3-phenyl-5-hydroxy-5-trichloromethyl-4,5-dihydro-1H-pyrazole-1-carboxyamide (PPCA) on body temperature and endotoxin-induced fever was investigated in mice. The subcutaneous (s.c.) administration of 1.5 mmol/kg dipyrone, MPCA or PPCA and the intracerebroventricular (i.c.v.) administration of 225 nmol dipyrone reduced basal rectal temperature. Intracerebroventricular administration of 225 nmol MPCA or PPCA did not alter basal rectal temperature. The administration of 0.15 mmol/kg (s.c.) or 25 nmol (5 microl) dipyrone (i.c.v.), MPCA or PPCA had no effect on basal rectal temperature, but reversed lipopolysaccharide-induced fever. These results suggest that MPCA and PPCA cause antipyresis, which is similar to that caused by dipyrone, and may be useful antipyretic agents.