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Biomedical subjects

Thomas M Cook

Publications and source records attributed to Thomas M Cook.

8 recordsLinked to original sources

Effect of aviation snip design and task height on upper extremity muscular activity and wrist posture.

Hand tools described as ergonomic in design are intended to reduce exposure to physical risk factors associated with work-related musculoskeletal disorders. Additionally, using the right tool for the job is believed to reduce exposure and, consequently, risk of disease. Sheet metal workers frequently use a cutting tool called aviation snips when fabricating and installing ductwork. The purpose of this laboratory simulation study was to determine the effect of (1) aviation snip design; and (2) work height on muscle activity, wrist posture, and user satisfaction among sheet metal workers. We hypothesized that specific aviation snips designs would be most appropriate for use at specific heights. Twenty-three sheet metal workers used three different designs of aviation snips to make curved cuts in sheet metal placed both at waist height and shoulder height. Conventional circular snips, straight snips, and an alternate design of offset snips were used. Upper extremity muscle activity was measured with surface electromyography, wrist posture was measured with electrogoniometry, and user satisfaction was rated by the participants on a survey. Statistically significant effects of snip design and task height on muscle activity, wrist posture, and user satisfaction were observed. However, no snip was preferable for all dependent variables. Work height had a greater effect on muscle activity and wrist posture than snip design. Field studies are indicated to determine the long-term effect of snip design on physical risk factors and risk of musculoskeletal disorders.

Adult↗

Surface cementation of stemmed tibial components in primary total knee arthroplasty: minimum 5-year follow-up.

Cement remains the "gold standard" for fixation in total knee arthroplasty. Between 1991 and 1998, 128 consecutive knees in 109 patients underwent primary cemented total knee arthroplasty using a surface cementation technique. The average follow-up was 95 (range, 63-155) months. Preoperative range of motion (ROM) averaged 5 degrees to 111 degrees which improved to 1 degrees to 116 degrees postoperatively. Modified Hospital for special surgery score (HSS) scores improved from 61 (range, 47-76) to 97 (range, 81-100) and the corresponding Knee Society Scores from 122 (range, 94-152) to 195 (range, 162-200). No osteolytic lesions were found; however, 3 tibias had radiolucent lines which were asymptomatic, nonprogressive, and not associated with implant failure. The average depth of penetration of cement was 2.7 mm. One knee (1%) required revision surgery for femoral loosening, and 1 required revision of the polyethylene liner. The present cementation technique provides excellent durable results at midterm follow-up.

Aged↗

Ten-year experience using an articulating antibiotic cement hip spacer for the treatment of chronically infected total hip.

Infection is a devastating complication after total-hip arthroplasty. Between June 1991 and December 2001, 42 patients were treated at our center for chronically infected total-hip arthroplasty using a 2-stage articulating antibiotic hip spacer technique. Of the 27 patients available for review, 26 (94%) remain clinically free of infection at an average 76 months (range, 28-148 months) postoperatively. Twenty-two (81%) patients had a positive identification of the infecting organism. All patients received a minimum of 6 weeks of intravenous antibiotics and the Harris Hip Scores improved from 53 (range, 36-68) to 92 (range, 81-99) postoperatively. Advantages of this technique include improved patient function, maintenance of bone stock and soft tissue tension, thus simplifying reimplantation.

Adult↗

Symptoms of musculoskeletal disorders among apprentice construction workers.

Musculoskeletal disorders (MSDs) are a major cause of work-related disability and lost-time illnesses for many occupational groups. This study determined the prevalence of musculoskeletal symptoms among young construction workers. A symptom and job factors survey was self-administered to 996 construction apprentices. Prevalence was determined by the percent of positive responses to musculoskeletal symptom questions. Odds ratios and 95 percent confidence intervals were the measures of association between prevalent musculoskeletal symptoms and demographic, leisure, and job factors and were determined by logistic regression. The low back was the site most commonly reported for job-related musculoskeletal symptoms (54.4%), which was also the most common reason for seeking care from a physician (16.8%) and missing work (7.3%). Number of years worked in the construction trade was significantly associated with knee (p-trend = 0.0009) and wrist/hand (p-trend < 0.04) MSD symptoms and was suggestive of an association with low back pain (p-trend = 0.05). "Working in the same position for long periods" was the job factor identified as most problematic, with 49.7 percent of all construction apprentices rating it as a moderate/major problem contributing to musculoskeletal symptoms. Musculoskeletal symptoms are a significant problem among young construction workers at the beginning of their careers. Prevention strategies are needed early in the apprentice training program to reduce the potential disability associated with work-related musculoskeletal symptom disorders.

Adult↗

Method for quantitatively assessing physical risk factors during variable noncyclic work.

OBJECTIVES: Assessing exposure to physical risk factors during variable noncyclic work can be problematic. The purpose of this study was to modify an existing data reduction method for directly quantifying physical exposures during variable noncyclic work. METHODS: Myoelectric activity of the finger flexors of two groups of workers, heavy equipment operators (N=25) and mechanics (N=25), was sampled to determine the intensity and duration of forceful exertions during normal tasks. Data were reduced with a modification of the exposure variation analysis (EVA), called clustered EVA (CEVA), using three intensity and two duration categories. A two-way, mixed-effects, repeated-measures analysis of variance evaluated the percentage of sampled work time in each CEVA category. RESULTS: CEVA was able to quantify variable noncyclic work, and it contrasted the work of the two groups, with simple effects significantly different for all the exposure categories. The mechanics performed high-intensity short-duration contractions 9.1% of the time, whereas the operators had similar contractions only 1.8% of the time. Conversely, the operators used low-intensity contractions of prolonged duration over 81% of the time, compared with only 43% for the mechanics. CONCLUSIONS: CEVA is a useful modification of EVA for contrasting the noncyclic work typical of understudied industries like construction. A simplification of electromyography with summary measures such as CEVA provides a comprehensible, yet accurate measure of forceful exertions during worktasks.

Adult↗

Carpal tunnel syndrome among apprentice construction workers.

BACKGROUND: In terms of lost-work time and restricted workdays, surgery, and rehabilitation, one of the most costly occupational musculoskeletal disorders is carpal tunnel syndrome (CTS). The purpose of this study was to determine the prevalence of CTS among apprentice construction workers. METHODS: This cross-sectional study included apprentices from four construction trades. Apprentices completed a self-administered questionnaire and received electrophysiologic studies assessing median nerve function across the carpal tunnel. A surveillance case definition for CTS was based on characteristic hand symptoms and the presence of median mononeuropathy across the carpal tunnel. RESULTS: Of the 1,325 eligible apprentices, 1,142 (86.2%) participated in the study. The prevalence of CTS among apprentices was 8.2%; sheet metal workers had the highest rate (9.2%). In operating engineers, the prevalence of CTS was significantly higher (OR = 6.9; 95% CI = 2.6-18.2) among the heavy equipment mechanics than the drivers of those vehicles. Body mass index, age, and self-reports of working overhead were associated with prevalent CTS. Less than 15% of the apprentices with CTS sought medical attention for their disorder. CONCLUSIONS: Many construction workers begin developing CTS before or during their apprenticeship. Few apprentices seek medical attention for hand symptoms characteristic of CTS. The results of this study indicate a public health need for the implementation of prevention strategies for CTS in the construction industry.

Adult↗

Translations of the humerus in persons with shoulder impingement symptoms.

STUDY DESIGN: Two-group mixed-model analysis of covariance and correlation analysis. OBJECTIVES: To determine whether differences in humeral translations exist between patients with shoulder impingement symptoms and an asymptomatic comparison group, and if so, to determine if shoulder range-of-motion (ROM) measures are associated with abnormal translations. BACKGROUND: Abnormal translations of the humeral head are believed to reduce the available subacromial space and to contribute to the development or progression of shoulder impingement symptoms. These abnormal translations have also been theorized to be related to tightness of the posterior capsule and decreased shoulder ROM. METHODS AND MEASURES: Three-dimensional humeral translations were tracked in symptomatic construction workers and an asymptomatic comparison group while elevating the arm in the scapular plane under no-load, 2.3-kg, and 4.6-kg hand-load conditions. Between-group comparisons were made across 3 phases of motion (30 degrees-60 degrees, 60 degrees-90 degrees, and 90 degrees-120 degrees) and the association between humeral translations and cross-body adduction and shoulder internal rotation ROM measures were determined by Pearson correlation analysis. RESULTS: Persons with shoulder symptoms demonstrated small but significant changes in anterior-posterior translations of the humerus. These changes for the 90 degrees-120 degrees phase of humeral elevation were moderately negatively associated with available cross-body adduction ROM. CONCLUSIONS: The identified kinematic deviations are consistent with possible reductions of the subacromial space. Further study of relationships between posterior capsule tightness, rotator cuff function, and abnormal humeral translations is warranted to better delineate underlying kinematic mechanisms that may contribute to shoulder impingement symptoms and to refine rehabilitation techniques.

Adult↗