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Biomedical subjects

M G Larson

Publications and source records attributed to M G Larson.

At least 109 records · Page 6Linked to original sources
PubMed1991

Validation of a surveillance case definition of carpal tunnel syndrome.

The National Institute for Occupational Safety and Health (NIOSH) has proposed a surveillance case definition for work-related carpal tunnel syndrome (CTS). The case definition requires the presence of median nerve symptoms; one or more occupational risk factors; and objective evidence of CTS including one of three physical examination findings or nerve conduction tests diagnostic of CTS. We evaluated the performance of the NIOSH case definition, restricting our analysis to cases in which physical examination findings served as the objective criterion. Nerve conduction studies were used as the gold standard. Seventy-eight workers were studied; 38 percent had CTS. The NIOSH case definition had sensitivity of 0.67 (95% CI = 0.57, 0.77), specificity of 0.58 (95% CI = 0.47, 0.69), and positive and negative predictive values of 0.50 (95% CI = 0.39, 0.61) and 0.74 (95% CI = 0.64, 0.84), respectively. Overall 38 percent of subjects were classified incorrectly. In a sample with a prevalence of 15 percent, as might be encountered in high risk workplaces, the positive predictive value would be 0.22. In conclusion, when physical examination findings serve as the objective criterion the performance of the case definition is modest reflecting the limited diagnostic value of its component tests and indicating that effective screening for CTS awaits improved diagnostic techniques.

Adult↗
PubMed1991

The outcome of decompressive laminectomy for degenerative lumbar stenosis.

The outcome of laminectomy for the relief of symptoms resulting from degenerative lumbar stenosis is not well established. Eighty-eight consecutive patients who had had a laminectomy for degenerative lumbar stenosis between 1983 and 1986 were studied. Eight of the patients had had a concomitant arthrodesis. The follow-up evaluation included a review of charts and standardized questionnaires that were completed by the patients. One year postoperatively, five patients (6 per cent) had had a second operation and five still had severe pain. By the time of the latest follow-up, in 1989, fifteen (17 per cent) of the original eighty-eight patients had had a repeat operation because of instability or stenosis; twenty-one (30 per cent) of the seventy patients who were evaluated by questionnaire in 1989 had severe pain. The factors found to be associated with a poor long-term outcome, defined as severe pain or the need for a repeat operation, or both, included co-existing illnesses (such as osteoarthrosis, cardiac disease, rheumatoid arthritis, or chronic pulmonary disease) (p = 0.004), the duration of follow-up (p = 0.01), and an initial laminectomy involving a single interspace (p = 0.04). We concluded that the long-term outcome of decompressive laminectomy is less favorable than has been previously reported, and that co-morbidity and a single-interspace laminectomy are risk factors for a poor outcome.

Aged↗
PubMed1990

The carpal tunnel syndrome: diagnostic utility of the history and physical examination findings.

STUDY OBJECTIVE: To assess the value of a history and physical examination findings in diagnosing the carpal tunnel syndrome, and to determine whether constellations of clinical findings identify patients at high or low risk for the carpal tunnel syndrome. DESIGN: Comparison of diagnostic tests with neurophysiologic testing. SETTING: Patients with upper extremity complaints of diverse causes referred to a neurophysiology laboratory for diagnostic studies. METHODS: Before nerve conduction testing, a history, demographic and physical examination data, and a hand pain diagram were obtained from each patient. Diagrams were categorized as indicating the classic carpal tunnel syndrome, or as probable, possible, or unlikely to indicate the carpal tunnel syndrome. Associations between clinical data and nerve conduction results were examined in univariate and multivariate analyses. RESULTS: Of 110 patients in the study, 44 (40%) had the carpal tunnel syndrome. Individually, the best predictors were hand pain diagram rating (positive predictive value, 0.59; 95% CI, 0.48 to 0.68) and Tinel sign (positive predictive value, 0.55, CI, 0.45 to 0.65). The combination of a positive Tinel sign and a probable or classic diagram rating had a positive predictive value of 0.71; CI, 0.53 to 0.85. Other findings from physical examination and the history were less useful. Just 9% of patients under 40 years of age with possible or unlikely diagram ratings had the carpal tunnel syndrome. CONCLUSIONS: With the exceptions of age, Tinel sign, and hand pain diagram rating, findings from the physical examination and the history had limited diagnostic utility. Patients under 40 years of age with possible or unlikely diagram ratings were at low risk for the carpal tunnel syndrome. This finding, which should be confirmed in an independent population, suggests that subsets of patients may be managed without nerve conduction studies.

Adult↗
PubMed1990

Comparisons of five health status instruments for orthopedic evaluation.

This study represents a long-term effort to find optimal techniques for evaluating outcome in patients who have undergone total joint arthroplasty. Sensitivity of five health status questionnaires was studied in a longitudinal evaluation of orthopedic surgery. The questionnaires (Arthritis Impact Measurement Scales [AIMS], Functional Status Index [FSI], Health Assessment Questionnaire [HAQ], Index of Well Being [IWB], and Sickness Impact Profile [SIP]) were administered to 38 patients with end-stage arthritis at three points in time: two weeks before hip or knee arthroplasty, and at three-month and 12- to 15-month follow-up. Response values (i.e., changes within patients) were calculated on four scales: global health, pain, mobility, and social function. By the three-month follow-up, most instruments detected large mean responses in global health, pain scores, and mobility. Smaller changes on these scales were found between three and 12 to 15 months. Social function showed small to modest gains at successive follow-ups. Standardized response means were calculated to assess sensitivity to detect change. Confidence intervals for these indices were constructed using a jackknife procedure, and significance tests were performed by pairing selected indices. Finally, the study projected sample sizes required to assess a new therapy, using each response. These statistical tools facilitated comparisons among instruments and may prove useful in other settings.

Aged↗
PubMed1990

HLA extended haplotypes in childhood and adult onset HLA-DR4-associated arthropathies.

Alpha HLA-DR4 extended haplotypes have been established by family studies in children and adults with chronic arthritis, the children having polyarticular juvenile rheumatoid arthritis and the adults rheumatoid arthritis. These diseases are probably the same disorder presenting at different ages. The results demonstrate age-related differences in the frequency of HLA-DR4 extended haplotypes between the two groups of patients. The childhood onset was associated with the presence of the HLA-B44, SC30, DR4 extended haplotype, whereas the adult form was more strongly associated with the HLA-Bw62, SC33, DR4 haplotype. These results suggest that differences in the age at onset are influenced by the MHC in addition to the presence of the HLA DR4 gene itself.

Adult↗
PubMed1990

A modification of the Health Assessment Questionnaire for the spondyloarthropathies.

A functional status measure was developed by adding 5 items to the Health Assessment Questionnaire (HAQ-S), and compared to anthropometric measures of spinal mobility. Forty-four patients with spondylitis were evaluated by the HAQ-S and measures of spine flexibility (finger-to-floor, Smythe test, neck rotation, and chest expansion). Modification of the HAQ raised the mean difficulty score by 29% from 0.38 (SD = 0.49) to 0.49 (SD = 0.51), indicating increased ability to capture functional limitations. Neck rotation correlated most strongly with the HAQ-S score (r = -0.57), which suggests an important role for this measure in clinical management and followup of spondylitis.

Adult↗
PubMed1990

A self-administered hand symptom diagram for the diagnosis and epidemiologic study of carpal tunnel syndrome.

Noninvasive tests for carpal tunnel syndrome (CTS) are of limited diagnostic value. A self-administered hand symptom diagram has been developed for use in the diagnosis and epidemiologic study of CTS. Diagrams are rated classic CTS, probable, possible or unlikely. Diagram ratings were compared with nerve conduction diagnoses in 110 patients with upper extremity complaints. A hand diagram rating of classic or probable CTS had sensitivity of 0.64, specificity of 0.73 and positive predictive value of 0.58. The negative predictive value of an unlikely diagram was 0.91. We conclude that the diagram is a useful diagnostic tool and may be valuable for occupational and population screening.

Carpal Tunnel Syndrome↗
PubMed1989

Reliability and validity of six systems for the clinical assessment of disease activity in systemic lupus erythematosus.

Six systems for defining and evaluating disease activity in patients with systemic lupus erythematosus (SLE) (the Ropes system, the National Institutes of Health [NIH] system, the New York Hospital for Special Surgery system, the British Isles Lupus Assessment Group [BILAG] scale, the University of Toronto SLE Disease Activity Index [SLE-DAI], and the Systemic Lupus Activity Measure [SLAM]) were tested on 25 SLE patients who were selected to represent a range of disease activity. The patients were evaluated independently by 2 physicians on 2 occasions approximately 1 month apart. Differences between patients demonstrated the largest source of variation in scores, accounting for 56-84% of the total variance, depending on the instrument. Differences between physicians (i.e., error) showed the next largest variation, 11-28% of the total variance, and differences between visits made up 5-16% of the total. The BILAG, SLE-DAI, and SLAM had the best inter-visit and inter-rater reliability. Convergent validity was shown by the strong correlations of scores among the different instruments (r = 0.81-0.97). All instruments correlated highly with the physicians' clinical impression of disease but less well with their evaluation of disease severity. The number of American Rheumatism Association criteria for SLE that were met by the patients correlated poorly with the physicians' global evaluation and with the scores of the instruments. The patients' self-reported disease activity scores correlated highly with the physicians' assessments of disease activity (r = 0.85-0.91), and the mean values from self-reports and from physicians' assessments were nearly equal. In contrast, severity scores correlated less well between self-reports and physician assessments (r = 0.49-0.69), and mean self-reported severity values were lower than the means from physicians. The BILAG, SLE-DAI, and SLAM systems appear to have better psychometric properties than the others for clinical research.

Adult↗
PubMed1989

Sensitivity of anthropometric techniques for clinical trials in ankylosing spondylitis.

To determine whether anthropometric techniques widely used for assessment of ankylosing spondylitis (AS) would be useful outcome measures in long-term clinical trials, 52 AS patients at the Royal National Hospital for Rheumatic Diseases were studied. All patients had well documented AS with a mean age of 38.1 years, and had been diagnosed for an average of 7.6 years. Measurements were taken before (B) and after (A) 3-week intensive inpatient physical therapy (PT). Short-term therapeutic effects (over 3 weeks) were significant (adjusted p less than 0.0001) for all five measures tested (chest expansion, finger-to-floor distance, height, lumbar flexion, and cervical rotation). Height (adjusted p less than 0.0001), finger-to-floor distance (adjusted p = 0.047) and cervical rotation (adjusted p = 0.012) diminished over the course of follow-up. Therefore, 3 weeks of hospitalization with intensive physical therapy produces measurable short-term change; minute but measurable change with treatment occurs even in long-standing AS; and detectable changes in physical measurements occur over a 5-year period even in long-standing AS. Anthropometric measurements are useful outcome variables for long-term clinical trials in AS, but the potential for improvement in clinical measurements in long-standing AS is predictably small.

Adult↗
PubMed1988

HLA and altered sex ratios in juvenile rheumatoid arthritis sibships.

Analysis of sex ratio in 301 siblings of 150 patients with early-onset pauciarticular juvenile rheumatoid arthritis revealed a male-to-female ratio of 1:2.00 in sibships with an HLA-B44+ proband, compared with a ratio of 1:1.05 in other sibships (G2 = 6.07, df = 1, p = 0.014). The siblings had a sex ratio of 1:0.8, when the HLA-B44 antigen was present in either parent but not transmitted to the proband. The capacity to distort the sex ratio was limited therefore to disease-associated HLA-B44 haplotypes.

Adolescent↗
PubMed1987

Effects of reducing physical therapy services on outcomes in total joint arthroplasty.

A natural experiment provided an opportunity to determine whether physical therapy (PT) service reduction would affect the outcomes of total joint arthroplasty. A sample of 200 patients with rheumatoid arthritis or osteoarthritis who underwent total hip or total knee replacement during successive reduction of services was randomly selected. The demographic and clinical characteristics of patients in each period were similar. Despite large differences between groups in hours of PT per patient, there were no major differences in length of stay between the groups, or compared to similar hospitals, functional status at discharge, or numbers of surgical complications. Implications for health services organization are discussed.

Aged↗
PubMed1986

Cost-effectiveness of total joint arthroplasty in osteoarthritis.

Although total joint replacement (TJR) is a major advance in the treatment of patients with osteoarthritis, its cost-effectiveness has been questioned. We report the results of a study of the costs and benefits of TJR in consecutive osteoarthritis patients, 6 months after the surgery. Health status was measured by the Index of Well-Being. Costs of services for arthritis were determined by interview and billing records. Six months after TJR, significant improvements were seen in global health and in functional status. The average cost of care for the 6 months prior to TJR was $933. The average cost during the 6 months beginning with the TJR was $22,730 per patient--due almost entirely to costs of surgery. In general, the surgery did not change work status, probably because the mean age of the patients was 66.4 years. There were large effectiveness/cost differentials (the larger the effectiveness/cost differential, the higher the degree of cost-effectiveness [CE]). At 6 months, for all patients, the CE was associated with initial health status. The highest CE was observed in 10 patients who initially had the poorest health. TJR is more cost-effective for patients with the most to gain and less effective for those with better preoperative health status.

Aged↗
PubMed1986

HLA-DP antigens in patients with pauciarticular juvenile rheumatoid arthritis.

The distribution of the recently described HLA-DP antigens was examined in a population of patients with pauciarticular juvenile rheumatoid arthritis and iridocyclitis, in an attempt to further characterize the immunogenetically determined susceptibility to this disease. There was a significantly increased frequency of the HLA-DPw2 antigen in the patients compared with the controls (67% versus 34%; odds ratio 3.9, P = 0.003 by Fisher's exact test). Population studies and family studies showed that this association with HLA-DPw2 was not secondary to linkage disequilibrium with the previously defined HLA-D region markers of disease (HLA-DR5 and HLA-DRw8) in these patients. These data raise the possibility that susceptibility to this form of juvenile rheumatoid arthritis may be regulated by more than one HLA-linked gene.

Arthritis, Juvenile↗
PubMed1985

Comparative measurement efficiency and sensitivity of five health status instruments for arthritis research.

Five health status instruments were administered in random order to 50 arthritis patients before and after total joint arthroplasty. Relative efficiency and sensitivity in measurement of change in pain, mobility and physical function, social role and social activity, and global health were assessed. The instruments had highly correlated scores, but had differences in certain dimensions. Inter-instrument differentials were larger for social and global outcomes than for pain or mobility. NO single instrument consistently outperformed the others. A method for determining relative efficiency is described.

Activities of Daily Living↗
PubMed1985

Complementation with HLA-A and HLA-D locus alleles in ankylosing spondylitis with peripheral arthritis.

Fifty-nine patients with HLA-B27 positive ankylosing spondylitis were HLA genotyped to look for immunogenetic differences between patients with associated peripheral arthritis and those with disease limited to the axial skeleton. An association was found between the peripheral arthropathy and 2 antigens, HLA-A11 and HLA-DR7 at the p less than 0.05 level. Complementation between these 2 alleles and HLA-B27 occurred in both the cis and trans positions. Four patients with peripheral arthritis had a rare HLA-B27 haplotype (HLA-B27, HLA-DR7) which was not found in the group with axial disease alone.

Adolescent↗
PubMed1984

Evaluation of comprehensive rehabilitation services for elderly homebound patients with arthritis and orthopedic disability.

Fifty-seven elderly homebound patients with arthritis and orthopedic disabilities were randomized to a goal-oriented outreach rehabilitation program or to usual treatment. Although 64% of patient goals were met, there were no overall significant differences in functional scores, institutionalization, or contentment between treatment and control periods. Twenty-three patients had maintained clinical improvement at the end of the study and some patients were dramatically improved with simple measures. The program's marginal costs were modest and consisted primarily of expenses associated with therapist's visits. The total costs of assistive devices and home modifications amounted to $1,902. Twenty-five percent of the homebound population could benefit from such services but the actual number who would partake is small.

Aged↗
PubMed1984

Inherited predisposition to iridocyclitis with juvenile rheumatoid arthritis: selectivity among HLA-DR5 haplotypes.

HLA-DR5 is associated with a chronic iridocyclitis and juvenile rheumatoid arthritis with onset in early childhood. Previously published data provided indirect evidence for selective linkage between two HLA-B alleles and HLA-DR5. To test this observation further, 38 families, the probands of which have chronic iridocyclitis and juvenile rheumatoid arthritis, were HLA typed so that haplotypes associated with disease could be established. HLA-DR5 was linked to HLA-Bw44 or to HLA-Bw35 and to HLA-Cw4 in the majority of haplotypes obtained in the probands. Both HLA-Bw44, -DR5 and HLA-Bw35, -Cw4, -DR5 occurred more commonly in the proband haplotypes than in the control haplotypes. The frequency of the haplotype HLA-Bw44, -DR5 was 0.133 compared with 0.007 (X2 = 27.04, P less than 10(-6] and for HLA-Bw35, -Cw4, -DR5, it was 0.093 compared with 0.11 (X2 = 13.83, P = 0.0002). The relative risks were 20.77 and 9.23, respectively, versus 3.52 for HLA-DR5 alone. HLA-Bw44 occurred much more commonly in proband HLA-DR5 haplotypes (0.455) compared with control HLA-DR5 haplotypes (0.067) (X2 = 8.26, P less than 0.01). Not all HLA-DR5-bearing haplotypes predisposed equally to chronic iridocyclitis and early-onset pauciarticular juvenile rheumatoid arthritis.

Arthritis, Juvenile↗