Evidence Report/Technology Assessment: Number 62

Diagnosis and Treatment of Worker-Related Musculoskeletal Disorders of the Upper Extremity

Summary


Under its Evidence-based Practice Program, the Agency for Healthcare Research and Quality (AHRQ) is developing scientific information for other agencies and organizations on which to base clinical guidelines, performance measures, and other quality improvement tools. Contractor institutions review all relevant scientific literature on assigned clinical care topics and produce evidence reports and technology assessments, conduct research on methodologies and the effectiveness of their implementation, and participate in technical assistance activities.

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Overview / Reporting the Evidence / Methodology / Findings / Future Research / Availability of Full Report


Overview

This report is a systematic evaluation of the evidence pertaining to a broad range of issues related to the diagnosis and treatment of worker-related upper extremity disorders (WRUEDs). For the purposes of this report, “worker-related” is defined as a disorder that affects workers, not as a disorder necessarily caused by work. Four disorders are the focus of this report; carpal tunnel syndrome, cubital tunnel syndrome, epicondylitis, and de Quervain's disease.

The first two disorders are the result of nerve entrapment. Carpal tunnel syndrome is the result of increased pressure on the median nerve in the carpal tunnel of the wrist, resulting in sensory and motor disturbances in the parts of the hand innervated by this nerve. Cubital tunnel syndrome results from increased pressure on the ulnar nerve in the cubital tunnel of the elbow, resulting in sensory and motor disturbances in the parts of the forearm and hand innervated by this nerve. The second two disorders are the result of stress to the tendons of the elbow and wrist, respectively. All four disorders can lead to pain, loss of function, and long-term disability.

The overall prevalence of carpal tunnel syndrome in the United States may be as high as 1.9 million people, and each year there are 300,000-500,000 operations for the condition. Epicondylitis has been reported to affect 4.23 individuals per 1,000 adults per year in the U.S. The prevalence of cubital tunnel syndrome and de Quervain's disease has not been established.

In this evidence report, the Evidence-based Practice Center (EPC) assessed the published literature describing the effects of these disorders, before and after treatment, on patients, particularly workers. They did this by examining the literature pertaining to 13 key questions.

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Reporting the Evidence

This report addresses 13 questions regarding worker-related disorders of the upper extremity. Eleven of these are condition-specific. Therefore, the EPC individually addressed them for each of the four above-mentioned disorders. Two questions are not condition-specific. Therefore, the EPC addressed them only once.

The 11 condition-specific Key Questions addressed in this evidence report are:

Question 1: What are the most effective methods and approaches for the early identification and diagnosis of worker-related musculoskeletal disorders of the upper extremity?

Question 2: What are the specific indications for surgery for worker-related musculoskeletal disorders of the upper extremity?

Question 3: What are the relative benefits and harms of various surgical and nonsurgical interventions for persons with worker-related musculoskeletal disorders of the upper extremity?

Question 4: Is there a relationship between specific clinical findings and specific treatment outcomes among patients with worker-related musculoskeletal disorders of the upper extremity?

Question 5: Is there a relationship between duration of symptoms and specific treatment outcomes among patients with worker-related musculoskeletal disorders of the upper extremity?

Question 6: Is there a relationship between factors such as patients' age, gender, socioeconomic status and/or racial or ethnic grouping and specific treatment outcomes among patients with worker-related musculoskeletal disorders of the upper extremity?

Question 7: What are the surgical and nonsurgical costs or charges for treatment of worker-related musculoskeletal disorders of the upper extremity?

Question 8: For persons who have had surgery for worker-related musculoskeletal disorders of the upper extremity, what are the most effective methods for preventing the recurrence of symptoms, and how does this vary depending on subject characteristics or other underlying health problems?

Question 9: What instruments, if any, can accurately assess functional limitations in an individual with a worker-related disorder of the upper extremity?

Question 10: What are the functional limitations for an individual with a worker-related musculoskeletal disorder of the upper extremity before treatment?

Question 11: What are the functional limitations of an individual with a worker-related musculoskeletal disorder of the upper extremity after treatment?

The two Key Questions that are not condition-specific are:

Question 12: What are the cumulative effects on functional abilities among individuals with more than one worker-related musculoskeletal disorder of the upper extremity in the same limb?

Question 13: What level of function can patients achieve in what period of time when they are required to change hand dominance as a result of injury to their dominant hand?

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Methodology

A panel of nine Technical Experts was employed to assist in defining the scope of this evidence report, developing its questions, and developing the criteria for retrieving and including articles.

To identify information for this evidence report, the EPC searched 31 electronic databases, the World Wide Web, and four U.S. Government databases. In addition to these searches, researchers also reviewed the bibliographies and reference lists of all studies included in this evidence report, searched Current Contents®/Clinical Medicine on a weekly basis, and routinely reviewed over 1,600 journals and supplements maintained in ECRI's collections.

To be included in this evidence report, an article had to meet a set of a priori retrieval criteria and a set of a priori question-specific inclusion criteria. The EPC designed broad retrieval criteria to ensure comprehensive retrieval. They retrieved an article whenever there was uncertainty about whether it met the retrieval criteria. They also retrieved articles when an abstract was not present in the search results, but when the title of the article suggested that it was relevant. The criteria for article retrieval are briefly summarized below:

Once an article was retrieved, it was examined to determine whether it met the question-specific criteria. The major criteria are briefly summarized below; additional question-specific inclusion criteria, which are not listed here, were also applied:

A global outcome is any score that attempts to encompass the overall success or failure of the treatment. It may be a numerical rating of overall symptom relief or patient satisfaction, a categorical rating such as excellent, good, fair or poor, or a dichotomous rating such as the answer to the question “Would you undergo this procedure again?”

Data from all articles that met our inclusion criteria were abstracted using electronic data abstraction forms. Separate data abstraction forms were designed for entering data about basic trial design information; patient signs, symptoms, comorbidities, characteristics, and treatments; reporting of treatment outcomes; surgical complications; and nerve conduction measurements.

The EPC employed a variety of statistical methods in this evidence report. Meta-analyses of studies of treatments were conducted using Hedges' d as a measure of each study's effect size, and then computing the precision-weighted summary d from the combined results of all studies. Hedges' d is the difference between the means of any study's two groups expressed in standard deviation units. Researchers employed two tests for heterogeneity, the Q statistic and each study's standardized residual. The EPC researchers regarded the data as heterogeneous if the results of either test were statistically significant.

Diagnostic test meta-analyses were performed according to the method of Littenberg and Moses. The researchers took the mean threshold as the best estimate of a single threshold, and the values of sensitivity and specificity at the mean threshold as the single best global estimate of test effectiveness. Before using the results of a meta-analysis of diagnostics, they verified that there was no statistically significant heterogeneity among the results of the included articles using the Q statistic. If heterogeneity was detected, they removed any subgroups that caused the heterogeneity from the analysis. If there were no subgroups in the analysis, or those subgroups did not cause the heterogeneity, they looked for data points that were outliers, and reported the meta-analytic results with and without exclusion of these outliers.

The EPC performed numerous other statistical computations in addition to those involved in performing meta-analyses. Briefly, these were:

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Findings

Carpal Tunnel Syndrome

Question 1: What are the most effective methods and approaches for the early identification and diagnosis of carpal tunnel syndrome?

Question 2: What are the specific indications for surgery for carpal tunnel syndrome?

Question 3: What are the relative benefits and harms of various surgical and nonsurgical interventions for persons with carpal tunnel syndrome?

Question 4: Is there a relationship between specific clinical findings and specific treatment outcomes among patients with carpal tunnel syndrome?

Question 5: Is there a relationship between duration of symptoms and specific treatment outcomes among patients with carpal tunnel syndrome?

Question 6: Is there a relationship between factors such as patients' age, gender, socioeconomic status and/or racial or ethnic grouping and specific treatment outcomes among patients with carpal tunnel syndrome?

Question 7: What are the surgical and nonsurgical costs or charges for treatment of carpal tunnel syndrome?

Question 8: For persons who have had surgery for carpal tunnel syndrome, what are the most effective methods for preventing the recurrence of symptoms, and how does this vary depending on subject characteristics or other underlying health problems?

Question 9: What instruments, if any, can accurately assess functional limitations in an individual with carpal tunnel syndrome?

Question 10: What are the functional limitations for an individual with carpal tunnel syndrome before treatment?

Question 11: What are the functional limitations of an individual with carpal tunnel syndrome after treatment?

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