The JOSPT's focus in this month's issue toward carpal tunnel syndrome (CTS) and work-related musculoskeletal disorders (WMSD) is meant to expose the orthopedic and sports therapist to evidence-based hand practices, novel basic-science findings, and new ways of thinking about the hand, along with a new set of clinical skills. By exposing these current approaches to the evaluation, differential diagnosis, treatment, and overall management of CTS and WMSD, collaborative relationships will blossom between hand specialists, physical and occupational therapists, and hand surgeons.

J Orthop Sports Phys Ther. 2004; 34(10):563-564. doi:10.2519/jospt.2004.0110

Key Words: carpal tunnel syndrome, hand, interdisciplinary approach, work-related musculoskeletal disorders

Carpal Tunnel Syndrome (CTS) is a pressure-induced neuropathy that causes sensorimotor disturbances of the median nerve, which impair functional ability. A clear history that elicits relevant personal and work exposures and the nature of symptoms can lead to a high probability of a correct diagnosis. Hand diagrams and diagnostic questionnaires are available to provide structure to this process. A variety of provocative tests have been described and have variable accuracy. The Phalen’s wrist flexion and the carpal compression tests have the highest overall accuracy, while Tinel’s nerve percussion test is more specific to axonal damage that may occur as a result of moderate to severe CTS. Sensory evaluation of light touch, vibration, or current perception thresholds can detect early sensory changes, whereas 2-point discrimination changes and thenar atrophy indicate loss of nerve fibers occurring with more severe disease. Electrodiagnosis can encompass a variety of tests and is commonly used to assess the presence/severity of neuropathic changes and to preclude alternative diagnoses that overlap with CTS in presentation. The pathophysiologic changes occurring with different stages of nerve compression must be considered when interpreting diagnostic test results and predicting response to physical therapy management.

J Orthop Sports Phys Ther. 2004;34(10):565-588. doi:10.2519/jospt.2004.1505

Key Words: hand, median nerve, wrist

The assessment and conservative interventions in patients with carpal tunnel syndrome (CTS) are described in this paper. Information about surgical procedures and postoperative care has also been included. It is difficult to make definitive conclusions about the literature regarding success of treatment for CTS due to variations in outcome measures, severity of CTS, and inconsistencies in duration, dosage, and follow-up time for interventions. Based on what is known to date, this author recommends that patients with mild or moderate CTS be provided with a conservative program of splinting the wrist in neutral for nocturnal wear. In addition, intermittent exercise (nerve-gliding exercises) and activity modification, including avoidance of protracted periods of sustained gripping activities and awkward wrist positions, can be useful. This conservative program may be complemented by pain-relieving modalities during times of activity and supplemental participation in other exercise such as yoga. If symptoms are not relieved to the satisfaction of the patient, or they recur, then it is incumbent upon the therapist to refer the patient to a hand surgeon for injection or possible surgical decompression.

J Orthop Sports Phys Ther. 2004;34(10):589-600. doi:10.2519/jospt.2004.1562

Key Words: carpal tunnel syndrome (CTS), intervention, nerve-gliding exercises

The purpose of this clinical commentary is to provide a comprehensive review of compressive neuropathies that may mimic carpal tunnel syndrome, provide the clinician with information to differentially diagnose these median nerve compression sites, and provide an evidence-based opinion regarding conservative intervention techniques for the various compression syndromes.

While rare in comparison to carpal tunnel syndrome, pronator syndrome and anterior interosseous nerve syndrome are proximal median nerve compressions that may be suspected if a patient with carpal tunnel syndrome fails to respond to conservative or surgical intervention. Differential diagnosis is based largely on the symptoms, patterns of paresthesia, and specific patterns of muscle weakness. Due to the relative rarity of pronator syndrome and anterior interosseous nerve syndrome, few controlled studies exist to determine the most effective treatment techniques. Based on sound anatomical and biomechanical considerations, anecdotal experience, and available research, however, treatment strategies for pronator syndrome and anterior interosseous nerve syndrome compression neuropathies can be divided into 4 major categories: (1) rest/ immobilization, (2) modalities, (3) nerve gliding, and (4) nonconservative treatment.

J Orthop Sport Phys Ther. 2004;34(10):601-609. doi:10.2519/jospt.2004.1359

Key Words: anterior interosseous nerve syndrome, differential diagnosis, hand, median nerve, pronator syndrome

The purpose of this commentary is to present recent epidemiological findings regarding work-related musculoskeletal disorders (WMSDs) of the hand and wrist, and to summarize experimental evidence of underlying tissue pathophysiology and sensorimotor changes in WMSDs. Sixty-five percent of the 333,800 newly reported cases of occupational illness in 2001 were attributed to repeated trauma. WMSDs of the hand and wrist are associated with the longest absences from work and are, therefore, associated with greater lost productivity and wages than those of other anatomical regions. Selected epidemiological studies of hand/wrist WMSDs published since 1998 are reviewed and summarized. Results from selected animal studies concerning underlying tissue pathophysiology in response to repetitive movement or tissue loading are reviewed and summarized. To the extent possible, corroborating evidence in human studies for various tissue pathomechanisms suggested in animal models is presented. Repetitive, hand-intensive movements, alone or in combination with other physical, nonphysical, and nonoccupational risk factors, contribute to the development of hand/wrist WMSDs. Possible pathophysiological mechanisms of tissue injury include inflammation followed by repair and/or fibrotic scarring, peripheral nerve injury, and central nervous system reorganization. Clinicians should consider all of these pathomechanisms when examining and treating patients with hand/wrist WMSDs.

J Orthop Sports Phys Ther. 2004;34(10):610-627.  doi:10.2519/jospt.2004.1399

Key Words: carpal tunnel syndrome, hand/wrist tendinitis, inflammation, neuroplasticity, repetitive-motion injury

Numerous terms, including repetitive-stress injuries and cumulative-trauma disorders, have been used to describe what is now commonly termed work-related musculoskeletal disorders. The etiology of work-related musculoskeletal disorders is multifactorial and includes physical, individual, and psychosocial factors that contribute to the presenting symptoms. Prolonged positioning away from the ideal posture will affect neural and other soft tissues in the upper extremity. Abnormal postures and positions may result in chronic nerve compression or may shorten muscles and, if the muscle crosses over a nerve, compression may occur. These postures may also contribute to muscle imbalance. A thorough clinical evaluation is necessary to identify all sites of nerve compression, muscle imbalance, and factors affecting patient symptoms so that appropriate intervention can be instituted. Management must include patient education, postural correction, and a specific physical therapy program to address the multiple levels of nerve compression and cervicoscapular muscle imbalance. In addition to physical therapy intervention, behavioral modification at home and at work may be necessary for successful management.

J Orthop Sports Phys Ther. 2004;34(10):628-637. doi:10.2519/jospt.2004.1447 

Key Words: cumulative-trauma disorders, hand, muscle imbalance, nerve compression, repetitive-stress injuries

Design of computer keyboards no longer is limited to the flat keyboards that are typically shipped with personal computers. Keyboards now exist that are split into halves and these halves can be slanted away from each other (creating a triangle between the halves), sloped downward toward the visual display terminal, tilted upward like a tent, or simply separated. These design features are intended to alleviate discomfort and possible musculoskeletal disorders that have been suggested to be associated with the extensive use of conventional computer keyboards. The geometry of conventional keyboards requires the wrists to be in 10° to 15° of ulnar deviation and 20° of extension and the forearms to be nearly fully pronated while typing. A review of the available experimental data collected on 10-digit touch typists indicates that (1) keyboards with a slant angle (half of the opening angle) of 10° to 12.5° or keyboards with halves separated to approximately shoulder width are both effective in placing the wrist in near neutral (0°) ulnar/radial deviation when typing, (2) wrist extension can be reduced to near neutral (0°) when a keyboard with a negative slope of 7.5° is used, contingent on the wrist rest also sloping with the keyboard, and (3) tilting the keyboard halves 20° to 30° is effective in reducing forearm pronation to approximately 45°. These studies also indicate that experienced 10-digit touch typists readily adapt (within 10 minutes) to these individual alternative keyboard features, and can type with approximately the same speed and accuracy as with the conventional keyboard. While placing the wrist and forearm in a more neutral position could, in theory, reduce the incidence of musculoskeletal disorders, randomized controlled trials are necessary before strong recommendations can be made on the effectiveness of alternative keyboards for the prevention and/or treatment of musculoskeletal disorders. In the absence of these randomized controlled trials, the information in this article provides preliminary guidance to clinicians in their evaluation of computer keyboards and workstations and their recommendations to patients.

J Orthop Sports Phys Ther. 2004;34(10):638-649. doi:10.2519/jospt.2004.1629

Key Words: alternative computer keyboard, office ergonomics, slant angle, slope angle, tilt angle