Clinical assessment of musculoskeletal disorders in workers exposed to hand-arm vibration.

OBJECTIVES: To describe the clinical assessment of musculoskeletal disorders among vibration-exposed workers and to review the experimental and epidemiological studies of the effects of vibration on the musculoskeletal system of the upper limbs.
METHODS: A total of 212 references in English was found in Pub Med for the years 1980-2000 that dealt with clinical assessment. Many of these references were reviews and few were original research dealing with test performance in diagnostic procedures.
RESULTS: The reported effects on bone are osteoporosis and cysts in the hands. Experiments have shown injuries to muscle cells in animals and additional physiological loading of muscles in humans by vibration. Low-frequency vibration exposure of high magnitude was associated with osteoarthrosis in the elbow, wrist and acromioclavicular joint and symptoms in the elbow and shoulder. Impacts, jerks and blows with high-energy transfer to the hands at low frequency might have the potential to result in musculoskeletal disorders considering the general model for injuries. Furthermore, the observed associations with vibration exposure and musculoskeletal disorders might result from the strong dynamic and static joint loading and the repetitive hand-arm motions required in tasks where hand-held machines are used. The clinical assessment of musculoskeletal disorders in workers exposed to hand-arm vibration consists of the clinical and exposure history and evaluation of the physical and laboratory findings. Since most patients with musculoskeletal disorders who are exposed to vibration are also exposed to other ergonomic stressors, accommodation of the injured worker has to take the whole work system into account (task, technology, environment and organisation).
CONCLUSIONS: The scientific evidence that vibration per se is a risk factor for musculoskeletal disorders is still weak although there is strong evidence that job tasks with vibrating machines are associated with musculoskeletal disorders. The clinical assessment of musculoskeletal disorders in exposed patients imposes special requirements.