Chronic regional muscular pain in women with precise manipulation work. A study of pain characteristics, muscle function, and impact on daily activities.

Pain characteristics, muscle function and impact on daily activities were studied in 39 women with chronic regional muscular pain (RMP). They were all blue-collar workers in work involving precise manipulations. The main location of the pain was in the neck-shoulder region. Nineteen age-matched women with fibromyalgia (FM) were studied in the same way as the RMP patients. Thirty-seven women with no pain and with the same age and weight as the RMP patients served as reference group with respect to muscle strength and endurance. A follow-up study was done with respect to pain distribution and other pain characteristics 20 months after the initial examination. The findings were of the same nature in the RMP and the FM groups. The intensity of pain, the lowering of pain threshold for pressure, and the degree of sleep disturbance were greater in the FM than in the RMP group. Isometric muscle strength and static muscular endurance were reduced in both FM and RMP compared to reference values. The reduction in strength and endurance was greater in FM than in RMP. Even if the impact on everyday activities were greater in FM than in RMP, the impact was substantial in RMP patients also, for example with regard to work capacity. There were no transitions from RMP to FM during the 20 months to follow-up. Three FM patients, however, did not meet the ACR criteria for FM at follow-up.