Upper Extremity Musculoskeletal Disorders In Female Machine milkers - An Epidemiological, Clinical and Ergonomic Study

Abstract: The aims of the thesis were to investigate the prevalence of the upper extremity musculoskeletal disorders in female milkers in relation to other occupational groups; to clarify the relationship between disorders and work environment, psychosocial and life style factors; to compare in a prospective study, pain, ache and discomfort reported by a questionnaire with clinical symptoms and sign; to examine milkers with wrist and hand disorders with regard to type and localization of the tissue injury; to quantify the work load on forearms, wrists and hands during machine milking. An increased risk developing symptoms in wrists and hands was noted in the active milker group compared to the non-milker and the nursing assistant group. Numbness in the wrist and hands was significantly more frequent in all agricultural groups than in the group of nursing assistants. The occurrence of symptoms in the upper extremities was not related to number of cows. Neither was a significant difference in experience of numbness, coldness or white fingers among milkers who were using vibration tools as compared to those who have never done so. Milkers working in a modernized dairy barn had fewer problems in the upper extremities than those who were working in a traditional barn. However only 13 of the 161 milkers had the possibility to work in a modern way. There was no relationship between symptoms and social and/or well-being factors among the milkers. A prospective study showed a persistent prevalence of wrist and hand symptoms among most of the milkers. In a clinical examination consisted of 80 randomized persons it was shown that 51 had some kind of symptoms in the wrist and hands. Fourteen of these had a clinical sign of median nerve entrapment. A further clinical study confirmed the result from the first study but the localization was most at the elbow region. A registration of the wrist positions and movements and the muscle activity in two different dairy barns showed that there exist extreme positions and movements. The results of the measurements of the muscle activity showed high peak loads which in combination with the positions and movements of the wrist might contribute to an increased risk of developing injuries. Preliminar result of an ergonomic study showed that by using a ”support arm” and a adjustable platform on the floor the work load could be reduced.