title: The risk factors for machine injury of the upper limb case-crossover study in Tikur Anbessa University Hospital, Addis Ababa, Ethiopia.
abstract: BACKGROUND
  Machinery is the single most common cause of acute occupational hand injury in our hospital.
  
  
  OBJECTIVE
  To identify the pattern and determine the causes of acute upper limb injury resulting from the use of machines.
  
  
  METHODS
  Case-crossover study design was used. Two hundred and nine (97%) of all 216 patients who had an acute upper limb injury when using a machine and who presented to Tikur Anbessa hospital between November 2004 and October 2005 were examined
  
  
  RESULTS
  The majority of our patients were young (mean age 28.5 years), male (95%) and working in manufacturing industry 181 (87%). Ninety (43%) were machine operator, and had worked less than one year 122 (58%) with short term contract 120 (57%). The majority were not trained formally either for the task they were doing 168 (80%), or for safety measures 178 (85%). A safety guard was present only in a few machines 31 (15%) and half of these were being used. Most of the injuries occurred shortly after lunch. Very many of the injuries were severe with a resulting amputation 47% and fracture 35%. The mean permanent disability was 20%. Doing unfamiliar tasks was associated with the highest relative risk (increase by 14 fold) followed by being rushed (RR = 12), being distracted (RR = 8), using alfunctioning equipment (RR = 8) and using unaccustomed technique to do a task (RR = 6). Wearing gloves decreased the risk by 83%. Job category, work experience, training on the task and safety training significantly modified the transient risk factors.
  
  
  CONCLUSIONS
  the incidence of occupational upper limb machinery injuries could be reduced by avoiding transient risk factors and by providing safety training.
authors.affiliation: Addis Ababa University, Medical faculty, Orthopedic surgeon, P.O. Box 8530, Addis Ababa, Ethiopia. eliasore2003@yahoo.com
authors.forename: Elias
authors.initials: E
authors.lastname: Ahmed
mesh_terms: D000062:Accidents, Occupational / Q000706:statistics & numerical data*; D000293:Adolescent; D000328:Adult; D018592:Cross-Over Studies; D004522:Educational Status; D005002:Ethiopia / Q000453:epidemiology; D005260:Female; D006230:Hand Injuries / Q000453:epidemiology / Q000209:etiology*; D006785:Hospitals, University; D006801:Humans; D015994:Incidence; D007221:Industry; D008297:Male; D008875:Middle Aged; D012306:Risk; D012307:Risk Factors; D017678:Sex Distribution; D011795:Surveys and Questionnaires; D015599:Trauma Severity Indices; D034941:Upper Extremity / Q000293:injuries; D055815:Young Adult