FACTA UNIVERSITATIS Series: Medicine and Biology Vol.12, No 3, 2005, pp. 179 - 184 UC 616.72 INFLUENCE OF REPETITIVE MICRO-TRAUMA ON PATHOGENESIS AND PROGRESSION OF HAND AND NECK OSTEOARTHROSIS Andjelka Hedrih 1 , Aleksandra Stanković 2 , Bojana Stamenković 2 1 Technology-Metallurgy Faculty, Belgrade 2 Institute for Prevention and Treatment of Rheumatic and Cardiovascular Diseases, Niška Banja, Serbia and Montenegro Summary. Repetitive micro-trauma is one of the causes of osteoarthrosis. The aim of our study was to determine if repetitive micro-trauma caused by prolonged use of a keyboard or a mechanical typewriter is associated with the increase in degenerative changes in the hand and cervical joints. We studied a sample of people of over 40 years of age, who have been working on a keyboard or a mechanical typewriter for at least 10 years. A clinical and radiological evaluation of the degree of osteoarthrosis of the hands and the neck spine was done according to the Kellgren-Lawrence grade; CRP and ESR were used as laboratory markers of secondary inflammation in osteoarthrosis. We also used some demographic and epidemiological data. We did a prospective study with 30 examinees, average age 47 years (SD 4.77), average effective working hours 8.88 (SD 6.59). The average usage of the keyboard was 18.71 years (SD 6.59). We found that the clinical degree of osteoarthrosis on distal interfalangeal joints (DIP) is in correlation with age (r = 0.516, p = 0.05) and years of working (r = 0.459, p = 0.05). The radiological grade of osteoarthrosis on DIP and proximal interfalangeal joints (PIP) are associated (r = 0.835, p = 0.01). We found no significant association with effective day working hours and the clinical and radiological grade of osteoarthrosis of DIP and PIP hand joints. The radiologically determined cervical osteoarthrosis grade is significantly higher than that of DIP (p = 0.004) and PIP (p = 0.035) joints of the hands. Key words: Osteoosteoarthrosis, hands, keyboard, cervical spine Introduction Osteoarthrosis or osteoosteoarthrosis (OA) is a degen- erative process the evolution of which comes with age. Women suffer more frequently than man, especially after menopause (1,2). The anatomic substrate of osteoarthrosis is progressive degeneration and loss of joint cartilage, reactive changes on bone ends and the subchondral bone, as well as in the sinovial membrane (3). The clinical mani- festations of osteoosteoarthrosis include: progressive joint pain, rigor, swelling of the joint, restrictive movements (1,3). Joint pain is the dominant symptom of OA. The association between joint pain and the radiographic fea- tures of OA is not constant. In studies preformed during the 1950s in the north of England, the relationship be- tween pain and the radiographic evidence of OA was con- siderably stronger for the hip than for the knee or distal interfalangeal joint (4). There are many factors that have its influence on the pathogenesis and evolution of osteoarthrosis: genetics, mechanical and biochemical factors, and immunology (1,5). Research has been done on risk factors for hand OA among Chinese residents (age 60-95, lower levels of edu- cation, higher bone mineral index and bone mineral den- sity) that has shown an increase in hand OA prevalence in men, but not in women. While older age and menarche are associated with increased OA prevalence, no such relation has been observed for age at menopause (6). Among women with hand OA, stronger pain is significantly asso- ciated with days of rising barometric pressure (P < 0.001). These findings have been obtained for the population 49 years of age and older (7). Mechanical factors are risk factors for OA and they include: trauma, joint shape and repetitive use- occupa- tional and leisure (4). The most acceptable theory of the pathogeneses of osteoarthrosis is a repetitive micro trauma (1,5,8). A repetitive micro trauma provokes the release of fibrinolitic factors that damage the joint car- tilage (9). The repetitive micro trauma of hands is com- mon in data input personnel, secretaries, and dentists (10). In Serbia, there are still workplaces where people use mechanical typewriters. Distal (DIP) and proximal (PIP) interfalangeal joints are exposed to stronger me- chanical force in mechanical typewriter use than in key- board usage. This will speed up the arthritic process. We hypothesized that in the population at risk, the re- petitive micro trauma which lasts for many years will contribute to a more progressive arthrotic process, com- pared to people without professional risk, and that the years of exposition are in a positive correlation with the degree of osteoarthrosis. Hours of working in a non-physiological neck posi- tion cause neck pain and difficulties in neck motion; after many years, arthrotic changes on the neck spine