Sang-arun Isaramalai, Kanokwan Hounsri, Chanon Kongkamol, Pornnit Wattanapisitkul, Napaporn Tangadulrat, Tippawan Kaewmanee, Varah Yuenyongviwat

Ergonomic hazards are the most important cause of knee osteoarthritis (OA) in aged para rubber farmers. Ergonomic management comprising improvement of working conditions and muscle-strengthening exercise has been well documented in terms of workers' health benefit. However, those interventions were not adequate to sustain the advantage. Few studies have demonstrated the effect of integrating participatory ergonomic management (PEM) in non-weight-bearing exercise (NWE) and progressive resistance exercise (PRE), and none has focused on aged para rubber farmers with knee OA. This study investigated the effect of PEM-NWE, PEM-PRE, and standard treatment (ST) on self-care and functional ability in the aged population. A single-blinded, clustered randomized controlled trial was carried out. Participants (n=75) from three different communities in southern Thailand were randomly assigned to PEM-NWE, PEM-PRE, and ST. Self-care and functional ability (pain, stiffness, and physical function) were examined at baseline (B), during the intervention at Week 5 (W5), and after its completion at Week 9 (W9). Mean comparison of those outcomes over time was made using Generalized Linear Mixed Models (GLMMs). Compared to the standard treatment, the means of both groups, PEM-NWE and PEM-PRE, were significantly increased in self-care and functional ability. However, no significant difference between PEM-NWE and PEM-PRE was found. Either or both interventions should be incorporated into nursing practice in order to promote occupational health and enhance quality of work life for Thai aged farmers. Further study on their cost-effectiveness is highly recommended.