Ergonomic rubber tapping knife relieves symptoms of carpal tunnel syndrome among rubber tappers

Rubber tapping is an occupation with a high risk for developing carpal tunnel syndrome (CTS). Exposure to excessive ulnar deviation and wrist flexion, among other risk factors, contributes to increased carpal tunnel pressure contributing to the development of carpal tunnel syndrome. Prior, an ergonomic tapping knife was developed to improve wrist posture and to prevent or reduce CTS symptoms in rubber tappers. This study evaluated changes in the severity of symptoms of carpal tunnel syndrome after using the ergonomically designed tapping knife. This was a non-randomized controlled trial among rubber tappers in Pawong subdistrict, Mueang district, Songkhla province, Thailand, conducted from September 2014 to March 2015. Two hundred and eight rubber tappers were assigned into two groups, an intervention group who used the new ergonomic rubber tapping knife and the control group who used the traditional knife. Both groups consisted of 52 tappers with CTS symptoms and 52 without CTS symptoms. All subjects were followed for 7 months after the new ergonomic knife was introduced to the intervention group. Face-to-face interviews using the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) were used for primary data collection, and the Rapid Upper Limb Assessment (RULA) was used to assess wrist posture before and after the intervention. The overall mean age of tappers was 49.7 years. The demographic characteristics of subjects were similar across all trial groups. The CTS symptom severity scores were significantly decreased and right wrist radial and/or ulnar deviation significantly reduced among tappers using the ergonomic knife compared with those of tappers using the traditional knife. The ergonomic rubber tapping knife was associated with a decrease in all CTS symptoms and improved wrist posture among the CTS participants, and reduced CTS symptom occurrence among non-CTS tappers. The results of this study suggest the ergonomic rubber tapping knife can be used to decrease the severity of CTS symptoms among CTS tappers and prevention to CTS symptom development among non-CTS tappers. •New ergonomic design rubber tapping knife had been developed for rubber tapper.•It could significantly decrease the severity of CTS symptoms among CTS tappers.•Furthermore, it could prevent CTS symptoms development among non-CTS tappers.