"Trigger Thumb" May Be Linked to Handgun Application

Several herbicide applicators have been diagnosed with ‘trigger thumb’ (Stenosing tenosynovitis) or ligament damage to the thumb possibly caused by excessive use, and/or stiff spring pressure with some handgun applicators. Trigger thumb involves the pulleys and tendons in the hand that bend the fingers/thumb. The condition can be relieved with a steroid injection at the base of the thumb, or surgery in more severe cases. 

Applicator comments

  • Rod Cook, La Plata County Weed Supervisor:  We hope to fix this problem by reducing the trigger spring pressure on the handgun.
  • Ted Brown, Clear Creek Co Weed Supervisor: I had trigger thumb in 2011, but haven’t had any recurrences; however, I’ve reduced using the handguns but will consider reducing spring pressure on triggers.   
  • Tina Booton, Weld Co Weed Supervisor: We try to use the keeper as much as possible on the trigger to reduce stress on the thumb.
  • Amy Sidener, Grand Co Weed Supervisor: I had damage to the CMC joint after 9 years of herbicide application with handguns. I have a "brace" that was built by an occupational therapist to assist with proper thumb positioning and have changed spray guns to something similar to the Hypro Hydra Gun--more ergonomic and the pressure on that joint is much less. Seems to help. 

* Bones that make up the base joint of the thumb – a Carpal (wrist) bone and a Metacarpal or long bone of the thumb – the (CMC) joint is the most common place in the hand for arthritis.