Hypothenar Hammer Syndrome (HHS) is a disease that can be easily confused with other disorders, such as hand-arm vibration syndrome (an occupational illness) or Raynaud’s disease, which is hereditary. HHS can lead to serious injury in the affected fingers—and could even result in their amputation without appropriate diagnosis and treatment.
So, it’s important that you understand HHS and its causes and symptoms, and educate workers on this disease so they can get treatment early if they start to see signs of the condition.
To help educate both employers and workers on HHS, the Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST) published an information pamphlet entitled Recognizing Hypothenar Hammer Syndrome.
The disease develops in workers who repeatedly use the palms of their hands to strike, flatten, press or twist objects, which can reduce blood flow circulating into the fingers, especially the middle, ring and little fingers. Even a single episode of trauma could cause the disease. The use of vibrating tools or tools that exert pressure on or repetitively strike the palm can also cause the disease.
The workers most vulnerable to HHS are machinists, construction workers, miners, mechanics, forestry workers and farmers. A number of tools can cause HHS, including electrical or pneumatic vibrating tools, brush cutters/trimmers, milling machines, grinding machines, jackhammers, impact wrenches, pliers and presses.
HHS can cause one or more symptoms, including:
White or blue, stiff and painful fingers
Hypersensitivity to cold
Decrease in muscle strength in the hand
Impression of a palpable mass in the palm
Pins and needles or numbness in the fingers.
Any delay in diagnosing HHS in its acute form could cause serious injury to the affected fingers, which could even result in amputation. So, workers must be vigilant and report early symptoms to their doctor immediately to avoid complications.
To avoid developing HHS, workers should:
Avoid using the palm of their hands as a hammer to strike a tool or an object.
Avoid using excessive force to grip objects such as impact wrenches, pliers, scissors, presses of every kind, or gearshifts.
Use work methods to avoid acute or repetitive trauma.
Switch tasks regularly or rest their hands.
Use properly maintained tools that are adapted to the task.