Vibration induced injury claims on the rise again? 

 Long before the recent noise induced hearing loss spike the claimant industry generated huge income from Hand Arm Vibration (‘HAVS’) claims usually brought by workers of former heavy industry.

Those claim numbers have now dipped and the nation has moved away from heavy industry but this is not to say that upper limb injuries have now gone away. Claims for repetitive injury continue to present.

These increasingly come from light industrial or office based employees whose work involves repetitive or awkward posture of the hand and wrist.

An increasing number of claimant firms advertise that compensation is available for Dupuytren’s Contracture. This is a thickening of the connective tissue in the palm of the hand which over time form chords that then contract. When those chords form along the tendons in the palm this can cause the finger to bend inwards, causing difficulty with day to day activities. The condition is relatively common in the UK but its precise cause is not known.

Dupuytren’s: Can the condition be caused by vibration?

The Industrial Injuries Advisory Council (‘’IIAC’’) originally concluded in 2006 that, whilst there was some evidence of a relationship to vibration, it was insufficient to meet their criteria. However, in 2014 the IIAC concluded that there was now sufficient epidemiological evidence that the use of vibratory tools doubled the risk.

Regulation 2 of the Social Security (Industrial Injuries) (Prescribed Disease) Amendment Regs 2019 now provides for payment of Industrial Injuries Disablement Benefit (IIDB) to those who have suffered from Dupuytren’s after having been involved in work of ten years or more which required use of hand held tools

Sound familiar? The rise of carpal tunnel claims

Insurers are already used to dealing with claims for carpal tunnel syndrome (‘CTS’). This condition is caused by pressure on the median nerve as it passes through the carpal tunnel. It causes pain, tingling and numbness. CTS became a prescribed disease for the payment of IIDB in 1993 following acceptance by the IIAC of evidence said to identify a doubling of the risk attributable to occupation. Like Dupuytren’s the condition is strongly associated with a number of constitutional factors and diseases such as obesity, age and arthritis. 

How should alleged vibration induced injury claims be handled?

Claims for CTS and Dupytren’s Contracture are likely to present much like your standard HAVS case. Both conditions can arise from the manual aspects of hand/wrist flexion and not solely or simply due to vibration so claimants can hedge their bets between allegations of vibration and of repetitive strain. These allegations of exposure should be closely scrutinised.

Defendants must have their own medical evidence to look for alternative explanations for the injury and comment on any competing risk factors. Causation is far from straightforward. There is no defined dose-response relationship, no known effect of multiple risk factors, no known pathological mechanism by which vibration causes the conditions and it is not known what specific aspect of using vibratory tools can cause/increase the risk of the conditions developing.

These complexities should be resolved by the traditional ‘but for’ test: So the question is would the claimant have developed the condition ‘but for’ the alleged exposure?

What should the market do?

Just because a condition has prescribed disease status for benefits, this should not equate to the establishment of medical causation, certainly not without challenge. This is the question that the prescription of Dupytren’s Contracture poses. The decision to prescribe a condition relies upon epidemiology, but as any disease lawyer knows the role of epidemiology in legal causation is highly contentious. After all, epidemiology isn’t a test of causation at all. It is a test of probability. Expert evidence is then key in dealing with these claims.

Claims handling

• Confirm the diagnosis which is usually based on the subjective response of the claimant and the history of exposure alone. Nerve conduction studies should be insisted upon.

• Choose your expert wisely! There are many medico-legal experts whose reports do not give due consideration to studies, casting doubt on the existence of any dose relationship and/or who fail to consider the more likely cause of injury based on individual risk factors.

• Evidence should be collated to estimate vibration exposure dose. Many of the studies which do suggest an association between carpal tunnel syndrome and vibration exposure involving individuals heavily exposed way in excess of the Exposure Action Value (EAV) of 2.5m/s².

• The Industrial Disease Claims Working Party (IDCWP) handling guidelines suggest apportionment of alleged vibration induced conditions should be “time on risk” apportionment method. Whilst this might be appropriate for commercial purposes in a single defendant case it might be better tactically to instead advance the ‘reservoir of tolerance’ argument.

• Given the apparent correlation between exposure dose and symptoms, the absence of complaint of HAVS alongside CTS or Dupytren’s Contracture might be viewed as a red flag.

Dupuytren’s Contracture and CTS cases may often be of relatively low value. They are still complex cases posing genuinely difficult questions. The challenge they present to insurers is about striking the right balance. The best approach has to be driven by proper strategic deployment of resources – picking the right cases to fight, against the right opponents with the right evidence. 

Author: Robert Smith - Partner