Engineering and ergonomics considerations in repetitive-strain injury legal cases
20 September 2016
This article discusses the weaknesses in defending civil claims relating to workplace repetitive strain injuries and how, more frequently, defence teams are being challenged in relation to compliance with specific statutory requirements, in an attempt to reduce the risk associated with the variables presented by cases of repetitive strain injury (RSI).
Legal cases cost money, both to take and to defend. Nobody initiates legal proceedings for a wrongdoing against them unless they have some hope or belief that they have a chance of recompense.
However, in Ireland, once a case is initiated online with the Injuries Board, it sets in motion a chain of events. This can involve solicitors, barristers, physicians, consultants (medical and subject matter experts), engineers, insurers, loss adjusters, liability adjusters, the claimant and the defence.
Some cases are ‘straightforward’. For example, when a person has sustained a cut when using a knife, the specific contribution the knife made to the injury can be ascertained, as can the size of the scar and the depth of the cut. In such a case, the long-term sequelae are relatively easy to quantify. The variables will only include such issues as contributory negligence and compliance with relevant applicable legal requirement.
However, when it comes to cases involving claims of RSI, things become less straightforward – partially due to the ongoing research relating to the prevalence of RSI, particularly carpel tunnel syndrome (CTS), in the general population. This is iindicated to be as high as one in 25 (1). In such cases, the variables presented in the case can be more influential in determining liability and quantum.
Successful civil litigation depends on a number of factors, including but not limited to:
- How evidence is presented;
- The understanding of the decision makers (solicitors, barristers and judges) on the exact circumstances of a claim;
- How that interpretation may influence the application of the burden of proof – for civil cases being on the ‘balance of probabilities’; and
- Compliance with statutory requirements.
However, even what seems at first as a simple interpretation of quite prescriptive statutory requirements, such interpretation in itself can be open to variation as it is very much dependent on the competence of the those doing the interpretation – producing yet another variable into the chances of winning or losing a civil action.
Claimants take cases on the basis that the balance of probabilities will fall in their favour, and defence teams prepare their defence of any claim on the balance of probabilities falling in their favour – suggesting that the more variables in the mix, the better the chances of winning or losing a case. To this end, taking or defending a claim can be a risky business.
Carpal tunnel syndrome
Looking at carpal tunnel syndrome specifically, although CTS remains an idiopathic syndrome, there are certain risk factors that have been associated with this condition. The most significant of these are environmental risk factors. Prolonged postures in extremes of wrist flexion or extension, repetitive use of the flexor muscles and exposure to vibration are the primary exposures that have been reported (2).
Despite this, however, there are still quite a number of variables that can be brought into the mix by either party. So, whenever possible, parties prefer to include specific statutory duties and failures in respect of same, to introduce some element of certainty into cases.
It is easier to establish this if an employer has in their possession a written risk-assessment or has conducted an assessment of a VDU (visual display unit) workstation, than it is to ascertain with a great deal of certainty that work carried out constituted a risk in respect of repetition or application of force. In Ireland, assessment must be in accordance with Chapter 5 of Part 2 (Regulations 70 to 73) and the related Schedule 4 to the Safety, Health and Welfare at Work (General Application) Regulations 2007 (S.I. No. 299 of 2007).
Of course, there are significant guidance documents in respect of what is considered to be repetitive or highly repetitive, but no one agreed global definition. According to the International Labour Organization, a task is highly repetitive if involves similar movements repeated more than 20 times per minute – but even with this definition, the term ‘similar hand movements’ is open to interpretation.
One individual might determine that a cycle is a combination of three tasks, whilst another might interpret each task as constituting a cycle.
So, when carrying out an engineering report for civil cases involving RSI, it is essential that the ergonomist consider all of the aforementioned risk factors, extremes of flexion or extension of the wrist, repetitive motion and exposure to vibration and applies their professional judgement in respect of same.
The expert ergonomist needs not only to have an arsenal of measuring equipment but even more importantly, a competent understanding of the holistic nature of ergonomics – ergonomic assessment in respect of RSI is not just a focus on, for example, how frequently a person uses a twisting motion, but must examine the duration of exposure, the forces and postures involved during the task completion.
Ita Leyden BE, MSc, CEng, C.MIOSH, ergonomist and forensic engineer, is the managing director of Leyden Consulting Engineers (LCE). LCE provides consultancy and training in all areas of workplace health and safety, with a specialist focus on ergonomics. LCE can be contacted on 051 364344 or www.LCE.ie.
1. ‘Prevalence of carpal tunnel syndrome in a general population.’
Atroshi I, Gummesson C, Johnsson R, Ornstein E, Ranstam J, Rosén I
JAMA. 1999 Jul 14; 282(2):153-8
2. ‘Carpal tunnel syndrome and hand-arm vibration syndrome. A diagnostic enigma.’
Pelmear PL, Taylor W. Arch Neurol. 1994 Apr; 51(4):416-20.