Tennis elbow can severely limit the ways in which a person is able to move their arm. Occupational health specialists Leigh Turvey and Anne Harriss examine a case study involving the injury and its impact on work.
Tennis elbow or, to give it its correct term, lateral epicondylitis (LE) is characterised by pain over the lateral epicondyle of the humerus. It is the second most commonly diagnosed musculoskeletal disorder of the upper extremities affecting both sexes between the ages of 35 and 54, typically affecting the dominant arm (Smidt and van der Windt, 2006). However, tennis is only one possible cause. Individuals whose work involves manual tasks combining forces and repetition are at an increased risk of developing this condition (Haahr and Andersen, 2003). This article explores the condition in relation to a worker's fitness to undertake computer work.
Zara, aged 40, is a secretary working in a small company. She is married and has a varied social life. She was referred to the OH service following a period of sickness absence resulting from severe elbow and lower-arm pain. She said that the pain had lessened when she rested her arm and, as she was keen to return to work, she sought advice regarding the prevention of symptoms reoccurring. The following assessment considered work tasks and factors that may cause or exacerbate her discomfort.
Zara had experienced steadily increasing pain in the elbow of her dominant arm, exacerbated by repeated movements. Tasks involving repetitive activities, including keyboard and mouse use, were almost intolerable. Her GP diagnosed LE and recommended that she take anti-inflammatory medication and rest the arm from any movements that exacerbated the pain for three weeks. These interventions reduced her symptoms.
Tennis elbow is the second most commonly diagnosed musculoskeletal disorder of the upper extremities affecting both sexes between the ages of 35 and 54."
LE is an overuse injury involving the extensor muscles originating on the lateral epicondylar region of the distal humerus. Inflammation results from overuse of the forearm and is caused mainly by repetitive wrist actions. This condition is characterised by pain and tenderness over the lateral aspect of the elbow radiating down the forearm. Exacerbation results from activities involving rotation and gripping, such as the opening of a door and the use of a computer mouse. The pathophysiology and treatment of this disorder has been controversial (Labelle et al, 1992). Several pathophysiological hypotheses have been proposed.
The clinical presentation of LE is easily recognisable, contrasting with the complex pathophysiology of the condition. The management of LE depends on both its severity and the length of time that it has been present. It is a challenging condition to treat and is likely to recur. The average duration of a typical episode can be from six to 24 months, with most patients (89%) reporting recovery within one year (Smidt and others, 2006).
In 1936, Cyriax suggested that this condition may resolve spontaneously within eight to 12 months of original onset. Spontaneous recovery has been challenged. Svernlov and Adolfsson (2001) found no outcome differences between patients with symptom durations longer or shorter than 12 months. The lack of medical evidence on the natural history of this condition poses an ethical predicament. Active treatment seems unwarranted in a condition that is likely to resolve on its own. However, when pain-relieving therapy is requested, it is not easily left unheeded.
Coombes and others (2008) suggest a new model of LE integrating current evidence of the pathophysiology providing a better rationale for its management. They propose that LE is grouped into three interrelated components:
- local tendon pathology;
- changes in the pain system; and
- impairment within the motor system.
Not all patients have all of these changes, but this model usefully describes the pathophysiology of symptoms of LE.
LE is an overuse injury: the tendon is unable to self-repair, leading to both microscopic and macroscopic changes. Zara experienced tendon damage resulting from repetitive movements associated with use of a computer mouse.
Tendons respond to mechanical forces by altering their structure, composition and mechanical properties, a process known as mechano-transduction (Cook and Purdam, 2008).
Interrelated components of LE
- Local tendon pathology.
- Changes in the pain system.
- Motor system impairment.
Pathological changes have been reported in the deep and anterior fibres of the proximal insertion of the extensor carpi radialis brevis (ECRB) tendon, thus defining LE as an "insertional tendinopathy" (Zeisig et al, 2006). This comprises a narrow attachment to the lateral epicondyle and a broad attachment to the inter-muscular septum. The deeper aspect merges with the lateral collateral ligament and indirectly with the annular ligament. These connections are believed to be involved in the natural dissipation of stress across a broad area. High levels of stress within the ECRB musculotendinous unit contribute to changes seen in LE (Lieber and Frieden, 1998).
Local tendon pathology may result from overuse, tensile, compressive or shear forces, leaving the tendon in a debilitated state. Ultrasound imaging has identified structural changes associated with LE, including tendon thickening, thinning and tears.
Pain system changes
Zara experienced elbow pain. The pain gate theory of Melzack and Wall (1965) suggests a mechanism in the brain acting as a gate increasing or decreasing the flow of nerve impulses from the peripheral fibres to the central nervous system (CNS). This "open" gate allows the flow of nerve impulses, enabling the brain to perceive pain.
The pain experienced from LE can be described as nociceptive pain. Nociceptors, or pain receptors, are free nerve endings (myelinated or unmyelinated) that respond to painful stimuli. They are found in all tissues except brain tissue and transmit information to the brain.
During inflammation, major plasticity changes occur in both the peripheral and CNS, lowering pain thresholds and resulting in allodynia and hyperalgesia. Silent nociceptors (ie afferent nerve fibres) are stimulated sending information to the CNS. Nociceptors are triggered by biological, electrical, thermal and chemical stimuli.
Pain perception occurs when these stimuli are transmitted to the spinal cord and then to the brain. The basic sensation of pain occurs at the thalamus, continuing to the limbic system and the cerebral cortex, where pain is then perceived and interpreted.
There is evidence of dysfunction of the motor system in LE, including diminished strength, morphological changes and altered motor control (Alizadehkhaiyat et al, 2007a and 2007b). This explains the difficulty that Zara experienced when gripping and controlling objects, including the computer mouse and opening doors, which affected her day-to-day activities.
An understanding of the underlying pathophysiology is helpful in understanding the effects of LE when making an assessment of the person in relation to their job tasks."
Bilateral deficits in wrist position during gripping, coupled with impairments in reaction time and speed of movement with reaching tasks in LE, possibly reflects alterations in central processing found in the pain system (Bisset et al, 2006). Morphological changes of muscle occur in the ECRB muscle of patients with long-standing LE. Signs of muscle fibre necrosis can occur if the condition is unresolved (Ljung et al, 1999a; Ljung et al, 1999b).
Motor control deficits have been noted with reduced activity of the ECRB muscle during gripping tasks, suggestive of a link between neuromuscular activity and symptoms (Alizadehkhaiyat et al, 2009).
An understanding of the underlying pathophysiology is helpful in understanding the effects of LE when making an assessment of the person in relation to their job tasks. An appreciation of the pathophysiological effects of this condition is helpful in order to understand changes to the structures involved. Reference to a biopsychosocial model that also considers psychological and social factors will aid the development of a return-to-work strategy.
As Burton et al (2008) highlight in their review of the management of work-related upper-limb disorders, psychosocial factors are highly relevant in relation to an effective return to work. There is a complex interplay between the person's beliefs regarding the severity and implications of their condition and their social and work environment. This interplay has the potential to affect their attitude to the work situation and the management of an effective return-to-work recovery strategy.
Psychosocial workplace factors have been a focus of many musculoskeletal disorders, but few have focused on tennis elbow. The study of Haahr & Andersen (2003) supports an association between physical workplace, home factors and LE. An important consideration was the impact of LE on the psychosocial aspect of Zara's life. Constant pain affects activities of daily living, increasing the risk of depression and anxiety disorders affecting work attendance.
The fitness-to-work framework of Murugiah (Murugiah et al, 2002) highlights the importance of variables including work tasks, working environment and the personal characteristics of the employee. Routine review of fitness following recent incapacity is one of the most valuable assessments in the employment situation.
Murugiah et al (2002) state that care must be taken to ensure that this assessment does not focus entirely on the functional and anatomical attributes, but it should take into account the job tasks that need to be carried out to facilitate the assessment.
One facet of this assessment was identification of how this upper-limb disorder affected Zara's health and her ability to perform activities of daily living.
When pain significantly restricts normal activities, there can be a negative impact on the person's psychological health, particularly when pain disrupts sleeping patterns. Although she experienced elbow pain when undertaking tasks such as lifting a filled kettle and using a keyboard, Zara was able to maintain all other activities of daily living. She was therefore very positive about achieving a full recovery. An effective return to her full job role was an important aspect of this. Integral to her returning to the workplace was an assessment of her job tasks and her use of work equipment.
Active and early involvement in the management of LE facilitated an effective return to work."
A display screen equipment (DSE) assessment, in compliance with the Health and Safety (Display Screen Equipment) Regulations 1992 (HSE, 2003), was undertaken as part of the assessment process. This involved consideration of tasks, equipment and environment (HSE, 2003). This assessment highlighted the impact of the client's condition on her ability to complete work tasks, including discomfort when using the mouse. The use of keyboard shortcuts was recommended as these significantly reduced the need to use the mouse.
Following the DSE assessment, a detailed report was sent to Zara's line manager. This included recommendations relating to limiting DSE work, initially to a maximum of three to four hours each day, with regular work task "rotation" and subsequent review by the OH specialist. Mouse use was identified as an exacerbating factor.
In addition to utilising keyboard shortcuts, the purchase of an alternative vertical mouse with side-functioning keys facilitating a neutral wrist position, which reduces elbow discomfort, was recommended. The purchase of voice-activated software was another option that would reduce the need to use both the mouse and the keyboard. Management was also reminded to take into consideration the effect of a reduction in Zara's computer-based tasks on the workload of her colleagues.
In conclusion, active and early involvement in the management of LE facilitated an effective return to work. The health assessment undertaken on the client was based on an understanding of the causes and pathophysiology of this musculoskeletal disorder.
The assessment was enhanced by undertaking a workplace task and DSE risk assessment, which identified the elements of Zarae_SSRqs work that could be causative factors or could have exacerbated her symptoms. While rest and conservative treatment were necessary initially, correct adjustments, including job rotation, limiting repetitive tasks and the purchase of a vertical mouse, facilitated a successful return to work and minimised a recurrence of this condition.
Anne Harriss is course director of occupational health programmes and reader in educational development at London South Bank University. Leigh Turvey is an occupational health nurse in a university OH service.
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