CHAPTER CONTENTSDefinition of work-related musculoskeletal disorders
(WRMSD) 127Risk factors associated with WRMSD 128Multifactorial 128
Models for the pathogenesis of WRMSD 130Repetitive movement 131
Definition 131Repetitive movement biological responses and
pathology 131Repetitive movement vulnerability of the hyperrnobile
Individual 131Force 132
Definition 132Force biological responses and pathology 132Force: vulnerability of the hypermobile
Individual 132Awkward posture 133
Definition 133Awkward postures biological responses
and pathology 133Awkward postures: vulnerability of
the hypermobile Individual 134Static postures 134
Definition 134Static postures biological responses
and pathology 134Static postures vulnerability of the hvperrnobue
Individual 135Whole body vibration (WBV) 135
Definition 135Whole body vibration biological responses and
pathology 135Whole body vibration vulnerability of the hvperrnobne
Individual 135Cool temperatures 135
Cool temperatures biological responses andpathology 135
Cool temperatures vulneraouuy of the hypermobileIndividual 136
Psychosocial Issues 136Psychosocial issues biological responses and
pathology 136Psychosocial issues vulnerability of the hvperrnobile
Application of ergonomic principles to reducethe risk of WRMSD in the hypermobileindividual 136
Ergonomics: the balance 137Primary prevention 137
Surveillance identilymq vulnerable JOintsand tissue 137
Education and training awareness of risk factors andrecommended posture, work practices and manualhandling techniques 137
Ergonomic assessment and management 138Secondary prevention 138
Job restrictions and task modifications 138Education and training to prevent persistence or
recurrence of Injury 139Ergonomic assessment and management 139
Tertiary prevention 139Rehabilitation and gradual return to work/conditioning
139Ergonomic assessment and management 140
9Joint hypermobility andwork-relatedmusculoskeletaldisorders (WRMSD)Jean Mangharam
Aims1. To provide the reader with background
information about WRMSD, including thedefinition, associated risk factors, proposedpathogeneses, and the associated biologicalresponses and pathology
2. To explore the potential impact of havinghypermobile joints and lax tissue on thedevelopment of WRMSD
3. To discuss pertinent ergonomic principlesand propose suitable applications.
DEFINITION OF WORK-RELATEDMUSCULOSKELETAL DISORDERS(WRMSD)
The prevalence of musculoskeletal disorders(primarily of the neck, upper limb and back)among the workforce of European UnionMember States and the United States of Americais high and continues to be a major reason forillness and financial burden in the workplace(Violante et al. 2000, European Agency for Safetyand Health at Work (EASHW) 1999, Kumar 2001).There is growing worldwide concern about theprevalence of musculoskeletal disorders in theworkplace. International meetings and work-shops such as the one carried out in April 1998 bythe World Health Organization in Sweden, andseveral large-scale projects to investigate the prob-lem, have been commissioned by national and
128 HYPERMOBILITY SYNDROME
international bodies. Three such investigationsand reviews include:
NIOSH (1997) The National Institutefor Occupational Safety and Health(USA) carried out an extensive criticalreview of epidemiological evidence forwork-related musculoskeletal disorders forthe neck, upper extremity and low back.The review identified a number of specificphysical exposures strongly associated withspecific WRMSD, especially when exposureswere intense, prolonged, and particularlywhen workers were exposed to severalrisk factors.
European Agency for Safety andHealth at Work (EASHW) (1999) TheEuropean Agency for Safety and Health atWork requested the Robbens Institute,University of Surrey, to describe and assessfindings of relevant research related towork-related upper limb disorders (WRULD).The review was detailed and systematicin its presentation of the nature of theproblem, and proposed models ofpathogenesis, biological responses andstrategies for prevention.
National Research Council (1999)The National Institutes of Health (NIH)in the USA requested that the NationalAcademy of Sciences and NationalResearch Council convene a panel of expertsto carefully examine questions raised byCongress concerning occupationalmusculoskeletal disorders. Comprehensiveinformation related to tissue mechanics,biological responses and proposed theoriesabout the interaction between workplaceextrinsic and individual intrinsic factorswere presented.
'Work-related musculoskeletal disorders' (WRMSD)is an umbrella term used to describe musculo-skeletal disorders which have been associated withthe work of the affected person. The term 'work-related upper limb disorders' (WRULD) refers
particularly to work-related musculoskeletal dis-orders of the neck and upper limb. Several termshave been used to describe WRULD, includingrepetitive strain injury (RSI in Australia andthe UK), occupational overuse syndrome (OOSin Australia), cumulative trauma disorders (CTDin USA), occupational cervicobrachial disorder(OCBD in Japan, Switzerland and Sweden),tension headache and occupational disorder (inFinland) and Occupational Complaint Number2101 (in the former Federal Republic of Germany)(Ireland 1995).
The term WRMSD does not suggest or implyaetiology, nor specify a risk factor or anatomicalregion affected. It suggests that the disorder ismusculoskeletal in nature and is related to theoccupation of those affected. The primary reasonfor the controversy surrounding the terminologyand classification of WRMSD is its complex mul-tifactorial aetiology, progression and prognosis(NIOSH 1997, Mayer et al. 2000). The WorldHealth Organization clarified this by stating that'Work-related diseases may be partially caused byadverse working conditions. They may be aggra-vated, accelerated or exacerbated by workplaceexposures and they may impair working capacity.Personal characteristics and other environmentaland sociocultural factors usually play a role asrisk factors in work-related diseases; whichmay often be more common than occupationaldisease' (WHO 1985, Identification and Controlof Work Related Diseases. Technical Report No.174. General: World Health Organization, citedin National Research Council and Institute ofMedicine 2001).
RISK FACTORS ASSOCIATEDWITHWRMSD
MultifactorialNIOSH (1997) found that the epidemiologicalstudies investigating the role of physical factors,work organizational and psychosocial factors in the
JOINT HYPERMOBILITY AND WORKRELATED MUSCULOSKELETAL DISORDERS 129
development of WRMSD for the neck, shoulder,elbow, hand and back were not guided by anestablished and consistent definition of WRMSD.The presentation of WRMSD may have been basedon clinical pathology, the presence of symptoms,objective pathological processes and/or workdisability (e.g. days away from work). Of thestudies reviewed, the most common health out-come was the occurrence of pain.
NIOSH (1997)and European Agency for Safetyand Health at Work (1999) have both stated thatthe lack of standardized criteria for definingWRMSD makes investigation and comparisonbetween studies difficult. NIOSH (1997) pointsout that it would be useful to have a concisepathophysiological definition and correspondingobjective clinical test for each WRMSD, to trans-late the degree of tissue damage or dysfunctioninto an estimate of current or future disability andprognosis. However, clinically defined WRMSDoften have no clearly delineated pathophysio-logical mechanisms for pathological processes.
Reviews of studies have shown that the phys-ical risk factors that have been associated withWRMSD include repetitive movement, forcefulmovements, heavy physical work, awkward pos-tures, static postures, contact stress (local mech-anical pressure or high-impact external forces),hand-tool vibration, whole body vibration andcool temperatures (NIOSH 1997,European Agencyfor Safety and Health at Work 1999, NationalResearch Council 1999).
NIOSH (1997) summarized the causal relation-ship between physical work factors and WRMSD(Table9.1). The studies reviewed displayed strongevidence of a causal relationship between postureas a risk factor on neck/shoulder disorders; acombination of risk factors (repetition, force andposture) on elbow disorders; a combination ofphysical risk factors (repetition, force, posture andvibration) on carpal tunnel syndrome; a combina-tion of physical risk factors (repetition, force andposture) on hand/wrist tendonitis, vibration onhand-arm vibration syndrome; and lifting/ force-ful movements and whole body vibration on
Table 9.1 Evidence for causal relationship betweenphysical work and WRMSD (NIOSH 1997)Body part Strong Evidence Insufficient EvidenceRisk factor evidence evidence of no effect
NeckandnecWshou~erRepetition V'Force V'Posture V'Vibration V'ShoulderPosture V'Force V'Repetition V'Vibration V'ElbowRepetition V'Force V'Posture V'Combination V'Hand/wrist - carpal tunnel syndromeRepetition V'Force V'Posture V'Vibration V'Combination V'Hand/wrist - tendonitisRepetition V'Force V'Posture V'Combination V'Hand-arm vibration syndromeVibration V'BackLifting/ V'
Whole body V'vibration
Static work V'posture
back disorders. There was insufficient evidenceof a causal relationship between vibration andneck/shoulder disorders; force and vibration onshoulder disorders; repetition and posture onelbow disorders; posture on carpal tunnel syn-drome; and static work postures on back disor-ders.