Work-Related Musculoskeletal Injuries and Prevention

Top Contributors - Yuan Chuang, Nupur Smit Shah and Kim Jackson  

Introduction

Risky postures at work

Work-related musculoskeletal injuries (WRMI), or work-related musculoskeletal disorders (WMSD), are any range of inflammatory disorders resulting from injury sustained while completing work duties. WMSDs are:

1. The result of regular exposure to work activities that contribute significantly to the development or exacerbation of painful symptoms
2. Conditions that are worsened or that persist due to work conditions.

Such can be the result of repetitive and frequent work activities resulting in overuse and strain to nerves, ligaments, muscles, tendons, joints, and spinal discs.

These disorders are also commonly referred to as repetitive strain injuries, cumulative trauma disorders, and overuse syndrome, among others. Due to the emphasis on upper extremity use in occupational tasks, the vast majority of WRMIs impact the hands, wrists, elbows, shoulders and neck; however, conditions involving the lower extremities and feet, as well as spine and back are common.WMSDs do not include conditions caused by slips, trips, falls, or related injuries, whether or not sustained in the workplace.

Prophylactic practices by workers such as strength training, stretching, yoga, massages, and diet maintenance, are the superior treatment for musculoskeletal injury.

For a comprehensive delve into this topic read Introduction to Occupational Health and partake in the Occupational Health Programme

WMSDs Categories

WMSDs can be broadly broken down into three categories:

1. Muscle injury
2. Tendon injury
3. Nerve injury. Common types of WMSDs include carpal tunnel syndrome (CTS), tendonitis, thoracic outlet syndrome (TOS), and back pain.

Watch this good 6 minute video on WMSD's.

Importance of Ergonomics

Work-related musculoskeletal disorders and their associated high costs are a large concern in the workplace. To reduce potential occupational injuries, a safe working environment must be created, and all workers must understand, accept, and use the principles of ergonomics.

Who’s at risk for developing WMSD?

Butchery

Industries with high rates of WMSDs include meatpacking, knit-underwear manufacturing, motor vehicle manufacturing, poultry processing, mail and message distribution, construction, butchery, food processing, machine operation, dental hygiene and dentistry, data entry, hand grinding and polishing, carpentry, industrial truck and tractor operation, nursing assistance, housecleaning, and, worldwide, agriculture.

General Risk Factor

Heavy physical work a risk factor

Work posture (especially awkward or improper posture)

• Heavy physical work
• Lifting
• Repetitive, labor-intensive work
• Vibration (via hand tools)
• Temperature extremes (low temperature)
• Individual risk factors including smoking, high BMI, and presence of co-morbidities

Organizational Risk Factors

• Lack of influence or control over one's job
• Being subjected to verbal abuse, or sexual harassment, at work

Risk Factors Specific to the Healthcare Setting

• 

  Hospital workers overworked?

  Lifting patients or equipment
• Transferring patients
• Responding to unexpected movement
• Manual therapy
• Failure to take rest breaks
• Inadequate staffing
• Inadequate training on injury prevention

Psychosocial Risk Factors 

• Low work content
• Low social support
• High perceived work load
• Time pressure
• Low job control
• Perceived stress
• High psychological stresses
• Providing domestic work
• Unsatisfactory leisure activities

External Risk Factors

High productivity demands- a risk factor

Low Back

• Small workspace
• High productivity demands
• Understaffing
• Pt’s size, condition, shape, assisting during gait, confused/agitated
• Unadjustable beds/mats/chairs/commodes
• Repetitive bending, twisting, lifting

Neck/Upper Back/Shoulder

• Type A personality
• Scheduling
• Rest breaks
• Work-load: OverTime, high work-load
• Repetitiveness
• Manual techniques
• High mental load eg Hectic work environment, exhaustion at end of day
• Blue collar work (Male)
  

Overuse symptoms in wrist

Hand and Wrist

• High volume of manual therapy
• Static positioning of a joint - decreased blood flow to area
• Sustained duration pressure through a joint
• Small, unsupported joints
• High work load
• Scheduling/decreased rest breaks

Internal Risk Factors

Hairdressers have ergonomic issues

Low Back

• Female: Height and weight less than male counterparts, pregnancy, increased stresses on body and increased ligamentous laxity
• Psychosocial Health, stress
• Lack of experience, uncomfortable requesting assistance
• Postural Stresses, eg stooping

Forward head posture

Neck/Upper Back/Shoulders

• Forward head posture

• Volume of pressing is greater than pulling - i.e. weaker posterior musculature
• Lack of stability through trunk and hips
• Age
• Smoking
• Mental stress
• Previous injury
• Unhealthy BMI

Wrist and Hand

• MCP is more commonly injured in younger therapists
• CMC is more commonly injured in older therapists
• Increased CMC joint laxity
• Decreased tip pinch strength
• Decreased Body Mass Index (BMI) 

Consequences of Injuries

1. Personal : Depression. Anger. Early signs of aging due to stress. Potential negative effects on family or relationship
2. Work-Related: Leave work Absentee Worker’s Compensation Lost productivity Retraining of staff
3. Economical Costs: The direct costs of an injury are the easiest to see and understand.  These costs include emergency room and doctor visits, medical bills, medicines, and rehabilitation. Indirect costs of an injury are often overlooked.  These costs can amount up to 4 times the direct cost of the injury.  Indirect costs include administrative time dealing with the injury and medical care, raises in insurance costs, replacing the hours lost of the injured employee with hiring another employee, loss of reputation and confidence in employees and clients, unwanted media attention, and more. The total costs of an injury are suprising.  Beyond the direct costs, the indirect costs greatly increase the overall costs.  This is the true amount that the injury will cost in terms of money.

Prevention of Injuries

Risk Assessment

• Employer’s responsibility
  • Eliminate or minimize work hazards
  • encourage open discussion among employees regarding injury and prevention
• To include (but not limited to):
  • Minimal lifting approach
  • Knowledge/training on proper use of equipment
  • Adequate staffing
  • Re-evaluating content and frequency of training courses
    • Especially w/ younger/newly hired PT’s
    • Training programs have little effect without aggressive ergonomic evaluation
  • PT available for staff

Training

• "...bodymechanics and back-care training are valid elements of injury prevention programs, but only when combined with an ergonomic approach..." -Owen and Garg
• "To help prevent shoulder injuries, employers should conduct a worksite evaluation, consider feasible control measures and train employees"
• "Integrating your entire body, using your body's weight, proper joint alignment, and a variety of movements will help develop dynamic body mechanics ensuring the successful use of your hands." - Barbara Frye

Custom Training

• Bio-mechanic and ergonomical training, lifting and manual handling with hand/body as main tool, safe use of equipment, effects sustained postures, caseload variation, work organization, working with other professionals
• Include Cognitive Behavioral Theory
  • Activity Pacing
    • Scheduling activities
  • Attention Diversion
    • Distracting patient
  • Cognitive Restructuring
    • Identify and restructure dysfunctional thoughts and emotions
  • Goal Setting
    • Patient-centered
  • Graded Exposure
    • Gradual systematic progression
  • Maintenance Strategies
    • Plan to manage flare-ups
  • Problem-solving Strategies
    • Define problem and how you are going to solve the problem

• Prompted “micro” breaks
  • Leads to increased work productivity
• However … risk reducing behaviors without immediate benefit are often NOT perceived as beneficial

Body Mechanics

Spinal Compression is a result of trunk extensor activation along with ligaments and discs trying to support the force from Lumbar spine up. According to NIOSH (National Institute for Occupational Safety and Health) spinal compression >3400N puts a person at risk of low back injury; with a maximum permissible limit of 6400N. When comparing 3 different (unspecified) lifting techniques, Gagnon et al. estimated compressive forces to be 5744-7951N at the L5/S1 disc space. This estimate exceeds the limit of risk but also exceeds the permissible limit defined by NIOSH.

Lifting Techniques

See Lifting

Prevention/Intervention Strategies

• Reporting Injuries
  • Makes the problem less invisible --> increase workplace safety
• Implementing mandatory “micro” rest breaks throughout the day
• Managing/Coping with stress
• Footwear
• Use your entire body when possible, especially large muscles that are meant to take the load
• Exercise
  • Increase core/trunk strength
  • Flexibility
  • Endurance
  • Mid and Lower Trap, Rotator Cuff
• Warming up prior
  • Stairs, walking ~5 min
  • Stretching/Going through the motions before a transfer/lift/manual therapy
• Maintain Healthy Weight/Lifestyle
• Posture Checks throughout day
  • Sitting, standing, patient care
• Ask for help
  • Work as a team (Co-treats)
• Use your whole body when performing manual therapy instead of just your upper extremities
• Use of Assistive Devices (including but not limited to):
• Battery operated lifts (hoyer lifts)
• Gait belts
• Draw sheets and friction reducing sheet