Work-Related Musculoskeletal Disorders

Work-Related Musculoskeletal Disorders (WMSDs)

• WMSDs are a group of painful disorders of muscles, tendons, and nerves resulting from injury sustained while completing work duties.
• They are the result of regular exposure to work activities that contribute significantly to the development or exacerbation of painful symptoms.
• Conditions that are worsened or that persist due to work conditions, such as repetitive and frequent work activities.

International Classification of Diseases for WMSDs

• Nerve root and plexus disorder:
  • Brachial plexus lesions
  • Unspecified nerve root and plexus disorder
• Mononeuritis of the upper limb and mononeuritis multiplex:
  • Carpal tunnel syndrome (median nerve entrapment)
  • Lesions of the ulnar nerve (cubital tunnel syndrome)
  • Lesions of the radial nerve
  • Mononeuritis of the upper limbs (unspecified)
• Other peripheral vascular disease:
  • Raynaud’s syndrome
  • Raynaud’s phenomenon (hand–arm vibration syndrome)
• Arterial embolism and thrombosis:
  • Arteries of the upper extremities (ulnar artery thrombosis)
• Other disorders of the cervical region:
  • Cervicobrachial syndrome (diffuse)
  • Unspecified musculoskeletal disorders and symptoms referable to the neck
• Peripheral enthesopathies and allied syndromes:
  • Disorders of the bursae and tendons in the shoulder region (rotator cuff syndrome, supraspinatus syndrome, bicipital tenosynovitis)
  • Enthesopathy of the elbow region (medial and lateral epicondylitis)
• Disorders of muscle, ligament, and fascia:
  • Unspecified disorder of muscle, ligament, and fascia
• Other disorders of the synovium, tendon, and bursae:
  • Synovitis and tenosynovitis
  • Trigger finger (acquired)
  • Radial styloid tenosynovitis (de-Quervain’s)
  • Other tenosynovitis of the hand and wrist
  • Specific bursitis
  • Unspecified disorder of the synovium, tendon, and bursa
• Other disorders of soft tissues:
  • Myalgia and myositis (fibromyositis)
  • Other musculoskeletal symptoms referable to the limbs (cramping, swelling)
  • Other, unspecified, disorders of soft tissue

Factors Associated with Adverse Outcomes

• Tasks that require horizontal work, such as fastening a screw into a horizontal desktop with a powered screwdriver, can be improved with in-line tools.

Ergonomic Interventions

• Handle design:
  • Redesign tools with longer handles or handle extensions to increase vertical reach and avoid raising hands above shoulder height.
  • Use high-friction materials for handles to reduce grip force.
  • Maintain neutral wrist posture and avoid excessive use of ‘pinch grip’.
  • Damp vibration from powered tools and encourage use of large muscle groups.
  • Upper arm posture should be elevated to avoid awkward postures.
• Tool design and posture:
  • Bend the handle (5–10 degrees) to avoid bending the wrist.
  • Avoid excessive use of ‘pinch grip’ and maintain neutral wrist posture.
  • Reduce required grip force and use high-friction materials for handles.
  • Add handles for carrying tools and resisting reaction torque.

Preventing WMSDs of Upper Limbs

• Tool design and posture:
  • Avoid excessive use of ‘pinch grip’ and maintain neutral wrist posture.
  • Reduce required grip force and use high-friction materials for handles.
  • Add handles for carrying tools and resisting reaction torque.
• Nerve injury:
  • Repeated or prolonged exertion causes injury to nerves supplying a muscle or passing through it.
  • Avoid awkward postures that ‘pre-load’ tendons and ligaments and stretch muscles and nerves.
• Tendon injury:
  • De Quervain’s tenosynovitis is characterized by pain on the thumb side of the wrist and impaired thumb function.
  • Avoidance of ulnar-deviated wrist postures is recommended.
• Bursa injury:
  • A bursa is a sac containing viscous fluid situated at places in tissues where friction would occur.
  • Overexertion and injury can cause inflammation of bursae, or bursitis.
• Peripheral neuropathies and non-localized arm pain:
  • Repetitive Strain Injury (RSI) describes a range of different problems that affect muscles, tendons, joints, and nerves in your upper body.
  • Repeated strain on these tissues can start to damage them, leading to symptoms such as pain and loss of strength.