Module 5: Work-Related Musculo-Skeletal Disorders - Clinical and Compensation Aspects

CLASSIFICATION:

Types of WRULDs:

Type 1:

• Well-defined musculo-skeletal conditions and nerve entrapment syndromes affecting the upper limbs.
• Carpal Tunnel Syndrome, De Quervain’s.
• Relatively clear cut characteristics and established treatment methods.

Type 2:

• Regional Pain Syndrome.
• Widespread dissemination of symptoms between neck and hand.
• Regional allodynia and hyperalgesia ® neural sensitisation and pain.

Classification according to affect on specific tissue:

• Tendon-related disorders.
• Nerve-related disorders.
• Bursa-related disorders.
• Blood vessel disorders.
• Other.

Tendon-related disorders:

Tendonitis.

• Confusion with terminology.
• Rare condition.
• Inflammation of tendon and tendon muscle (for example, Achilles tendon in conjunction with tendinosis).
• Promote collagen production & reduce paratendon inflammation.

Tendinosis - common:

• Sports Medicine.
• Intratendinous collagen degeneration due to:
  • Aging.
  • Microtrauma (chronic overuse repetitive movements).
  • Vascular compromise.
• Examples: epicondylitis, rotator cuff syndrome.

Treatment of tendinosis:

• Combat collagen breakdown.
• Relative rest for reasonable period.
• Strengthening and graduated loading of tendon (eccentric).
• Facilitate collagen production and maturation ® normal strength.

Tenosynovitis:

• Rapid repetitive movements especially of hands and fingers leading to
  • inflammation of synovial lining of the tendon sheath, leading to
  • inflammation of synovial lining of the tendon sheath, causing
  • swelling, causeing pain and resulting in
  • restricted movement of tendon in sheath.
• Repeated exposure leasd to increased scar tissue, causing increased pain and decreased mobility and hence decreased strength.
• Examples: Trigger Finger, De Quervain’s.

Nerve-Related Disorders:

• Nerves need to undergo mechanical changes (compression, elongation, cross-sectional changes, etc.) for normal functioning.
• Decreased mechanical changes leading to physiological changes (such as a decreased axoplasmic flow, etc.).
• Dysfunctional nerve, leading to
  • Pain.
  • Paraesthesia.
  • Sensory changes in areas supplied by nerve.
• Carpal Tunnel Syndrome.
• Pronator Teres Syndrome .
• Cubital Tunnel Syndrome.
• Guyon tunnel Syndrome.
• Radial Tunnel Syndrome.
• Anterior Interosseous Nerve Syndrome.
• Posterior Interosseous Nerve Entrapment, etc.

Bursa-related disorders:

Bursa are fluid-filled sacks that protect muscles, tendons and skin from friction against bones during joint movement.

• Overexertion leading to inflammation (bursitis), resulting in swelling & dull, aching pain.
• Examples:
  • Olecranon bursitis (beat elbow).
  • Subacromial bursitis.
  • Subdeltoid bursitis.

Blood-vessel disorders:

• Usually due to vibration or hammering leading to vasospasm and decreased circulation.
• Excessive exposure leadint to decreased circulation + neurological findings (decreased motor function of hand and arm).
• Examples:
  • Raynaud’s Phenomenon.
  • Hand Arm Vibration Syndrome.
  • Hypothenar Hammer Syndrome

Other Disorders:

• Static loading:
  • Occurs proximally when repetitive movement occurs distally
  • Static loading leading to muscle imbalances and trigger points resulting in pain
  • Examples: Tension neck syndrome, myalgia, strains, etc.
• Effect on muscles and joints:
  • Problematic to prove objectively.
  • Controversial.