Tenosynovitis

Basics

Definition:
- Inflammation and pain of the tendon and tendon sheath
- Caused by acute or chronic inflammation, overuse, or infection
- Can lead to pain, decreased ROM, necrosis, and tendon rupture
Anatomy:
- Synovial sheaths cover tendons as they pass through osseofibrous tunnels
- Visceral and parietal layers of the synovium lubricate and nourish the tendons
Pathophysiology:
- Inflammation: Proliferation of fibrous tissue causing painful friction, impingement/constriction of the tendon. High association with DM and RA
- Overuse: Repetitive microtrauma resulting in inflammation and fibrosis
- Infection: Most common in acute setting:
  - Introduced into tendon sheath via:
    - Skin wound/puncture is most common
    - Hematogenous spread
Flexor tenosynovitis (FTS) of hand: Closed space infection of the flexor tendons. An orthopedic emergency
- Most common mechanism is penetrating injury at flexion creases of the finger
- Causes include:
  - Penetrating trauma
  - Bites
  - High-pressure injection (Paint sprayer, grease gun)
  - Air tools
  - Hydraulic equipment: May appear minor on the surface but are associated with high incidence of FTS
  - Hematogenous or direct spread from deep space or joint infection

de Quervain tenosynovitis:
- Caused by overuse
- Inflammatory in nature
- Two thumb tendons: The abductor pollicis longus (APL) and extensor pollicis brevis (EPB)
- Near the thumb base, the APL and EPB traverse together through a thick fibrous sheath forming a tunnel at the radial styloid process
- Overuse causes thickening of extensor retinaculum and subsequent canal narrowing
Nongonococcal infectious tenosynovitis:
- Staphylococcus aureus and Streptococci are most common in penetrating injuries, but often polymicrobial
- Pasteurella multocida associated with cat bites
- Eikenella corrodens associated with human bites
- Pseudomonas is seen in patients with diabetes or marine-associated injuries
- Mycobacterium species may occur in immunocompromised patients. Suspect in chronic, indolent infections
Gonococcal tenosynovitis:
- Disseminated Neisseria gonorrhoeae
Fungal tenosynovitis may occur from puncture wounds due to thorns or woody plants

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