DESCRIPTION

Trigger finger, also known as digital stenosing tenosynovitis and flexor tenosynovitis, is a disruption of smooth tendon gliding and inflammatory narrowing of the digital flexor pulley sheaths in the digits leading to a catching and/or locking sensation with flexion and extension of the affected digit.

EPIDEMIOLOGY

ETIOLOGY AND PATHOPHYSIOLOGY

• The result of fibrocartilaginous metaplasia of the flexor digitorum superficialis tendon and/or pulley from prolonged inflammation causing narrowing around the pulley.
• This can occur at any of the five pulleys along the flexor tendon—A1 pulley is the most common.
• If flexor tendon becomes nodular, the triggering phenomenon is worse because the nodule has difficulty passing under the A1 pulley.
• Because intrinsic flexor muscles are stronger than extensors, the finger can get stuck in the flexed position.
• The ring finger and thumb of the dominant hand are most commonly affected.
• No clear association with repetitive movements (1).

RISK FACTORS

• Diabetes mellitus
• Rheumatoid arthritis
• Hypothyroidism
• Mucopolysaccharide disorders
• Amyloidosis

GENERAL PREVENTION

• Most cases are idiopathic.
• No clear association with occupational-related or repetitive activities (1)

COMMONLY ASSOCIATED CONDITIONS

• Orthopedic conditions:
  • Rheumatoid arthritis
  • Calcific tendinitis
  • Septic tenosynovitis
  • Carpal tunnel syndrome
  • Congenital trigger thumb
• Medical conditions:
  • Diabetes
  • Amyloidosis
  • Hypothyroidism
  • Sarcoidosis
  • Gout
  • Pseudogout