Trigger finger is also known as tenosynovitis which affects the flexor sheaths of 4th finger and thumb. A narrowing of flexor pulley sheaths combined with hypertrophy and inflammation of the tendon/sheath interface causes trigger finger or Stenosing tenosynovitis. It involves the A1 pulley sheath at metacarpophalangeal joint mainly proximal portion of the tendon. Tenosynovitis can also occur at A2 and A3 flexor sheath of proximal interphalangeal joint and distal interphalangeal joint. Sometimes there is swelling or formation of nodule at flexor aspect base of digit where the tendon is locked while extending the finger from bending position.
- Tenderness in nodule area mainly palmar aspect at base of the affected finger.
- Snapping sound at flexor tendon while bending and extending finger.
- Catching or locking of finger in flexor position.
- Carpal tunnel syndrome
- Thyroid disease
- Rheumatoid arthritis
- Traumatic forces
In children appears as developmental with mismatch in size of the flexor tendon of the thumb and its tendon sheath; the fibroblast proliferation result in decrease in size of the tendon and A1 pulley e.g., hurler syndrome and juvenile Rheumatoid arthritis
Diagnostic ultra sound helps in demonstrate the thickening of the pulley along with inflammation and irregularity of underlying flexor tendon.
Radiographs help in occult fractures in fingers.
- Medications: Anti-inflammatories help to reduce swelling & inflammation of the tendons.
- Injection: Corticosteroid injection at the base of the affected digit on ventral aspect reduces tendon sheath swelling & alleviates pain.
- Icing: Application of ice for 10mins 3-4 times a day will help reduce swelling of the tendon sheath, thereby reducing strain.
- Physiotherapy: Exercises for increasing the grip strength, stretching the wrist musculature, strengthening the ventral flexor & dorsal extensor compartment using Thera bands, strengthening of wrist and digit muscles using therapeutic ball and isometric resisted exercises. Tendon glides helps prevent locking of digits & increases range of motion.
- Modalities: Application of ultrasound 3MHz pulsed mode for 5-7 min at the ventral flexor aspect of base of affected digit helps reduce the swelling & alleviates pain. IFT modality helps to reduce pain.