Trigger finger / Thumb
Trigger finger presents with discomfort in the palm during movement of the involved digits. Gradually, or in some cases acutely, the flexor tendon causes a painful click as the patient flexes and extends the digit. The patient may present with a digit locked in a particular position, usually in flexion, which may need gentle passive manipulation into full extension. Spontaneous resolution of symptoms can occur in patients with trigger thumb.
Epidemiology
- 28 cases per 100 000 population per year = lifetime risk of 2.6%
- This rises to 10% in patients with diabetes
- Diabetic patients are less likely to respond to conservative treatment.
- Two peaks in incidence occur
- under the age of eight (F:M = 1:1). Thumb effected in 90%
- fifth and sixth decades (F:M = 6:1). Finger or thumb effected
Pathophysiology
- Discrepancy in the diameter of the flexor tendon and its sheath at the level of the metacarpal head.
- High pressures occur on maximal flexion and during tight grip.
- Recurrent microtrauma causes tendon and sheath hypertrophy
- The narrowed tunnel obstruction usually overcome by powerful flexors
- Weaker extensors unable to counteract
Treatment
- Steroid injection is successful in >90% of patients with a palpable nodule or with symptoms present <6/12.
- With a suitable knowledge of the anatomy, giving a single steroid injection is safe
- The steroid should be injected around the A1 pulley, not into the tendon sheath
- Percutaneous trigger release is safe and effective and "can be done in the outpatient clinic".
- NSAIDs alone do not have any benefit other than temporary relief of pain in the palm
- Splintage is used to reduce tendon movement to allow the
synovitis around the pulley to resolve
- Success rates for splintage range from 50% to 70%
- Patients with longer duration of symptoms were less likely to benefit from splintage.
- Please discuss with the ED duty consultant before referral to orthopaedics
Treatment in children
- Children represent a distinct group of patients
- The thumb is involved in 90% of cases.
- Good results (50%-80% success) can be obtained with physiotherapy with or without splintage.
- Success rates seem to be higher in younger children.
