Trigger Finger (Digital Stenosing Tenosynovitis)
BASICS
- Definition: Condition causing painful locking, catching, or snapping of the affected digit due to stenosis and inflammation at the A1 pulley of the flexor tendon sheath.
- Etiology: Not primarily caused by repetitive use. Due to fibrocartilaginous metaplasia and thickening of the tendon sheath or pulley.
- Common Digit: Thumb is most often involved.
EPIDEMIOLOGY
| Parameter | Value |
|---|---|
| General adult prevalence | 2.6% |
| Peak age | 5th to 6th decade |
| Sex ratio | Female:Male = 6:1 |
| Diabetics affected | ~10% |
| Pediatric cases | Rare, but can occur (esp. congenital trigger thumb) |
RISK FACTORS
- Diabetes mellitus (esp. insulin-dependent)
- Rheumatoid arthritis
- Hypothyroidism
- Mucopolysaccharidosis
- Amyloidosis
- Sarcoidosis
- Gout / Pseudogout
ASSOCIATED CONDITIONS
| Orthopedic | Systemic |
|---|---|
| Carpal tunnel syndrome | Diabetes |
| Congenital trigger thumb | Amyloidosis |
| Septic tenosynovitis | Hypothyroidism |
| Rheumatoid arthritis | Sarcoidosis |
DIAGNOSIS
HISTORY
- Clicking, catching, or snapping during flexion/extension of finger
- Locking in flexed position (severe cases)
- Morning stiffness or pain at the palmar MCP region
- Functional limitations: difficulty grasping, writing, buttoning
Green’s Classification
| Grade | Description |
|---|---|
| 1 | Palm pain/tenderness at A1 pulley |
| 2 | Catching of digit |
| 3 | Locking, passively correctable |
| 4 | Fixed locking (not passively correctable) |
PHYSICAL EXAM
- Tenderness/nodule over A1 pulley
- Visible or palpable snapping/catching
- Loss of active/passive extension in severe cases
- No neurological deficits
DIAGNOSTIC TESTS
- Not required for diagnosis
- Ultrasound/MRI: only for atypical cases
- May show thickened pulley, synovial sheath effusion, or tendon nodules
DIFFERENTIAL DIAGNOSIS
- Dupuytren contracture
- Flexor tendon ganglion
- MCP joint sprain
- Diabetic cheiroarthropathy
- Osteoarthritis
TREATMENT
GOALS
- Relieve pain
- Restore smooth, unrestricted digit movement
- Prevent recurrence
CONSERVATIVE THERAPY
| Modality | Notes |
|---|---|
| NSAIDs | Reduce pain; do not reduce mechanical triggering |
| Splinting | MCP joint in slight flexion (10–15°); up to 6–10 weeks |
| Steroid Injection | 57–90% effective; preferred first-line for most |
| Activity modification | Decrease triggering/aggravating activities |
Note: Triamcinolone preferred; palmar injection at proximal phalanx may reduce pain during injection.
MEDICAL THERAPY
| Drug | Role |
|---|---|
| NSAIDs | Symptomatic only |
| Triamcinolone injection | High success (esp. single digit, non-diabetics) |
| Diclofenac injection | Option in diabetics to avoid hyperglycemia |
| Repeat steroids | Less effective than first injection |
INDICATIONS FOR REFERRAL
- Failure of conservative therapy (after ≥2 injections or 6–10 weeks splinting)
- Severe contracture or locked digit (Grade 4)
- Pediatric cases needing surgical correction
SURGICAL OPTIONS
| Procedure | Notes |
|---|---|
| Open A1 pulley release | Gold standard; >90% success; more invasive |
| Percutaneous release | >90% success; less invasive; may use ultrasound guidance |
ADDITIONAL THERAPIES
- Physical therapy: tendon gliding, ROM exercises
- Splint types:
- MCP splinting (preferred)
- DIP splinting (50% effective in one study)
- Post-release exercises:
- Digit blocking (MCP blocked, PIP flexed)
- Heat, ultrasound, massage
COMPLEMENTARY THERAPIES
- Extracorporeal shock wave therapy (ESWT)
- Under investigation for inflammatory suppression
FOLLOW-UP AND ONGOING CARE
| Component | Notes |
|---|---|
| Follow-up | Only if symptoms persist or after surgery |
| Monitor | Pain, ROM, glucose if diabetic post-injection |
| Post-op care | Early mobilization after release to prevent adhesions |
PROGNOSIS
| Therapy | Outcome |
|---|---|
| Steroid injection | Effective in most; recurrence more likely in diabetics or multiple digit involvement |
| Surgery | High success (>90%), low recurrence, better for refractory or severe cases |
Diabetic patients may have recurrence or temporary hyperglycemia post-injection (up to 5 days).
COMPLICATIONS
| Conservative | Surgical |
|---|---|
| Steroid injection: | Skin depigmentation, fat necrosis, transient hyperglycemia |
| Surgery: | Digital nerve injury, infection, bleeding, ROM loss (up to 28%), rare: A2 pulley injury → bowstringing |
CODES
| ICD-10 | Description |
|---|---|
| M65.30 | Trigger finger, unspecified |
| M65.319 | Trigger thumb, unspecified |
| M65.329 | Other trigger digit, unspecified |
CLINICAL PEARLS
- Trigger finger causes pain + mechanical catching of the digit.
- Initial treatment: NSAIDs, splinting, steroid injection
- Steroid injections work best if early and single digit involved
- Surgery (open or percutaneous) = definitive for refractory cases
- Always assess for diabetes and RA in patients with multiple digit involvement