Trigger Finger (Stenosing Flexor Tenosynovitis)
The diagnosis is trigger finger (stenosing flexor tenosynovitis), characterized by a palpable nodule on the palmar aspect of the MCP joint combined with a clicking sensation during finger flexion and extension. 1, 2
Clinical Presentation
The combination of a clicking sensation with a palpable palmar nodule at the MCP joint is pathognomonic for trigger finger 2, 3:
- The nodule represents thickening of the flexor tendon that catches on the A1 pulley during finger motion 3
- Clicking, catching, or locking occurs as the thickened tendon passes through the narrowed A1 pulley during flexion and extension 1, 2
- Pain is typically present at the palmar MCP joint, especially with gripping activities 3
- Morning stiffness and difficulty extending the finger are common associated symptoms 2
Key Diagnostic Features
The diagnosis is primarily clinical and straightforward 3:
- Palpable nodule or thickening along the flexor tendon at the level of the A1 pulley (palmar MCP joint) 2
- Triggering or catching sensation that patients can often demonstrate during active finger flexion/extension 1, 2
- Tenderness to palpation over the A1 pulley region 3
- Possible locked position in severe cases, requiring passive manipulation to extend 2
Important Differential Considerations
While trigger finger is the clear diagnosis here, be aware of rare mimics 4:
- Intrinsic MCP joint pathology (osteophytes, loose bodies) can rarely cause similar clicking, but these lack the characteristic palmar nodule and occur within the joint itself rather than along the tendon sheath 4
- The presence of a palpable palmar nodule essentially confirms trigger finger over other causes of clicking 2, 4
Risk Factors to Consider
Certain populations have higher prevalence 1, 2, 3:
- Middle-aged women are most commonly affected 2
- Diabetes mellitus increases risk substantially (up to 20% of diabetic adults) 1, 2
- Rheumatoid arthritis, gout, and other connective tissue disorders are associated with secondary stenosing tenosynovitis 2
Treatment Approach
First-line treatment consists of corticosteroid injection into the tendon sheath at the A1 pulley level 1, 5:
- Single injection resolves symptoms in 61% of patients, with nearly 90% success rate when including re-treatment of recurrences 5
- Splinting can be used adjunctively or for patients who decline injection 1
- Surgical A1 pulley release is indicated for patients who fail conservative treatment or have recurrent symptoms despite injection 1, 2
- Diabetic patients, particularly those on insulin, have lower injection success rates and may benefit from earlier surgical referral 1
Clinical Pitfall
Do not confuse the palmar nodule with a ganglion cyst or other mass - the nodule in trigger finger moves with tendon excursion during finger flexion/extension, whereas other masses are typically fixed 2, 3