Flexor tendon entrapment of the digits is a common condition encountered in primary care practice. This painful condition is known as a trigger finger, and it can produce locking of the finger in the position of flexion. Locking is released by forced extension of the digit, which may produce a click that can be felt and occasionally heard. Although the fourth finger is most commonly involved, multiple fingers and the thumb are also commonly reported as trigger fingers. Tenderness is common but not always present. Most diagnoses are made from the classic physical findings.
The problem with a trigger digit is mechanical. A nodular expansion of the tendon can develop, moving with finger motion and catching within the annular A1 pulley over the metacarpophalangeal joint. Alternately, the pulley can become too tight, constricting a normal-sized tendon. Trigger fingers occur in children, usually on the thumb, and probably represent a congenital discrepancy between the size of the tendon and that of the tendon sheath.
Trigger fingers were historically referred to as stenosing tenosynovitis, but histologic studies fail to document inflammation. Primary disease occurs more often in middle-aged women and is believed to develop from degenerative changes in the flexor tendons and A1 pulleys. Secondary trigger fingers develop from conditions that affect the connective tissues, such as rheumatoid arthritis, diabetes mellitus, and gout.
In-office surgical release of the pulley is highly effective but may be beyond the purview of primary care physicians. Corticosteroid injection (0.5 mL of triamcinolone [10 mg/mL] mixed with 0.5 to 1.5 mL of 1% lidocaine) can be highly successful, especially early in the course of the disorder. Injection is performed into the tendon sheath, not into the tendon. Steroid therapy may relieve discomfort and produces a cure in up to 85% of individuals with the disorder. If two or three injections fail to result in complete resolution, consultation with a hand surgeon should be sought.
INDICATIONS
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RELATIVE CONTRAINDICATIONS
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PROCEDURE
The fourth finger is commonly involved. The condition causes locking of the flexor tendon in a position of flexion.
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(1) Trigger finger most commonly involves the fourth finger. |
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Place the supine hand flat on a firm surface. After sterile preparation of the skin, the needle is inserted vertically into the skin (Figure 2A). The correct insertion site generally is in the palm, where the tendon crosses the distal palmar crease (Figure 2B).
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(2) The needle is inserted vertically into the palm where the tendon crosses the distal palmar crease. |
PITFALL: Novice physicians frequently inject at the base of the digit (i.e., crease where the digit meets the palm). This is well above the metacarpophalangeal joint and above the A1 pulley. The joint can be palpated through the palm; it is at least 1 cm proximal to the crease at the base of the finger.
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Insert the needle until the tip reaches the tendon. Back out the needle 1 to 2 mm to facilitate injection into the sheath (Figure 3A). Some experts advocate insertion of the needle tip at a 45-degree angle (rather than vertical or 90 degrees) with the bevel downward to facilitate injection into the sheath (Figure 3B). Palpate the site with the nondominant (noninjecting) hand to confirm injection into the sheath.
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(3) Insert the needle until the tip reaches the tendon, and then back out the needle 1 to 2 mm to facilitate injection into the sheath. |
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Move the finger immediately after injection to distribute the steroid. A bandage can be applied over the injection site. Nonsteroidal antiinflammatory medication is prescribed for at least 72 hours to reduce the chance of postinjection flare (i.e., increased pain induced by the steroid crystals).
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(4) Move the finger immediately after injection to distribute the steroid. |
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CODING INFORMATION
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INSTRUMENT AND MATERIALS ORDERING
Syringes (1 or 3 mL), needles (25 or 27 gauge, 5/8 inch), and alcohol swabs are available from local surgical supply houses or pharmacies. Steroid solutions are available from manufacturers or local pharmacies. Celestone Soluspan (betamethasone sodium) is produced by Schering-Plough, Kenilworth, NJ (http://www.schering-plough.com), Aristocort (triamcinolone diacetate) and Aristospan (triamcinolone hexacetonide) can be obtained from Baxter-Lederle, Deerfield, IL (http://www.baxter.com); and Depo-Medrol (methylprednisolone acetate) is available from Pharmacia Upjohn, Basking Ridge, NJ (http://www.pharmacia.com). A suggested tray for performing soft tissue aspirations and injections is listed in Appendix D Skin preparation recommendations appear in Appendix H.
BIBLIOGRAPHY
Anderson B, Kaye S. Treatment of flexor tenosynovitis of the hand (“trigger finger”) with corticosteroids. Arch Intern Med 1991;151:153–156.
Brown JS. Minor surgery: a text and atlas, 3rd ed. London: Chapman & Hall Medical, 1997:164–165.
Hollander JL. Arthrocentesis and intrasynovial therapy. In: McCarthy DJ, ed. Arthritis, 9th ed. London: Henry Kimptom Publishers, 1979:402–414.
Leversee JH. Aspiration of joints and soft tissue injections. Prim Care 1986;13:579–599.
Moore JS. Flexor tendon entrapment of the digits (trigger finger and trigger thumb). J Occup Environ Med 2000;42:526–545.
Owen DS, Irby R. Intra-articular and soft-tissue aspiration and injection. Clin Rheumatol Pract 1986;Mar-May:52–63.
Reisdorf GE, Hadley RN. Treatment of trigger fingers and thumbs. In: Benjamin RB, ed. Atlas of outpatient and office surgery, 2nd ed. Philadelphia: Lea & Febiger, 1994:92–96.
Rettig AC. Wrist and hand overuse syndromes. Clin Sports Med 2001;20:591–611.
Saldana MJ. Trigger digits: diagnosis and treatment. J Am Acad Orthop Surg 2001;9:246–252.