| Patient Education |
|
Click here for patient education.
|
|
You are in: eMedicine Specialties >
Orthopedic Surgery > HAND AND UPPER EXTREMITY
Trigger Finger
Article Last Updated: May 8, 2008
AUTHOR AND EDITOR INFORMATION
Section 1 of 12  
Author: Satishchandra Kale, MD, FRCS(Edin), FRCS Ed(UK), Dip Sports Med, Honorary Assistant Professor of Trauma and Orthopedics, University of Bombay, India; Consultant, Department of Orthopedics, Dr R N Cooper Hospital, Brahmakumaris Global Hospital, India
Satishchandra Kale is a member of the following medical societies: British Orthopaedic Association
Editors: Joseph E Sheppard, MD, Associate Professor of Clinical Orthopedic Surgery, Chief of Hand and Upper Extremity Service, Department of Orthopedic Surgery, University of Arizona Health Sciences Center, University Physicians Healthcare; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Harris Gellman, MD, Consulting Surgeon, Broward Hand Center, Voluntary Clinical Professor of Orthopedic Surgery and Plastic Surgery, Departments of Orthopedic Surgery and Surgery, University of Miami School of Medicine
Author and Editor Disclosure
Synonyms and related keywords:
TF, trigger digit, trigger thumb, snapping digit, locking digit, stenosing tendovaginitis, peritendinitis stenosans, digitus saltans
One of the most common upper limb problems to be encountered in orthopedic practice, trigger finger (TF), also known as trigger digit or stenosing tendovaginitis, has remained a mystery with regard to its formation.
Related eMedicine topic:
Trigger Finger [Physical Medicine and Rehabilitation]
Related Medscape topics:
Specialty Site Orthopaedics
Orthopaedics News
History of the Procedure
In the past, triggering of the digits was treated by splinting in extension, which caused stiffness and consequently loss of metacarpophalangeal and interphalangeal flexion. Due to dissatisfaction with this form of treatment, researchers used intrasheath steroid injections, which resulted in a high proportion of good results.1 Surgery, in the form of release of the A1 pulley, became popular when splinting and/or injection therapy failed or in the presence of other pathology, such as rheumatoid arthritis, in which injection treatment proved futile or there was a risk of tendon rupture or infection. In an uncomplicated case of trigger digit, the first-line therapy is still generally agreed to be injection into the tendon sheath, with surgical release of the A1 pulley as second-line treatment.
Related Medscape topic:
Resource Center Joint Disorders
Problem
TF is one of the most common causes of hand pain and disability. The condition begins as discomfort in the palm during movements of the involved digit(s). Gradually or, in some cases, acutely, the flexor tendon causes painful popping or snapping as the patient flexes and extends the digit. The patient may present with a digit locked in a particular position, more often flexion, which may require gentle, passive manipulation into full extension.2 The phenomenon is due to a mismatch between the size of the flexor tendon and the retinacular pulley. This is usually caused by the formation of a nodule in the flexor digitorum superficialis (FDS) tendon, in the region of the metacarpal head where the tendon glides under the A1 pulley; in rare instances, a nodule distal to it in the tendon of the flexor digitorum profundus could be the culprit.
A few case reports have documented rare causes of TF, including tenosynovitis that itself resulted from a Mycobacterium kansasii infection in an immunocompetent patient; triggering following the development of calcific tendonitis has been reported in a child. Such cases should invoke a high degree of suspicion.
Related eMedicine topic:
Flexor Tendon Anatomy
Frequency
Stenosing tendovaginitis is much more common in women, with a frequency 2-6 times than that observed in men. Several series found the peak incidence of trigger digit to be in individuals aged 55-60 years. Age distribution has not changed significantly despite an increase in computing activities and repetitive tasks. Increased incidence in the dominant hand is observed. The involvement of several fingers is not unusual. The most commonly affected digit is the thumb, followed by the ring, long, little, and index fingers. Triggering seems to occur more frequently in patients with rheumatoid arthritis (RA) or diabetes mellitus (DM). These patients also seem to be more resistant to injection treatment.3, 4
Etiology
Trauma/local Systemic causes of TF are collagen-vascular diseases, including RA, DM, psoriatic arthritis, amyloidosis, hypothyroidism, sarcoidosis, and pigmented villonodular synovitis. Septic causes of TF are secondary infections (eg, tuberculosis). Idiopathic The etiology of TF is unknown or uncertain; suspect nodule or pulley morphology change. Other causes that can simulate locking include the following:
- Collateral ligaments of the metacarpophalangeal (MCP) joint catch on a bony prominence on the side of the metatarsal head (osteophyte).
- Localized swelling in the flexor digitorum profundus (FDP) gets entrapped at the decussation of the FDS.
- A partially lacerated flexor tendon catches against the A1 pulley or the FDS decussation.
- A nodule in the FDS catches against the A3 pulley.
- Locking is simulated by abnormal sesamoids.
- A loose body is present in the MCP joint.
- Snapping or subluxation of the extensor digitorum communis (EPC) occurs.
Pathophysiology
A mismatch between the flexor tendon and the proximal pulley mechanism occurs in most cases. Several studies have demonstrated a correlation between this condition and activities that require exertion of pressure in the palm while a powerful grip is employed or that involve repetitive, forceful digital flexion (eg, arc welding, use of heavy shears). Proximal phalangeal flexion in power-grip activities causes high annular loads at the distal edge of the A1 pulley. Hueston and Wilson have suggested that bunching of the interwoven tendon fibers causes the reactive intratendinous nodule observed at surgery.5
Clinical
Symptoms of TF are as follows:
- Locking or catching during active flexion-extension activity (Passive manipulation may be needed to extend the digit in the later stages.)
- Stiff digit, especially in long-standing or neglected cases
- Pain over the distal palm
- Pain radiating along the digit
Signs of TF are as follows:
- Triggering on active or passive extension by the patient
- Palpable snapping sensation or crepitus over the A1 pulley
- Tenderness over the A1 pulley
- Palpable nodule in the line of the FDS, just distal to the MCP joint in the palm
- Fixed-flexion deformity in late presentations, especially in the proximal interphalangeal (PIP) joint
- Evidence of associated conditions (eg, RA, gout)
- Early signs of triggering in other digits (may be bilateral)
The chief indications for surgical management of this condition are as follows:
- Failure of splinting and/or injection treatment
- Irreducibly locked TF
- Trigger thumb in infants (Without surgical release, these infants are likely to develop a fixed flexion deformity of the interphalangeal joint.)
Related eMedicine topic:
Trigger Thumb
Tendon sheaths of the long flexors run from the level of the metacarpal heads (distal palmar crease, superficial; volar plate, deep) to the distal phalanges. They are attached to the underlying bones and volar plates, which prevent the tendons from bowstringing. Predictable and efficient thickenings in the fibrous flexor sheath act as pulleys, directing the sliding movements of the fingers. The 2 types of pulleys are annular (A) and cruciate (C). Annular pulleys are composed of single fibrous bands (ie, rings), while cruciate pulleys have 2 crossing fibrous bands. The order of the pulleys from proximal to distal is as follows:
- The A1 pulley overlies the MCP joints. It is released during surgery for TF.
- The A2 pulley overlies the proximal end of the proximal phalanx.
- The C1 pulley overlies the middle of the proximal phalanx.
- The A3 pulley lies over the PIP joint.
- The C2 pulley lies over the proximal end of the middle phalanx.
- The A4 pulley lies over the middle of the middle phalanx.
- The C3 pulley lies over the distal end of the middle phalanx.
- The A5 pulley lies over the proximal end of the distal phalanx.
The A2 and A4 pulleys are vital in preventing bowstringing of the flexor tendons and have to be preserved or reconstructed following any damage to them.
No absolute contraindications exist for surgical management.
Lab Studies
- TF is a clinical diagnosis. Occasionally, the nodule in the tendon is easily felt, and a palpable and audible click can be appreciated when the triggering is relieved with forced extension of the digit.
- Perform relevant diagnostic tests for DM, RA, hypothyroidism, or gout, as suspected.
Imaging Studies
- Radiology rarely is indicated.
- Hand radiographs are performed only if abnormal pathology (eg, abnormal sesamoids, loose bodies in the MCP joint, osteoarthritic spurs on the metacarpal head, avulsion injuries of collateral ligaments) is suspected.
Histologic Findings
The A1 pulley exhibits a marked degree of hypertrophy, described as a white, cicatricial, collarlike thickening. Microscopy demonstrates degeneration, cyst formation, and plasma-cell infiltration. Microscopic studies have demonstrated chondrocytic proliferation of type III collagen, instead of chondrocyte presence in the normal innermost or friction layer of the A1 pulley. The amount of extracellular matrix is increased significantly when compared with controls.
Sampson and colleagues concluded that the underlying pathobiologic mechanism for triggering is fibrocartilaginous metaplasia of the pulleys due to trauma or disease.6 Several studies have failed to demonstrate the presence of acute or chronic inflammatory cells within the tenosynovium. The suffix "itis" in the term stenosing tendovaginitis actually is a misnomer unless the condition is associated with RA or inflammatory arthritis.
Staging
Green's classification of triggering is used only for clinical grading and documentation. No correlation is established between the grading scheme and the outcome following injection therapy.
- Grade I (pretriggering) - Pain; history of catching that is not demonstrable on clinical examination; tenderness over the A1 pulley
- Grade II (active) - Demonstrable catching, but with the ability to actively extend the digit maintained
- Grade III (passive) - Demonstrable locking in which passive extension is required (grade III A) or in which the patient is unable to actively flex (grade III B)
- Grade IV (contracture) - Demonstrable catching, with a fixed flexion contracture of the PIP joint
Medical Therapy
Most trigger digits in adults can be managed successfully with local steroid injections and splinting.7 Oral or topical pharmacologic measures have not been demonstrated to be effective. Steroid injection into the tendon sheath A variety of preparations have been used, and most are uniformly successful in relieving symptoms. Most commonly, cortisone, prednisolone, dexamethasone, and triamcinolone are employed.8, 9 A highly satisfactory rate of success can be predicted in female patients and in patients with single digit involvement, short duration of symptoms (ie, <4 mo), no associated conditions (eg, RA, DM), or a discrete, palpable nodule The author's technique for steroid injection is as follows:
- A mixture of triamcinolone, 1% lidocaine, and 0.5% bupivacaine is used, in a ratio of 2:1:1, respectively. Adrenaline is not used.
- The nodule in the palm is well localized and circled out using an indelible skin marker.
- The procedure is performed in an office setting, using strict aseptic precautions, with alcoholic Betadine used for injection-site preparation.
- Ethyl chloride is used only if requested; frequently, it is unnecessary, and most patients tolerate this procedure quite well.
- A 26-gauge needle is introduced in a proximal-to-distal direction in the nodule, making an angle of 45° with the palm (see Image 1).
- The needle enters the nodule with a distinct grating sensation and is verified by asking the patient to move the digit when it is possible to clearly observe the needle moving with the digit (see Image 2).
- The syringe with the steroid preparation then is attached to the needle. Attempting to inject the drug with light pressure confirms the intratendinous location of the needle.
- The needle is withdrawn very carefully until a give-way sensation is felt, indicating that the tip of the needle is out of the tendon and in the sheath. The preparation is injected. A small water-impermeable dressing is applied.
- The patient is actively encouraged to move the digit; in most cases, the triggering is relieved.
- A follow-up appointment is made for 3-4 weeks after the treatment. Splinting is not used routinely for these cases, although a hand-based MP-block Orthoplast splint has been described as useful.
Although injection treatment has long been administered by "feel" and experience, a study suggests that a technique using ultrasound for steroid injection may maximize the injection's accuracy and, consequently, its beneficial effects in the treatment of trigger digits.10 Complications No major complications are noted. A transient rise in blood and urine sugar levels is common in patients with diabetes. Advise these patients that this is likely to occur. Theoretically, repeated steroid injections could cause attrition and/or rupture of tendons, but only 1 case has been reported to date.11 Results following injection treatment In an attempt to determine factors involved in the successful use of this technique, Freiberg and colleagues divided patients into groups based on the ability of the examiner to palpate a discrete, versus a diffuse, nodular consistency of the flexor sheath.12 Digits with a discrete palpable nodule had a 93% success rate with a single injection of triamcinolone at 3 months' follow-up, whereas digits with a diffuse pattern had a 52% failure rate. Marks and Gunther reported an 84% success rate in trigger digits and a 92% success rate in trigger thumbs following a single injection of triamcinolone.1 Griggs and co-investigators reported an overall success rate of 50% in patients with DM.13 Patients with insulin-dependent diabetes had a higher incidence of multiple digit involvement and required surgical release more frequently than did patients who were not insulin dependent.3, 4 Splinting For those patients who decline injection, consider splinting the involved digit. The MCP joint is splinted in approximately 15° of flexion. Very few series use splinting in isolation. Although the results are claimed to be efficacious, splinting clearly is inferior to injection treatment or surgery.
Surgical Therapy
Early series recommended surgical treatment as straightforward and highly effective, while regarding prolonged conservative treatment as unreliable and expensive. Subsequent series documented poor results from surgical treatment in 7-9% of cases. In 1972, Lapidus reversed his previous recommendation for operative treatment of stenosing tendovaginitis of the digits after he and Guidotti reported uniformly good results following a single injection of prednisolone into the tendon sheath.14 Rhoades and colleagues subsequently reported a 72% success rate in a series of 53 digits following injection and immobilization.15 Injection therapy generally is now agreed to be the first line of management. Surgery is reserved for individuals in whom injection treatment has failed or in whom other pathology, particularly RA, is suspected to be causing triggering that cannot be treated conservatively.16
Preoperative Details
- Only digits that actively trigger must be considered for operative release.
- PIP contractures or thumb triggering are not suitable for percutaneous release, and the A1 pulley always is transected under direct vision. Patients with PIP joint contractures undergo a period of hand therapy and splinting prior to the procedure.
- A tourniquet always is used to obtain a clean operative field.
- Approximately 4-5 mL of 1% lignocaine is used to infiltrate the skin overlying the A1 pulley, with injection performed deeper to the tendon sheath.
- The transverse incision is marked with a skin marker corresponding to the digit to be surgically treated (see Image 3). The proximal edge of the A1 pulley coincides almost exactly with the distal palmar crease in the fourth and fifth rays, with the proximal palmar crease in the index, and with the halfway point between the 2 creases in the middle finger.
Intraoperative Details
- The MP joint is hyperextended to displace the neurovascular structures dorsally, minimizing the risk of injury.
- A transverse incision measuring 1-1.5 cm is made over the involved metacarpal head.
- Blunt dissection is used to spread the subcutaneous fat and expose the tendon sheath.
- The proximal edge of the A1 pulley is identified, and a scalpel blade is used to divide the entire A1 pulley in the midline under vision. Care is taken to avoid incising too distally and risk cutting into the A2 pulley, which can result in bowstringing. A study suggests that the proximal part of the A2 pulley can be safely incised if the release of the A1 pulley in isolation does not result in relief of triggering.17 This is still experimental and is best left to the hand or plastic and reconstructive surgeons.
- The patient is asked to actively move the digit to confirm full release. Meticulous hemostasis is achieved with a bipolar cautery, and the wound is closed with 2-3 skin sutures.
- The hand is left free, and motion is encouraged immediately following the procedure.
- If a percutaneous approach is favored, a pair of blunt-ended, fine scissors is introduced through the incision, and the A1 pulley is transected (see Image 4). Care is taken not to drift too distally. Disappearance of a grating sensation indicates complete section of the pulley through a separate, distal oblique incision.
- On rare occasions, sectioning the A1 pulley does not relieve triggering, indicating that the A3 pulley might be involved. If that is the case, the A3 pulley requires division.
Postoperative Details
- Active motion is encouraged on the day of surgery.
- Anti-inflammatory drugs and elevation are advised for a period of 2-3 days following surgery.
- Sutures are removed on day 10 following the procedure.
Follow-up
Routine follow-up frequently is unnecessary.
Complications of TF surgery are as follows:
- Tenderness over the site of the incision occurs quite frequently but usually settles on its own.
- Digital nerve injury is extremely rare despite the fact that the digital nerves lie within 2-3 mm of the midline. Prompt repair or reconstruction is indicated in the event of this unfortunate complication. Observation for suspected neurapraxia is appropriate.
- Superficial scoring of the FDS tendon has been reported frequently but does not require further treatment.
- Accidental cutting into the A2 pulley can cause bowstringing, with loss of full finger flexion. Pulley exploration and reconstruction may be indicated if bowstringing does not resolve.
- Recurrence has been reported but is extremely rare.
- Infection is a risk in patients who are diabetic or immunosuppressed and may be problematic if septic flexor tenosynovitis results.
- A study suggests that peri-operative characteristics and outcomes differ between trigger finger and thumb and that the surgical outcome for trigger finger is poorer than that for trigger thumb (partly due to flexion contracture of the PIP joint).18
Percutaneous TF release has been reported by several authors to be safe and efficacious. Success rates of 74-94% with no complications have been reported at medium-term follow-up. The procedure is advised for individuals with established primary TF who have symptoms lasting longer than 4 months or for patients in whom injection therapy has failed to relieve symptoms. It is considered a reasonable choice following 1 injection failure and actually may confer cost benefits through permanent relief.
Carlson and Curtis prefer a midaxial injection at the level of the midproximal phalanx as a simple and painless way to access the flexor sheath for the purpose of injection.19 Open versus percutaneous release Although the results of percutaneous release are well established, open technique is absolutely essential for the thumb or little finger, or in the presence of PIP contractures. Percutaneous release should be reserved for the index, middle, and ring fingers. In children, triggering is uncommon and has varying causes.20 Release of the A1 pulley alone does not always correct the problem. Additional treatment (eg, resection of 1 or both limbs of the FDS tendon, A3 pulley release) may be required and is recommended in RA tenosynovitis.21 Kapandji enlargement-plasty of the A1 pulley Future treatment of TF may involve Kapandji enlargement-plasty of the A1 pulley. The Kapandji enlargement-plasty of the A1 pulley involves enlargement of the pulley by making a diagonal incision in it, followed by suture instead of simple longitudinal division, thus increasing the mean diameter of the canal. In a study by Migaud and colleagues, 15 patients who underwent this procedure and who were followed up for a mean period of 5 years had complete symptomatic relief without any recurrences.22 This procedure is complex and technically demanding.
| Media file 1:
Introduction of the needle into the tendon sheath at 45° to the palm for injection treatment. |
 |  View Full Size Image | |
Media type: Photo
|
| Media file 2:
Movement of the needle with flexion of the digit confirms correct positioning of the needle for injection treatment. |
 | View Full Size Image | |
Media type: Photo
|
| Media file 3:
Incision marked out in the distal palmar crease for surgical division of the A1 pulley. |
 | View Full Size Image | |
Media type: Photo
|
| Media file 4:
A1 pulley is sectioned using blunt-tipped, fine scissors, keeping strictly in the midline. Note the digit being held in a hyperextended position by an assistant to displace the neurovascular bundles away from the midline. |
 | View Full Size Image | |
Media type: Photo
|
- Marks MR, Gunther SF. Efficacy of cortisone injection in treatment of trigger fingers and thumbs. J Hand Surg [Am]. Jul 1989;14(4):722-7. [Medline].
- Fam AG. Regional pain problems. In: Klippel JH, Dieppe PA, eds. Practical Rheumatology. London, England: Mosby; 1997.
- Stahl S, Kanter Y, Karnielli E. Outcome of trigger finger treatment in diabetes. J Diabetes Complications. Sep-Oct 1997;11(5):287-90. [Medline].
- Baumgarten KM, Gerlach D, Boyer MI. Corticosteroid injection in diabetic patients with trigger finger. A prospective, randomized, controlled double-blinded study. J Bone Joint Surg Am. Dec 2007;89(12):2604-11. [Medline].
- Hueston JT, Wilson WF. The aetiology of trigger finger explained on the basis of intratendinous architecture. Hand. Oct 1972;4(3):257-60. [Medline].
- Sampson SP, Badalamente MA, Hurst LC, et al. Pathobiology of the human A1 pulley in trigger finger. J Hand Surg [Am]. Jul 1991;16(4):714-21. [Medline].
- Murphy D, Failla JM, Koniuch MP, et al. Steroid versus placebo injection for trigger finger. J Hand Surg [Am]. Jul 1995;20(4):628-31. [Medline].
- Ring D, Lozano-Calderón S, Shin R, et al. A prospective randomized controlled trial of injection of dexamethasone versus triamcinolone for idiopathic trigger finger. J Hand Surg [Am]. Apr 2008;33(4):516-22. [Medline].
- Peters-Veluthamaningal C, Winters JC, Groenier KH, et al. Corticosteroid injections effective for trigger finger in adults in general practice: a double-blinded randomized placebo controlled trial. Ann Rheum Dis. Jan 7 2008;[Medline].
- Godey SK, Bhatti WA, Watson JS, et al. A technique for accurate and safe injection of steroid in trigger digits using ultrasound guidance. Acta Orthop Belg. Oct 2006;72(5):633-4. [Medline].
- Jianmongkol S, Kosuwon W, Thammaroj T. Intra-tendon sheath injection for trigger finger: the randomized controlled trial. Hand Surg. 2007;12(2):79-82. [Medline].
- Freiberg A, Mulholland RS, Levine R. Nonoperative treatment of trigger fingers and thumbs. J Hand Surg (Am). 1989;May 14(3):553-8. [Medline].
- Griggs SM, Weiss AP, Lane LB, et al. Treatment of trigger finger in patients with diabetes mellitus. J Hand Surg [Am]. Sep 1995;20(5):787-9. [Medline].
- Lapidus PW, Guidotti FP. Stenosing tenovaginitis of the wrist and fingers. Clin Orthop Relat Res. Mar-Apr 1972;83:87-90. [Medline].
- Rhoades CE, Gelberman RH, Manjarris JF. Stenosing tenosynovitis of the fingers and thumb. Results of a prospective trial of steroid injection and splinting. Clin Orthop Relat Res. Nov 1984;236-8. [Medline].
- Hoppenfeld S, deBoer P. Surgical Exposures in Orthopaedics: The Anatomic Approach. Philadelphia, Pa: JB Lippincott; 1984.
- Al-Qattan MM. Trigger fingers requiring simultaneous division of the A1 pulley and the proximal part of the A2 pulley. J Hand Surg Eur Vol. Oct 2007;32(5):521-3. [Medline].
- Moriya K, Uchiyama T, Kawaji Y. Comparison of the surgical outcomes for trigger finger and trigger thumb: preliminary results. Hand Surg. July 2005;10(1):83-6. [Medline].
- Carlson CS, Curtis RM. Steroid injection for flexor tenosynovitis. J Hand Surg [Am]. Mar 1984;9(2):286-7. [Medline].
- Cardon LJ, Ezaki M, Carter PR. Trigger finger in children. J Hand Surg [Am]. Nov 1999;24(6):1156-61. [Medline].
- Wolfe SW. Tenosynovitis. In: Green DP, ed. Green's Operative Hand Surgery. vol 2. 4th ed. New York, NY: Churchill Livingstone; 1998.
- Migaud H, Fontaine C, Brazier J, et al. [Kapandji enlargement plasty of A1 pulley. Results in 15 primary trigger fingers with a 5 year (2-8 years) follow-up]. Ann Chir Main Memb Super. 1996;15(1):37-41; discussion 42. [Medline].
Trigger Finger excerpt Article Last Updated: May 8, 2008
|
