Trigger Finger

Welcome to Texas State University's Evidence-based Practice project space. This is a wiki created by and for the students in the Doctor of Physical Therapy program at Texas State University - San Marcos. Please do not edit unless you are involved in this project, but please come back in the near future to check out new information!!

Original and Lead Editors - Holly Pulket, Hilary Zachary, Angela Dempski, Dana Williams, Shannon Davis

Search Strategy

Databases: CINAHL, PUBMED, PeDro, MEDLINE

Keywords: trigger finger, trigger thumb, stenosing tenosynovitis, flexor tenosynovitis, flexor tendon stenosis, A1 pulley AND tendonitis, A2 pulley AND tendonitis

Timeline: 9/15/2011 - 11/28/2011

Definition/Description

Each digit of the hand has the ability to move freely throughout a full ROM into flexion and extension. The efficiency, fluidity, and forcefulness of such movement is made possible by several "pulleys" along each digit of the hand. These pulley systems are comprised of a series of retinacular-type structures that are either annular or cruciform in nature. There are five annular pulleys (A1-A5) and three cruciform pulleys (C1-C3).

File:Finger pulleys.jpg

Courtesy of www.netterimages.com

Trigger finger is a common condition that is thought to be caused by inflammation and subsequent narrowing of the A1 pulley of the affected digit, typically the third or fourth. Commonly, trigger finger is referred to as "stenosing tenosynovitis." However, there have been histologic studies showing that the inflammation occurs more so in the tendon sheaths rather than the tendosynovium, making this name a false depiction of the actual pathophysiology of the condition.

Epidemiology/Etiology

Trigger finger can occur in anyone, but it is statistically shown that women in their fifth to sixth decade of life are more likely to develop the condition than men and nearly six times more frequently. The chance of developing trigger finger is 2-3%, but in the diabetic population, it rises to 10%. The reason is not of glycemic nature, but rather is the cause of the duration and progression of the disease. Trigger finger can also concomitantly occur in patients with:

• Carpal tunnel syndrome
• DeQuervain's disease
• Hypothyroidism
• Rheumatoid arthritis
• Renal disease
• Amyloidosis

There have been many potential causes of trigger finger discussed throughout the literature. However, there is little to no evidence on a precise etiology of the condition. Caused by a difference in diameters of a flexor tendon and its retinacular sheath due to thickening and narrowing of the sheath.

Characteristics/Clinical Presentation

Trigger finger has a range of clinical presentations.  Initially, the patient may present with painless clicking with movement of the digit that can progress to painful catching or popping, typically at the MCP or PIP joints. Possible additional symptoms are stiffness and swelling (especially in the morning), loss of full flexion/extension, palpable painful nodule, and/or finger locked into a flexed position. Other signs and symptoms are slight thickening at the base of the digit and pain that may radiate to the palm or to the distal aspect of the digit.

Differential Diagnosis

The main characteristic of trigger finger is a popping and/or catching with movement of the digit. However, this characteristic is not unique to just trigger finger. Other etiologies associated with a locking digit include:

• Dupuytren's contracture
• Focal dystonia
• Flexor tendon/sheath tumor
  
• Sesamoid bone anomalies
• Post-traumatic tendon entrapment on the metacarpal head
• Hysteria 

Complaints of pain at the MCP joint could be associated with any of the following:

• DeQuervain's (for trigger thumb only)
• Ulnar collateral ligament injury/Gamekeeper's thumb
• MCP joint sprain
• Extensor apparatus injury
• MCP joint osteoarthritis

 

Diagnosis of trigger finger can be confirmed with the injection of lidocaine into the flexor sheath, which should relieve pain and allow flexion/extension of the joint. Imaging is not typically indicated, but ultrasound and MRI may be used to rule out other etiologies.

Outcome Measures

• Numeric Pain Rating Scale
  
• Grip Strength (Jamar dynameter)  
• DASH Outcome Measure
  
• Stages of Stenosing Tenosynovitis
• Participant Perceive Improvement in Symptoms
• Open & Close Hand 10 Times

Table 1. Stages of Stenosing Tenosynovitis (SST) 
Stage Symptoms
1 = Normal
2 = A painful palpable nodule
3 = Triggering
4 = The proximal interphalangeal (PIP) joint locks into flexion and is unlocked with active PIP joint extension
5 = The PIP joint locks and is unlocked with passive PIP joint extension
6 = The PIP joint remains locked in a flexed position

Table 2. Participant Perceived Improvement in Symptoms
Rating Symptoms
1 = Resolved
2 = Improved, but not completely resolved
3 = Not resolved
4 = Resolved, but triggering at the distal interphalangeal/proximal interphalangeal joint(s)
5 = Resolved at ten weeks versus six weeks

Open & Close Hand 10 Times

Patient is to actively make ten fists. The number of triggering events in ten active full fists is then scored out of 10. If patient’s finger remains locked at any time, the test is completed and an automatic score of 10/10 is recorded.

Examination

Hx:

• Recent trauma 
• Job related repetitive movements
• Locking or snapping while flexing or extending the affected digit 
• Radiating pain to the palm or digits
  

PMH:

• Diabetic individuals are 4x more likely to develop trigger finger 
• Disorders causing connective tissue changes such as RA and Gout
  

Observation:

• A digit locked in flexion
• Bony proliferative changes in the subadjacent DIP joint

Palpation:

• Painful nodule in the palmar MCP secondary to intratendinous swelling

ROM:

• Loss of motion, particularly in extension
  

MMT:

• Flexor Digitorum Profundus
• Flexor Digitorum Superficialis 
• Grip strength using the Jamar Dynameter

Note: If the finger is locked, testing may not be possible.

Joint Accessory Mobility:

• PIP, MCP, DIP, and CMC of all affected digits
• Surrounding tissues 
• Wrist joint

Special Tests:

• Open and Close hand 10x

Medical Management

The chronic nature of the symptoms associated with trigger finger makes conservative treatment difficult and often frustrating. Still conservative care (listed below in PT Management) is always recommended as a treatment plan prior to surgical intervention.

Corticosteroids

Corticosteroid use has been shown to be effective in reducing pain and the frequency of triggering.  The shot is injected into the affected tendon and reduces the inflammation and pressure on the tendon for better gliding through the flexor pulleys.  Ultimately, application, by a primary care provider, is an effective and safe alternative to surgical therapy.  Patient satisfaction, safety, and functional improvement are characteristic of steroidal injections in comparison to surgical treatment.  Open and percutaneous surgical division of the A1 pulley is associated with higher costs, longer absence from work, and the possibility of surgical complications.  Studies have also shown the combination of corticosteroid injections with lidocane to have significantly more effectiveness than lidocane alone.

Possible Side effects:
Flaring at injection site, local infections, tendon ruptures, allergic reactions, and atrophy of subcutaneous fat tissue.

Contraindications:
Those under the age of 18, those with prior treatment or surgery to the area within the last six months, or possible traumatic or neoplastic origin of symptoms.

Open Surgical Technique

This technique, considered to be the gold standard, is performed by making a longitudinal incision in the palmar crease over the metacarpophalangeal joint of the involved digit and followed by release of the flexor digitorum superficialis and profundus tendons.  This procedure, which lasts 2-7 minutes, has a longer average time of discomfort (45 days) post-op.  An advantage to this technique is it allows the pulley to be visualized and there is less risk of damage to the digital nerves compared to endoscopic techniques.

Video courtesy of the American Society for Surgery of the Hand

Endoscopic Surgical Technique

This technique is performed by making two incisions: one at the palmar crease over the metacarpophalangeal and the other at the volar crease of the finger.  An endoscope is then introduced to cut the pulley to allow a release of the flexor tendons.  This procedure lasts 2-9 minutes and has a shorter average time of discomfort (23 days) post-op.  Other advantages are absence of scars and scar related problems and shorter post-op rehabilitation.  However, there is a large learning curve and the instruments are costly.

Percutaneous Release

This technique can be performed with or without imaging.  Non-image-guided (blind) percutaneous release is performed by using anatomical landmarks to avoid injury to the tendons and neurovascular structures.  The recovery time is shorter than an open surgery but the potential for damage to digital nerves is more probable, especially to digits 1, 2, and 5.  A new technique using ultrasound-guidance helps clearly identify the tendons and neurovascular structures, preventing potential complications that are present with non-image-guided percutaneous release and also compares favorably with surgical techniques.

Physical Therapy Management

As with all disorders of the upper extremity, proximal segments must be screened.  Also, because an individual's posture can contribute to distal problems, it should be addressed to provide the patient with optimal outcomes.

Patient Education

Since trigger finger is observed as an overuse injury, educating the patient is very important.

Education should be given on:

• Rest
• Modifications of activities, such as those involving a grip or fist, by using specialized tools
• Splinting
• Icing/Heat
• Posture
  

Splinting

One of the first steps in treatment is to stop doing activities that aggravate the condition.  Splinting is one of the best ways to limit motion. Most authors agree that the intent of splinting is to alter the biomechanics of the flexor tendons while encouraging maximal differential tendon glide.  However, authors disagree on which joints to include in the splint and the degree of joint positioning.  There are various ways to splint a patient but, ultimately, it will depend on what provides the patient with the most relief. Splints are usually worn for 6-10 weeks. It should be noted, however, that splinting yields lower success rates in patients with severe triggering or longstanding duration of symptoms.

Multiple studies have been done concerning the effectiveness of splinting and trying to find the best type of splinting.

Two major types of splinting most recently studied:

1. Splinting at the DIP joint.  This showed to have resolution in 50% of the patient’s symptoms.
2. Splinting at the MCP joint with 15 degrees of flexion.  This showed to have resolution of the patient’s symptoms at both 65% and 92.9%, which is consistent with the current literature.

              

Other Options

Modalities such as heat, ice, ultrasound, electric stimulation, massage, stretching, and joint motion (active and passive) can have some positive effects on trigger finger. It is thought that heat can help by providing increased blood flow and extensibility to the tendon.  Following heat with stretching is thought to provide more extensibility with plastic deformation.  Additionally, the joint movement and mobilizations increase joint and soft tissue mobility via a slow, passive therapeutic traction and translational gliding.

Although the evidence is lacking there have been some documented cases and studies of improvement with various combinations of these techniques:

• 74 patients were treated with ten sessions of wax therapy, ultrasound, stretching muscle exercises and massage yielded 68.8% resolution of symptoms and remained symptom free 6 months out.
  
• 60 trigger thumbs in 48 children were treated daily with passive exercise of their affected thumb by their mother resulting in a cure rate of 80% for stage 2 and 25% for stage 3 thumbs after an average of 62 months.
  
• Case Study: Both ART (Active release technique) and Graston techniques, followed by ice post-tx and self-mobilizations of the thenar eminence and 1st digit yielded no pain and only slight irritation at the joint capsule with mild weakness after 8 treatments.  The patients were given thera-putty and released with exercises (flexion, extension, abduction, adduction) to continue STR.  At the follow-up period of 14 months patients still reported complete resolution and pre-injury strength.
  

Key Research

1. Makkouk AH, Oetgen ME, Swigart CR, Dodds SD. Trigger finger: etiology, evaluation, and treatment. Curr Rev Musculoskelet Med. 2008; 1:92–96.

2. Colbourn J, Heath N, Manary S, Pacifico D. Effectivenes of Splinting for the Treatment of Trigger Finger. Journal of Hand Therapy.2008; 21(4):36-343.

3. Salim, N., S. Abdullah, J. Sapuan, and N. H. M. Haflah. Journal of Hand Surgery (European Volume) 0th ser. 0.0 (2011): 1-8. 

Resources

add appropriate resources here

Clinical Bottom Line

Trigger finger is a common condition related to inflammation and narrowing of the A1 pulley that can cause pain, clicking, catching, and loss of motion. While corticosteroid injections and surgery can be used in more chronic and severe cases, physical therapy may be effective as part of a conservative management. Treatment should focus on patient education, splinting, therapeutic exercise, and modalities.

Recent Related Research (from Pubmed)

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