Trigger Finger Release

Randy Bindra, MD, FRACS

Dr. Bindra or an immediate family member has received royalties from Acumed LLC and Integra LifeSciences and serves as a paid consultant to or is an employee of Acumed LLC and Integra LifeSciences.

This chapter is adapted from Bindra R, Sinclair, M: Trigger Finger Release, in Flatow E, Colvin AC, eds: Atlas of Essential Orthopaedic Procedures. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2013, pp 253-257.

INTRODUCTION

Trigger finger, also known as stenosing tenosynovitis, is a painful catching of a digit with attempted active extension.

This occurs most commonly at the level of the A1 pulley because of a disparity in the size of the flexor tendons and the surrounding tendon sheath, resulting in interference with smooth tendon gliding. The pathologic changes observed with this disorder include stenosis of the fibrous flexor tendon sheath due to chronic inflammation as well as a reactive nodule within the flexor digitorum superficialis tendon.

The highest incidence of trigger finger is seen in patients who are approximately 60 years of age; it is more common in females. Although trigger finger is most frequently idiopathic, certain activities that require repetitive finger flexion and diabetes have been independently associated with this condition. The thumb and the ring finger are the most commonly affected digits. A trigger thumb in a child may present as a congenital anomaly.

The diagnosis of trigger finger is a clinical one, based on history and physical examination. Clinical presentation varies with the stage of the disease.¹ In grade 1 (mild), there is a history of catching of the finger that is not reproducible on physical examination and tenderness over the A1 pulley. In grade 2 (moderate), catching of the digit is observed, but the patient can actively extend the digit. In grade 3 (severe), the flexed digit requires manual passive extension or the patient is unable to flex the digit to the point of triggering. Grade 4 (locked) is characterized by catching with a fixed flexion contracture of the proximal interphalangeal (PIP) joint.

PATIENT SELECTION

Special Populations/Situations

Certain populations that present with triggering require special consideration.

Children

Children with trigger thumbs present with an inability to straighten the interphalangeal (IP) joint rather than catching of the digit. The deformity is usually first noted at approximately 6 months of age, but late presentation is not uncommon because of the compensatory hyperextension of the metacarpophalangeal (MCP) joint. Spontaneous resolution is possible, and a period of observation for at least 6 months is recommended, especially in children younger than 3 years.² Persistent triggering requires surgical release to avoid fixed IP contractures.

Trigger fingers, in contrast to trigger thumbs, are much more rare in children, accounting for 7% to 14% of all trigger digits in children, and usually indicate underlying aberrant anatomy of the tendon-pulley system that requires more extensive surgical exploration and management. Multiple trigger digits may be present in children with lysosomal storage disorders.³

Patients With Diabetes

Although a steroid injection into the tendon sheath is the appropriate initial treatment for trigger finger, studies have reported a lower success rate of approximately 50% in diabetic patients compared with 86% in nondiabetic patients.⁴ Additionally, diabetic patients must be informed of the potential for a hyperglycemic effect with injection that can last up to 5 days.⁵ Lastly, residual stiffness of the PIP joint after treatment is common in diabetics, generally leading to less satisfactory outcomes in this group.

Patients With Rheumatoid Arthritis

The primary underlying pathology in rheumatoid arthritis is synovitis within the tendon sheath, not stenosis of the A1 pulley. Not only will pulley release be ineffective in symptom resolution, it may actually cause functional deterioration by contributing to ulnar drift of the fingers.
Treatment of these patients should include early surgical intervention with flexor tenosynovectomy to remove the diseased tenosynovium surrounding the tendon.⁶ If the condition fails to respond to this treatment or the patient continues to have triggering when evaluated intraoperatively, resection of the ulnar slip of the flexor digitorum superficialis can be performed with reliable results.⁷

Patients With Distal Triggering

Rarely, patients will have triggering related to the A3 pulley at the level of the PIP joint. The report of pain at the PIP joint is consistent with physical examination findings— tenderness palmar to the PIP joint rather than the MCP joint and often a palpable swelling within the flexor tendon adjacent to the PIP joint. These patients characteristically have triggering that occurs when the PIP joint is at or beyond 90° of flexion. The tendon involved is the flexor digitorum profundus, and symptoms can also be found at the distal interphalangeal joint. An A3 pulley excision has been shown to be successful in these patients.⁸

Patients With Proximal Interphalangeal Contracture

In patients with long-standing and severe disease with inability to straighten the finger, secondary contracture of the PIP palmar plate may develop. In these cases, patients should be advised of the possibility of residual flexion contracture of the digit following release of the A1 pulley.

Indications

Initial treatment of trigger finger should be nonsurgical.⁹ In nondiabetic patients, either a single corticosteroid injection or a series of up to three injections have been found to be a successful treatment in 75% of the patients at 6-month follow-up.⁴^,¹⁰^,¹¹ Despite the fact that multiple studies have confirmed a lower success rate for corticosteroid injections in patients with diabetes, this should remain the first line of treatment in these patients. In the discussion of a treatment plan with patients with diabetes, they must be informed of the lower success rate of injection as well as the potential for hyperglycemia following injection.⁴^,⁵

Percutaneous release may be considered in selected cases of triggering of the long and ring fingers. Performed in the outpatient clinic, the procedure has been reported to be successful in up to 91% of patients.¹^,¹² Practice in a cadaver model followed by open release using an 18-gauge needle is recommended before performing percutaneous release in the clinic.¹²

Specific indications for open trigger finger release include failed nonsurgical management with steroid injection, failed percutaneous trigger finger release, and long-standing or severe disease.¹⁰^,¹³

Patient characteristics that contribute to a higher risk of failure of nonsurgical management and likely surgical treatment include younger age, insulin-dependent diabetes mellitus, involvement of multiple digits, and/or a history of other tendinopathies of the upper extremity.¹⁰

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