- About Trigger Finger
Trigger Finger (Stenosing Flexor Tenosynovitis)
Steven J. Meyers, MD, and Michael L. Lee, MD
Trigger finger is a painful snapping phenomenon that occurs as the finger flexor tendons suddenly pull through a tight A1 pulley portion of the flexor sheath. The underlying pathophysiology of trigger finger is an inability of the two flexor tendons of the finger (FDS and FDP) to slide smoothly under the A1 pulley, resulting in a need for increased tension to force the tendon to slide and a sudden jerk as the tendon nodule suddenly pulls through the constricted pulley (triggering). The triggering can occur with flexion or extension of the finger or both. Whether this pathologic state arises primarily from the A1 pulley becoming stenotic or from a thickening of the tendon remains controversial, but both elements are usually found at surgery.
Clinical History and Examination
Trigger finger most commonly occurs in the thumb, middle, or ring fingers of postmenopausal women and is more common in patients with diabetes or rheumatoid arthritis, Dupuytren’s contracture, and other tendinitis (de Quervain’s tendinitis or lateral epicondylitis [“tennis elbow”]). Patients present with clicking, locking, or popping in the affected finger that is often painful, but not necessarily so.
Patients often have a palpable nodule in the area of the thickened A1 pulley (which is at the level of the distal palmar crease) (Fig. 1–14). This nodule can be felt to move with the tendon and is usually painful to deep palpation.
To induce the triggering during examination, it is necessary to have the patient make a full fist and then completely extend the fingers, because the patient may avoid triggering by only partially flexing the fingers.
Spontaneous long-term resolution of trigger finger is rare. If left untreated, the trigger finger will remain a painful nuisance; however, if the finger should become locked, the patient may develop permanent joint stiffness. Historically, conservative treatment included splinting of the finger in extension to prevent triggering, but this has been abandoned because of stiffening and poor result.
Currently, nonoperative treatment involves injection of corticosteroids with local anesthetic into the flexor sheath. The authors’ preference is 0.5 ml lidocaine, 0.5 ml bupivicaine, and 0.5 ml methoprednisolone acetate (Depo-Medrol) (Fig. 1–15). A single injection can be expected to relieve triggering in about 66% of patients. Multiple injections can relieve triggering in 75 to 85% of patients.
About one third of patients will have lasting relief of symptoms with fewer than three injections, which means that about two thirds will require surgical intervention.
Surgery of trigger finger is a relatively simple outpatient procedure done with the patient under local anesthesia. The surgery involves a 1- to 2-cm incision in the palm to identify and completely divide the A1 pulley.
Pediatric Trigger Thumb
Pediatric trigger thumb is a congenital condition in which stenosis of the A1 pulley of the thumb in infants causes locking in flexion (inability to extend) of the IP joint. It often is bilateral. There usually is no pain or clicking, because the thumb remains locked. About 30% of children have spontaneous resolution by 1 year. The rest require surgical intervention to release the tight A1 pulley by about 2 to 3 years of age to prevent permanent joint flexion contracture.