A CUMULATIVE TRAUMA ILLNESS
Trigger Thumb and Fingers

Kenneth J. Garrod, M. D. Diplomate, American Board of Orthopaedic Sugery Member, American Society for Surgery of the Hand Fellow, American Academy of Orthopaedic Surgeons

Stenosing tenosynovitis of the flexor tendons of the hand, better known as trigger finger and trigger thumb, is a common condition in the hand. Patients with this condition present with symptoms of pain and discomfort at the metacarpophalangeal joint crease of the thumb and finger initially, and commonly progress to painful snapping, catching or triggering in these digits during thumb and finger motion. This snapping may occur during flexion or extension. Patients will usually point to the IP or PIP joints of the thumb or hand because each joint appears to jump or lock during flexion or extension. Anatomically, however, the flexor tendons catch at the proximal edge of the digital flexor sheath, as the tendons glide into flexion and extension (Fig. 1). The condition most commonly occurs in the middle or ring finger. Inflammation at the A1 pulley causes discrepancy in the size of the tendon and the pulley. The tendon becomes thickened proximal to the A1 pulley and during flexion, the increased flexor tendon diameter prevents the digit from extending (Fig. 2).

Trigger thumb and finger occurs most commonly in middle-aged women. Patients may present with multiple finger involvement which may be caused by an underlying medical condition which increases the inflammation about the flexor tendons. Rheumatoid arthritis, gout, connective tissue diseases and diabetes mellitus may cause connective tissue changes which increase the risk of triggering. In the work place, activities that require increased flexion and extension of the thumb and fingers may result in increased inflammation about the flexor tendon tenosynovium, especially in activities that require repetitive flexion or power gripping.

Physical examination of these patients will show an area of discomfort at the metacarpophalangeal crease of the thumb or in the distal palmar crease of the hand. These anatomical creases are located just over the proximal edge of the A1 pulley. Palpating these areas during flexion and extension of the thumb and fingers will usually show enlargement of the flexor tendon which is called a flexor tendon nodule. In addition, retinacular cysts or small joint ganglions may be palpated in these areas.

Conservative treatment is very successful in these patients. Work activities that require repetitive flexion and extension gripping or other provocative activities should be modified. Some have advocated the use of oral nonsteroidal anti-inflammatories and day-time splinting of the affected joint in extension. Most commonly, the use of a steroid injection in the area of the A1 pulley is indicated. Cure rates approach 80% with minimal complications. Injection is easily carried out by placing a 25 gauge needle at a 45-degree angle to the longitudinal axis of the affected metacarpal (Fig. 3). After injection, patients use their fingers normally with a decrease in pain and triggering normally seen over a seven-to-ten-day period.

Surgical release of the A1 pulley may be performed under local anesthesia as an outpatient procedure in those patients with no relief of symptoms. Most patients and employees can return to work within a two to four week period after surgery depending on the requirements of their jobs.