Trigger finger

What is a trigger finger?

Trigger finger is a common complaint that causes pain and locking of the fingers. The problem of trigger finger is due to the tendons of the fingers, and the sheath in which they run. The tendons are like ropes that attach to the ends of your fingers. When your muscle contracts, the flexor tendons pull the fingers into a fist. The tendons run part of their course through a sheath called the flexor tendon sheath. In trigger finger, this mechanism of movement is inhibited. function.

Pathophysiology: Normally, the tendons of the finger flexors glide back and forth under a restraining pulley. Thickening of the flexor tendon sheath causes restriction of the normal gliding mechanism. A nodule may develop on the tendon, causing the tendon to get stuck when the patient is attempting to extend the digit, thereby causing difficulty. With more forceful attempts to extend the digit, either by increased force from the finger extensors or by application of an external force (eg, using the other hand), the digit classically snaps open with significant pain at the distal palm and into the proximal aspect of the affected digit.

Signs and symptoms

• The most classic complaint is difficulty achieving full extension of a single digit, which eventually releases or snaps open with pain at the distal palm and into the digit.
• Multiple digits may be involved in trigger finger in individuals with diabetes or rheumatoid arthritis.
• Other patients may have a painful nodule in the distal palm without any catching or triggering.
• Some patients report stiffness in the fingers, especially after periods of inactivity such as sleeping.
• Some patients may have a history of repetitive trauma to the affected area.
• Patients may have a history of diabetes or rheumatoid arthritis.
• Some patients report swelling of the affected digit, particularly at the base or proximal aspect of the digit.

On examination

• At the level of the distal palmar crease, a tender nodule can be palpated, usually overlying the metacarpophalangeal (MCP) joint.
• The affected digit may lock within a flexed position or, less commonly, within an extended position. When the patient attempts to move the digit more forcefully beyond the restriction, the digit may snap or trigger beyond the restriction. The triggering movement is very painful for the patient.
• In severe cases, the patient is unable to move the digit beyond the restriction, so no triggering occurs.
• With a trigger thumb, the tenderness to palpation is found at the palmar aspect of the first MCP joints, rather than over the distal palmar crease.
  

Causes of Trigger Finger:

Most clinicians believe that the disorder is caused by the tendon sheath because it becomes thickened or swollen and pinches the tendon and prevents it from gliding smoothly. But common sense reveals that the history of patients suffering with Trigger Finger have one common denominator, overuse, excessive use and/or abuse of the hands from work and recreational activities. Trigger Finger is usually (not always) the result of direct injury to the tendon via micro-tears resulting from direct and sudden trauma or tasks that required repetitive use of the hands over long periods of time. And as the body attempts to heal itself causes the formation of scar tissue / fibrotic adhesion, and the swelling of the tendon sheath is a secondary injury caused by friction between the adhesion and the tendon sheath as the finger is flexed and extended. This friction causes irritation, swelling, and inflammation to both the adhesion on the tendon and to the tendon sheath, thus resulting in a perpetual cyclic injury, starting with the adhesion on the tendon, then the adhesion irritates the sheath, then the sheath swells and pinches down more so it irritates the adhesion even more, and continuing to go back and forth again and again with both the tendon and its sheath contributing to the cause-effect of Trigger Finger.

*Other contributors/factors of Trigger Finger are Rheumatoid Arthritis, partial tendon lacerations, repeated trauma from pistol gripped power tools, or long hours grasping a steering wheel.

What you feel?

Trigger fingers cause pain in the palm of the hand and snapping, clicking or triggering of the involved finger. In the beginning, finger movement is uneven. Untreated, this progresses to snapping of the finger as one makes a fist. With time, the finger gets unexpectedly locked when one tries to hold an object. Finally, the finger locks in bent position as the tendon gets locked outside the flexor tendon sheath or the sleeve. Rarely, the patient cannot make a full fist as tendon becomes locked inside the sleeve of the tendon. It is painful to unsnap and straighten the finger. Finally, the finger becomes locked in the bent position and cannot be unlocked any more. Trigger finger may occur in one or more fingers at the same time or may occur in different fingers at different times.

Rehabilitation Program:

Successful Treatment for Trigger Finger:

1. Transverse Friction Massage across the tender nodule/adhesion on the affected finger.
2. Immediately follow by performing passive and active stretches to the affected finger.
3. Active strengthening exercises of the extensor muscles that extend the fingers and wrist, in order to hold and maintain the length to the tendon that you just stretched
4. Acupuncture
5. Ultrasound and laser