What is it?
Trigger finger (also called stenosing flexor tenosynovitis) is an inflammation of the flexor tendon sheath of the finger (or thumb). The tendons for each finger travel through a tunnel which acts as a pulley anchoring the tendon to the bone. The tunnel provides nutrition to the tendon as well as mechanical stability. Irritation or inflammation of the tunnel can occur as the result of repetitive use. See figure 1a and 1b.
Swelling of the tunnel occurs and nodules can form on the tendon. This prevents smooth gliding of the tendon through the pulley. The tendon may “catch” causing the finger to lock in a bent position. Diabetes mellitus predisposes to the development of trigger finger.
How did I get it?
Irritation or inflammation of the fibro- osseous tunnel through which the tendon passes can occur from repetitive use and is more common in patients with diabetes mellitus. Swelling and nodule formation can prevent smooth gliding of the tendon and can cause it to “catch” locking the finger in the bent position.
How is a diagnosis made?
The diagnosis of trigger finger is provided by the characteristic nature of the triggering/catching of the fingers or thumb. Only rarely are x-rays ultrasounds or other scans required.
What are the symptoms?
Patients often complain of pain and a sensation of “snapping” when they bend the affected digit. Pain may also radiate into the palm. Watch the video below for more information.
What should I do?
Trigger finger tends not to get better on its own. Trying to avoid bending the finger to avoid triggering and icing the area may allow the inflammation and irritation to settle. If symptoms do not settle quickly you will need to seek medical attention. A hand occupational therapist, general practitioner or sports doctor will be those most able to provide assistance.
What does rehab involve?
The goals of treatment are to reduce swelling and inflammation in the flexor tendon sheath, to allow smoother movement of the tendon under pulley, and to perform stretching exercises in extension to prevent recurrence.
Hand therapy: Initial therapy during the first four to six weeks is with immobilization. Patients should restrict gripping and pinching and should apply ice to the area to reduce pain. Once the acute symptoms have resolved, patients can begin gentle stretching exercises in extension of the fingers to continue rehabilitation and prevent recurrence.
Cortisone injection: Patients with severe locking or patients who have not benefited from 4-6 weeks of immobilisation may benefit from a cortisone injection. While cortisone is avoided in many conditions, studies have shown that cortisone is both safe and effective for this condition.
Appropriate aftercare is critical to the success of a cortisone injection:
- Rest for three days, avoiding all gripping and grasping
- Buddy tape to the adjacent finger for the first few days
- Apply ice (15 minutes every four to six hours) and take Panadol / Panamax as needed for pain
- Protect the fingers for three to four weeks by avoiding repetitive gripping, grasping, pressure over the knuckles and vibration
- Begin passive stretching exercises of the finger in extension at three weeks
- Use padded gloves or padded tools for long-term prevention in recurrent cases
The injection may be repeated in six weeks if symptoms have not improved by at least 50 percent.
Surgery is indicated when locking and pain persists despite two consecutive cortisone injections.