Outline:   
Tenosynovitis of flexor digitorum is also called "flicking-sounded finger or trigger finger". It occurs mostly in the thumb, sometimes in the second or third finger only, occasionally in several fingers simultaneously. The neck of metacarpal bone and the shallow groove on the palmar aspect of metacarpophalangeal joint as well as sheath-like ligament consist of bony fibrous tubes through which long flexor tendon of thumb, deep flexor tendon digitorum and superficial flexor tendon digitorum respectively pass.

If the bony fibrous tube repeatedly rubs against the flexor tendon because of a long period of repeated flexion and extension of fingers, or is pressed and squeezed by the hard object and the end of metacarpal bone because of a long term of holding up a hard object forcefully, there will occur local congestion and edema, hence degeneration of the fibrous tube. As a result, the tube cavity becomes stenosed, and the flexor tendon is compressed, becoming thinner with its two ends enlarged, showing a shape of "gourd". Thus, the finger will present a clicking movement when it flexes due to the bulgy part of the flexor tendon going through the stenosed fibrous tube.


Major points for diagnosis  
1. There is a strain history of finger movement.
 
2. At the beginning, the sick finger fails to extend and flex. Exertion in extension and flexion will cause pain and a flicking movement. The disease gets worsened after getting up in the morning and after physical labor, and gets better after activity or hot compress.

3. There is a tender spot on the palmar aspect of metacarpal end where a grain-sized node may be felt. Press the node and ask the patient to perform full extension and flexion of fingers, there will appear remarkable pain and a flicking sound from it. In the severe case, the finger is unable to straighten itself out after flexion.


Treatment  
Tenosynovitis of flexor digitorum is mainly treated by the external therapy.

Tendon-smoothing manipulation:    
The operator holds up the sick wrist with his left hand, and performs the manipulations of pressure, transverse push, and longitudinal push and pressure on the node region with his right thumb. Finally, he grasps the end knuckle of sick finger and suddenly pulls it towards the distal end. The effect will be better if there is a flicking sound. Give the manipulation once every day or every other day.
 
Herbal therapy Shangke Xiaoyan Paste can be used externally.
Fixation Bandage or hard paperboard is used to wrap and fix the metacarpophalangeal joint in an extension position for 2 or 3 weeks, restricting the movement and relieving symptoms. This is used in patients with serious symptoms.
 
Acupuncture therapy:
Taking painful spots at the node and around it as acupoints. Perform the acupuncture therapy every other day.
 
Hydro-acupuncture therapy:
One milliliter of 1% procaine plus 12.5 mg prednisolone is taken for injection intrathecally, once a week, 3 or 4 times totally.
 
Small needle-knife therapy:
After routine disinfection of the skin and local anesthesia, taking the grain-like node as the center, insert the small needle-knife into the node deep to the sheath, then along the course of tendon, prick and cut the sheath upwards and downwards, not laterally for fear of injury of tendon, nerve and blood vessel. If the flicking sound disappears and the motion of fingers gets normal, it means the sheath has been cut. If the wound is big, it should be sutured with one stitch, otherwise, there is no need for suture. Finally cover the wound with sterile gauze and bandage it forcefully.