This is a tightening and thickening of a fibrous tunnel that starts at the base of each finger and thumb through which the flexor tendons pass (the flexor tendons are the tendons that bend the fingers into the palm). They are more common in females and particularly common in post-menopausal women. Trigger finger has been called stenosing tenosynovitis (inflammation of tendon) and stenosing tenovaginitis (inflammation of tunnel through which the tendon travels). Neither is accurate as the suffix "-itis" means inflammation and inflammation is rarely if ever found in this condition under the microscope
There are also other associated conditions:
De Quervain's disease
However by far the most common cause of this condition is idiopathic and this is a medical term for "we don't know".
The ring finger is the most common and the middle finger is the next most common then the little and the index is the rarest. Trigger thumb is as common as the middle finger.
There is no association with occupation.
There is no association with trauma or any form of repetitive "injury".
There is also another peak of incidence and that is in childhood with a peak age of about 3.
The analogy of the trigger finger is a bicycle brake cable (Boden cable). The bicycle brake cable has a metal cord which is surrounded by a white plastic sheath the cord moves in and out of the sheath. If there is a lump in the cord either the cord won't go into the sheath and the brakes don't go on or the lump gets stuck inside the sheath and the brakes get stuck on. A trigger digit involves a lump in the tendon caused by a constriction of the fibrous tunnel through which it passes. That lump is similar to the lump in the bicycle brake cable.
Patients generally complain of a clicking finger. The finger is often painful particularly in the morning. Sometimes the finger locks down and again this again can occur in the morning.
It is possible to feel a lump in the tendon just at the base of the finger. If you place your thumb at the base of the affected finger and press hard and then bend the finger in and out you can feel a lump moving underneath your thumb.
In children the condition generally affects the thumb, the parents notice that the child has got a bent thumb and cannot straighten it although sometimes it does straighten and the child tends to squeal! The condition may be on both sides and there may be a familial tendency. In this type there may be spontaneous resolution in 1 out of 3 cases. This resolution drops to 10% in those identified at 3 years but the majority of the cases seen at 5 years require surgical release.
Trigger fingers can be treated either by injection, which is 50 - 60 % successful or surgery which is 95% successful. The operation will be dealt with under operation details. A trigger finger is generally injected at about the level of the palmar crease that is the crease in the palm nearest the finger with some steroid and local anaesthetic. This funnily enough feels like an injection into the finger and sometimes Mr Field injects twice in this area. There is a sensation of the finger filling up with fluid although only 0.5ml of steroid mixture is injected. The patient is then sent away for 3- 4 months and reviewed in the outpatients. If the injection has worked obviously no further treatment is necessary, if it hasn't then an operation may be necessary. The steroid injection can take two weeks to work.