TRIGGER FINGERS - GENERAL
Trigger finger, also called “Stenosing Tenosynovitis”, is a common hand ailment. The first sign of the condition may be a slight difficulty or clicking when bending a finger to make a fist. Later, you may need to use your other hand to bend or straighten the finger. When the finger does move, you may feel a snap or click, as it suddenly gets "unstuck". This is the triggering that gives the condition its name. The diagnosis of a trigger finger is made with a simple physical examination. X rays and other tests generally are not needed unless multiple fingers are triggering. In this case blood tests are recommended to exclude an underlying cause for the triggering eg Diabetes or an inflammatory arthritis.
HOW DOES THE PROBLEM DEVELOP?
Along the palmar surface of each finger there is a smooth tunnel called the flexor sheath. The tendons that bend the finger run in this tunnel. Thickenings of the tunnel are called pulleys and these prevent the tendons from bowstringing when the finger bends. The tunnel is lined by synovium – a tissue which lubricates the tunnel.
A Trigger finger develops when the synovium around a tendon in a finger or thumb becomes chronically inflamed and / or thickened. The tendon starts catching as it enters the opening of the tunnel. The tendon bunches up on itself forming a nodule that can be felt in the palm.
WHAT CAUSES TRIGGER FINGERS ?
Often many factors play a role. One may have many factors but no symptoms of the condition and then one day develop the symptoms. The activity or factor which precipitated the symptoms may therefore act as “the last straw”. In many cases no obvious precipitant is identified and the condition arose because one got a little older.
Causes of Trigger fingers:
- Age - The condition is more frequent as you get older
- Genetic - (often runs in families)
- Diabetes
- Family history of Diabetes
- Obesity
- Pregnancy
- Fluid retention
- High Cholesterol
- Hormonal – eg under-active Thyroid, Polycystic Ovary Syndrome
- Inflammatory Arthritis eg Rheumatoid, Psoriatic arthritis
- Unusual Activity eg Renovating, Pruning garden or lifting babies etc
- Sport / Work - Change in intensity of activity – eg when you first start a new job and have not trained for that activity . (ie “Too hard / Too soon” and analogous to running a marathon but not training )
- Work relatedness? – in general to be a work related condition it needs to be Highly repetitive + Highly forceful and / or involving significant vibration stress
One has to ask is it Work USE or Work OVERUSE? Defining something as work related when there is another cause can result in prolonged and inappropriate treatment and unrealistic expectations from treatment.
The term “RSI” suggests that using your hand causes pain and is NOT a diagnosis. In general it is a recipe for misdiagnosis.
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TREATMENT:
1. Rest / Activity modification
2. Anti-vibration glove e.g. for power tool workers.
3. Anti inflammatory tablets or creams.
4. Cortisone injection: (Cortisone Injections)
- 1 or 2 only - multiple injections can damage the tendon and should be avoided.
- reduce inflammation in or around tendons and may take 24 - 48 hours to take effect.
- a local anaesthetic Lignocaine + cortisone (Celestone).
- Lignocaine lasts for about 1 hour so the finger will be numb for this period. Avoid injury to the finger while it is numb. Beware burns from coffee cups.
- The cortisone is mixed with a special carrier, so that it stays in the place where it was injected. Therefore, injections in one finger or part of your body do not “count”" when deciding whether or not to have an injection in another finger or part of the body. Because the carrier restricts the cortisone to the area of the injection, usually there are few general effects to the body from the cortisone such as would be expected if cortisone was taken by mouth. Occasionally one sees an increase in blood sugar in Diabetic patients. This does not seem to be a significant problem.
- The duration of action of cortisone is very variable but it usually works for about 1-3 months. Often by that time the problem which caused the irritation around the has resolved. If not, then there may be a recurrence of the original discomfort and a second injection might be necessary.
Problems are very rare:
1. Ache
After the local anaesthetic. This usually lasts for a day or so and then as the cortisone starts to work, the discomfort goes away.
2. Tissue damage
Multiple injections in the same area should be avoided because although the cortisone does reduce swelling and provide pain relief, it has also been shown to cause some damage to the tendons and joints after multiple injections in the same spot.
3. Infection or Allergic reactions or side effects to the medications which are injected are rare. Local reactions to the injection are slight and should be limited to local tenderness and perhaps some redness and swelling for the first day. The pain should not be more than that easily relived with aspirin or Panadol.
Report any pain, redness or swelling in excess of that described above to your doctor immediately. Although extremely rare, infection is possible following a cortisone injection.
Recent research by Ye & Myers has shown that there is no difference in outcome between cortisone injections performed by Hand surgeons compared with injections performed under ultrasound guidance.
Trigger finger Injection Technique
5. Surgery:
- May be recommended when other treatment fails or when the finger is locking.
Post – operative exercises:
- After the procedure, finger exercises are encouraged immediately. See below. 5 repetitions of 10 each / day until full movement is gained. After the sutures are removed start massaging the scar firmly twice a day with Sorbolene cream to soften the scar. Some patients benefit from a few visits to a Hand Therapist.
- It is common for the second joint (PIP joint) in the finger to develop a bend of ~20* for 1 – 2 months. It is important to start stretching this joint after the surgery
Other exercises include:
Revised 25 / 3 / 2015