Wednesday, 25 May 2016

Minor injuries - three questions that will determine what to do every time (Easter Egg - Finger injuries)

What is a minor injury?  What is minor to you or to me may not be minor to the child or parent.  Many a time I have been surprised by how pleased a child is to need a cast, or how distressed they are to be given a splint or dressing that needs to be kept dry.  I seem to ruin many a trip to Skeg Vegas in this way.

So, since our opinion seems unimportant, we must ask the important questions.  There are only three:



Lets try these questions on an injured finger.  Jacinda has injured a couple of fingers when they were hyperextended (bent back) by a basketball.

Question 1 - Does it need to be fixed?

Fingers are quite good in this respect because they are easy to inspect and (most) people have a finger on the other side to compare to.  So we allow the finger to fall as it is and see how it aligns with the other fingers.  If a finger is angulated or rotated it will need to be fixed.

Fingers should look well aligned when relaxed.
If there is an apparent angulation or rotation, this needs to be corrected before the fracture sets otherwise there may be a long term functional defect.

Question 2 - Might there be a sneaky injury?

That is very unlikely, but then that is what is so sneaky about sneaky injuries.  They come too rarely for us to expect them.  In fingers, there are three possibilities.

Possibility one is a flexor tendon rupture.  All we need to do to check for this is check flexion twice.  The first time is a simple flexion to test the deep flexor tendon (FDS) and the second is with the other fingers held in extension by the examiner.  This inactivates the deep flexor tendon  so that the superficial tendon (FDS) can be tested.



Possibility two is an extensor tendon rupture.  This is essential to detect and easy to test for.  The finger must be extended against the examiner's finger in order to exclude the 'mallet finger' injury.


Possibility three is a collateral ligament rupture. Gentle lateral force will detect any instability of the interphalangeal joints.



Question 3 - Does it need to be immobilised?

Jacinda's finger wasn't bent or twisted on examination.  Nothing was ruptured.  It just hurts.  It may even have a fracture.  The question remains, can and should it be immobilised?

The figure below, from Elselvier Journals "Isolated finger injuries in children — incidence and aetiology" shows that fingertips are the most common finger injury in children.


The thing about fingertips is that you can't really immobilise them and they don't really need it.  The fibrous sheath does that job for you.  You can immobilise the distal interphalangeal joint if needed but in doing so you will put pressure on the fingertip.  So, immobilisation can make pain worse as well as better.  Each injury is judged on its own merits.

Immobilisation can also make things worse by making things stiff.  Taking an extreme example, when someone comes out of a cast after a month or more- their joint is so stiff that it may not move at all.  If immobilisation is not needed, it is best to avoid making things worse.



More on that story in a later post.

Finally, one of the most easily treated finger injuries.  As per the above research, finger tips are often injured.  One common problem is the subungual haematoma.  Because nailbeds are sensitive, the pressure of a collection of blood trapped under a finger nail is very painful.


A hole made in the middle of the nail overlying the haematoma will relieve that pressure and reduce the pain considerably.  This can be done with a special tool but if you are patient, a standard needle also gets there in the end.

Many thanks to the hand models for consenting to their fingers to be photographed in the name of science. So, go ahead and treat a finger.  All you have to do is answer three questions.

Edward Snelson
@sailordoctor
Southwest Sheffield Thumb War Champion 1994

Disclaimer: All rights reserved on images in this post.  Feel free to post your reservations.

Reference
N.V Doraiswamy, Isolated finger injuries in children — incidence and aetiology, Injury

You might also like to read about the general principles of treating (and not treating) minor injuries in children.


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