I've answered a complaint on precisely one of these - as a registrar back in
1991 - but not seen one since then! As several people have pointed out,
almost any fracture can be sufficiently undisplaced as to make it invisible
on the first films. The important thing to consider is, though, how
important is it if you miss such a fracture?
Well, if it's a scaphoid, and particularly if it's a femoral head, then it
can be very important. Both bones are affected by avascular necrosis. The
femoral head in particular can move from an undisplaced fracture to a
completely off-ended mess in a matter of days. That's a disaster for the
blood supply of that femoral head, and changes the patient's prognosis from
a few months on crutches, but a full recovery, to a lifetime of hip
arthroplasties.
Missing an ulnar shaft fracture is quite innocuous. This is a direct
fracture - most ulnar shaft fractures are - so the fragments are closely
bound to their unfractured neighbouring radial shaft by the tough fibrous -
but radiologically invisible - interosseous membrane. So these fragments
cannot displace. Such fractures always heal and such fractures do not
require POP to make them heal.
From a medicolegal perspective it's very straightforward: the patient won't
make any money if you miss this diagnosis. It's so rare that such a case
will not win on liability, i.e. it's not practical to review and re-xray all
these patients, and such a case certainly won't win on causation, i.e. no
harm arises from missing such an injury, even when you do miss it.
Monteggia is the famous exception: it's a direct fracture alright but
displaces so much that the interosseous membrane is torn, the proximal ulna
parts company from the proximal radius, which dislocates from the
radiohumeral joint. They have such a classic mechanism and
deformity/disability that they can't be missed.
Finally, Philip is right, we have lost a certain amount of quality by going
digital, but it's not image manipulation that excites me about PACS, it's
simply image availability that makes it so special. Any film, any time,
anywhere...no questions asked. But I do worry about the blurring of the
edges...or could that just be my advancing presbyopia!
AF
----- Original Message -----
From: "Scott, Charles" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, December 21, 2006 12:31 PM
Subject: Late fractures on Xray.
> We have just had a case where a 25 year old woman was hit on the forearm
> and she sustained a "defensive" injury of the distal ulna. She had
> local tenderness on the distal ulna only with no other bony tenderness.
> Xray was normal, so she was discharged. 3 days later she attends St
> Elsewhere's because the arm is still very sore and they find this.
>
> Even with hindsight the original film is normal. We know these things
> happen but what is the scientific reason the fracture doesn't show on
> the original film taken on the day of injury? And how often should we
> re-xray patients who complain that the limb still hurts? We are
> familiar with the scaphoid scenario but should this apply to all
> fractures? I think not as this is a rare occurrence, but still going to
> cause us trouble via the complaints procedure. The exception is I
> think patients who return with pain in the hip; we always re-xray hips
> as fractures are well known to show late. Is it that the ulna injury
> is a variety of stress fracture which are notorious as only showing on
> X-ray after a few weeks, but why should a single blow to the forearm be
> a stress injury?
>
> I am reminded of the cartoon boulders which when hit remain intact for a
> second then crack progressively before disintegrating. Did this lady
> have a "Looney Tunes fracture"?
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