Xray of Carpal Fx.

[bigdan]

Orthopods and Hand surgeons...

I'm an occupational therapist in NY, looking for your insight on a question posed to me by one of my staff...

WHY is it that a carpal fracture wil not/might not show on a radiograph for up to four weeks? My gut response was that it has something to do with the poor vascularity of the carpal bones, but I can't make any sense of that gut feeling.

Any thoughts?

dc

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[maxheadroom]

Most people would say that it's due to a lack of distracting forces. The carpal ligaments are fairly tight and they will hold the (near) correct anatomic alignment despite simple fractures. The vascularity has no impact upon the ability to detect a fracture early.

 

[Voxel]

The ability to detect some carpal bone fractures acutely depends on whether the fractures are displaced or impacted and the stability of the wrist ligaments and joints. Anatomic wrist alignment is maintained by both carpal ligments and joints. If neither of these are disrupted and/or the fx is small, then non-displaced fractures are not visualized because of lack of any distinguishing features from normal (non-fractured) wrist anatomy.

 

[FliteSurgn]

This is the exact reason that anyone that has a good clinical exam for scaphoid fracture should be treated as such. As an example...When I was a moonlighter at a "doc-in-the-box", we did occupational medicine for some of the big factories in the area. I saw a guy one day that had injured his wrist 3 or 4 months before my exam. His x-rays were negative at the time of his injury, so the doc that initially saw him set him up for physical therapy. He had been coming back to the "clinic" every couple of weeks and being rescheduled for physical therapy by different docs each time. People were even saying that the patient must not be compliant since he wasn't improving. Well, when I finally saw him I couldn't find evidence that anyone had ever x-rayed his wrist again. Lo and behold a terrible non-union scaphoid fracture that may (will) impair this man's wrist for the rest of his life.

 

[maxheadroom]

Hellooooooooooo SLAC wrist . . . dammit . . .

 

[bigdan]

Flite-
Right. I get concerned when there's notoriously poor blood flow to these bones and they don't get any better after the four week standard therapy treatment...our docs locally have been great about x-rays 4 weeks post just to confirm/rule out the fx.

dc

 

[Cassidy61]

Actually, you don't get a SLAC (ScaphoLunate Advanced Collapse) wrist, you get a SNAC (Scaphoid Nonunion Advanced Collapse) wrist. SLAC is from an untreated scapholunate dissociation, SNAC is from a nonunion. Besides doing a through exam, getting appropriate radiographs will usually show you even a non displaced scaphoid fx. For instance, if you suspect a SL tear, you can get a clenched fist view (stresses SL lig) and compare it to the other side. Also, if you suspect a scaphoid fx, you might want to get an ulnar deviated scaphoid view.

 

[PA_to_MD]

If you have tenderness in the snuffbox without radiographich evidence. You can either put them in a thumb spica cast/splint and repeat the x-ray in 10-14 days or you can get an MRI to evaluate for fracture at the initial presentation. I would never do any type of therapy with clinical evidence of fracture, waiting 4 weeks after therapy is a malpractice suit waiting to happen.

 

[RADRULES]

Hmmm... we have always used a fairly simple formula to catch most scaphoid fx, a true navicular view is part of our wrist protocol, which will show the vast majority of fx in my experience.

If a patient has snuffbox tenderness, we usually get them back in a week, at which time sclerosis will usually identify an occult fx.

 

[bigdan]

PA to MD-
I don't disagree with you; I can recall, however, prescriptions that come in with a dx. of "hand pain", that are not blatant clinical presentations of carpal bone fractures...

dc

 

[Ex-fix]

Carpal fractures can be difficult fractures to dx. many patients have snuff box tenderness. Almost every distal radius fx has snuff bos tenderness. Tenderness on the scaphoid tubercle. High energy injuries usually present with obvious displacement. However, subtle injuries are more difficult to diagnose. Scaphoid factures are the most common. Scaphoid fractures are difficult to dx because: 1) The normal scaphoid aligment doesn't project a true AP of the scaphoid (you need a 30 deg sup view); 2) the vasularity of the scaphoid is in retrograde fashion. So fracutres occurring proximally may not be present in the initial radiographs. It take 10-14 to show enough bone resorption to deliniate a fx line. If you suspect a scaphoid fracture initally, the pt. should be plaace in a thumb spica cast for 10-14d. If radiographs are negative, but fx is still expected clinically, an MRI or bone scan can be performed. Many of us orthopods prefer MRI now because it can show other ligamentous injuries in the wrist.

Other carpal fractures can hardly ever be diagnosed on X-Ray (ie hamate fxs). These other fractures require a CT and/or MRI. Many of these other fracture present as chronic non-unions. Patients present with hand/wrist pain with gripping activities (golf, raquetball, baseball). In short, don't hesitate to order test if carpal fractures are suspected. The outcome of a missed fracture makes the treatment more intense for the patient in the long run.

 

[PA_to_MD]

All distal radius fractures are immobilized with a splint initially, so that hand therapy isn't an issue for these cases. Isolated scaphoid fractures are not that difficult to pick up clinically. Other carpal fractures can be picked up by an acurate history and physical exam. Hook of Hamate fractures are easily diagnosed with the carpal tunnel view.

 

[maxheadroom]

Isolated scaphoid fractures are the most commonly missed carpal fracture. (reference Green's)

 

[PA_to_MD]

This maybe so but it is clinical error that is the reason for it. Any good orthopod will be aware of this. That statement is a warning for the cavalier that only treat what they see on x-ray.

 

[Docxter]

Don't clump all carpal bone fractures as "carpal fractures". Not all carpal fractures are scaphoid fractures. The individual fractures can differ quite a lot with each other and the ease of detecting fractures on x-ray or the different views needed to optimally see the fracture, their treatments, or their complications..

PA to MD mentioned that hook of hamate fractures are easily identifiable by carpal tunnel views. Simply not true. I've seen many cases that were not identifiable on x-ray including special views (even in retrospect) and the diagnosis was made by MRI or CT. Most of these patients were jumping from orthopod to orthopod with weeks of pain and most did not give any history of acute trauma. Hook of hamate fractures are common among golfers and tennis players and can be a fatigue fracture. These patients may have full range of motion and may sometimes even have no point tenderness.

 

[Ex-fix]

All distal radius fractures are immobilized with a splint initially, so that hand therapy isn't an issue for these cases. Isolated scaphoid fractures are not that difficult to pick up clinically. Other carpal fractures can be picked up by an acurate history and physical exam. Hook of Hamate fractures are easily diagnosed with the carpal tunnel view.

We immobilize our distal radius fractures in casts initally, unless there is significamt swelling, or planned ORIF or CRPP in the next day or two.
I disagree with your statement about hamate fractures. They are not easily diagnosed with plain radiographs. Many are non-displaced. Read your texts. Unless significant displacement occurs, these require special studies to make the diagnosis. Isolated scaphoid fractures are rather easy to diagnose, becuase about every primary or emergency care practitioner knows the steps in diagnosing these injuries.

I'm not going to get into the derrrangements of carpal kinematics, because that is another discussion.

Ex-fix