A 16yo M presents after falling forwards off a skateboard onto a R outstretched hand (FOOSH). He describes immediate pain in the wrist and some mild swelling.
Presents to my clinic the next morning with mild swelling of the wrist. On examination he had a generally tender wrist all over with no obvious deformity, neurovasc intact, with some mild tenderness in the snuff box, and mild tenderness on telescoping of the thumb (axial loading).
Xray reveals no fractures and no obvious injury to the scaphoid. I place him in a thumb spica cast and get him to come back in 10 days for repeat xray.
So. How good is my examination? Can I rely on tenderness or telescoping of the thumb? Is there another test I could do instead? How good are we at picking up scaphoid fractures on xray? When should I consider CT, MRI, bone scan – and which one? Do I have to put him in a thumb spica cast?
So many questions?! And I was previously feeling pretty good about what I did for scaphoid fractures. But you know, I haven’t read any evidence on this – so let’s meducate myself (and feel free to have a look yourself too).
Question 1 – (Refresher) What is the basic anatomy of the scaphoid and associated structures?
Two ways to do this. Firstly, here is a brilliant, fun, and entertaining look at relevant scaphoid anatomy and surface anatomy by Andy Neil from emergencymedicineireland.com – Video Link – Their website – Link
If you prefer to read and look at diagrams at your own pace there is a great interactive Radiology Masterclass on the scaphoid here with radiology features of the scaphoid and injuries – Link
Question 2 – What is the most common mechanism of injury?
“The typical trauma mechanism is a fall on the outstretched hand with the wrist in radial deviation inducing impact of the palm.” – Discussed in International Journal of Emergency Medicine 2011. This is a really well written article and good overall summary – Link
Question 3 – How do you examine a wrist with suspected scaphoid injury?
Let’s have a look at a good example. Here is a great guide to examination of the wrist by EM Capetown – Link
Question 4 – What are the best clinical signs, and their evidence, to assess for scaphoid # / injury?
So how good is my ‘anatomical snuff box’ (ASB) tenderness’ and ‘telescoping the thumb (axial loading)’. Well, there is no consensus on the ‘best test’.
ASB had 100% sensitivity but specificity ranges from 20% to 98% in different studies?! This nice summary article in ‘Best BETs’ suggests a combination of ASB + Axial compression + scaphoid tubercle tenderness gives almost 100% sensitivity and high specificity (so likely to have some false positives) – Link
The scaphoid tubercle can be palpated with pressure at the base of the thenar eminence (thumb). Axial loading can be performed by holding the thumb and applying pressure proximally against the scaphoid.
Acta Orthop Belgium 2006 has an article called “Development of a clinical decision tool for suspected scaphoid fractures” There is a great table which shows the sensitivity and specificity of our clinical examination findings – Link
Question 5 – How good are we at picking up scaphoid fractures on plain xray?
Initial radiographs pick up approx 70%. Not great really.
Bhat M, McCarthy M, Davis TR, Oni JA, Dawson S. MRI and plain radiography in the assessment of displaced fractures of the waist of the carpal scaphoid. J Bone Joint Surg Br. 2004;86(5):705–13
Question 6 – What can go wrong with scaphoid fractures?
Well if you miss the fracture, non union and severe arthritis can occur. It is a mess and treatment outcomes for salvage procedures are not good. Here is a discussion of what can go wrong if it is missed – Australian Doctor article 2011 “Fractured” – Link
Question 7 – So is it worth doing a follow up xray at 7-14 days?
It has become a standard practice, and something I was taught, to re x-ray at 7-14 days to look for signs of healing.
“The theory is that during this period the fracture will become visible on radiographic images due to resorption around the fracture line. Several authors have contested the validity of this approach… A reliability coefficient of more than 60% is needed for a diagnostic test to be considered reliable. Over-all, the inter-observer reliability coefficient [for repeat xray at 14 days] was 33%” – Clinical Radiology 2005 – Link
Question 8 – If doing an xray at 10-14 days is not clinically reliable, what other imaging options do we have? And costs?
There has been a move towards earlier more advanced methods of imaging. A great study from Ballarat discusses the use of day 1 CT in patients with suspected scaphoid fractures who have a normal xray. They argue the benefits of not needing to early immobilise these patients is worth the healthcare cost. Sensitivity 72-100% and Spec 80-100%. To read further look here – Published in Western Journal of Emergency Medicine – 2009 – Link – NB: Even if using a CT and no evidence of fracture, they suggested patient should be reviewed at 10 days. If still symptoms at 10 days then they should have a follow up MRI.
I am always concerned about radiation with CT’s. CT of the scaphoid (hand), however, only involves 0.5 milliSv of radiation – 25 chest xrays (or less) (CT Abdomen 500 CXrays). (Probably less important organs in the hand than in the abdomen also!)
It is confusing in under 14yo’s. Scaphoid fractures are less common in this young group and they are also less likely to lose significant income through loss of work. Ballarat’s guidelines suggest CT is not as good in under 14’s (I cannot find the direct reference – there is alot of them!) Here is a flow chart from WA Health showing imaging planning for paediatric suspected scaphoid fracture. Note the use of immobilisation for 10 days and then re-xray (being used as a ‘rule in’ test if positive). If no fracture seen then MRI – Link
Essentially MRI is the gold standard with negative predictive value, sensitivity and specificity, approaching 100%. They are expensive in Australia and difficult to access but most guidelines will include this (WA Health imaging flow chart – Link.) and for a CT if MRI cannot be done. A Nuclear medicine scan also has very good sens/spec (particularly after 5 days) but has larger radiation doses, and higher costs. Ultrasound has been shown to be unreliable to rule out a scaphoid fracture.
These other imaging modalities are discussed here in an article by LITFL (good article because it was the ED consultant who had the fracture! (ie. vested interests!)). – Link – and also in a more detailed article in International Journal of Emergency Medicine 2011 – Link (nice article – worth a look).
Question 9 – So, to thumb spica or not? Short or long arm cast?
So to start this debate, here is an article studying the biomechanics of forces on the scaphoid with a thumb spica cast vs a short arm cast with the thumb free. They suggest no change to pressure or mobility of the scaphoid with either cast – Hand 2008 – Link
An often quoted study is from 1991, 300 scaphoid fractures were immobilised in either colles or thumb spica. Outcome showed no difference in nonunion at 6 months. Journal of Bone and Joint Surgery 1991 – Link
And then we disappear into the murkiness. I really struggle to find much evidence in regards to thumb spica vs colles type cast (short arm) vs long arm cast (I thought this would have been studied well by now).
Canadian Family Physician 2000 talks about using short or long arm casts depending on where the fracture is in the scaphoid eg. waist (short arm), proximal pole (long arm cast) – Link
Looking at most Australian guidelines/websites they recommend short arm thumb spica casts. This is also what I was taught. Seems more research is required to justify this though…
Here is the Ballarat ED Clinical Practice Guidelines – Link
Question 10 – What are some tips/tricks to placing a scaphoid thumb spica plaster?
I always make up the scaphoid spica by putting on a short arm cast and then adding another piece to make the thumb spica. I think it can be done better.
Here is a ‘cut out’ guide for making a plaster template from Life in the Fastlane – Link
And here is a video of an associate professor of emergency medicine at Medical College of Wisconsin applying a thumb spica fibreglass cast – Link
Question 11 – Ok so what if they DO have a scaphoid fracture on imaging. What will our orthopaedic colleagues do?
Generally if patients have a fracture I refer them to a local fracture clinic (which I think is probably standard practice around Australia? Please let me know if you don’t?).
Surgery, or not surgery. There is a move towards operative management for even acute non displaced fractures. Literature had classically stated a 10% non union rate for nonoperative management vs a 0% non union rate for surgical fixation. A study in J Bone and Joint Surgery 2008 challenges this by following 75 scaphoid fractures for 10 years. There was no long term benefit of internal fixation in this study – Link –
Another study in Unfallchirurg (I don’t know what that stands for in German!) in 2011 found a more rapid return to work rate and better functional status, pain, and overall satisfaction with surgical repair but more complications with union and secondary operative requirements – Link
Here is an orthopaedic discussion on scaphoid ORIFs, details of when they consider surgery, and what they would do – Orthobullets – Link
Do you want to see a video of one of these being repaired? Curious? Here’s one by hand surgeon Mike Hayton – Link
Question 12 – How do you follow up scaphoid fractures?
A discussion of the treatment options, healing, and outcomes is discussed in “Assessment of scaphoid fracture healing” in Current Review Musculoskeletal Medicine 2011 – Link
Question 13 – How long does the cast need to be on?
Distal 1/3rd – 6-8 weeks
Middle 1/3rd – 8-12 weeks
Proximal 1/3rd – 12-23 weeks
Ref: LITFLane – Link
Question 14 – Post scaphoid injury, what advice should I give for rehabilitation/exercises?
A good handout for patients with pictures of exercises they should perform for rehab of their wrist after a scaphoid fracture are shown here from the summit medical group – Link
Question 15 – Any good patient information sheets?
I really quite like these patient.co.uk information sheets. Another high quality one on scaphoid fractures – Link
So, how does this change my practice?
So for my 16yo M he examines positively for anatomical snuff box tenderness, axial loading, and now I also examine his scaphoid tubercle for tenderness. Given these are positive I send him for plain xrays. If he returns with a normal xray I give him some options.
The best is an MRI now. If this is negative then he can go on his merry way comfortable that it is incredibly unlikely he has an occult fracture. Problem is this will cost him (locally here) $250 and he may have to wait a day or two (in the meantime I will put him in a splint (either plaster or to our local ortho store for a plastic one)).
Otherwise, if he cannot afford this or doesn’t want to wait, I can offer him a CT. If this is clear then I can allow him to go, perhaps with a splint for pain relief, but he must return at 7-10 days for re-examination. If suspicious at that time he goes for MRI.
OR I can put him in a cast now, and re-xray at 10 days. If still clinically sore and still no fracture at 10 days then I can offer him CT/MRI or Nuclear medicine scan.
IF he is fractured then I will place him in a short arm thumb spica cast (using the template from above) and refer him to fracture clinic where they may discuss surgical options or conservative measures. They will probably convert to a fibreglass cast at this time also.
PHEW!! I think the conclusion here is that we need some more guidelines, research, and clarity! It has changed my thinking though, I will be a bit more pragmatic about offering more advanced imaging for the plumber who will lose two weeks work if I thumb spica him, who even then may not have a fracture and he has had significant financial loss! He may well just want the CT or MRI so he can get it sorted and return to work sooner.
PLEASE debate this! If you do differently, if you have different local services available, if I have missed any obvious research, please let me know! If not just for my learning but also for any other interested parties.
Thanks for reading! Hope some of this helps!
Cheers, Rob. @RobaPark