FOAM4GP Map – Scaphoid Fractures. Thumbing through the research.

Clinical Case

skateboarding_fail-13343-300x240

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?

Anatomy videoLet’s start our discussion of scaphoid fractures with a quick revision of anatomy. (Some Lovers… TPTTCH).

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

Axial

Question 2 – What is the most common mechanism of injury?

IJEM

“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

Scaphoid fracture Examination

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’.

Best bets

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.

Sens and Spec

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?

Australian DoctorWell 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.

Clinical Radiology“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?

MRI

From “Close to Home” by John McPherson

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

IJEMEssentially 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?

HandSo 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

Journal of Bone and Joint SurgeryAn 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

Short arm thumb spica (From LITFL - Link)

Short arm thumb spica (From LITFL – 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).

Long arm thumb spica

Long arm thumb spica

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

Life the fast lane

And here is a video of an associate professor of emergency medicine at Medical College of Wisconsin applying a thumb spica fibreglass cast  – Link

Thumb Spica

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?).

Orthobullets

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

Scaphoid Repair

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?

SummitA 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?

Patient.co.ukI 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.

Photoshop

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.

autopsy

Ref: “Stu’s views” – Medical jokes – Link

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

11 thoughts on “FOAM4GP Map – Scaphoid Fractures. Thumbing through the research.

  1. Another great post Rob. Good to see you discuss the uncertainty regarding thumb spica casts, have been doing some reading on it myself lately and whilst I’m unconvinced that they’re necessary, the current evidence base does make it a little harder to bite the bullet and just do Colles’ style short arm casts, even though it would be so much faster and more convenient for the patient!

  2. Dear Rob,

    Another fantastic post and summary!

    Before I give my 2c on this clinical scenario, I like to reflect on the Dave Sackett vision of EBM – that it is the combination of best external evidence, patient values and expectations, and clinical expertise. The research evidence (of which the majority in this scenario has not been in the primary care setting) needs to be applied in a critical manner, appropriate to the context and setting in which care is provided.

    Even in my context (Inner Sydney suburb), MRIs are not that easy to obtain within a narrow time window (i.e., 1-2 days). There is the upfront financial cost, not to mention the time cost – MRIs take longer to do than plain radiographs or CTs.

    I think my approach in the context of the above evidence would be very similar to yours. Assuming clinical features suggestive of a scaphoid fracture, x-ray first, which can probably be done on the day. A 70% pick up rate may not be “great”, but it is still the majority of them. If the film is normal, then I think that a discussion for the options needs to be made with the patient.

    (1) Cast + wait and see for a fortnight seems like a pretty reasonable approach for individuals where the loss of function of a hand for the short-term is not a major issue. If the individual is substantially better symptom-wise at the end of 2 weeks, then we’ve avoided the costs involved in further investigations.

    I wasn’t aware of the rather limited diagnostic utility of a follow up film, so thanks for looking that up! I think that if the patient still has symptoms at this point, a CT would be reasonable for most patients. MRI might be better, but it appears that the practical difference between the two at this point is marginal.

    (2) Early (ASAP) CT of the wrist would appear to be a very pragmatic approach for individuals who want to avoid wrist immobilisation. According to the ED observational study, the normal CT has a very high NPV – effectively excluding a fracture (in the context of young adult patients with clinical features of scaphoid # and a normal initial x-ray). Given the primary care population is likely to have a lower prevalence rate of fractures compared to an ED one, the NPV will probably even be higher.

    What is less clear is what an abnormal CT finding means… Given that study had smallish numbers and no gold standard comparison, it is difficult to know what proportion of patients with positive CTs actually have clinically important abnormalities.

    (3) Early MRI of the wrist is a possible strategy but I doubt that it is particularly pragmatic in most contexts at present.

    [rant]
    Philosophically, I think that we also have an opportunity in Australia to avoid some of the poor referral patterns for MRI that perhaps occur for CT. At present, I’m really appreciative of the fact that urgent (on day/next day) MRIs are available in the private community sector for important/time sensitive indications (e.g., stroke, intracranial masses, spinal lesions). I’ve had patients who have presented a day or two after a probable minor CVA/TIA at home, gotten them an MRI/A of the head, made the diagnosis, and packaged them to receive definitive inpatient care without the diagnostic fluffing around in the public system. We won’t have access to this if private MRI services are flooded with low acuity and inappropriate requests.
    [/rant]

    Cheers,
    Michael

    • Thanks Michael,

      You make some very good points again. Abnormal CT for me means splinting and off to fracture clinic so further decision making for me on this point is mute. It is then up to the surgeon to review CT and decide what they want to do +/- MRI for operative planning.

      I think CT is more practical at this point until the price/availability of MRI improves.
      Cheers, Rob.

  3. Hi Rob
    I know you poo-pooed the evidence for US of scaphoid on twitter when I mentioned it – but here is my slant…

    It has a high specificity, better than “snuff box tenderness”. And even though the sensitivity might be low – this is still useful when applied correctly to the poor patient.

    For example, patient with normal Xray but immediate + US for scaphoid # – they can be told up front – this is a 6 week injury and they will need serial assessment / imaging. No need to wait days for a CT or MRI -they know right away.

    If the Xray and US are negative – then you can always revert to plan A.

    Casey

    • Hi Casey,

      Firstly, I am a budding US fan and cannot wait to get my hands on my first machine to help me with my clinical examinations in clinic. However. The point you bring up here allows us to talk a little about sensitivity and specificity.

      The issue for me when assessing a scaphoid is that I want to rule it out – requiring a very high sensitivity to say that I have not missed a scaphoid fracture. If I cannot rule it out, I then need a very high sensitivity test to help me rule it out, or I am treating the patient as if they DO have a fracture and casting them and sending them to fracture clinic. I think this is probably the most typical GP setting.

      The use of CT or MRI, which both have high sensitivity, can reassure me that if they are negative I can rule out a scaphoid fracture, which ALTERS my patient management because I can now send them off without a cast and reassess if required at 7-10 days.

      Let’s say I am a GP who is in a setting where US is available – which I think is a small subgroup of the normal GP population (as most GP’s work in Urban practices which do not have this facility). But lets say that I do have one. One of the major limitations in US diagnosis of Scaphoid fractures in the literature is inter-rater reliability and requirement for an experienced ultrasonographer. I would be a brave GP who states that a patient does NOT have a fracture on US and rule out a scaphoid fracture.

      So let’s assume that I DO have an US machine, I look at several possible Scaphoid fractures every day, and am comfortable with my diagnosis. Let’s say that I do see a fracture on US. I now tell the patient they have a scaphoid fracture and send them to fracture clinic with a cast on – where the Orthopedic surgeon reads my letter which says I have seen a scaphoid fracture on US – which they then will likely ignore and go and order an MRI or CT anyway (even for pre-op planning perhaps).

      So if I assume I have access to an ultrasound machine (which most GP’s do not), I am comfortable at interpreting scaphoid US’s (which I think most would not), and I see a fracture on the US – the benefit is, as you point out, that I can tell them they have a fracture – and then do exactly what I was going to do before anyway. If I do not see a fracture, I still do exactly what I was going to do anyway.

      Most GP’s would have better access to experienced CT scanning rather than experienced US scanning (the other option being I send them to an Ultrasonographer – where in Geelong there is currently a 6 week wait publicly).

      I agree Casey, US is a fascinating modality and can be useful if you see a fracture to tell the patient that they have one. I just think the significant limitations in availability, and also it’s poor ability to ‘rule out’ a scaphoid fracture, when compared to a CT/MRI, makes it a secondary or third choice in imaging modalities at the moment.

  4. Hi Rob
    Agree with your discussion of the test characteristics of US vs CT or MR.
    In my world though US is competing with “clinical examination” – so I think it ads quite a bit of diagnostic accuracy over the infamously chancy guesswork of clinical assessment alone.

    Agree that if you work in suburban practice then maybe no difference in management – however if you leave the metro area or do evenings / weekends in places sans Xray / CT etc then it is a useful, fast and relatively simple scan to do. I see it more as an extension of the clinical assessment, rather than a definitive test – it is about being able to tell the patient more here and now.
    For some – it makes no difference – but there is no downside if you understand the lowish sensitivity.
    C

    • Hi Casey,

      Thanks for the extra points. If you plan to upgrade your US machine any time soon I just wanted to remind you that Xmas is coming and I was never one to turn down a hand-me-down!

      Cheers, Rob.

  5. Pingback: Comment: Scaphoid fractures. Thumbing through the research | Michael Tam

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