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Predicting CRPS

By Timothy Cocks Science and the world 05 Nov 2014

In keeping with other efforts to raise awareness about CRPS, here’s a great little article from Moseley et al (2013) that represents that rare case of a scientific paper that is easily accessible and provides immediately useful clinical information.

Intense Pain Soon After Wrist Fracture Strongly Predicts Who Will Develop Complex Regional Pain Syndrome: Prospective Cohort Study

“An important finding was that it was possible to obtain predictions that were nearly as accurate as those obtained using the 4-predictor model using just 1 predictor: average pain severity over the last 2 days, assessed in the first week after wrist fracture. This suggests that it may be possible, in clinical practice, to identify most people who will subsequently develop CRPS simply by asking, in the first week after fracture, about the severity of pain experienced over the preceding 2 days. This simple assessment can be carried out in seconds and can be conducted by telephone if needed.

In this population, people with pain intensity equal to or less than 4 are unlikely to develop CRPS, but people with pain scores equal to or greater than 5 are at high risk of developing CRPS.

A pain score equal to or greater than 5 in the first week after fracture should be considered to be a ‘‘red flag’’ for CRPS.”

The complete four-predictor model consisted of the following features:

1. Pain- rated by the subject on a VAS of 0 (no pain at all) to 10 (worst possible pain)

2. Swelling- the circumference of the thumb and first three digits measured by the researchers and expressed as a proportion of the measurements of the unaffected hand.

3. Dysynchiria- the presence of sensation in the affected hand when pinprick and allodynia testing were undertaken on the unaffected hand being viewed in a mirror, with the affected hand hidden. That is, sensation provoked by the illusion of the affected hand being touched.

4. Left/Right Discrimination deficit- tested using in house software (similar to Recognise)


The authors caution readers “not to infer causal relationships between the 4 predictors (pain, reaction time, dysynchiria, and swelling) and the development of CRPS” and that the guidelines must be considered provisional until further validation in other samples.

Predicting the next, obvious, question the authors note that “the best available evidence from high quality randomized trials and systematic reviews suggests that it may be possible to reduce the incidence of CRPS with high-dose vitamin C”.

Using the findings of this well designed and robust (near consecutive sample of 1,549 patients) study, clinical scientists at the coal face, seeing people with high pain ratings soon after wrist fracture, might consider the findings of left/right discrimination deficits and dysynchiria in this population and reason that a left/right discrimination assessment, with a trial of carefully graded left/right discrimination training might be appropriate, followed by explicit motor imagery and sensibly introduced mirror therapy – I would.


-Tim Cocks


PS – Full, open access article at the link above!


Find out more about Graded Motor Imagery at and where you can find the print and ebook version of The Graded Motor Imagery Handbook.





  1. Anecdotally, during the patient’s initial examination, i have noted in many patients with with CRPS a consistent pattern of onset, that typically includes a significant pain intensity complaint, early on after the injury. This article supports that observation for me. It also makes me consider the possibility of increased neural sensitivity in those individuals with a more significant pain complaint early on after injury, even if they don’t develop full-on CRPS. A small piece of my reasoning process i suppose……. but relevant, for my practice.

    1. Thanks Bob

      What a shift it has been – I can recall seeing patients as a student that were reporting very high levels of pain and in the quiet conversations with the tutor after being told that they were probably exaggerating or just trying to get a bit more attention… Now we can use the ‘gifts from neuroscience’ to make much better reasoned decisions – accept the patient’s reports of their pain, consider what is happening with that persons biology, psychology and social circumstances and provide an explanation and plan for treatment!

  2. Perfect timing, Tim. I just had a colleague today ask about onset of CRPS, albeit the topic was the Lis franc injury. Will share this with him, to interpret as he sees fit. Thanks!

    1. Hi Wesley
      Always nice to hear the blog can be useful out there in the clinical world.

      1. From my own personal observations over the years such sufferers have always had some form of pyschological issue going on which had been impacting on the quality of their life for many years. I think we should be screening far more the psychosocial aspects of a patient for potential development of such conditions.
        London 😘

  3. Hi,
    This is a well done study and well summarized.

    I would like to learn when earliest a person can have CRPS after an injury or trauma? Apart from the CRPS diagnostic criteria, does duration of onset of symptoms and signs of CPRS has any contribution on CRPS diagnosis? I realise that the one criteria is to rule out the other probable cause or diagnosis of CRPS where duration has role to play.

    Thanking you in advance.



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