The Sharp-Purser test is often used by physical therapists to identify atlantoaxial instability, however experts argue that it lacks reliability and validity along with concerns of safety.
- The Sharp-Purser Test: A useful Clinical Tool or an Exercise in Futility and Risk
- Jim Meadows published this article in the Journal of Manual and Manipulative Therapy in 1998 and it highlights 6 reasons we should reconsider using the Sharp-Purser Test in clinic.
- The main points can be boiled down to this
- The test has not been studied in patients post trauma, only in patients with ankylosing spondylitis, rheumatoid arthritis and Down’s Syndrome.
- If paresthesia is produced with cervical flexion, which is rare, the Sharp-Purser maneuver should not be performed and could be dangerous.
- Paresthesia in more than one limb with cervical flexion would warrant a referral to another provider/imaging and then there is no need to perform the Sharp-Purser maneuver.
- Jim argues that the test is unlikely to change our clinical management, and in all scenarios the patient would be referred for more testing making the test obsolete with availability of x-rays, MRI, and CT scans.
As a physical therapist that’s a Fellow of AAOMPT, I always felt better about performing cervical manipulations if my examination revealed a negative Sharp-Purser Test.
- However, a systematic review in Physical Therapy Journal (free to read/download) found the clinical applicability of all upper cervical instability tests is lacking and have several biases.
- My own experience with the Sharp-Purser Test led to a false positive in a patient with cervical myelopathy:
- It’s because of this case I no longer use the Sharp-Purser Test and primarily use a basic range of motion assessment and neurological screen for my physical exam in conjunction with the patient’s history.
- Check out a great article by Dr. Sizer and colleagues on Medical Screening for Red Flags for patients referred for spine pain and considerations for your own examination.
- I now agree with Jim, that if a patient demonstrates myelopathic signs and symptoms with cervical flexion, there really is no need to perform the Sharp-Purser maneuver since no matter what you’re going to refer the patient for imaging.
My experience with the Sharp-Purser Test motivated my colleagues and I to perform a systematic review with the goal of identifying all study types (including case reports) and was published in the Journal of Manual and Manipulative Therapy in 2019.
Our findings are highlighted in this infographic (Download full size PDF here: Sharp Purser Test Infographic):
We included all study types that performed the Sharp-Purser Test on a patient or participant, including RCTs, validity and reliability studies, and case reports.
Of the case reports we included, a negative Sharp-Purser Test often preceded manual therapy treatment to the neck or thoracic spine, whereas a positive Sharp-Purser Test led to referral for more imaging.
- The way the test is used in case reports highlights how clinicians are using the test in practice.
- Check out Tables 3 and 4 in the article.
Several randomized controlled trials that involved cervical/thoracic manipulation or dry needling used the Sharp Purser Test to exclude participants with potential cervical instability, however there’s no evidence that they ever excluded anyone.
Despite mounting evidence that the Sharp-Purser Test lacks validity, reliability and may be unsafe to use clinically, it still remains a widely used test.
In a very interesting musculoskeletal imaging case published in JOSPT a negative Sharp-Purser Test (along with other tests) preceded a diagnosis of vertebral artery dissection that was confirmed with imaging.
- In this case, the negative Sharp-Purser Test likely decreased the clinician’s suspicion of upper cervical instability, however it’s tough to know if a negative test can help you rule out upper cervical instability.
- Our systematic review, found a range of sensitivities reported in the literature for the Sharp-Purser Test from as low as 0.19 to as high as 1.00.
Lastly, we could not find any evidence in the scientific literature that that the Sharp-Purser maneuver is unsafe, however if the transverse ligament is compromised it may be a risky test to perform, and carry unnecessary risk if you’re going to refer the patient for imaging anyway.
Check out our systematic review for more information and download the PDF version of our infographic here: Sharp Purser Test Infographic.
Best wishes,
CJM