Archive for the ‘Orthopedics’ Category

Signs of cervical spinal cord compression

August 18, 2011

This is a retrospective, unblinded  study of 120 patients without comorbidities undergoing laminoplasty for cervical myelopathy, defined as increased signal intensity (ISI) in T2-weighted magnetic resonance imaging (MRI).

On physical examination, the most sensitive findings were:

  • Hyperreflexia of knee 94%
  • Hoffmann reflex (“flexion of the ipsilateral thumb and/or index finger was considered as positive”) 81%
  • Babinski sign 53%
  • Ankle clonus 35%

These results are likely inflated due to lack of control group which prevented blinding.  In addition, the authors noted that the signs were less sensitive in patients with mild disability. Regardless, I suspect the relative values of the signs are correct and I was surprised on the value of the Hoffmann reflex.


Chikuda H, Seichi A, Takeshita K, Shoda N, Ono T, Matsudaira K, Kawaguchi H, & Nakamura K (2010). Correlation between pyramidal signs and the severity of cervical myelopathy. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 19 (10), 1684-9 PMID: 20229121

Accuracy of physical examination in subacromial impingement syndrome

January 28, 2010
In this study of 55 patients, the authors studied five findings and concluded, “The cut point of 3 or more positive of 5 tests can confirm the diagnosis…, while less than 3 positive of 5 rules out.” If you look at the accuracies and the predictive values below, I think you will agree these results are overstated and not very helpful clinically. The shoulder is still very hard to examine.
Diagnostic Accuracy for Impingement Shoulder Tests among 55 patients with a prevalence of impingement of 29%
Finding Sensitivity (%) Specificity (%) Kappa Positive predictive value Negative predictive value
Hawkins-Kennedy 63 62 39 40 61
Neer 81 54 40 42 13
Painful arc 75 67 45 48 13
Empty can (Jobe) 50 87 47 61 19
External rotation resistance 56 87 67 64 17
3 or more of 5 findings positive 75 74 54 12

How to do the tests

YouTube videos demonstrating the tests

This has been added to


Michener LA, Walsworth MK, Doukas WC, & Murphy KP (2009). Reliability and diagnostic accuracy of 5 physical examination tests and combination of tests for subacromial impingement. Archives of physical medicine and rehabilitation, 90 (11), 1898-903 PMID: 19887215

New bedside finding for carpal tunnel syndrome needs more study

September 18, 2009

New bedside finding for carpal tunnel syndrome. J Hand Surg [Am]. 2008 Nov;33(9):1518-24. PMID: 18984333

At most, this is a new finding to watch for in future research. This study has problems; details are below.

The authors report that in 119 patients with clinically diagnosed carpal tunnel syndrome seen by a single surgeon and 109 controls recruited from a church, the Scratch Collapse test was able to distinguish carpal tunnel syndrome with accuracy of:

Predictive values and prevalence cannot be calculated since this was not a consecutive sample of patients suspected of having carpal tunnel syndrome.

Problems with this study are:

  • Use of case control design rather than a cross sectional study of consecutive patients
  • No true reference standard
  • Subjective interpretation of an abnormal response

Acute, traumatic knee effusions

February 13, 2009

Diagnostic value of history taking and physical examination to assess effusion of the knee in traumatic knee patients in general practice. Arch Phys Med Rehabil. 2009 Jan;90(1):82-6. PMID: 19154833

In this study of patients with traumatic knee injuries of less than 5 weeks duration, the prevalence of effusion was 31% by magnetic resonance imaging. Almost three quarters of patients with an effusion had meniscal or ligament tear.

The accuracy of ballottement was disappointing: sensitivity and specificity 83% and 49%, respectively. The accuracy of self-reported swelling was similar, with sensitivity and specificity 80% and 45%, respectively.

The negative predictive value of ballottement was 86% for patients in this study with a pretest probability of 31% (click here to adjust the pretest probability).

This study has been added to