New bedside finding for carpal tunnel syndrome

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:

• Sensitivity 64%
  
• Specificity 99%

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

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 in detecting effusion 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 http://en.citizendium.org/wiki/Knee_injury.