Best Evidence Topics


Cruikshank J, Meakin A, Breadmore R, et al
Early computerized tomography accurately determines the presence or abscence of scaphoid and other fractures
Emergency Medicine Australasia
2007; 19, 223-228
  • Submitted by:Craig Ferguson - SPR
  • Institution:Salford Royal Foundation Trust
  • Date submitted:24th March 2009
Before CA, i rated this paper: 5/10
1 Objectives and hypotheses
1.1 Are the objectives of the study clearly stated?
  Yes. To validate the use of early CT compared with the current diagnostic algorithm for clinical fractured scaphoid.
2 Design
2.1 Is the study design suitable for the objectives
  Would have been better if all patients had the same gold standard applied, i.e. a MR scan. Also the MR scans were not done in a blinded fashion.
2.2 Who / what was studied?
  Patients presenting with a history consistent with scaphoid fracture and snuffbox tenderness but no fracture seen on initial x-ray.
2.3 Was this the right sample to answer the objectives?
2.4 Is the study large enough to achieve its objectives? Have sample size estimates been performed?
  Doesn't describe formal sample size estimates. Does state that authors intended to recruit 100 patients which they state would have provided acceptable confidence intervals. In the event they only managed to recruit 55 patients and excluded 8 of those. In addition the incidence of fracture was higher than they had expected.
2.5 Were all subjects accounted for?
  Yes, figure 1 provides a informative breakdown of numbers included and outcomes.
2.6 Were all appropriate outcomes considered?
  I think so. There does appear to be one patient who was not felt to have a fracture on clinical examination but had an MR scan on account of an abnormal CT scan both of which showed a fracture. So there may have been other patients who had sub-clinical fractures but normal CT scans who did not go on to get MR scans. Was there any possibility of false positive scans?
2.7 Has ethical approval been obtained if appropriate?
2.8 Was an independent blinded gold standard test applied to all subjects?
  No. Gold standard consisted of repeat x-ray and clinical examination. In patients with clinical suggestion of a fracture or a positive CT scan with a negative repeat x-ray they went on to have MRI performed in a non-blinded fashion.
3 Measurement and observation
3.1 Is it clear what was measured, how it was measured and what the outcomes were?
  Doesn't describe who reported the radiological investigations. Mentions that the recruiting doctors were of varying seniority, did they interpret the original x-ray or was it a consultant radiologist?
3.2 Are the measurements valid?
  Mentions that 2/3 of possible patients were recruited but doesn't state why 1/3 were missed. No patient demographics were provided so not possible to compare the patients recruited with those not recruited. Is there any selection bias?
3.3 Are the measurements reliable?
  Not clear who interpreted the radiological investigations and whether it was one person or a wide variety of people and whether there was any attempt to measure reliability of reporting.
3.4 Are the measurements reproducible?
  Could construct a similar study.
4 Presentation of results
4.1 Are the basic data adequately described?
  No table 1 with patient demographics.
4.2 Are the results presented clearly, objectively and in sufficient detail to enable readers to make their own judgement?
  Table 2 is clearly presented.
I am surprised that there were no patients with a normal CT scan and x-ray who still had snuffbox tenderness at 10 days.
4.3 Are the results internally consistent, i.e. do the numbers add up properly?
5 Analysis
5.1 Are the data suitable for analysis?
5.2 Are the methods appropriate to the data?
5.3 Are any statistics correctly performed and interpreted?
6 Discussion
6.1 Are the results discussed in relation to existing knowledge on the subject and study objectives?
6.2 Is the discussion biased?
7 Interpretation
7.1 Are the authors' conclusions justified by the data?
7.2 What level of evidence has this paper presented? (using CEBM levels )
7.3 Does this paper help me answer my problem?
  Further study would be interesting with greater numbers and a consistent, blinded gold standard.
After CA, i rated this paper: 5/10
8 Implementation
8.1 Can the test be implemented in practice?
  In my practice access to CT scan is limited and it would not be practical to attempt implementation.
8.2 What aids to implementation exist?
8.3 What barriers to implementation exist?
  Cost and limited time access.
8.4 Are my patients the same as the patients tested?
  Not sure, no demographic data provided.
8.5 Will the test improve diagnosis in my patients?