Best Evidence Topics

Decision rule

Emond M. Le Sage N. Lavoie A. Rochette L.
Clinical factors predicting fractures associated with an anterior shoulder dislocation.
Academic Emergency Medicine.
11(8):853-8, 2004 Aug.
  • Submitted by:Steffen Genthe - Emergency Medicine Resident
  • Institution:Grand Rapids Medical Education and Research Center
  • Date submitted:18th May 2005
Before CA, i rated this paper: 7/10
1 Objectives and hypotheses
1.1 Are the objectives of the study clearly stated?
  Yes. (p. 853). " identify risk factors for fractures associated with anterior shoulder dislocation treated in the emergency department."
2 Design
2.1 Is the study design suitable for the objectives?
  Yes, to an extent. A retrospective case-control study is suitable. Of course, a prospective study would attain a higher level of evidence.
2.2 Who / what was studied?
  Chart review of consectutive records of patients presenting with shoulder dislocations between 1-1-95 and 12-1-2000 at a university ED in Quebec.
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?
  It is large enough to generate odds ratios with significant confidence intervals. It does not appear sample size estimates were performed.
2.5 Were all subjects accounted for?
  Yes. 414 anterior dislocations; 80 excluded, 334 included.
2.6 Were all potential predictors included during derivation?
  Certainly, not all predictors can be included. It does appear that clinically important and available predictors were considered.
2.7 Were all appropriate outcomes considered?
  Yes. Fractures vs. no fracture.
2.8 Has ethical approval been obtained if appropriate?
2.9 Has the decision rule been validated?
  No. (Yes - within the sample - see below.)
2.10 Are the derivation and validation data set independent?
  No. Results were crossvalidated within the sample.
3 Measurement and observation
3.1 Is it clear what was measured, how it was measured and what the outcomes were?
  Yes. Fractures (divided into clinically-significant and insignificant) were associated with anterior shoulder dislocations.
3.2 Are the measurements valid?
  Yes. Patients were classified by their formal radiology reports.
3.3 Are the measurements reliable?
  Yes, implicitly.
3.4 Are the measurements reproducible?
  Yes, implicitly, with regard to "clinically-significant" fractures.
4 Presentation of results
4.1 Are the basic data adequately described?
  Yes. (See tables 1-2.)
4.2 Are the results presented clearly, objectively and in sufficient detail to enable readers to make their own judgement?
  Yes. All patients were accounted for.
4.3 Are the results internally consistent, i.e. do the numbers add up properly?
  Yes. (See table 4.2) Also, incomplete charts were excluded.
5 Analysis
5.1 Are the data suitable for analysis?
  Yes. Outcomes are yes/no questions and are easily analyzed statistically.
5.2 Are the methods appropriate to the data?
  Yes. Univariate analysis. (Alcohol intoxicated individuals were excluded due to insufficient numbers.)
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?
  Yes. Multiple previous studies are discussed.
6.2 Is the discussion biased?
  No. Limitations of the study are frankly addressed.
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)
  2b (See CEBM criteria on the BestBETs website for details.)
7.3 Does this paper help me answer my problem?
  Yes, it helps. However, odds ratios of 4 to 5 are not high enough to establish a usable prediction rule.
The fact that 0% of non-traumatic dislocations were associated with fracture may be useful.
After CA, i rated this paper: 5/10
8 Implementation
8.1 Can this decision rule be implemented in practice?
  Yes, changes to order / not order an x-ray are easiliy implemented. However, more data regarding LOW probablility of fracture (the most potentially cost/ time/morbidity-reducing) are needed.
8.2 What aids to implementation exist?
  As in 8.1, no "aid" is necessary; as an x-ray is either ordered or not. Given the odds ratios in this study, one would certainly be more apt to order x-rays in select patient populations.
8.3 What barriers to implementation exist?
  Better information on low-risk predictors for fracture; see 8.1 above.