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Introduction
  • A method utilized in evidenced based medicine to determine the clinical value of a study
  • See details of Clinical Design Trials 
Different Levels of Evidence
 
Level 1
  1. Randomized controlled trial (RCT)
    • a study in which patients are randomly assigned to the treatment or control group and are followed prospectively
  2. Meta-analysis of randomized trials with homogeneous results
Level 2  
  1. Poorly designed RCT
    • follow up less than 80%
  2. Prospective cohort study (therapeutic) 
    • a study in which patient groups are separated non-randomly by exposure or treatment, with exposure occurring after the initiation of the study
  3. Meta-analysis of Level 2 studies
Level 3
  1. Retrospective cohort study
    • a study in which patient groups are separated non-randomly by exposure or treatment, with exposure occurring before the initiation of the study
  2. Case-control study
    • a study in which patient groups are separated by the current presence or absence of disease and examined for the prior exposure of interest
  3. Meta-analysis of Level 3 studies 
Level 4
  1. Case series
    • a report of multiple patients with the same treatment, but no control group or comparison group
Level 5
  1. Case report (a report of a single case)
  2. Expert opinion 
  3. Personal observation
 
 JBJS LOE
AAOS Recommendations
 

AAOS Evidence-Based Practice Committee

  Recommendations in Clinical Practice Guidelines

Strong • Two or more HIGH quality studies
Moderate  • One HIGH or 2 MODERATE quality studies
Weak 

• One MODERATE or 1 or more LOW quality studies

Consensus
• Expert opinion (no studies)* Only used in one circumstance: It pertains to medical interventions that potentially prevent loss of life or limb (catastrophic consequences).

 
 
 

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Questions (10)

(OBQ11.239) In the study by Moseley et al published in the New England Journal of Medicine, 180 patients with knee osteoarthritis were randomly assigned via sealed envelope to receive arthroscopic d├ębridement, arthroscopic lavage, or placebo surgery. Outcomes were assessed by blinded evaluators at several points over a 2 year period with the use of five self-reported pain and function scores. There was a greater than 90% follow-up in the study. This study is best described as having which level of evidence? Review Topic

QID: 3662
1

Therapeutic study, evidence level I

86%

(708/828)

2

Therapeutic study, evidence level II

7%

(60/828)

3

Diagnostic study, evidence level I

2%

(16/828)

4

Diagnostic study, evidence level II

1%

(6/828)

5

Prognostic study, evidence level I

4%

(32/828)

Select Answer to see Preferred Response

PREFERRED RESPONSE 1
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(OBQ13.33) A physician is interested in using platelet-rich plasma (PRP) for treatment of osteochondral lesions of the talus. He is reviewing a prospective cohort study that compares 40 patients treated with PRP and cast immobilization for 6 weeks vs. 36 patients treated conservatively with cast immobilization for 6 weeks. All patients were treated at the same time and institution. The study was not randomized although treatment and control groups were matched appropriately to reduce selection bias. Follow-up in each group was >80% over 1 year. The paper reported significant improvement with use of PRP based on three standard foot and ankle outcome scores (AOFAS, SF-36, FOAS). What is the level of evidence for this study? Review Topic

QID: 4668
1

Level I

3%

(83/3141)

2

Level II

71%

(2230/3141)

3

Level III

23%

(709/3141)

4

Level IV

3%

(90/3141)

5

Level V

0%

(6/3141)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

(OBQ10.242) Which of the following study designs represent a level III evidence study? Review Topic

QID: 3341
1

Prospective, randomized controlled trial

1%

(16/1500)

2

Retrospective case-control study

74%

(1103/1500)

3

Retrospective case series

17%

(249/1500)

4

Prospective cohort study

7%

(108/1500)

5

Expert opinion

1%

(17/1500)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

(OBQ12.188) An orthopaedic resident wants to answer a focused research question of whether mobile bearing knee arthroplasty has superior functional outcomes compared to fixed bearing knee arthroplasty. The resident mathematically combines the results from multiple retrospective cohort studies following QUORUM (Quality of Reporting of Meta-analyses) guidelines. What is the highest level of evidence that this meta-analysis can achieve? Review Topic

QID: 4548
1

Level I

8%

(308/4026)

2

Level II

23%

(930/4026)

3

Level III

57%

(2307/4026)

4

Level IV

10%

(412/4026)

5

Level V

1%

(36/4026)

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

(OBQ12.100) A therapeutic study presents a systematic review of 15 high-quality randomized controlled trials with homogeneous results. What level of evidence is this considered? Review Topic

QID: 4460
1

I

70%

(2517/3582)

2

II

14%

(517/3582)

3

III

9%

(322/3582)

4

IV

4%

(148/3582)

5

V

1%

(50/3582)

Select Answer to see Preferred Response

PREFERRED RESPONSE 1

(OBQ08.127) Using levels of evidence in research studies, which of the following represents a level II study? Review Topic

QID: 513
1

Retrospective case control study

9%

(127/1460)

2

Prospective cohort study

84%

(1226/1460)

3

Case report of 3 patients with the same disease

1%

(8/1460)

4

High-quality randomized prospective clinical trial

6%

(93/1460)

5

The opinion of a review panel at the annual AAOS meeting

0%

(2/1460)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2
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