Article
How user-friendly and valid are outcomes measures and instruments for the lower extremity?
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Published: | October 23, 2013 |
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Background: This review investigates if published outcomes measures for the lower extremity have been validated for clinical use and are sufficiently user-friendly.
Methods: A total of 166 lower extremity - foot (30), calcaneus (10), ankle (41), knee (54), pelvis (3) and hip (28) - outcomes measures and instruments were identified in the literature.
An outcome measure was deemed to be valid (i.e. it measures what it was designed to measure) if:
Content: the content was developed by a team of professionals or through statistical modeling
Construct: the instrument was validated against a generic instrument or correlated with hypothesized subscales from another instrument
Criterion: the instrument was validated against a gold standard instrument or is predictive of a future outcome
No points were awarded if a validation study had not been carried out, and no points were awarded in any of the 3 categories if they were found to be not valid. 1 point was awarded if the category was deemed valid, yielding a maximum possible score of 3 points.
Clinical utility was assessed by awarding points for both patient-friendliness (acceptability) and clinician-friendliness (feasibility) of the tool. Patient-reported and mixed patient-reported and clinician-based instruments were awarded 2 points if < 10 questions were asked, 1 point for 11-25 questions, and no points for >25 questions. All clinician-based outcomes were automatically awarded 2 points for patient-friendliness.
Results:
Element examined: Number
Lower extremity outcome measures and instruments: 166
Patient-reported: 82/166
Clinician-based: 84/166
Maximum validation & clinical utility score of 7: 4/166
Maximum clinical utility score of 4: 30/166
Patient-reported: 30/30
Clinician-based: 0/30
Validated (at all): 108/166
Patient-reported: 73/108
Clinician-based: 35/108
Validated across 3 categories: 26/108
Patient-reported: 24/26
Clinician-based: 2/26
Validated across 2 categories: 48/108
Patient-reported: 34/48
Clinician-based: 14/48
Validated across 1 category: 34/108
Patient-reported: 15/34
Clinician-based: 19/34
Conclusions: Published outcome measures should be used with caution. It is advisable for surgeons wishing to use one:
- to check if it has been previously validated
- to ascertain to what extent the measure was validated
- and against which previously published instrument(s) it was validated as available instruments can vary in methodological strength
While there is no "magic formula", patient-reported instruments on average recorded higher scores for methodological strength and clinical utility than clinician-based instruments.