Development and Validation of a Lower-Extremity Activity Scale
Bibliographic record
Abstract
BACKGROUND: Valid outcome measurement tools are required to reliably demonstrate the effectiveness and clinical outcomes of lower-extremity arthroplasty. Having ascertained a lack of a practical and valid measure of the change in actual daily physical activity that occurs prior to and following lower-limb arthroplasty, we developed and validated a lower-extremity activity scale. METHODS: The eighteen-level self-administered scale was developed with the aid of content experts to ensure face validity. Validity and reliability were assessed with the use of (1) pedometer measurements of seventy subjects over seven days; (2) next-of-kin proxy measurements of the activity levels of ninety patients before they underwent lower-limb arthroplasty; and (3) application, and correlation with the Western Ontario and McMaster Universities Osteoarthritis Index scores, in a prospective seventeen-center clinical study of 297 consecutive patients undergoing revision total knee arthroplasty. In this latter study, demographic and comorbidity data were also collected. Univariate and bivariate correlations were performed, and a multivariate structured equation modeling approach was used to further test responsiveness, reliability, and validity of the lower-extremity activity scale. RESULTS: Pedometer readings correlated with the activity levels derived with the lower-extremity activity scale (r = 0.79). Of note was the finding that age, weight, and body mass index did not correlate well with the average number of steps per day (r = -0.32, -0.32, and -0.25, respectively). A significant correlation was found between the lower-extremity activity scores recorded by the patients and those reported by their next of kin (Pearson correlation, r = 0.715; p = 0.0001) and between the initial lower-extremity activity scores and two-week-retest scores (intraclass correlation = 0.9147; p < 0.0001), demonstrating the validity and reliability of the scale. The lower-extremity activity scale was responsive, accurately reflecting changes in the patient's condition between baseline and the time of follow-up (p < 0.001), and it was reliable, with baseline values correlating with follow-up scores (p < 0.001). The convergent validity of the lower-extremity activity scale was established by correlations with the function scores (r = -0.301, p < 0.001) and pain scores (r = -0.241, p < 0.001) derived with the Western Ontario and McMaster Universities Osteoarthritis Index and with a higher number of comorbidities (r = -0.244, p < 0.001). Multivariate path modeling further demonstrated diminished activity in patients who had more difficulty in functioning and a greater number of comorbidities. CONCLUSIONS: We developed a lower-extremity activity scale and validated that it was an effective instrument for the assessment of patients' actual activity levels. It is easy to apply and interpret, and it is valid and ready for use in the clinical setting. This scale will allow more accurate analysis and prediction of outcomes. Consequently, it will become a useful, practical adjunct to objective clinical decision-making and intervention for patients undergoing arthroplasty.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".