Pitfalls of Using Patient Recall to Derive Preoperative Status in Outcome Studies of Total Knee Arthroplasty
Bibliographic record
Abstract
BACKGROUND: It is essential to adjust for the level of preoperative pain and functional status when measuring the outcome of total knee arthroplasty. Some study designs rely on postoperative patient recall to derive preoperative status. In this study, we compared prospectively collected preoperative data with data derived from patient recall of preoperative status three months after total knee arthroplasty. METHODS: Patients were recruited as part of a prospective observational study of the outcome of primary total knee arthroplasty for osteoarthritis at four centers in the United States, six centers in the United Kingdom, and two centers in Australia. Independent research assistants recruited patients and collected data with use of a uniform documentation system preoperatively and three months postoperatively. Preoperative data included the findings of a clinical history and physical examination, demographic information, socioeconomic status, and scores from two health-status instruments: the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and the Medical Outcomes Study Short Form-36 Health Survey (SF-36). Postoperative data included the WOMAC and SF-36 scores and patient recall of preoperative status on selected items from these health-status measures. RESULTS: A total of 862 patients were recruited, and recall data were available for 770 patients (89%). The mean age was seventy years (range, thirty-eight to ninety years), and 59% of the patients were women. Comparisons of prospective and recall data on individual pain and function items showed poor-to-fair agreement (weighted kappa, 0.20 to 0.41). Patients recalled significantly more pain than they had reported preoperatively (p < 0.001), but there were random recollection errors for the function items. There was only moderate correlation between the prospective and recalled summary scores for pain (Spearman r = 0.53) and function (Spearman r = 0.48). In addition, 61% of the recalled pain scores and 50% of the recalled function scores differed from the prospective scores by more than 10 points (10% of the total range). CONCLUSIONS: Patients' recall of preoperative pain and functional status three months after total knee arthroplasty demonstrated only moderate agreement with what the patients had reported prospectively. Researchers who use recall data to derive preoperative status must recognize these limitations when drawing conclusions about the effectiveness of total knee arthroplasty.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.550 | 0.671 |
| Meta-epidemiology (narrow) | 0.002 | 0.002 |
| Meta-epidemiology (broad) | 0.004 | 0.004 |
| Bibliometrics | 0.008 | 0.012 |
| Science and technology studies | 0.003 | 0.008 |
| Scholarly communication | 0.006 | 0.004 |
| Open science | 0.005 | 0.006 |
| Research integrity | 0.002 | 0.004 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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; the direct Gemma label and the distilled Codex classifier agree on what is shown here.
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".