Is the Canadian Orthopaedic Foot and Ankle Society Ankle Arthritis Score (COFAS AAS) Associated with the Need for Revision Surgery?
Bibliographic record
Abstract
Category: Ankle Arthritis Introduction/Purpose: There has been limited evidence to support the effective use of a patient reported outcome measure (PROM) for patients that have undergone surgical treatment for end-stage ankle arthritis (ESAA). This study used longitudinally collected patient-data from a cohort of patients in the Canadian Orthopaedic Foot and Ankle Society (COFAS) ankle arthritis study to evaluate whether the post-operative COFAS Ankle Arthritis Score (COFAS AAS), a patient-reported outcome (PROs), was associated with need for revision surgery. Methods: Between 2001 and 2010, a cohort of 623 patients and 653 ankles undergoing total ankle replacement or ankle arthrodesis were enrolled in a multicenter prospective ankle reconstruction study. At pre-surgical baseline, key patient level variables were collected including demographics, body mass index, and comorbidities. The COFAS AAS, a patient-reported outcome measure was collected at baseline and annually post-surgically. Time to revision surgery was modeled using a proportional hazards model which controlled for age, sex, BMI, diabetic status, smoking status, inflammatory arthritis, and surgery on the right or left side and time varying PROs. Results: 531 ankles in 509 patients with complete pre and post-operative data were included. Seventy of the cohort underwent metal component revision procedures during the follow up time period . The remaining 461 unrevised ankles had a minimum 2 year follow up (average of 3.4 years). Baseline COFAS AAS, age, sex, side, BMI, diabetic status, smoking status, and inflammatory arthritis were not statistically associated with the need for revision surgery. However, revision surgery was found to be associated with a higher post-operative COFAS AAS, and with a longer follow-up. The hazard ratio for the COFAS AAS indicates that for every one-point increase in the score, the rate of revision surgery was one percentage point higher at each post-operative time point. Conclusion: This study demonstrated that patients who reported higher levels of post-operative functional impairment, as indicated by a higher COFAS AAS, were more likely to undergo a revision surgery. This finding is also based on duration of follow-up, with the risk of revision surgery rising with length of follow up. This study provides further evidence for the utility of the COFAS AAS in the clinical setting. Further investigation is warranted to better understand the COFAS AAS’s ability to measure clinically meaningful change in an individual patient not requiring revision surgery.
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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 | 0.001 | 0.007 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 source (direct Gemma or distilled Codex), 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".