A 20-Year Follow-up After First-Generation Autologous Chondrocyte Implantation
Bibliographic record
Abstract
BACKGROUND: Treating articular cartilage defects is a demanding problem. Although several studies have reported durable and improved clinical outcomes after autologous chondrocyte implantation (ACI) over a long-term period, there is no report with over 20 years' follow-up. PURPOSE: To evaluate clinical outcomes after first-generation ACI for the treatment of knees with disabling, large single and multiple cartilage defects for which patients wished to avoid prosthetic arthroplasty, with a minimum of 20 years' follow-up. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: ) per knee. Kaplan-Meier survival analysis and functional outcome scores, including the modified Cincinnati Knee Rating System, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Short Form-36 (SF-36), were used. Patients also self-reported an improvement in pain with a visual analog scale and a satisfaction survey. RESULTS: The 20-year survival rate was 63% (95% CI, 40%-78%). The evaluation of the 15 knees with retained grafts demonstrated that all clinical scores except the WOMAC subscore for stiffness and SF-36 mental component summary score improved significantly and were sustained to 20 years postoperatively. Ninety-three percent of these patients rated knee-specific outcomes as good or excellent. The outcomes for 9 of 24 knees were considered failures, including 5 undergoing revision ACI and 4 being converted to arthroplasty at a mean of 1.7 and 5.9 years, respectively. Only 1 of 5 knees that underwent revision ACI was converted to arthroplasty at 1.9 years after the index surgery, and the other 4 patients were able to maintain their biological knee. Overall, 20 years later, 79% of patients maintained their native knee, for which they initially sought treatment, and were satisfied when evaluated. CONCLUSION: First-generation ACI provided satisfactory survival rates and significant clinical improvements over a 20-year follow-up, which offers an important standard for comparison with newer-generation ACI technologies of the future.
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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 | 0.002 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.003 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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; 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".