The Long-Lasting Effects of “Placebo Injections” in Knee Osteoarthritis: A Meta-Analysis
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Objectives To quantify the placebo effect of intraarticular injections for knee osteoarthritis in terms of pain, function, and objective outcomes. Factors influencing placebo effect were investigated. Design Meta-analysis of randomized controlled trials; Level of evidence, 2. PubMed, Web of Science, Cochrane Library, and grey literature databases were searched on January 8, 2020, using the string: (knee) AND (osteoarthritis OR OA) AND (injections OR intra-articular) AND (saline OR placebo). The following inclusion criteria were used: double-blind, randomized controlled trials on knee osteoarthritis, including a placebo arm on saline injections. The primary outcome was pain variation. Risk of bias was assessed using the RoB 2.0 tool, and quality of evidence was graded following the GRADE (Grading of Recommendations Assessment, Development and Evaluation) guidelines. Results Out of 2,363 records, 50 articles on 4,076 patients were included. The meta-analysis showed significant improvements up to the 6-month follow-up: Visual Analogue Scale (VAS)-pain −13.4 mean difference (MD) (95% confidence interval [CI]: −21.7/−5.1; P < 0.001), Western Ontario and McMaster Osteoarthritis Index (WOMAC)-pain −3.3 MD (95% CI: −3.9/−2.7; P < 0.001). Other significant improvements were WOMAC-stiffness −1.1 MD (95% CI: −1.6/−0.6; P < 0.001), WOMAC-function −10.1 MD (95% CI: −12.2/−8.0; P < 0.001), and Evaluator Global Assessment −21.4 MD (95% CI: −29.2/−13.6; P < 0.001). The responder rate was 52% (95% CI: 40% to 63%). Improvements were greater than the “minimal clinically important difference” for all outcomes (except 6-month VAS-pain). The level of evidence was moderate for almost all outcomes. Conclusions The placebo effect of knee injections is significant, with functional improvements lasting even longer than those reported for pain perception. The high, long-lasting, and heterogeneous effects on the scales commonly used in clinical trials further highlight that the impact of placebo should not be overlooked in the research on and management of knee osteoarthritis.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.003 | 0.007 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.003 | 0.003 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 it