Comparative efficacy of polyacrylamide hydrogel versus hyaluronic acid and corticosteroids in knee osteoarthritis: A retrospective cohort study
Bibliographic record
Abstract
This study investigates whether intra-articular polyacrylamide hydrogel (iPAAG) provides superior outcomes compared to conventional injections, namely hyaluronic acid (HA) and corticosteroid, in managing knee osteoarthritis (KOA). This retrospective cohort study included primary KOA patients (Kellgren-Lawrence grade II-IV) treated between January 2023 and December 2024 with 1 of 3 intra-articular injections: iPAAG (6 mL Arthrosamid), HA (2 mL, 60 mg Artroaid), and Steroid (40 mg methylprednisolone acetate, Arhropan). Outcomes were assessed at baseline, 3, 6, and 12 months. Primary outcomes were the Visual Analog Scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index. Clinically meaningful improvements were evaluated using minimal clinically important difference (MCID) and patient acceptable symptom state thresholds. A total of 150 patients (n = 50 per group) were included. The groups were comparable at baseline in median age (HA: 66; Steroid: 69.5; iPAAG: 69.5; P = .104), sex (female: 72%, 62%, 66%; P = .566), median body mass index (30.4, 30.6, 30.7 kg/m2; P = .716), and Kellgren-Lawrence distribution (P = .765). Baseline median VAS was 7, dropping to 3 in all groups at 3 months (P < .001). At 6 months, they rose to 4 (HA), 5 (Steroid), and 4 (iPAAG) (P < .001). By 12 months, VAS returned to baseline in HA and Steroid, while iPAAG remained slightly improved (P = .219). iPAAG outperformed Steroid at 6 months (P < .001), but not HA (P = 1.000). No significance at 12 months (P = .128). Baseline median Western Ontario and McMaster Universities Osteoarthritis Index scores were 49.5 (HA), 59.5 (Steroid), and 57 (iPAAG), improving at 3 months to 42.5, 48.5, and 45 (P < .001). At 6 months, scores were 45, 57, and 47.5 (P < .001). At 12 months, HA and Steroid returned to baseline, while iPAAG remained stable (P = .979). iPAAG was better than Steroid at 6 months (P = .008), but not HA (P = .066). Although overall differences at 12 months were significant (P = .044), pairwise comparisons were not. iPAAG showed the highest patient acceptable symptom state rates (72%, 54%, and 42% at 3, 6, and 12 months), and greatest minimal clinically important difference achievement at 3 and 6 months, though without significant intergroup differences (P > .05). iPAAG offers comparable short-term efficacy and modest advantage at 6 months. However, long-term superiority is limited. It may be a complementary option in individualized osteoarthritis management. Further prospective studies are needed to define its optimal use.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".