Table 4.
Subgroup analysis of personal and study-related factors affecting medium-term (6–7 months) pain relief with PRP vs. control interventions
| Comparison | No. of groups | MD (95% CI) | p-value |
|---|---|---|---|
| Shoulder pathology | <0.05 | ||
| Rotator cuff lesions | 9 | 0.90 (0.31 to 1.49) | |
| Adhesive capsulitis | 1 | 1.84 (1.33 to 2.35) | |
| No. of injections | <0.05 | ||
| 1 | 5 | 0.75 (0.41 to 1.10) | |
| >1 | 5 | 1.23 (0.27 to 2.20) | |
| PRP-leucocyte concentration | <0.05 | ||
| LR-PRP | 2 | 0.75 (0.01 to 1.49) | |
| LP-PRP | 4 | 1.06 (–0.15 to 2.28) | |
| PRP platelet concentration | <0.05 | ||
| ≥5× | 4 | 1.03 (0.37 to 1.69) | |
| <5× | 4 | 0.52 (0.19 to 0.86) | |
| Platelet separation technique | <0.05 | ||
| Single centrifugation | 3 | 0.48 (0.11 to 0.84) | |
| Double centrifugation | 7 | 1.19 (0.50 to 1.87) | |
| Platelet activating agent | <0.05 | ||
| Used | 4 | 1.03 (0.37 to 1.69) | |
| Not used | 3 | 0.48 (0.11 to 0.84) | |
| Injection volume | <0.05 | ||
| ≤3 mL/injection | 3 | 0.94 (–0.13 to 2.01) | |
| >3mL/injection | 7 | 1.03 (0.30 to 1.75) |
Analysis was done after exclusion of study by Wongworawat (unpublished trial), Wesner et al.’s study (total sample was very less; total 7) [11], and one group of Cai et al.’s study (where PRP was compared with combination of PRP and hyaluronic acid) [15].
PRP: platelet rich plasma, MD: mean difference, LR: leucocyte rich, LP: leucocytes poor.