Baseline characteristics of patients*
| Platelet-rich plasma group (n=30) | Platelet-poor plasma group (n=30) | No injection group (n=30) | |
|---|---|---|---|
| Age (years) | 26.6±5.9 26.3 (21.2–31.4) | 25.6±5.8 24.9 (22.1–29.3) | 25.5±5.7 24.3 (20.7–29.4) |
| Male gender | 30 (100.0) | 30 (100.0) | 30 (100.0) |
| Sports category | |||
| Athletics | 0 (0.0) | 2 (6.7) | 2 (6.7) |
| Basketball | 1 (3.3) | 1 (3.3) | 0 (0.0) |
| Decathlon | 1 (3.3) | 0 (0.0) | 0 (0.0) |
| Football | 22 (73.3) | 22 (73.3) | 22 (73.3) |
| Futsal | 3 (10.0) | 3 (10.0) | 2 (6.7) |
| Handball | 1 (3.3) | 1 (3.3) | 1 (3.3) |
| Hockey | 1 (3.3) | 0 (0.0) | 1 (3.3) |
| Physical coach football | 0 (0.0) | 0 (0.0) | 1 (3.3) |
| Squash | 0 (0.0) | 1 (3.3) | 0 (0.0) |
| Volleyball | 0 (0.0) | 0 (0.0) | 1 (3.3) |
| Weightlifting and bodybuilding | 1 (3.3) | 0 (0.0) | 0 (0.0) |
| Level of sports | |||
| Professional | 30 (100) | 28 (93.3) | 29 (96.7) |
| Competitive | 0 (0) | 2 (6.7) | 1 (3.3) |
| Sprinting type of injury | 14 (46.7) | 20 (66.7) | 22 (73.3) |
| Previous hamstring injuries | 19 (63.3) | 15 (50.0) | 15 (50.0) |
| Previous ipsilateral hamstring injuries | 10 (33.3) | 10 (33.3) | 8 (26.7) |
| Maximum pain score with the injury | 6.8±2.2 7 (5.0–8.0) | 6.6±1.8 7 (5.0–8.0) | 6.9±1.7 7 (6.0–8.0) |
| Length of the pain palpation (cm) | 6.7±3.7 5 (4.0–9.5) | 7.6±3.9 7.75 (4.5–10.0) | 6.5±3.3 6 (4.0–8.0) |
| Width of the pain palpation (cm) | 3.4±1.7 3 (2.0–4.5) | 4.4±2.9 3.5 (3.0–6.0) | 3.7±1.9 3.5 (2.5–4.5) |
| No full knee extension deficit at rest | 2 (6.7) | 1 (3.3) | 0 (0.0) |
| Painful passive straight leg raise (yes only) | 30 (100.0) | 29 (96.7) | 25 (83.3) |
| Days between injury and intervention (days) | 1.8±0.9 2 (1.0–3.0) | 1.8±1.1 1 (1.0–3.0) | 2.3±1.1 2 (1.0–3.0) |
| MRI characteristics of oedema | |||
| Anteroposterior (cm) | 2.3±1.4 2 (1.4–2.9) | 2.5±1.5 2.2 (1.4–3.0) | 2.7±1.7 2.25 (1.2–4.1) |
| Anteroposterior (%) | 43.0±25.0 36 (24.0–52.0) | 41.0±25.0 38 (26.0–51.0) | 46.0±28.0 41 (22.0–66.0) |
| Mediolateral (cm) | 2.4±1.3 2.4 (1.2–3.2) | 2.1±1.2 1.8 (1.4–2.8) | 2.3±1.3 2.4 (1.1–3.3) |
| Mediolateral (%) | 53.0±28.0 47 (29.0–73.0) | 48.0±24.0 43 (31.0–69.0) | 50.0±24.0 51 (31.0–63.0) |
| Craniocaudal (cm) | 15.8±8.2 14.05 (9.1–23.0) | 14.6±7.4 14.4 (9.2–20.2) | 15.5±6.1 15.8 (10.6–20.0) |
| Volume (cm3) | 77.6±108.5 29.21 (9.9–82.0) | 61.9±83.4 33.41 (7.4–64.6) | 75.8±74.6 62.83 (10.0–135.7) |
| Cross-sectional area (%) | 28.0±28.0 17 (8.0–39.0) | 24.0±23.0 15 (8.0–33.0) | 29.0±24.0 23 (9.0–51.0) |
| Distance from most caudal ischial tuberosity (cm) | 9.6±7.7 9.4 (2.3–16.6) | 12.0±8.3 11.9 (3.3–19.5) | 9.5±7.0 8.7 (4.5–13.0) |
| Grade I | 17 (56.7) | 16 (55.2) | 13 (43.3) |
| Grade II | 13 (43.3) | 13 (44.8) | 17 (56.7) |
*Data are either shown as mean±SD and median (IQR) for continuous variables or frequency and valid column percentage (%) for categorical variables.