Table 3.
Early and later functional outcomes on postoperative Day (POD) 1, 2, 3, at 6 weeks, 3 months, and 12 months
| Functional outcome | High concentration group | Low concentration group | Placebo infusion group | p value |
|---|---|---|---|---|
| Distance walked (m) | ||||
| POD 1 am | 3 (0–6) | 4 (0–10) | 6 (0–11) | 0.71 |
| POD 1 pm | 8 (1–15) | 12 (3–21) | 14 (6–23) | 0.57 |
| POD 2 am | 39 (28–51) | 40 (28–51) | 44 (32–56) | 0.83 |
| POD 2 pm | 48 (37–57) | 55 (37–73) | 52 (41–63) | 0.72 |
| POD 3 am | 65 (55–75) | 66 (51–81) | 57 (45–69) | 0.48 |
| POD 3 pm | 54 (41–67) | 51 (33–68) | 47 (33–62) | 0.78 |
| Active flexion (degrees) | ||||
| POD 1 am | 61 (53–69) | 55 (47–63) | 56 (49–62) | 0.41 |
| POD 1 pm | 72 (63–80) | 66 (57–75) | 60 (53–67) | 0.09 |
| POD 2 am | 71 (63–79) | 61 (54–69) | 66 (58–72) | 0.18 |
| POD 2 pm | 75 (68–82) | 68 (62–75) | 64 (56–71) | 0.08 |
| POD 3 am | 79 (73–86) | 78 (71–85) | 71 (64–78) | 0.15 |
| POD 3 pm | 78 (67–89) | 78 (69–87) | 71 (63–78) | 0.39 |
| Passive flexion (degrees) | ||||
| POD 1 am | 86 (80–91) | 84 (79–89) | 76 (69–83) | 0.03* |
| POD 1 pm | 91 (85–96) | 92 (87–98) | 76 (70–82) | < 0.001* |
| POD 2 am | 86 (81–93) | 81 (76–86) | 81 (76–87) | 0.23 |
| POD 2 pm | 88 (83–93) | 86 (81–91) | 81 (73–88) | 0.18 |
| POD 3 am | 91 (85–96) | 87 (82–92) | 84 (79–89) | 0.15 |
| POD 3 pm | 88 (79–97) | 85 (81–88) | 81 (76–86) | 0.23 |
| Quadriceps strength (pounds) | ||||
| Preoperative | 18 (15–20) | 17 (15–20) | 17 (15–19) | 0.98 |
| POD 1 am | 4 (2–6) | 6 (4–8) | 5 (3–7) | 0.47 |
| POD 1 pm | 5 (3–7) | 6 (4–8) | 6 (4–7) | 0.67 |
| POD 2 am | 5 (4–7) | 6 (4–7) | 5 (4–7) | 0.78 |
| POD 2 pm | 6 (5–8) | 7 (5–9) | 6 (5–8) | 0.60 |
| POD 3 am | 8 (6–9) | 8 (6–11) | 7 (5–8) | 0.41 |
| POD 3 pm | 8 (6–10) | 11 (8–13) | 9 (7–11) | 0.14 |
| WOMAC score | ||||
| Preoperative | 44 (40–48) | 46 (41–51) | 43 (37–49) | 0.70 |
| 6 weeks | 30 (23–38) | 31 (25–36) | 33 (28–38) | 0.74 |
| 3 months | 22 (15–30) | 21 (16–25) | 24 (17–30) | 0.81 |
| 12 months | 17 (7–27) | 22 (14–30) | 18 (9–27) | 0.68 |
| SF-36 score | ||||
| Preoperative | 91 (86–97) | 91 (86–96) | 90 (84–97) | 0.96 |
| 6 weeks | 70 (58–81) | 69 (57–81) | 73 (63–83) | 0.89 |
| 3 months | 80 (68–91) | 75 (64–86) | 88 (78–98) | 0.17 |
| 12 months | 97 (90–104) | 102 (100–104) | 103 (100–106) | 0.07 |
Data are presented as mean (95% confidence interval). Significant results are underscored by an asterisk. High concentration group, infusion of ropivacaine 0.2%; low concentration group, infusion of ropivacaine 0.1%; placebo infusion group, infusion of normal saline 0.9%.