| Mean (SD) Time Period | RLAI N = 235 | OA N = 70 | P-Value (P?R Treatment Difference) | ||||||
| Retrospective (R) | Prospective (P) | P - R | P-Value | Retrospective (R) | Prospective (P) | P - R | P-Value | ||
| 0 - 3 months | 7.4 (12.3) | 5.8 (11.7) | −1.6 (15.8) | 0.12 | 3.7 (8.0) | 6.1 (9.9) | 2.4 (12.1) | 0.10 | NA |
| 0 - 6 months | 10.5 (18.6) | 7.4 (15.0) | −3.1 (22.0) | 0.032 | 5.0 (10.4) | 7.1 (11.0) | 2.1 (13.5) | 0.19 | NA |
| 0 - 12 months | 15.9 (30.5) | 9.6 (21.9) | −6.3 (35.5) | 0.007 | 7.3 (12.9) | 7.4 (11.0) | 0.1 (15.9) | 0.95 | 0.0035 |
| 0 - 18 months | 20.0 (34.4) | 10.8 (29.8) | −9.2(43.4) | 0.001 | 10.8 (16.9) | 7.6 (11.0) | −3.2 (18.3) | 0.15 | NA |
| 0 - 24 months | 24.1 (38.4) | 11.5 (32.3) | −12.6 (46.7) | <0.001 | 14.9 (21.3) | 7.6 (11.0) | −7.3 (22.5) | 0.009 | 0.0886 |
| 3 - 24 months | 16.7 (31.6) | 5.7 (29.2) | −11.0 (41.0) | <0.001 | 11.1 (19.0) | 1.5 (5.5) | −9.7 (19.2) | <0.001 | NA |