Variable | Estimated marginal mean (95% CI) | Mean change/year (95% CI) | p for interaction with time | ||||||
---|---|---|---|---|---|---|---|---|---|
Preoperative (n = 912) | 2 years (n = 912) | 5 years (n = 718) | 10 year (n = 261) | linear | quadratic | linear | quadratic | ||
Knee flexion (°) | |||||||||
Final knee flexion < 130 | 119.5 (114.6, 124.3) | 123.0 (118.2, 127.8) | 124.7 (119.8, 129.6) | 118.2 (112.5, 123.8) | 2.2 (1.6, 2.9) | −0.2 (− 0.3, − 0.2) | 0.006 | 0.023 | |
Final knee flexion ≥130 | 131.4 (126.6, 136.2)*** | 134.6 (129.8, 139.3)*** | 137.3 (132.5, 142.1)*** | 136.6 (131.5, 141.7)*** | 1.9 (1.4, 2.3) | −0.1 (− 0.2, − 0.1) | |||
Flexion contracture (°) | |||||||||
Final knee flexion < 130 | 10.4 (8.2, 12.5) | 3.3 (1.2, 5.4) | −2.1 (−4.2, 0.0) | 2.8 (0.4, 5.2) | −4.2 (− 4.5, −3.9) | 0.4 (0.3, 0.4) | n.s. | n.s. | |
Final knee flexion ≥130 | 9.7 (7.6, 11.7) | 3.2 (1.1, 5.2) | −1.9 (−4.0, 0.2) | 2.0 (−0.2, 4.2) | −3.9 (− 4.1, − 3.7) | 0.3 (0.3, 0.3) | |||
Range of motion (°) | |||||||||
Final knee flexion < 130 | 107.7 (100.2, 115.2) | 117.4 (109.9, 124.8) | 124.0 (116.5, 131.6) | 114.3 (105.6, 123.1) | 5.9 (4.8, 7.0) | −0.5 (− 0.7, − 0.4) | n.s. | 0.028 | |
Final knee flexion ≥130 | 119.5 (112.1, 126.9) | 127.7 (120.4, 135.1) | 134.8 (127.4, 142.2) | 132.5 (124.6, 140.4)** | 4.8 (4.1, 5.5) | −0.4 (− 0.4, − 0.3) | |||
Knee Society score | |||||||||
Final knee flexion < 130 | 58.9 (52.4, 65.5) | 85.7 (79.3, 92.1) | 105.9 (99.4, 112.4) | 86.2 (78.5, 94.0) | 16.1 (15.0, 17.1) | −1.3 (− 1.5, − 1.2) | n.s. | n.s. | |
Final knee flexion ≥130 | 59.2 (52.7, 65.6) | 85.9 (79.6, 92.3) | 106.2 (99.8, 112.6) | 86.9 (80.1, 93.8) | 16.0 (15.3, 16.7) | −1.3 (− 1.4, − 1.3) | |||
Knee Society function score | |||||||||
Final knee flexion < 130 | 50.3 (40.3, 60.3) | 73.0 (63.2, 82.9) | 87.2 (77.2, 97.3) | 57.7 (45.9, 69.5) | 14.0 (12.7, 15.4) | −1.3 (− 1.5, − 1.2) | 0.007 | n.s. | |
Final knee flexion ≥130 | 50.7 (40.8, 60.6) | 73.5 (63.6, 83.3) | 90.1 (80.2, 100.0) | 71.0 (60.4, 81.5) | 13.7 (12.9, 14.6) | −1.2 (− 1.3, − 1.1) | |||
Hospital for Special Surgery score | |||||||||
Final knee flexion < 130 | 63.7 (57.5, 69.9) | 83.8 (77.6, 89.9) | 97.9 (91.7, 104.1) | 78.8 (71.5, 86.0) | 12.2 (11.4, 13.0) | −1.1 (− 1.2, − 1.0) | 0.029 | n.s. | |
Final knee flexion ≥130 | 64.1 (58.0, 70.2) | 84.7 (78.7, 90.8) | 100.2 (94.1, 106.3) | 84.8 (78.3, 91.3) | 12.4 (11.8, 12.9) | −1.0 (− 1.1, − 1.0) | |||
WOMAC (total) | |||||||||
Final knee flexion < 130 | 39.9 (32.6, 47.1) | 19.9 (12.7, 27.0) | 4.9 (−2.4, 12.1) | 20.0 (11.9, 28.1) | −12.0 (− 13.0, − 11.1) | 1.0 (0.9, 1.1) | 0.003 | n.s. | |
Final knee flexion ≥130 | 40.7 (33.5, 47.8) | 18.8 (11.7, 26.0) | 1.8 (−5.4, 8.9) | 15.0 (7.5, 22.5) | −13.0 (− 13.6, − 12.4) | 1.0 (1.0, 1.1) | |||
WOMAC (pain) | |||||||||
Final knee flexion < 130 | 6.4 (5.1, 7.6) | 2.1 (0.9, 3.4) | −1.3 (−2.5, −0.0) | 1.0 (−0.4, 2.4) | − 2.5 (− 2.7, − 2.3) | 0.2 (0.2, 0.2) | n.s. | n.s. | |
Final knee flexion ≥130 | 6.6 (5.4, 7.8) | 2.1 (0.9, 3.3) | − 1.5 (− 2.7, − 0.3) | 1.1 (− 0.2, 2.4) | −2.7 (− 2.8, − 2.6) | 0.2 (0.2, 0.2) | |||
WOMAC (stiffness) | |||||||||
Final knee flexion < 130 | 3.2 (2.5, 3.9) | 1.4 (0.7, 2.1) | 0.0 (− 0.7, 0.7) | 1.0 (0.2, 1.8) | −1.1 (− 1.2, − 1.0) | 0.1 (0.1, 0.1) | n.s. | 0.027 | |
Final knee flexion ≥130 | 3.3 (2.6, 4.1) | 1.3 (0.6, 2.0) | −0.2 (− 0.9, 0.5) | 1.1 (0.4, 1.8) | −1.2 (− 1.3, − 1.1) | 0.1 (0.1, 0.1) | |||
WOMAC (physical function) | |||||||||
Final knee flexion < 130 | 30.8 (24.9, 36.6) | 16.2 (10.5, 21.9) | 5.7 (−0.1, 11.5) | 18.6 (12.0, 25.2) | −8.8 (−9.6, −8.0) | 0.76 (0.67, 0.85) | 0.001 | n.s. | |
Final knee flexion ≥130 | 31.0 (25.3, 36.7) | 15.2 (9.5, 20.9) | 3.0 (−2.7, 8.7) | 13.3 (7.3, 19.3) | −9.4 (−9.9, −8.9) | 0.77 (0.71, 0.82) |