Age, years; mean ± SD | 55.8 ± 0.2 | 55.8 ± 0.2 | 58.0 ± 1.1 | 0.07 | 55.4 ± 0.2 | 58.0 ± 0.6 | <0.01b |
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Sex: female, % | 79 | 79 | 95 | 0.10 | 82% | 68% | 0.01b |
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Body mass index, kg/m2; mean ± SD | 26.2 ± 0.1 | 26.3 ± 0.2 | 29.1 ± 1.0 | <0.01b | 26.3 ± 0.2 | 25.9 ± 0.5 | 0.60 |
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Ethnic group (white versus other), % | 98 | 97 | 100 | 0.47 | 98 | 100% | 0.32 |
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Education level | | | | | | | |
% ≤ high school graduate, % | 73 | 73 | 84 | | 73 | 77 | |
% college or university degree, % | 27 | 27 | 16 | 0.29 | 27 | 23 | 0.55 |
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Participants (%) with >1 comorbidity, % | 45 | 46 | 47 | 0.91 | 52 | 40 | 0.13 |
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NRS of the past week, mean (IQR) | 3.5 (2.0–5.0) | 3.5 (2.0–5.0) | 4.5 (3.0–6.0) | 0.04b | 3.6 (2.0–5.0) | 4.3 (2.0–6.0) | 0.03b |
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WOMAC pain, mean (IQR) | 25 (10–35) | 25 (10–35) | 35 (20–40) | 0.02b | 27 (15–40) | 31 (15–45) | 0.07 |
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WOMAC physical function, mean (IQR) | 23 (10–34) | 24 (10–34) | 34 (20–44) | <0.01b | 25 (10–35) | 31 (18–40) | 0.02b |
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WOMAC joint stiffness, mean (IQR) | 33 (25–50) | 33 (25–50) | 47 (38–63) | <0.01b | 34 (25–50) | 38 (25–50) | 0.30 |
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Pain coping strategies, mean (IQR) | | | | | | | |
Pain transformation | 2.1 (1.8–2.5) | 2.2 (1.8–2.8) | 2.2 (1.8–2.5) | 0.67 | 2.2 (1.8–2.8) | 2.2 (1.8–2.7) | 0.67 |
Distracting | 2.2 (1.8–2.6) | 2.2 (1.8–2.6) | 2.3 (1.8–2.8) | 0.69 | 2.2 (1.8–2.6) | 2.2 (1.8–2.8) | 0.55 |
Reducing demands | 2.0 (1.7–2.3) | 2.0 (1.7–2.3) | 2.0 (1.3–2.7) | 0.83 | 2.0 (1.7–2.3) | 1.9 (1.7–2.3) | 0.16 |
Resting/avoidance | 1.8 (1.4–2.2) | 1.8 (1.4–2.2) | 2.0 (1.6–2.4) | 0.09 | 1.8 (1.4–2.2) | 1.8 (1.5–2.0) | 0.93 |
Worrying | 1.6 (1.2–1.8) | 1.6 (1.2–1.8) | 1.6 (1.2–2.0) | 0.87 | 1.6 (1.2–1.8) | 1.6 (1.2–1.9) | 0.79 |
Retreating | 1.5 (1.1–1.9) | 1.6 (1.1–1.9) | 1.5 (1.1–1.7) | 0.56 | 1.5 (1.1–1.9) | 1.5 (1.0–1.7) | 0.34 |
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Smoker or previous smoker, % | 14 | 15 | 0 | 0.07 | 15 | 6 | 0.07 |
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Alcohol consumption, % | 78 | 77 | 65 | 0.23 | 79 | 71 | 0.18 |
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Use of pain medication, % | 38 | 38 | 21 | 0.13 | 39 | 34 | 0.45 |
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Morning stiffness knees <30 minutes, % | 53 | 62 | 83 | 0.06 | – | – | – |
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Morning stiffness hips <60 minutes, % | 36 | – | – | – | 55 | 64 | 0.20 |
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Heberden nodes hands, % | 48 | 48 | 56 | 0.53 | 50 | 59 | 0.22 |
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Bouchard swellings hands, % | 19 | 19 | 21 | 0.81 | 22 | 17 | 0.42 |
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ESR, mm/hour ± SD | 9.8 ± 0.3 | 10.1 ± 0.3 | 10.7 ± 1.7 | 0.77 | 9.9 ± 0.4 | 12.9 ± 1.4 | 0.05b |
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| | TKA− 1480 knees | TKA+ 22 knees | P1-value | THA− 1014 hips | THA+ 62 hips | P1-value |
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Palpable warmth of the knee joint, % | – | 3 | 18 | <0.01b | – | – | – |
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Joint space tenderness of the knee, % | – | 12 | 18 | 0.59 | – | – | – |
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Bony enlargements of the knee, % | – | 2 | 0 | 0.51 | – | – | – |
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Crepitus during knee flexion, % | – | 10 | 23 | <0.01b | – | – | – |
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Positive knee refill test (effusion), % | – | 4 | 14 | 0.02b | – | – | – |
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Painful active knee flexion, % | – | 13 | 36 | <0.01b | – | – | – |
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Painful active knee extension, % | – | 8 | 23% | 0.04b | – | – | – |
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ROM knee flexion, mean ± SD | – | 135° ± 0.2° | 127° ± 2.6° | <0.01b | – | – | – |
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ROM knee extension, mean ± SD | – | 3° ± 0.1° | 3° ± 0.8° | 0.94 | – | – | – |
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JSN knee score >0, % | – | 55 | 86 | 0.03b | – | – | – |
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Femoral or tibial OP score >0, % | – | 45 | 91 | <0.01b | – | – | – |
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Tibial attrition, % | – | 0 | 10 | <0.01b | – | – | – |
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Femoral or tibial sclerosis, % | – | 1 | 10 | <0.01b | – | – | – |
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Tibial spiking, % | – | 32 | 63 | 0.03b | – | – | – |
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K/L score 1 (versus K/L score 0), % | – | 39 | 86 | <0.01b | 26 | 72 | <0.01b |
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ROM hip flexion ≤ 115°, % | – | – | – | – | 41 | 68 | <0.01b |
|
ROM hip internal rotation ≤ 15°, % | – | – | – | – | 4 | 26 | <0.01b |
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Painful active hip flexion, % | – | – | – | – | 17 | 48 | <0.01b |
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Painful active hip internal rotation, % | – | – | – | – | 16 | 46 | <0.01b |
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JSN hip score>0 (AP), % | – | – | – | – | 31 | 79 | <0.01b |
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JSN hip score>0 (FP), % | – | – | – | – | 11 | 60 | <0.01b |
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Acetabular or femoral OP score >0, % | – | – | – | – | 35 | 78 | <0.01b |
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Femoral subchondral sclerosis, % | – | – | – | – | 1 | 26 | <0.01b |
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Cam-type deformity (α angle >60°),c % | – | – | – | – | 11 | 38 | <0.01b |
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Dysplasia (Wiberg angle <25°),b % | – | – | – | – | 5 | 17 | <0.01b |