Table 4.
Differences in patient characteristics and self-reported outcome between patients with high and low pain catastrophizing score
| All patients | TKA | UKA | |||||
|---|---|---|---|---|---|---|---|
| PCS < 11 | PCS > 21 | P-value | PCS < 11 | PCS > 21 | PCS < 11 | PCS > 21 | |
| n = 205 | n = 207 | n = 138 | n = 165 | n = 67 | n = 42 | ||
| Female (%) | 106 (51.7) | 112 (54.1) | 0.63 | 73 (52.9) | 92 (55.8) | 33 (49.3) | 20 (47.6) |
| Age years (SD) | 67.7 (9.2) | 66.7 (10.0) | 0.37 | 68.1 (9.0) | 67.0 (9.9) | 66.7 (9.5) | 65.9 (10.4) |
| BMI kg/m2 (SD) | 28.2 (4.3) | 29.7 (4.4) | < 0.001 | 28.0 (4.2) | 29.8 (4.5) | 28.7 (4.4) | 29.3 (4.1) |
| Alcohol > 24 g/Day (%) | 11 (5.6) | 9 (4.6) | 0.70 | 7 (5.2) | 8 (5.1) | 4 (6.5) | 1 (2.3) |
| Smoking (%) | 25 (12.6) | 33 (16.9) | 0.22 | 21 (15.4) | 27 (17.2) | 4 (6.5) | 6 (15.8) |
| Co-morbiditya (%) | 139 (67.8) | 153 (73.9) | 0.24 | 100 (72.5) | 124 (75.2) | 39 (58.2) | 29 (69.0) |
| Walking aid (%) | 24 (12.1) | 38 (19.5) | 0.03 | 21 (15.4) | 30 (19.1) | 3 (4.8) | 8 (21.1) |
| Living alone (%) | 53 (26.8) | 42 (21.5) | 0.23 | 37 (27.2) | 33 (21.7) | 16 (25.8) | 9 (23.7) |
| Operated bilateralb (%) | 20 (9.7) | 16 (7.7) | 0.52 | 13 (9.4) | 13 (7.9) | 7 (10.5) | 7 (7.1) |
| Outcome | |||||||
| Preoperatively | |||||||
| OKS (IQR) (n = 412) | 29 (9) | 21 (8) | < 0.001 | 28 (10) | 21 (8) | 31 (8) | 22 (8) |
| Pain (%) (n = 412) | 127 (61.2) | 187 (90.3) | < 0.001 | 89 (64.5) | 152 (92.1) | 38 (56.7) | 35 (83.3) |
| SF-36 (PF) (IQR) (n = 404) | 50 (35) | 35 (25) | < 0.001 | 50 (35) | 35 (25) | 57.5 (30) | 35 (20) |
| EQ 5D (IQR) (n = 376) | 0.72 (0.08) | 0.66 (0.33) | < 0.001 | 0.72 (0.05) | 0.66 (0.33) | 0.77 (0.10) | 0.59 (0.40) |
| 4 months | |||||||
| OKS (IQR) (n = 336) | 39 (10) | 36 (12) | 0.001 | 37 (11) | 35 (11) | 41 (8) | 37 (12) |
| Pain (%) (n = 412) | 32 (17.7) | 56 (33.9) | 0.001 | 25 (20.8) | 47 (36.2) | 7 (11.5) | 9 (25.7) |
| SF-36 (PF) (IQR) (n = 346) | 80 (25) | 75 (30) | 0.004 | 75 (30) | 75 (30) | 85 (15) | 80 (30) |
| EQ 5D (IQR) (n = 331) | 0.82 (0.23) | 0.82 (0.28) | 0.023 | 0.82 (0.28) | 0.82 (0.28) | 0.84 (0.18) | 0.82 (0.23) |
| 12 months | |||||||
| OKS (IQR) (n = 412) | 42 (10) | 38 (13) | < 0.001 | 41 (11) | 37 (14) | 44 (8) | 41 (8) |
| Pain (%) (n = 412) | 21 (10.2) | 49 (23.7) | < 0.001 | 16 (11.6) | 42 (25.5) | 5 (7.5) | 7 (16.7) |
| SF-36 (PF) (IQR) (n = 401) | 85 (25) | 75 (30) | 0.001 | 80 (30) | 75 (32.5) | 85 (20) | 80 (20) |
| EQ 5D (IQR) (n = 397) | 0.84 (0.22) | 0.82 (0.28) | 0.002 | 0.84 (0.22) | 0.82 (0.28) | 1 (0.28) | 0.82 (0.23) |
Parentheses are percentage unless otherwise specified. Pain is dichotomized from OKS q1 in “no pain” (none/very mild/mild) and “pain” (moderate/severe). P-value for outcome is measured from multivariate repeated measurements ANOVA for OKS and SF36 (PF) and chi square test and Wilcoxon signed-rank test for pain and EQ.5D
acardiac disease, pulmonary disease, high blood pressure, hypercholesterolaemia, diabetes, psychiatric disorder, previous stroke, and previous venous thromboembolic event
bPatients having two knee arthroplasties within 12 months