Table 2.
Patient demographics for the population studied, by head size
| All patients | 28 mm (Reference) | Head size 32 mm | 36 mm | p-value a | |
|---|---|---|---|---|---|
| Number (%) | 4,596 | 1,864 (40.6) | 869 (18.9) | 1,863 (40.5) | |
| Patient factors | |||||
| Age, mean (SD) range | 66.0 (9.7) 25.2–95.1 | 68.0 (8.9) 31.0–95.1 | 68.2 (10.1) 26.2– 94.1 | 62.9 (9.5) 25.2–90.2 | < 0.001 |
| Females, n (%) | 2,620 (57.0) | 1,303 (69.9) | 535 (61.6) | 782 (42.0) | < 0.001 |
| ASA, n (%) | < 0.001 | ||||
| 1 | 804 (17.5) | 286 (15.3) | 93 (10.7) | 425 (22.8) | |
| 2 | 3,360 (73.1) | 1,410 (75.6) | 644 (74.1) | 1,306 (70.1) | |
| 3+ | 432 (9.4) | 168 (9.0) | 132 (15.2) | 132 (7.1) | |
| BMI (SD) range b | 29.0 (5.4) 15–65 | 28.7 (5.2) 15–56 | 29.1 (5.6) 16–50 | 29.5 (5.4) 16–65 | 0.03 |
| Comorbidities, n (%) | |||||
| Heart disease | 388 (8.4) | 152 (8.2) | 91 (10.5) | 145 (7.8) | 0.05 |
| Stroke | 67 (1.5) | 29 (1.6) | 13 (1.5) | 25 (1.3) | 0.9 |
| Diabetes | 355 (7.7) | 158 (8.5) | 70 (8.1) | 127 (6.8) | 0.2 |
| Hypertension | 1,764 (38.4) | 739 (39.7) | 366 (42.1) | 659 (35.4) | 0.001 |
| Circulation | 221 (4.8) | 102 (5.5) | 45 (5.2) | 74 (4.0) | 0.09 |
| Lung | 270 (5.9) | 112 (6.0) | 42 (4.8) | 116 (6.2) | 0.3 |
| Depression | 309 (6.7) | 126 (6.8) | 44 (5.1) | 139 (6.7) | 0.07 |
| Preoperative general health | 0.02 | ||||
| Excellent | 265 (5.8) | 100 (5.4) | 53 (6.1) | 114 (6.1) | |
| Very good | 1,413 (30.7) | 566 (30.4) | 235 (27.0) | 611 (32.8) | |
| Good | 2,008 (43.7) | 862 (46.2) | 394 (45.3) | 755 (40.5) | |
| Fair | 781 (17.0) | 285 (15.3) | 165 (19.0) | 330 (17.7) | |
| Poor | 129 (2.9) | 51 (2.7) | 22 (2.5) | 53 (2.8) | |
| Preoperative disability | 2,229 (48.5) | 928 (50.0) | 448 (51.6) | 853 (45.8) | 0.007 |
| Surgical factors | |||||
| Chemical VTE prophylaxis | < 0.001 | ||||
| LMWH only | 2,583 (56.2) | 1,115 (59.8) | 518 (59.6) | 950 (51.0) | |
| Aspirin only | 415 (9.0) | 146 (7.8) | 50 (5.8) | 219 (11.8) | |
| Other | 544 (11.8) | 163 (8.7) | 98 (11.3) | 283 (15.2) | |
| None | 304 (6.6) | 133 (7.1) | 36 (4.1) | 135 (7.3) | |
| Not recorded | 750 (16.3) | 307 (16.5) | 167 (19.2) | 276 (14.8) | |
| Mechanical VTE prophylaxis | < 0.001 | ||||
| Compression stockings (CS) | 1,249 (27.2) | 500 (26.8) | 222 (25.6) | 527 (28.3) | |
| CS + mechanical pump | 918 (20.0) | 296 (15.9) | 134 (15.4) | 488 (26.2) | |
| Foot pump only | 523 (11.4) | 278 (14.9) | 86 (9.9) | 159 (8.5) | |
| Mechanical calf pump only | 756 (16.5) | 312 (16.7) | 173 (19.9) | 271 (14.6) | |
| Other | 22 (0.5) | 7 (0.4) | 0 (0.0) | 15 (1.0) | |
| None | 378 (8.2) | 164 (8.8) | 87 (6.8) | 127 (6.8) | |
| Not recorded | 750 (16.3) | 307 (16.5) | 167 (19.2) | 276 (14.8) | |
| Bearing | < 0.001 | ||||
| Metal-on-polyethylene | 2,171 (47.2) | 1,423 (76.3) | 510 (58.7) | 238 (12.8) | |
| Ceramic-on-polyethylene | 361 (7.9) | 198 (10.6) | 100 (11.5) | 63 (3.4) | |
| Ceramic-on-ceramic | 2,064 (44.9) | 243 (13.0) | 259 (29.8) | 1,562 (83.8) | |
| Anesthesia | < 0.001 | ||||
| Regional | 2,077 (45.2) | 871 (46.7) | 303 (34.9) | 903 (48.5) | |
| General | 827 (18.0) | 312 (16.7) | 168 (19.3) | 347 (18.6) | |
| Regional and general | 906 (19.7) | 357 (19.2) | 224 (25.8) | 325 (17.4) | |
| Not recorded | 786 (17.1) | 324 (17.4) | 174 (20.0) | 288 (15.5) | |
| Lead surgeon grade | < 0.001 | ||||
| Consultant | 3,475 (75.6) | 1,484 (79.6) | 618 (71.1) | 1,373 (73.7) | |
| Other | 1,121 (24.4) | 380 (20.4) | 251 (28.9) | 490 (26.3) | |
| Position | 0.02 | ||||
| Lateral | 3,598 (78.3) | 1,449 (77.7) | 666 (76.6) | 1,483 (79.6) | |
| Supine | 248 (5.4) | 108 (5.8) | 36 (4.1) | 104 (5.6) | |
| Not recorded | 750 (16.3) | 307 (16.5) | 167 (19.2) | 276 (14.8) |
ASA: American Society of Anaesthesiologists score; PROMs: patient-reported outcomes measures.
a
Difference between groups with 1-way ANOVA (continuous data variables) or chi-squared test (categorical data variables).
b
BMI (body mass index) data on 2,726.