Table 1.
Descriptive characteristics of the total hip and total knee arthroplasty study cohort
| Characteristic | All | Pre-operative opioid user | Post-op 35 days opioid user | Post-op 90 days opioid user |
|---|---|---|---|---|
| n (%) | 1771 (100) | 310 (17.5) | 735 (41.5) | 313 (17.7) |
| Age, mean (SD) | 67.3 (9.7) | 65.4 (9.9) | 67.2 (9.4) | 65.9 (9.2) |
| Sex, female | 953 (53.8) | 188 (60.6) | 437 (59.5) | 202 (64.5) |
| Hospital, Private | 928 (52.4) | 125 (40.3) | 372 (50.6) | 153 (48.9) |
| Surgery Joint | ||||
| Knee | 1017 (57.4) | 165 (53.2) | 524 (71.3) | 237 (75.7) |
| Hip | 754 (42.6) | 145 (46.8) | 211 (28.7) | 76 (24.3) |
| Bilateral | 88 (5.0) | 9 (2.9) | 53 (7.2) | 22 (7.0) |
| Previous TKA | 473 (26.7) | 52 (16.8) | 117 (15.9) | 49 (15.7) |
| Previous THA | 292 (16.5) | 89 (28.7) | 181 (24.6) | 73 (23.3) |
| BMI, mean (SD) | 31.0 (6.4) | 32.2 (7.0) | 31.7 (6.7) | 32.6 (7.2) |
| Education (highest level) | ||||
| Year 10 or below | 656 (37.0) | 122 (39.4) | 283 (38.5) | 202 (64.5) |
| Senior Secondary or above | 1115 (63.0) | 188 (60.7) | 441 (60.0) | 192 (61.3) |
| Comorbid condition | 1605 (90.6) | 285 (91.9) | 686 (93.3) | 301 (96.2) |
| Acute major complication | 59 (3.3) | 9 (2.9) | 40 (5.4) | 59 (18.8) |
| Post major complication | 135 (7.6) | 29 (9.4) | 93 (12.7) | 135 (43.1) |
| Tobacco use | ||||
| Current smoker | 152 (8.6) | 41 (13.2) | 83 (11.3) | 42 (13.4) |
| Former smoker | 735 (41.5) | 128 (41.3) | 302 (27.6) | 129 (41.2) |
| Length of Stay, mean (SD) | 5.6 (2.5) | 5.5 (2.5) | 6.0 (2.6) | 6.5 (3.2) |
| Discharge Destination | ||||
| Inpatient Rehabilitation | 523 (29.5) | 77 (24.8) | 274 (37.3) | 127 (40.6) |
| Employed at time of surgery | 492 (27.8) | 83 (26.8) | 185 (25.2) | 78 (24.9) |
| EQ-5D Baseline | ||||
| Mobility | ||||
| No problems | 129 (7.3) | 7 (2.3) | 40 (5.4) | 9 (2.9) |
| Slight problems | 375 (21.2) | 41 (13.2) | 142 (19.3) | 64 (20.4) |
| Moderate problems | 776 (43.8) | 122 (39.4) | 331 (45.3) | 135 (43.1) |
| Severe problems | 460 (26.0) | 133 (42.9) | 209 (28.4) | 96 (30.7) |
| Unable | 15 (0.84) | 6 (1.9) | 8 (1.1) | 6 (1.9) |
| Self-care | ||||
| No problems | 952 (53.8) | 122 (39.4) | 407 (55.4) | 163 (52.1) |
| Slight problems | 441 (24.9) | 91 (29.4) | 172 (23.4) | 77 (24.6) |
| Moderate problems | 672 (37.9) | 73 (23.5) | 110 (15.0) | 54 (17.3) |
| Severe problems | 295 (14.6) | 21 (6.8) | 38 (5.17) | 15 (4.8) |
| Unable | 83 (4.7) | 2 (0.7) | 1 (0.1) | 1 (0.3) |
| Activities | ||||
| No problems | 252 (14.2) | 22 (7.1) | 107 (14.6) | 34 (10.8) |
| Slight problems | 453 (25.6) | 63 (20.3) | 177 (24.1) | 80 (25.6) |
| Moderate problems | 672 (37.9) | 117 (37.7) | 272 (37.0) | 114 (36.4) |
| Severe problems | 295 (16.7) | 80 (25.8) | 132 (18.0) | 62 (19.8) |
| Unable | 83 (46.8) | 27 (8.7) | 42 (5.7) | 20 (6.4) |
| Pain/Discomfort | ||||
| No pain or discomfort | 40 (2.2) | 1 (0.3) | 10 (1.4) | 2 (0.6) |
| Slight pain or discomfort | 279 (15.8) | 18 (5.8) | 103 (14.0) | 31 (9.9) |
| Moderate pain or discomfort | 826 (46.6) | 118 (38.1) | 337 (45.9) | 131 (41.9) |
| Severe pain or discomfort | 513 (29.0) | 134 (43.2) | 237 (32.2) | 116 (37.1) |
| Extreme pain or discomfort | 97 (5.4) | 38 (12.3) | 43 (5.8) | 29 (9.3) |
| Depression/Anxiety | ||||
| Not anxious/depressed | 965 (54.5) | 126 (40.6) | 366 (49.8) | 150 (47.9) |
| Slightly anxious/depressed | 474 (26.8) | 97 (31.3) | 204 (27.8) | 31 (9.9) |
| Moderately anxious /depressed | 230 (13.0) | 63 (20.3) | 113 (15.4) | 58 (18.5) |
| Severely anxious or depressed | 64 (3.6) | 15 (4.8) | 34 (4.6) | 13 (4.2) |
| Extremely anxious or depressed | 18 (1.0) | 8 (2.6) | 8 (1.1) | 7 (2.2) |
| Health Status VAS, mean (SD) | 70.9 (18.6) | 64.0 (20.2) | 69.2 (18.7) | 66.4 (19.2) |
| Baseline Oxford Score, mean (SD) | 21.2 (8.6) | 16.5 (20.2) | 20.0 (8.3) | 18.7 (8.2) |
Legend: Number and percentage shown unless otherwise stated; Hospital = private or public hospital; Total Knee Arthroplasty; THA- Total Hip Arthroplasty; Baseline measure = pre-operative measure; EQ-5D: EuroQol 5 dimensions; Health Status VAS- EQ-5D Visual analogue scale (VAS) (100 = the best health you can imagine); Oxford Knee or Hip Score (tool range 0-48, higher scores are better).