Baseline demographic and clinical characteristics of study participants.
| Characteristic | IA-BoNT/A, n = 23*, mean (SD) or % | IA-placebo, n = 26*, mean (SD) or % |
|---|---|---|
| Mean age, (SD), yrs | 67.1 (10.1) | 66.8 (11.5) |
| Men, n (%) | 18/23 (78) | 23/26 (88) |
| Caucasian, n (%) | 22/23 (96) | 25/26 (96) |
| Mean comorbidity index** | 13.0 (5.5) | 12.5 (28.7) |
| Mean pain duration of total knee arthroplasty (TKA), yrs | 4.8 (5.1) | 4.1 (4.6) |
| Primary/revision TKA | 16/7 | 21/5 |
| Current treatment, n (%)† | ||
| Nonsteroidal antiinflammatory drugs | 15/23 (65) | 21/26 (81) |
| Narcotics | 10/23 (43) | 10/26 (38) |
| Acetaminophen | 11/23 (48) | 8/26 (31) |
| Other†† | 8/23 (35) | 8/26 (31) |
| Primary outcome | ||
| VAS pain severity, 0–10 | 7.2 (1.1) | 7.5 (1.3) |
| Secondary outcomes | ||
| WOMAC physical function, 0–100 | 56.5 (8.9) | 63.3 (17.5) |
| WOMAC pain, 0–100 | 58.0 (13.6) | 67.1 (15.3) |
| WOMAC stiffness, 0–100 | 64.1 (20.4) | 64.4 (18.9) |
| WOMAC total, 0–100 | 63.2 (9.3) | 70.6 (16.8) |
| Timed Stands Test, seconds | 49.9 (31.5) | 50.8 (29.3) |
| Timed Up and Go Test, seconds | 18.3 (13.8) | 18.5 (12.7) |
| Active flexion | 83.3 (22.5) | 86.2 (16.7) |
| Active extension | 170.7 (10.9) | 167.8 (10.0) |
| McGill affective dimension | 6.1 (2.9) | 5.3 (3.1) |
| McGill sensory dimension | 16.7 (6.5) | 17.3 (6.8) |
| McGill total score | 22.8 (8.2) | 22.7 (8.8) |
↵* Data from 49 patients with 49 TKA, i.e., only one TKA per patient.
↵** Comorbidity assessed using self-reported validated comorbidity index51.
↵† Many patients were taking multiple medications.
↵†† Included capsaicin and medications used for treatment of neuropathic pain, including gabapentin, sertraline, amitryptiline, trazodone, fluoxetine, venlafaxine, topiramate. IA: intraarticular; BoNT/A: botulinum toxin A; VAS: visual analog scale; WOMAC: Western Ontario McMaster University Arthritis Index.