Baseline characteristics: subjects and treatment factors.
| Variables | Full Sample | First Followup Visit | 6-month Visit | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Nonresponder | Responder | Nonresponder | Responder | |||||||
| N | Values | N | Values | N | Values | N | Values | N | Values | |
| Demographic/prior knee injury | ||||||||||
| Age, yrs, mean (SD) | 199 | 62.8 (10.3) | 53 | 62.6 (9.9) | 146 | 62.9 (10.5) | 159 | 63.4 (10.5) | 40 | 60.5 (9.5) |
| Females, frequency (%) | 199 | 105 (52.8) | 52 | 22 (41.5) | 146 | 83 (56.9) | 159 | 83 (52.2) | 40 | 22 (55.0) |
| Pain | ||||||||||
| KOOS pain subscale score (0–100)* | 199 | 44.4 (36.1–55.6) | 53 | 44.4 (38.9–61.1) | 146 | 44.4 (36.1–52.8) | 159 | 44.4 (36.1–55.6) | 40 | 44.4 (36.1–52.8) |
| Pain on nominated activity, VAS (0–10 cm)** | 190 | 7.0 (5.6–8.1)¤ | 49 | 7.0 (5.2–8.4) | 141 | 7.0 (5.8–8.0) | 152 | 7.0 (5.5–8.1) | 38 | 7.2 (6.4–8.1) |
| Pain in last week VAS (0–10 cm)** | 194 | 6.5 (5.0–8.0)¤ | 50 | 6.8 (3.3–8.0) | 144 | 6.5 (5.0–8.0) | 154 | 6.5 (4.8–8.0) | 40 | 6.5 (5.1–8.1) |
| No. pain sites | 177 | 4.0 (2.0–5.0) | 47 | 4.0 (2.0–6.0) | 130 | 3.0 (2.0–5.0) | 143 | 4.0 (2.0–5.0) | 34 | 2.0 (2.0–4.0) |
| Chronic widespread pain (ACR), frequency (%) | 150 | 39 (26.0) | 38 | 11 (29.0) | 112 | 28 (25.0) | 120 | 36 (30.0) | 30 | 3 (10.0) |
| Psychological factors | ||||||||||
| HADS anxiety | 170 | 6.5 (3.0–9.0) | 45 | 6.0 (3.0–9.0) | 125 | 7.0 (3.0–9.0) | 137 | 7.0 (3.0–9.0) | 33 | 5.0 (2.0–9.0) |
| HADS depression | 170 | 4.0 (2.0–8.0) | 45 | 5.0 (3.0–8.0) | 125 | 4.0 (2.0–7.0) | 137 | 5.0 (2.0–8.0) | 33 | 3.0 (2.0–6.0) |
| IPQ-B consequences score | 175 | 6.0 (4.0–8.0) | 46 | 7.0 (4.0–8.0) | 129 | 6.0 (4.0–8.0) | 141 | 7.0 (4.0–8.0) | 34 | 6.0 (4.0–7.0) |
| IPQ-B timeline score | 172 | 10.0 (8.0–10.0) | 46 | 10.0 (7.0–10.0) | 126 | 9.0 (8.0–10.0) | 139 | 10.0 (8.0–10.0) | 33 | 8.0 (6.0–10.0) |
| IPQ-B personal control score | 173 | 5.0 (2.0–7.0) | 45 | 5.0 (2.0–6.0) | 128 | 4.0 (2.0–7.0) | 140 | 5.0 (2.0–7.0) | 33 | 4.0 (3.0–7.0) |
| IPQ-B treatment score | 174 | 8.0 (5.0–10.0) | 46 | 7.0 (5.0–8.0) | 128 | 8.0 (6.0–10.0) | 141 | 8.0 (5.0–10.0) | 33 | 8.0 (7.0–9.0) |
| IPQ-B identity score | 175 | 7.0 (6.0–9.0) | 46 | 7.5 (5.0–8.0) | 129 | 7.0 (6.0–9.0) | 142 | 7.0 (6.0–9.0) | 33 | 7.0 (6.0–8.0) |
| IPQ-B illness concern score | 174 | 7.0 (5.0–9.0) | 46 | 7.5 (5.0–9.0) | 128 | 7.0 (5.0–9.0) | 141 | 7.0 (5.0–9.0) | 33 | 7.0 (5.0–8.0) |
| IPQ-B coherence score | 172 | 8.0 (7.0–10.0) | 46 | 8.0 (6.0–10.0) | 126 | 8.0 (7.0–10.0) | 139 | 8.0 (7.0–10.0) | 33 | 8.0 (7.0–10.0) |
| IPQ-B emotional representation score | 172 | 5.0 (2.0–7.0) | 46 | 5.0 (2.0–8.0) | 126 | 5.0 (2.0–7.0) | 139 | 5.0 (2.0–7.0) | 33 | 5.0 (1.0–7.0) |
| Quality of life | ||||||||||
| SF-12 physical component summary, mean (SD) | 184 | 32.3 (8.7) | 50 | 31.7 (8.8) | 134 | 32.5 (8.7) | 147 | 32.2 (8.9) | 37 | 32.6 (8.0) |
| SF-12 mental component summary, mean (SD) | 184 | 49.2 (11.7) | 50 | 47.2 (12.8) | 134 | 50.0 (11.2) | 147 | 48.8 (11.8) | 37 | 51.2 (10.9) |
| Treatment-related factors | ||||||||||
| Synovial fluid aspiration, frequency (%) | 199 | 89 (44.7) | 53 | 32 (60.4) | 146 | 57 (39.0) | 159 | 73 (45.9) | 40 | 16 (40.0) |
| Ultrasound-guided knee injection, frequency (%) | 199 | 79 (39.7) | 53 | 18 (34.0) | 146 | 61 (41.8) | 159 | 62 (39.0) | 40 | 17 (42.5) |
| Clinical-related factors (subset n = 101†) | ||||||||||
| Quadriceps muscle strength, Nm/kg | 98 | 0.6 (0.4–1.1) | 23 | 0.7 (0.3–1.5) | 75 | 0.6 (0.4–1.1) | 77 | 0.6 (0.3–1.0) | 21 | 1.0 (0.5–1.2) |
| Knee range of movement, degrees | ||||||||||
| Flexion | 101 | 120.0 (111.0–127.0) | 23 | 122.0 (106.0–127.0) | 78 | 120.0 (112.0–127.0) | 79 | 120.0 (111.0–126.0) | 22 | 121.0 (114.0–128.0) |
| Extension | 101 | 172.0 (170.0–176.0) | 23 | 172.0 (170.0–177.0) | 78 | 172.0 (170.0–176.0) | 79 | 172.0 (170.0–176.0) | 22 | 172.0 (170.0–177.0) |
Values are median (IQR) unless otherwise specified.
↵* KOOS pain subscale is scored from 100 (no pain) to 0 (extreme pain).
↵** VAS are scored from 0 (no pain) to 10 (pain as bad as you can imagine).
↵¤ N < 199 indicates patients not completing this particular element of the questionnaire.
↵† Clinical tests were performed in a subset of 103 patients only; 2 patients did not complete KOOS. KOOS: Knee Injury and Osteoarthritis Outcome Score; VAS: visual analog scale; IQR: interquartile range; HADS: Hospital Anxiety and Depression Scale; IPQ-B: Illness Perception Questionnaire-Brief; SF-12: Medical Outcomes Study Short Form-12; ACR: American College of Rheumatology.