Descriptive statistics for the study population. N (%) is given for categorical variables; mean (± SD) for continuous variables.
| All Subjects, n = 728 | Isolated PFJ, n = 193 | Isolated TFJ, n = 112 | Mixed, n = 321 | None, n = 102 | |
|---|---|---|---|---|---|
| Age, yrs | 66.5 (7.4) | 66.1 (7.2) | 66.7 (8.1) | 66.7 (7.4) | 66.0 (7.2) |
| BMI, kg/m2 | 29.4 (4.8) | 29.8 (4.5) | 29.9 (4.5) | 30.1 (4.9) | 28.7 (5.1) |
| BMI (% obese) | 326 (45) | 85 (44) | 51 (46) | 155 (48) | 35 (34) |
| Sex (% female) | 499 (68) | 146 (76) | 70 (63) | 223 (69) | 60 (59) |
| History of knee surgery or injury | 156 (21) | 35 (18) | 37 (33) | 70 (22) | 14 (14) |
| Presence of periarticular lesions* | 128 (18) | 21 (11) | 27 (24) | 68 (21) | 12 (12) |
| Daily medication use | 96 (13) | 22 (11) | 17 (15) | 43 (13) | 14 (14) |
| Injection in last 6 months | 328 (45) | 79 (41) | 55 (49) | 130 (41) | 64 (63) |
↵* Defined as prepatellar or pes anserine bursitis on magnetic resonance imaging. PFJ: patellofemoral joint; TFJ: tibiofemoral joint; BMI: body mass index.