Table 1.

Descriptive statistics for the study population. N (%) is given for categorical variables; mean (± SD) for continuous variables.

All Subjects, n = 728Isolated PFJ, n = 193Isolated TFJ, n = 112Mixed, n = 321None, n = 102
Age, yrs66.5 (7.4)66.1 (7.2)66.7 (8.1)66.7 (7.4)66.0 (7.2)
BMI, kg/m229.4 (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 injury156 (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 use96 (13)22 (11)17 (15)43 (13)14 (14)
Injection in last 6 months328 (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.