Table 2.
Baseline demographic data, structural and pain characteristics
| Primary Cases |
Primary Controls |
p value* |
|||
|---|---|---|---|---|---|
| Group 1 (n=173) | Group 2 (n=91) | Group 3 (n=89) | Group 4 (n=174) | ||
| Age, years | 61.8 ± 8.6 | 63.2 ± 8.4 | 59.5 ±8.8 | 62.1 ± 9.1 | 0.892 |
| Female sex, number (%) | 99 (57) | 38 (42) | 56 (63) | 113 (65) | 0.785₸ |
| Body mass index, kg/m2 | 30.5 ± 4.6 | 30.8 ± 4.6 | 31.0 ± 4.9 | 30.6 ± 4.8 | 0.585 |
| KLG, number (%) | |||||
| 1 / 2 / 3 | 19 (11) / 76 (44) / 78 (45) | 13 (14) / 38 (42) / 40 (44) | 9 (10) / 55 (62) / 25 (28) | 19 (11) / 99 (57) / 56 (32) | 0.047₸ |
| JSN Medial, number (%) | |||||
| 0 / 1/ 2 | 35 (20) / 60 (35) / 78 (45) | 18 (20) / 33 (36) / 40 (44) | 29 (33) / 35 (39) / 25 (28) | 57 (33) / 61 (35) / 56 (32) | 0.024₸ |
| JSN Lateral, number (%) | |||||
| 0 / 1/ 2 | 169 (98) / 4 (2) / 0 (0) | 90 (99) / 1 (1) / 0 (0) | 87 (98) / 2 (2) / 0 (0) | 170 (98) / 4 (2) / 0 (0) | 0.801₸ |
| Pain freq., number (%)^ | |||||
| None / Infreq. / Freq. | 29 (17) / 74 (43) / 70 (40) | 19 (21) / 31 (34) / 41 (45) | 17 (19) / 37 (42) / 35 (39) | 36 (21) / 7 7 (44) / 61 (35) | 0.619₸ |
| WOMAC-pain | 2.0 ± 2.5 | 3.1 ± 4.0 | 1.9 ± 2.6 | 2.6 ± 3.1 | 0.356† |
| Analgesic use, number (%)# | 118 (68) | 47 (52) | 54 (61) | 98 (57) | 0.008₸ |
| Extensor strength, N/kg | 4.1 ± 1.5 | 4.5 ± 1.5 | 3.8 ± 1.3 | 4.2 ± 1.4 | 0.757 |
| Flexor strength, N/kg | 1.7 ± 0.8 | 1.8 ± 0.8 | 1.5 ± 0.6 | 1.7 ± 0.7 | 0.811 |
Primary cases: knees with radiographic and pain progression (group 1). Controls: knees with radiographic but not pain progression (group 2), knees with symptomatic but not radiographic progression (group 3), and knees without radiographic or symptomatic progression (group 4).
Values are mean ± standard deviation unless otherwise indicated.
based on pain frequency status in the past year: Frequent pain defined as ‘pain, aching or stiffness in or around the knee on most days for ≥one month during the past 12 months’; Infrequent pain defined as the above symptoms but at any time in the past 12 months (not on most days for ≥one month).
used medication for pain, aching or stiffness during previous 12 months for either knee.
p values represent comparisons between the primary pre-specified analysis groups (cases: group 1; controls: group 2, 3, 4) using independent samples t-tests unless indicated otherwise.
chi-squared tests for data in contingency tables.
Mann-Whitney U-test as data not normally distributed.
KLG, Kellgren Lawrence grade; JSN, joint space narrowing; N, Newtons; WOMAC, Western Ontario McMasters Osteoarthritis Index.