The determinants of change in tibial plateau bone area in osteoarthritic knees: a cohort study

Table 1 Characteristics of the study population

	Total (n = 126)	Men (n = 58)	Women (n = 68)	P ^a
Age, years	63.6 ± 10.1	64.2 ± 10.0	63.2 ± 10.3	0.58
Height, cm	167.7 ± 9.1	174.6 ± 6.8	161.8 ± 6.1	<0.001
Weight, kg	81.4 ± 15.5	85.1 ± 14.9	78.3 ± 15.3	0.01
BMI, kg/m²	28.9 ± 5.1	27.8 ± 3.8	29.9 ± 5.8	0.02
WOMAC score	436 ± 224	411 ± 214	457 ± 232	0.25
SF-36 score	98 ± 7	98 ± 6	99 ± 8	0.25
Physical activity	6.2 ± 1.8	6.7 ± 1.7	5.8 ± 1.8	0.01
Time between scans, years	1.95 ± 0.21	1.94 ± 0.19	1.96 ± 0.23	0.58
OA grade^b
Grade of medial osteophytes
<2	107	50	57	0.50
≥ 2	18	7	11	0.35
Grade of medial JSN
<2	90	35	55	0.04
≥ 2	35	22	13	0.13
Grade of lateral osteophytes
<2	103	48	55	0.49
≥ 2	22	9	13	0.39
Grade of lateral JSN
<2	116	55	61	0.58
≥ 2	9	2	7	0.10
Tibial plateau area, mm²
Medial	2054.6 ± 363.9	2331.1 ± 304.3	1860.2 ± 263.2	<0.001
Lateral	1407.2 ± 256.7	1533.4 ± 244.9	1328.2 ± 232.8	<0.001

Except where indicated otherwise, values are means ± standard deviations. ^aMen vs women, by independent t-tests or chi-square test, as appropriate. ^bValues are the number of subjects in each grade category. One radiograph was lost after the study commenced. BMI, body mass index; JSN, joint-space narrowing.; MRI, magnetic resonance imaging; OA, osteoarthritis; SF-36, 36-Item Short-Form Health Survey; WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index.

ISSN: 1478-6362