Knee cartilage loss in symptomatic knee osteoarthritis over 4.5 years

Table 1 Characteristics of study population

Characteristic	Eligible population (n = 105)	Subjects with MRI at 4.5 years (n = 78)	Subjects lost to follow-up at 4.5 years (n = 27)	p ^a
Age, years	62.5 (10.7)	63.8 (10.6)	61.6 (11.3)	0.65
Number of women, %	59 (53%)	44 (54%)	17 (63%)	0.50
Height, cm	168 (9.3)	168 (9.2)	167 (9.5)	0.45
Weight, kg	80.1 (15.0)	80.5 (15.3)	79.3 (14.4)	0.72
BMI	28.4 (5.1)	28.4 (4.8)	28.7 (5.9)	0.79
Womac
Pain	79 (45)	78 (43)	81 (53)	0.82
Stiffness	38 (23)	37 (21)	42 (28)	0.39
Function	298 (171)	290 (161)	324 (201)	0.47
Total	416 (228)	406 (214)	449 (272)	0.49
Kellgren Lawrence^b
I	11	7	4
II	48	35	13
III	45	35	10	0.10
Knee angle^c, degrees	181 (6)	181 (6)	180 (5)	0.38
Tibial plateau area, mm²
Medial	2,065 (405)	2,085 (394)	2,008 (438)	0.42
Lateral	1,358 (257)	1,352 (239)	1,374 (308)	0.73
Cartilage volume at baseline, mm³
Medial	1,754 (500)	1,780 (513)	1,676 (459)	0.33
Lateral	1,945 (580)	1,946 (576)	1,946 (602)	0.98
Annual cartilage loss over first period, %
Medial	4.3 (6.3)	4.3 (6.5)	4.3 (7.4)	0.87
Lateral	4.7 (6.8)	4.1 (5.9)	6.1 (4.6)	0.15

Results are reported as mean (SD), except where variables are categorical. Body mass index (BMI) is measured as weight in kilograms divided by the square of height in metres; WOMAC, Western Ontario and McMaster University Osteoarthritis Index. ^aThe p value for difference between subjects who had undergone baseline magnetic resonance imaging (MRI) and had subsequently completed 5-year MRI and those who did not complete 5-year follow-up. Comparisons made with Student's t test or χ², for categorical variables, or Eta test for categorical variable by nominal. ^bOne X-ray was lost after study began. ^cAngles available for 96 subjects.

ISSN: 1478-6362