Medium-term efficacy of arthroscopic debridement vs conservative treatment for knee osteoarthritis of Kellgren-Lawrence grades I-III

Table 4 Visual analogue scale scores at rest time of the two groups before and after treatment

		VAS score, mean ± SD
	n	Before treatment	1st mo after treatment	3rd mo after treatment	6th mo after treatment	12th mo after treatment	24th mo after treatment
Group A	98	1.22 ± 2.03	0.49 ± 1.19	0.02 ± 0.14	0.02 ± 0.14	0.02 ± 0.14	0.02 ± 0.14
Group B	80	1.21 ± 2.01	0.68 ± 1.39	0.21 ± 0.59	0.21 ± 0.59	0.21 ± 0.59	0.21 ± 0.59
t value		0.039	-	-	-	-	-
t′ value		-	-0.942	-2.851	-2.851	-2.851	-2.851
P value		0.969	0.348	0.005	0.005	0.005	0.005

Statistical difference between the two groups was tested by t test or t′ test. The comparisons between visual analogue scale (VAS) scores at rest time before treatment and VAS score at rest time at 1, 3, 6, 12, and 24 mo after treatment were performed by analysis of variance. Further pairwise comparisons of multiple data were conducted by the S-N-K method (q test) when variance was homogeneous, or Games-Howell method when variances was not homogeneous. Statistical significance was set at P < 0.05. n: Number of patients of the two groups; SD: Standard deviation; VAS: Visual analogue scale; Group A: Arthroscopic debridement group; Group B: Conservative treatment group.