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

Table 2 American hospital for special surgery knee scores of the two groups before and after treatment

		HSS 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	78.65 ± 11.20	87.76 ± 9.10	91.08 ± 5.67	91.88 ± 6.48	92.18 ± 5.90	92.08 ± 5.85
Group B	80	79.10 ± 11.41	85.05 ± 10.21	87.19 ± 9.32	87.46 ± 9.91	87.79 ± 9.59	87.31 ± 10.15
t value		0.263	-1.867	-	-	-	-
t′ value		-	-	-3.277	-3.433	-3.584	-3.729
P value		0.793	0.064	0.001	0.001	0.000	0.000

Statistical difference between the two groups was tested by t test or t′ test. The comparisons between American hospital for special surgery knee (HSS) scores before treatment and HSS scores 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; HSS: American hospital for special surgery knee score; Group A: Arthroscopic debridement group; Group B: Conservative treatment group.