Abstract: Objective To study the clinical effect of arthroscopic debridement combined with sodium hyaluronate injection for senile knee osteoarthritis(KOA). Methods A total of 80 senile patients with KOA from February,2013 to February,2014 were randomly divided into the control group(n=36)and the experiment group(n=44),the patients in the control group received single arthroscopic debridement treatment,and the patients in the experiment group received arthroscopic debridement combined with sodium hyaluronate injection.The differences of clinical efficacy rate,the recurrence rate,IL-1 level in synovial fluid and serum nitric oxide level,the score by Lysholm Knee Scoring Scale before treatment,3 months and 12 months after the treatment were compared between the two groups. Results The clinical efficacy rate in the experiment group was significantly higher,the recurrence rate was significantly lower when compared with the control group(P<0.05).The difference in the level of IL-1 in synovial fluid and serum nitric oxide before the treatment were no significant(P>0.05),but decreased after the treatment,especially in the experiment group(P<0.05).There was no significant in the difference of Lysholm score before the treatment(P>0.05),but at 3 months and 12 months after the treatment the Lysholm score in both groups increased,especially in the experiment group(P<0.05). Conclusion Arthroscopic debridement combined with sodium hyaluronate injection can improve the effect of senile knee osteoarthritis,which may be associated with the change IL-1 and NO levels.