Study On The Prevention Of Postoperative Infection After Rabbit Knee Joint Surgery With Povidone-Iodine Irrigation

Objective Povidone-iodine(PI)solution is widely used in surgery.However,there is much controversy about how to use PI solution irrigate before closing the incision.This research will study on the effects of different concentrations of PI solution in irrigating the joint cavity during artificial joint replacement,we hope to acquire an optimal concentration,which can not only reduce the postoperative infection rate,but reduce the toxic effects on the tissues and cells around joints.It also provides reference for the irrigation protocol in joint surgery.Methods Fifty New Zealand white rabbits were randomly divided into 5 groups,each with unilateral knee surgery.After the intra-articular cavity was opened,a titanium screw was drilled into the distal medullary cavity to get rigid fixation,and then 0.5 ml of Staphylococcus aureus ATCC25923 with a concentration of 1.0×10~7CFU/mL was implanted into the joint cavity for 3 minutes.The five groups were used 5%,0.5%,0.05%PI solution,3%hydrogen peroxide solution,and physiological saline respectively to irrigate the joint cavity and washed for 3 minutes under low pressure,and then the incision was sutured after flushing the incision with saline.Blood was collected from the ear-vein on one day before,and 1,3,7 and 14 days after surgery to test for C-reactive protein and erythrocyte sedimentation rate,as well as renal function tests.After two weeks,all rabbits were sacrificed and the joint cavity was opened to check the extent of joint infection and tissue damage around the joints.Tissue microbiological culture results,C-reactive protein and erythrocyte sedimentation rate were used to evaluate the infection.The pathological scores of the articular cartilage of the femur were evaluated local toxicity,and the renal function was evaluated systemic toxic effects.Results The infection rates of the 5 groups were:50%(5%)in the 5%PI group,40%(4/10)in the 0.5%PI group,20%(2/10)in the 0.05%PI group,30%(3/10)in the hydrogen peroxide group,and 30%(3/10)in saline group.The differences in infection rates among the groups were tested using Fisher's exact test,and the difference was not statistically significant(p>0.05).There was no significant difference in CRP and ESR between the groups.The results of cartilage pathological examination showed that the difference between the group and other groups was statistically significant(p<0.05).The toxicity of 5%PI solution was strongest.With the dilution of PI concentration,the local toxicity gradually decreased.The results of renal function showed no significant difference between the groups(p>0.05).Conclusion 0.5 ml of Staphylococcus aureus at a concentration of 1.0×10~7 cfu/ml may cause knee joint infection in New Zealand white rabbits.Irrigating with sufficient saline reduce the occurrence of postoperative infection after rabbit knee joint surgery.Compared with saline group or hydrogen peroxide solution,PI solution may not be more effective in irrigating the joint cavity of New Zealand white rabbits.However,knee joint irrigating with PI solution may cause injury to the cartilage and other soft tissues,and its toxicity is positively correlated with the concentration.PI solution irrigating in the knee joint did not cause an adverse effect on renal function.