I'd like to thank my co-authors as well as Anna for allowing us to present. Our disclosures are in the app. So after simple arthroscopic knee procedures, patients typically return to function with the aid of oral prescriptions. However, certain patients, particularly those with pre-existing arthritis, may have a prolonged recovery with continued pain and inflammation. In these scenarios, it is not uncommon to provide an intra-articular corticosteroid injection to decrease post-operative pain and decrease inflammation and speed their functional recovery. While efficacious, the safety of such practices have yet to be fully examined. Therefore, the purpose of the current study was to examine any association between the timing of ipsilateral post-operative corticosteroid injection following simple knee arthroscopy and infection. We used the Pearl Diver Humana and Medicare datasets to identify patients undergoing simple knee arthroscopic procedures with the following CPT codes, and we excluded any patients undergoing more complex procedures such as ligamentous reconstruction, meniscal repair, cartilage restoration procedures, and procedures done for infection. We identified patients who received ipsilateral post-operative injections using the CPT code and J code for steroid injections, and we created a match control cohorts based on CPT, age, gender, obesity, tobacco, diabetes, in a 10 to 1 basis. Each cohort was then queried for an infection within 90 days after the injection date. The rates of infectious complications were then compared using a binomial logistic regression analysis. So we looked at more than 2,700 post-operative injections in the private payer dataset, and we identified a control infection rate of .5%, and patients who underwent injections within two weeks of their surgery had 3.4% infection rate four weeks 2.0, and these were significant as compared to the controls. We further looked at this data and compared cohorts. We noted that patients who underwent injections within two and four weeks, as compared to patients who underwent injections six to eight weeks after surgery, continued to have a significantly increased risk of post-operative infection within 90 days. Similarly, we looked at the Medicare dataset and found similar numbers. The control infection rate was .2%, and the infection rates within two and four weeks were 3.4 and 3.2, both of which were statistically significant, and we looked at this data and compared the weekly cohorts. We also noted patients who underwent injections within two and four weeks had significantly increased risk of infection as compared to patients who underwent these injections six and eight weeks after their operation. So there are several hypotheses of why this could be happening. I think one of which could be that these early post-operative infections may have been thought to be inflammatory responses to begin with, and they were injected for inflammation, and the infection was, in fact, missed. Secondly, I think the injection could infer with the immunologic response to bacterial exposure that occurs during surgery, and finally, the injection itself could be introducing bacterial contamination, resulting in this infection. Regardless, corticosteroids in the early post-operative period may be associated with these infectious complications, and any injection within four weeks of surgery should make the surgeon cognizant of possible underlying infection. And based on these results, we would recommend waiting at least four weeks post-operatively before administering corticosteroid following simple knee procedures. Thank you. __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

intra-articular corticosteroid injections

arthroscopic knee procedures

post-operative corticosteroid injections

infection rates

timing of injections