Abstract
The diagnosis of septic arthritis following arthroscopic anterior cruciate ligament (ACL) reconstruction is often elusive and can only be confirmed by joint aspiration, although arthrocentesis carries a risk for superinfection. C-reactive protein (CRP) may prove a useful laboratory test to substantiate clinical suspicion. The present study investigated the post-operative variations of CRP in 58 patients (age range 15–52, median age 25) undergoing ACL reconstruction with either bone-patellar tendon-bone (BPTB) or hamstring tendon (HT) who did not develop infection at 6 months follow-up. CRP titre was determined on the 1st, 3rd, 7th, 15th, and 30th post-operative day by immunoprecipitation in patients divided according to the type of autograft (BPTB: 13 patients; HT: 45 patients). Mean CRP significantly increased on the 1st post-operative day, peaked on the 3rd day and decreased on the 7th day, while levels on the 15th and 30th days did not differ from baseline. The trend of CRP changes did not differ in relation to the type of autograft. The results of our study suggest that close clinical surveillance may be advisable when CRP levels deviate from the reference values 2 weeks after surgery. In these circumstances, suspicion of septic arthritis warrants aspiration and culturing in order to avert a diagnostic delay.