Differential Diagnosis of Reactive and Infectious Arthritis after Anterior Cruciate Ligament Reconstruction

Abstract

Summary. Relevance. Negative results of the anterior cruciate ligament (ACL) reconstruction occur in 10-20% of cases. The incidence of infectious arthritis can reach up to 1.7% and even up to 7.1%, according to the literature. However, ACL reconstruction can be complicated not only by infectious but also by reactive arthritis. Differential diagnosis between infectious and reactive arthritis is often hard to be done, but it is necessary for effective treatment.
 Objective: to determine the possible causes of the development of reactive and infectious arthritis after ACL reconstruction, peculiarities of their diagnostics and differential diagnostics.
 Materials and Methods. The literature data regarding the frequency of reactive and infectious arthritis after various methods of surgical treatment of ACL injury and the use of different types of implants, as well as laboratory indicators of the activity of the inflammatory process in the postoperative period and such indicators in reactive and infectious arthritis, were analyzed. We also analyzed literature data on the sensitivity and specificity of various methods of microbiological studies in patients with infectious synovitis or arthritis.
 Results. Numerous probable causes of a higher incidence of infectious arthritis in ACL reconstruction are suspected. Synthetic implants may be the cause of the development of reactive arthritis, according to a number of studies. Our experience in using different biodegradable fixators from various manufacturers suggest that the percentage of complications depends not only on the fact of the biodegradability of the implant, but on its composition, and even on the percentage of tricalcium phosphate or the manufacturer. Therefore, it is impossible to unambiguously state that biodegradable fixators are worse or better then metallic or non-biodegradable polymeric ones. However, on average, if we consider all existing fixators from various manufacturers, the number of complications when using biodegradable implants is higher. Diagnosis of reactive arthritis is often based on negative bacteriological findings. Given the not always high sensitivity of bacteriological inoculation of synovial fluid and the duration of the investigation, we cannot rely only on its results.
 Conclusions. The most difficult for differential diagnosis between infectious and reactive arthritis (synovitis) is acute synovitis after ACL reconstruction with normal results of bacteriological studies, but high biochemical parameters of inflammation. We suggest to suspect infectious arthritis after ACL reconstruction in the following hemogram values: 1) CRP >40-50 mg/l, 2) ESR >30-50 mm/h, 3) fibrinogen >800 mg/ml, 4) procalcitonin in blood plasma >0.5 ng/ml, 5) leukocytosis and left shift of the leukocyte formula, with the following synovial fluid test parameters: a) CRP >40-50 mg/l, b) leukocytosis with an increase in the percentage of polymorphonuclear leukocytes >75%.