IMPROVEMENT OF CLINICAL, LABORATORY AND INSTRUMENTAL DIAGNOSTIC CRITERIA FOR SEPTIC OSTEOARTHRITIS OF THE KNEE JOINT

Septic osteoarthritis of the knee is a serious infectious-inflammatory condition characterized by rapid progression of synovial inflammation, cartilage destruction, periarticular tissue involvement and, in advanced cases, osteomyelitis and systemic complications. Early diagnosis remains challenging because the clinical manifestations of septic arthritis may overlap with crystal arthropathy, rheumatoid arthritis, traumatic synovitis and exacerbation of degenerative osteoarthritis. The aim of this study was to substantiate an integrated approach to the early diagnosis of septic osteoarthritis of the knee based on clinical, laboratory and instrumental parameters. The analysis demonstrates that no single diagnostic indicator is sufficiently reliable in all patients. Clinical signs such as acute pain, swelling, local hyperthermia, restricted range of motion and joint effusion should be interpreted together with serum inflammatory markers, particularly C-reactive protein, erythrocyte sedimentation rate and leukocyte count. Synovial fluid analysis, including leukocyte count, polymorphonuclear cell percentage, Gram staining, microbiological culture and crystal examination, remains a central diagnostic component. Ultrasound provides rapid detection of effusion and facilitates aspiration, whereas magnetic resonance imaging is particularly valuable for assessing synovitis, bone marrow edema, abscess formation and associated osteomyelitis. A combined diagnostic algorithm may improve early recognition and reduce the risk of delayed treatment.