Predictors for recurrence of chronic osteomyelitis following long bones cavity defect replacement with synthetic materials

Background. Recent scientific literature only has a few studies highlighting the factors affecting the development of recurrent infection after surgical treatment of chronic osteomyelitis. Aim of the study: to determine significant risk factors of infection recurrence during one- and two-stage treatment of a cavity defect with synthetic materials in patients with chronic osteomyelitis and to create an assessment scale for prediction of the treatment outcome based on this data. Material and Methods. The retrospective study comprised 131 patients with chronic osteomyelitis of the long bones. The patients were divided into two groups based on the treatment outcome: group 1 (n=90) - successful elimination of infection; group 2 (n=41) - recurrent osteomyelitis after one-stage or during two-stage treatment. Differences between the groups were assessed to identify factors that affect the risk of recurrence. Multivariate analysis was performed using the classification tree method ​​to develop a scale for the comprehensive risk assessment of osteomyelitis recurrence (CRAOR). Results. The following factors affecting the treatment outcome were assessed: location (r=0.205, p=0.019); duration of osteomyelitis (r=0.23, p=0.007); history of debridement operations (r=0.264, p=0.002); bone defect volume (r=0.175, p=0.045); physiological class according to Cierny-Mader (r=0.188, p=0.004); anatomical type of osteomyelitis according to Cierny-Mader (r=0.15, p=0.086); nature of the pathogen (r=0.123, p=0.162). The degree of the osteomyelitis recurrence risk, threshold values ​​for quantitative factors and the total score the scale were established. In patients with a score 5, the risk of osteomyelitis recurrence increased by 8.1 times in one-stage treatment compared to patients with a score ≤5 (OR 8.143, CI 1.008-65.882). In two-stage treatment, patients with a score 5 had the risk of osteomyelitis recurrence increased by 4.1 times compared to patients with a score ≤5 (OR 4.059, CI 0.461-35.714). Based on the scale, an algorithm of treatment for these patients was developed.