Effect of metabolic syndrome on union rate of fractures

Increase of inflammatory markers is the most important problem in metabolic syndrome. Creactive protein (CRP) is an undefined component of metabolic syndrome, and its increase is regarded as a dependent risk factor to cause complications. Considering the high prevalence of metabolic syndrome and relation of these diseases with different inflammatory factors, it is assumed this syndrome may affect fractured bone healing process. Therefore, the hypothesis is studied for the first time in analytical study.
This analytical and descriptive study was conducted on 48 patients with isolated fracture of tibia and femur shafts resulting from low-energy trauma. In this study, 24 patients with metabolic syndrome criteria matched considering age, gender, type of fracture, and treatment method were compared with 24 metabolically health persons. Level of high sensitivity hs-CRP (High-sensitivity CRP) inflammatory marker was also determined in these patients. Union rate and duration as well as a relation between inflammatory marker and union rate were studied.
Prevalence of nonunion and delayed union were seen in 8 (33.3%) and 3 (12.5%) patients with metabolic syndrome, respectively. However, there was not any case of nonunion in the metabolically health group. There was a statistically significant difference between these groups. According to the regression model, hs-CRP level played a significant role with sensitivity of 95% considering nonunion prediction [P = 0.001, OR (Odds ratio) = 2.3 and CI (Confidence interval) 95% = 1.4-3.8] while other factors of metabolic syndrome did not play any important role in nonunion prediction.
Prevalence of nonunion in patients with metabolic syndrome suffering from a fracture and undergoing orthopedic surgery is higher than healthy people. It seems that the increase of inflammatory markers plays an important role in causing and predicting of nonunion in these patients.