Abstract: Objective To analyze the risk factors of soft tissue complications after closed calcaneal fractures,and to construct and evaluate a nomogram prediction model.Methods 218 patients with closed calcaneal fracture admitted to our hospital from January 2016 to June 2021 were retrospectively analyzed and divided into complication group (n=43) and non-complication group (n=175) according to whether postoperative soft tissue complications occurred.Logistic regression was used to analyze the risk factors of soft tissue complications after calcaneal closed fracture.A nomogram model was constructed to predict the occurrence of soft tissue complications after closed calcaneal fracture.The nomogram model was validated by receiver operating characteristic (ROC) curve and calibration curve.Results There was no significant difference between the group with postoperative soft tissue complications and the group without postoperative soft tissue complications in terms of gender,hypertension,antibiotic application time,and bone grafting methods (P >0.05),and there was no significant difference in age,smoking history,diabetes,the time from injury to operation,whether a drainage tube was placed,whether non-contact technology was used to protect the soft tissue during the operation,the operation time,the type of fracture,and the type of incision (P<0.05).Logistic regression analysis showed that:a history of smoking,no drainage tube,no non-contact technique to protect soft tissue during operation,operation time ≥1.5h,and incision type of “traditional L” were risk factors for soft tissue complications after closed calcaneal fractures (P<0.05).ROC results showed that the area under the curve for predicting the occurrence of soft tissue complications after closed calcaneal fractures was 0.874 (95%CI:0.805 to 0.943).The slope of the calibration curve of the nomogram model of soft tissue complications after closed calcaneal fractures was close to 1,Hosmer-Lemeshow goodness of fit test showed χ²=6.158,P=0.291.Conclusion A history of smoking,no drainage tube,no non-contact technique to protect soft tissue during operation,operation time ≥1.5h,and incision type of “traditional L” are all risk factors for soft tissue complications after closed calcaneal fractures.The nomogram prediction model constructed based on the above risk factors can individually predict the risk of soft tissue complications after closed calcaneal fractures.

Key words: closed calcaneal fractures; postoperative soft tissue complications; influencing factors; nomogram model