BACKGROUND:Titanium elastic intramedullary nailing for the treatment of significantly displaced midshaft clavicle fractures has the characteristics of minimally invasive and elastic fixation.The displacement of the fracture is closely related to the later function.However,there are few studies on the three-dimensional displacement analysis of the fracture ends before surgery and after intramedullary fixation such as titanium elastic intramedullary nailing.OBJECTIVE:To explore the three-dimensional displacement of fracture ends after midshaft clavicle fracture and fixation with titanium elastic intramedullary nails,and to analyze the risk factors.METHODS:A total of 91 patients with midshaft clavicle fracture(fracture end shortening ≥15 mm)admitted to Wendeng Orthopedic Hospital of Shandong Province from April 2019 to April 2024 were selected,including 57 males and 34 females,aged(51.73±10.21)years old.All patients received closed reduction and internal fixation with titanium elastic intramedullary nail.CT scans of the affected clavicle were performed before and on the first day after surgery.The CT data were imported into Mimics software for modeling.The length of the clavicle,lateral displacement of the fracture end,and rotation of the distal end of the fracture along the X,Y,and Z axes were measured and recorded before and after surgery.Pearson correlation coefficient was used for correlation analysis of various parameters,and generalized linear regression was used to evaluate risk factors.RESULTS AND CONCLUSION:(1)Preoperatively,the variable that increased the risk of lateral displacement was the number of comminuted bone fragments,the variable that increased the risk of shortening displacement was male patients,and the variable that increased the risk of Z-axis rotation was the left limb.Shortening displacement was significantly positively correlated with lateral displacement(r=0.715,P＜0.001);shortening displacement was significantly positively correlated with X-axis rotation displacement and Y-axis rotation displacement(r=0.265,P=0.028;r=0.303,P=0.011);lateral displacement was significantly positively correlated with Y-axis rotation and Z-axis rotation(r=0.258,P=0.032;r=0.250,P=0.038);X-axis rotation was significantly positively correlated with Y-axis rotation(r=0.382,P=0.001),and Z-axis rotation was significantly positively correlated with Y-axis rotation(r=0.280,P=0.020).(2)Postoperatively:The number of scapula fractures and comminuted bone fragments were variables that increased the risk of postoperative shortening and lateral displacement:Preoperative X-,Y-,and Z-axis rotation displacements were risk variables that increased postoperative X-,Y-,and Z-axis rotation displacements,respectively.Postoperative lateral displacement was significantly positively correlated with postoperative shortening and displacement(r=0.584,P=0.000),and postoperative lateral displacement was also significantly positively correlated with postoperative Y axis rotation and Z axis rotation(r=0.360,P=0.002;r=0.250,P=0.038).Postoperative Y axis rotation was significantly positively correlated with postoperative Z axis rotation(r=0.248,P=0.040).(3)The results showed that the three-dimensional displacement of the clavicle end before and after surgery was affected by many factors,especially the number of comminuted bone fragments,scapula fractures,gender,and original rotation displacement.At the same time,there were complex correlations between various displacements,especially the correlation between shortening displacement and lateral displacement was the strongest.

BACKGROUND:Titanium elastic intramedullary nailing for the treatment of significantly displaced midshaft clavicle fractures has the characteristics of minimally invasive and elastic fixation.The displacement of the fracture is closely related to the later function.However,there are few studies on the three-dimensional displacement analysis of the fracture ends before surgery and after intramedullary fixation such as titanium elastic intramedullary nailing.OBJECTIVE:To explore the three-dimensional displacement of fracture ends after midshaft clavicle fracture and fixation with titanium elastic intramedullary nails,and to analyze the risk factors.METHODS:A total of 91 patients with midshaft clavicle fracture(fracture end shortening ≥15 mm)admitted to Wendeng Orthopedic Hospital of Shandong Province from April 2019 to April 2024 were selected,including 57 males and 34 females,aged(51.73±10.21)years old.All patients received closed reduction and internal fixation with titanium elastic intramedullary nail.CT scans of the affected clavicle were performed before and on the first day after surgery.The CT data were imported into Mimics software for modeling.The length of the clavicle,lateral displacement of the fracture end,and rotation of the distal end of the fracture along the X,Y,and Z axes were measured and recorded before and after surgery.Pearson correlation coefficient was used for correlation analysis of various parameters,and generalized linear regression was used to evaluate risk factors.RESULTS AND CONCLUSION:(1)Preoperatively,the variable that increased the risk of lateral displacement was the number of comminuted bone fragments,the variable that increased the risk of shortening displacement was male patients,and the variable that increased the risk of Z-axis rotation was the left limb.Shortening displacement was significantly positively correlated with lateral displacement(r=0.715,P＜0.001);shortening displacement was significantly positively correlated with X-axis rotation displacement and Y-axis rotation displacement(r=0.265,P=0.028;r=0.303,P=0.011);lateral displacement was significantly positively correlated with Y-axis rotation and Z-axis rotation(r=0.258,P=0.032;r=0.250,P=0.038);X-axis rotation was significantly positively correlated with Y-axis rotation(r=0.382,P=0.001),and Z-axis rotation was significantly positively correlated with Y-axis rotation(r=0.280,P=0.020).(2)Postoperatively:The number of scapula fractures and comminuted bone fragments were variables that increased the risk of postoperative shortening and lateral displacement:Preoperative X-,Y-,and Z-axis rotation displacements were risk variables that increased postoperative X-,Y-,and Z-axis rotation displacements,respectively.Postoperative lateral displacement was significantly positively correlated with postoperative shortening and displacement(r=0.584,P=0.000),and postoperative lateral displacement was also significantly positively correlated with postoperative Y axis rotation and Z axis rotation(r=0.360,P=0.002;r=0.250,P=0.038).Postoperative Y axis rotation was significantly positively correlated with postoperative Z axis rotation(r=0.248,P=0.040).(3)The results showed that the three-dimensional displacement of the clavicle end before and after surgery was affected by many factors,especially the number of comminuted bone fragments,scapula fractures,gender,and original rotation displacement.At the same time,there were complex correlations between various displacements,especially the correlation between shortening displacement and lateral displacement was the strongest.