CT Classification And Treatment Strategy Of Tibial Avulsion Fracture Of Posterior Cruciate Ligament Of Knee Joint

Background: The posterior cruciate ligament(PCL)originated from the lateral medial femoral condyle and showed footprint.The insertion point is located in the depression between the posterior edge of the medial and lateral tibial condyles,and PCL restricts tibial inversion.Tibial avulsion fracture of posterior cruciate ligament(PCL)is a special type of fracture in the knee joint,and its diagnosis and treatment are difficult.At present,the classification of tibial insertion avulsion fracture of posterior cruciate ligament is relatively simple at home and abroad.Traditional Meyers and McKeever classification can be divided into three types: Type ?: non-displaced fracture;Type ?: folded,one side connected;Type ?:completely displaced fracture.The traditional type of Meyers and McKeever did not consider the factor of avulsion range of tibial insertion of PCL,and did not classify it from three-dimensional perspective.Objective: Tibial avulsion fracture of PCL is very common in clinic.Conservative treatment,arthroscopy(sports medicine),open reduction and internal fixation(trauma orthopaedics)are the common treatment methods for such fractures.Arthroscopy technology in sports arthrology department is relatively mature.However,there is no scientific and complete theoretical guidance in orthopaedics of trauma,including the choice of surgical approach and internal fixator.Based on this,the aim of this study is to classify the avulsion fracture of tibial insertion of PCL.According to the classification of each fracture,a detailed surgical plan is formulated to guide the treatment through the classification.Methods: Data of patients with PCL tibial avulsion fracture from March 1,2013 to March 10,2019 were collected.According to the inclusion criteria and exclusion criteria,29 patients were included in the study group,including 20 males and 9 females.classification was made according to the avulsion range of tibial insertion of PCL,the integrity of fracture fragments and the displacement degree of fracture fragments.Type ?: no displacement fracture in the posterior intercondylar fossa(fracture avulsion is limited to the posterior intercondylar fossa,fracture displacement is less than 3 mm);Type ?: Displacement fracture of posterior intercondylar fossa(avulsion range is limited to posterior intercondylar fossa,displacement degree of fracture > 3mm)Type ?a: Complete fracture,slight displacement of fracture,with posterior elevation of avulsion(hinge mechanism);Type ?b: Fracture fragments were intact and fracture ends were completely separated.Type ?c: comminuted fracture.Type ?: Fractures beyond the posterior intercondylar fossa(fracture avulsion beyond the posterior intercondylar fossa)Type ?a: Complete simple fracture.Type ? b: comminuted fracture;Type ? C: Complex compound fracture.Based on the situation of each type,the corresponding treatment plan was formulated.All patients were followed up by Wechat,outpatient appointment and regular follow-up.And according to the recovery of patients,guide their functional exercise.Result: Among the 29 patients,9 were type ?,4 of them were treated with full-length plaster fixation and conservative treatment.The other 5 cases were treated by minimally invasive small incision and hollow pull screw.Among them,there were 4 patients with type ?a,4patients with type ?b and 3 patients with type ?a.Minimally invasive small incision and hollow pull screw were also used in these three types of patients.Among them,there were 5 patients with type ?c and 2 patients with type ?b.The two types of patients were treated by open reduction and internal fixation.Among them,2 patients with type ?c were treated by combined approach.The tibial plateau fracture was first reduced and then fixed with PCL avulsed bone.Five patients with ligament injury were treated with bone anchor to repair the injured ligament.Bone healing was observed in all patients.At the last follow-up,knee joint function was evaluated according to HSS score.Among them,19 cases were excellent,7 cases were good,3 cases were normal and 0 cases were poor.The total excellent and good rate was89.7%.According to the follow-up of 29 patients with tibial avulsion fracture of PCL after operation,no late complications such as chronic osteomyelitis,nonunion,joint stiffness and malunion of fracture were found.Conclusion: Three-dimensional CT classification of PCL tibial avulsion fracture is the first putting forward in the world.The classification is based on3D-CT imaging,a three-dimensional type,which takes into account the related factors of fracture,including fracture avulsion range,bone integrity and bone displacement degree.The type provides a scientific treatment strategy for orthopaedic traumatologists and sports medicine doctors.Type ? and type ?a:conservative treatment;Type ?,?a,?b,?a: minimal y invasive small incision and hol ow pul screw;Type ?c and ?b: open reduction + hollow pull screw,buried head screw(involving joints),bone anchor;Type ?c: Fixed tibial plateau first,then repairedand reconstructed PCL avulsedbone.