Schatzker Type Ⅳ Tibial Plateau Fracture Involving The Posterior Lateral Condyle Treated By A Modified Peroneal Head Approach With Gerdy’s Nodal Osteotomy

PartⅠ Research on Clinical Efficacy of Gerdy Nodal Osteotomy via Modified Fibular Head Approach for Schatzker Type Ⅳ Tibial Plateau Fracture Involving Posterior Lateral CondylarPurpose:To investigate the clinical efficacy of the modified peroneal head approach with Gerdy’s node osteotomy in the treatment of Schatzker type Ⅳ tibial plateau fractures involving the posterior lateral condyle.Methods:Fifty-two patients with Schatzker type Ⅳ tibial plateau fractures involving the posterior lateral condyle admitted to Lianyungang The First hospital between January 2016 and March 2021 were divided into group A and group B for a randomized control study.Group A(experimental group)had 27 patients,including 15 males and 12 females,aged from 18 to 64 years,with the mean age of 45.9±11.0 years.Patients in group A received modified fibular head approach with anterolateral Gerdy’s node osteotomy to treat bone fracture and used medial support plate and lateral rafting plate to fix the fracture.In group B(control group),25 patients including 11 males and 14 females were aged from 17 to 63 years,with the mean age of 42.0±12.4 years,and they received the posterior medial inverted L approach combined with the anterolateral approach to treat the fracture,and the fracture was fixed with the medial support plate and the posterior lateral support plate.Patients in both groups were operated by two senior physicians with similar years of experience.The length of surgery,intraoperative bleeding,days of hospitalization,and recovery of knee function according to the Hospital for Special Surgery(HSS)Knee Score System at the one-year follow-up were collected.Results:Patients in group A had a mean surgery time of 2.53 ± 0.29 h,bleeding volume of 378.89 ± 114.68 ml,mean days of hospitalization of 16.04 ± 6.47 d,mean Rasmussen score for quality of fracture reduction immediately after surgery of 17.19±1.12,and HSS score of 87.96± 2.71 at one year postoperatively.In 27 patients,1 case had local necrosis of the medial skin margin.with delayed healing after dressing change and without incision infection.Patients in group B had a mean surgery time of 2.85±0.52 h.bleeding volume of 536.80±204.70 ml.mean days of hospitalization of 20.20±8.15 d.mean Rasmussen score for quality of fracture reduction immediately after surgery of 16.24±1.73.and HSS score of 86.32±3.46 at one year postoperatively.In 25 patients.4 cases had local necrosis of the posterior medial curvilinear skin margin.3 cases had delayed healing after dressing change.and 1 case had acute MRSA infection that healed after debridement with intravenous vancomycin.All 52 patients had no loosening of the internal fixation.and all fractures healed on radiographs.with no vascular or nerve injury or other surgery-related complications.Conclusion:In Schaztke type Ⅳ tibial plateau fractures involving the posterior lateral condyle,the modified peroneal head approach with Gerdy’s node osteotomy allows sufficient space for direct exposure and operation of the fracture.The medial support plate combined with lateral rafting locking plate is reliable for fracture fixation.convenient for surgical position and intraoperative fluoroscopy.And it also has few complications,good postoperative function recovery.and shows satisfactory curative effect.PartⅡ Finite Element Analysis of Two Internal Fixation Configurations for Posterior Lateral Condylar Fractures at the Tibial Plateau Treated by Gerdy Nodal OsteotomyPurpose:Study the fixation strength of inverted L-shaped anterolateral locking steel plates combined with anterior-posterior oriented screw fixation via gerdy nodule osteotomy for posterior lateral condylar fractures at the tibial plateau to further validate the conclusions of the Part I.Methods:Based on the thin-layer CT data from the left knee of a normal young female volunteer,and then the fracture shape and internal fixation configuration data were extracted from the postoperative thin-layer CT of a young female patient with a posterior lateral condylar fracture in the left tibial plateau treated by gerdy nodule osteotomy,and the fracture model of the posterior lateral condylar fracture in the tibial plateau treated by gerdy nodule osteotomy was constructed by Mimics and HyperMesh software.On the constructed model,it was simulated that the inverted L-shaped anterolateral locking steel plate combined with anterior-posterior oriented screw fixation of the posterior lateral bone block after fracture reduction.Using finite element analysis,the stress and displacement of the fracture block and internal fixation material under human standing load were analyzed and compared with the lateral bone block after fixation with a simple inverted L-shaped anterolateral locking steel plate.Results:After applying human load stresses to the model,when the fracture was fixed with the anterolateral locking steel plate alone,the maximum load on the posterior lateral bone block was 9.886 MPa,the maximum displacement between the fracture blocks was<0.1 mm(0.027 mm),and the stress distribution on the two posterior raft screws was larger,with a maximum of 13.023 MPa.As for the anterolateral locking steel plate combined with steel plate external anterior-posteriorly oriented screw fixation of the fracture,the maximum load on the posterior lateral bone block was 7.374 MPa,the maximum displacement between the fracture blocks was<0.1 mm(0.096 mm),and the stress distribution on the raft screws was relatively even,with a maximum of 11.637 MPa.Conclusion:The stability of both internal fixation methods can meet the needs of rehabilitation training after fracture fixation.The addition of an anterior-posteriorly oriented screw outside the anterolateral locking steel plate can disperse the stress in the metaphysis,reduce the stress distribution in the posterior-lateral fracture block,and increase the local and overall stability.