Biomechanical And Clinical Study Of Bicortical ICBG Combined With Internal Compression Fixation Of Locking Plate For Tibial Plateau Fracture

Part One Biomechanical comparison of different bone grafts and internal fixators for Schatzker type Ⅱ tibial plateau fracturesObjective:To investigate the biomechanical characteristics and stability of different bone grafts and internal fixators for Schatzker type Ⅱ tibial plateau fracture.Methods:Twenty-four cadaveric specimens of adult lower extremity anticorrosion knee joints were collected,and the Schatzker Ⅱ tibial plateau fracture models were made according to the pre-designed method.The 24 tibial specimens were divided into A(A1,A2),B(B1,B2),C(C1,C2)and D(Dl,D2)groups by random number table method.After reduction of all fracture specimens,un-structural iliac crest bone grafting(ICBG)was performed on specimens in groups A1,B1,Cl,and D1,and structural ICBG was performed on specimens in groups A2,B2,C2,and D2.Group A were fixed with proximal 2-hole Golf locking plates,group B were fixed with proximal 2-hole Golf locking plates combined with compression bolt,group C were fixed with proximal 3-hole lateral tibial "L" locking plates combined with compression bolt,and group D were fixed with proximal 3-hole lateral tibial "L" locking plates combined with compression bolt.A self-design bone cement ball with a diameter of 4 cm was used as a pressure mold to conduct local vertical loading mechanical experiments on the tibia specimens in each group after fixation,and the load when the depressed fracture fragment was vertically displaced by 2 mm was recorded.The same preserved distal femur specimens were used to conduct vertical loading mechanical experiments on the fixed tibia specimens in each group.The vertical displacement of split bone blocks at 100,400,700,1000N and the vertical displacement of split bone blocks at 100-300N,100-500N,100～700N,100～1000N were recorded.Results:When the displacement of the depressed fracture fragment reached 2 mm,the load difference between the structural ICBG group and the un-structural ICBG group in groups A,B,C,and D were statistically significant(P<0.05).There was a statistically significant difference between the A1,B1,C1 and D1 load groups(P=0.006),and the load of B1 and D1 groups were significantly greater than that the load of A1 and C1 groups.There were significant statistical differences among A2,B2,C2 and D2 loading groups(P<0.001),and the loading value of D2 group was significantly higher than that of A2,B2 and C2 groups.When the distal femur was used for axial loading and cyclic loading,the split fracture fragments in the structural ICBG group and the un-structural ICBG group were subjected to axial loads of 100,400,and 700N and cyclic loads of 100 to 300N,100 to 500N and 100-700N,there was no significant difference in the displacement of the split fracture between the groups with the same fixation method(P>0.05).However,when the axial load was 1000 N and the cyclic load was 100-1000 N,there was a statistically significant difference in the displacement of the split fracture fragments between the groups with the same fixation method(P<0.01).Under the condition of unstructured ICBG or structured ICBG,there were statistically significant differences between groups A and B,and between groups C and D(P<0.05).Conclusions:Compared with un-structural ICBG,structural bicortical ICBG can prevent the secondary collapse of the articular surface of the platform more effectively.The single-side locking plate combined with compression bolt fixation can provide better joint surface support and axial compression resistance for Schatzker II type tibial plateau fractures,with better mechanical stability.After receiving a structural bicortical ICBG and compression bolts,the "L" locking plate of the proximal 3-hole lateral tibia showed the advantage of "raft" fixation.Part Two Clinical study of biocortical ICBG combined with internal compression fixation of locking plate for depressed tibial plateau fractureObjective:In clinical practice,the combination of lilac crest bone grafts(ICBG)and locking plate fixation is a common technique for the treatment of depressed tibial plateau fractures.The objective of this study was to introduce and evaluate the clinical efficacy of lilac crest bone grafts(ICBG)combined with internal compression fixation of locking plate for depressed tibial plateau fracture.Methods:All patients with depressed tibial plateau fractures who underwent structural bicortical autologous ICBG combined with internal compression fixation of locking plate in our prospective study from January 2016 to February 2018.A total of 47 patients with depressed tibial plateau fractures were recruited,of which 4 patients were lost to follow-up due to other reasons.All 43 patients were followed up for more than 30 months.Demographic data,imaging data(X-ray and CT scans),operation-related data,complications and follow-up data(including visual analog scale(VAS)pain score,Hospital for Special Surgery(HSS)functional score and 36-item health Survey scale(SF-36))were recorded in the database.The degree of depression of preoperative tibial plateau and the loss of secondary reduction of articular surface after surgery were measured by the picture archiving and communication system(PACS)in our hospital.Results:Forty-three of the included patients completed the follow-up.No malreduction was observed.Based on the immediate postoperative imaging,the intra-articular step-off was significantly reduced(8.19 mm preoperatively vs 1.30 mm immediate postoperatively,P<0.001).From the immediate operation to the latest follow-up,the reduction was maintained significantly well,with a non-negligible absolute difference(0.18 mm,P=0.108).A remarkable secondary loss of reduction(intra-articular step off>3 mm)was found in two elderly patients.The incidence of complications related to the bone-graft donor and bone-graft site was 2.33%and 4.65%,respectively.At the final follow-up,the mean HSS score of the knee was 98.19±2.98,and the mean SF-36 score was 95.65 ± 4.59.Conclusions:Structural bicortical autologous ICBG combined with internal compression fixation of locking plate is a safe and effective technique for the treatment of depressed tibial plateau fractures.Part Three Unilateral locking plate versus unilateral locking plate combined with compression bolt for Schatzker Ⅰ-Ⅳ tibial plateau fracturesObjective:The quality and durability of fracture reduction play an important role in the functional prognosis of articulation.The purpose of this study was to investigate the radiological and clinical effects of compression bolts in the treatment of Schatzker I-IV tibial plateau fractures.Methods:Between May 2015 and April 2018,a total of 96 consecutive adult patients with operatively treated Schatzker Ⅰ-Ⅳ tibial plateau fractures were included and divided into 2 groups according to the internal fixations:Group 1(unilateral locking plate)and Group 2(unilateral locking plate combined with compression bolt).Demographic data,fracture characteristics,imaging data(knee X ray,CT scan and 3D reconstruction),operative indicators,clinical outcomes and postoperative complications were retrospectively collected from 2 groups.Postoperative reduction quality and secondary reduction loss were evaluated by measuring postoperative intraarticular step displacement,platform widening,medial tibial Angle and posterior Angle.Clinical outcomes were assessed using the Western Ontario and McMaster University Osteoarthritis Index(WOMAC),Hospital for Special Surgery Knee HSS Score,Lysholm Exercise Score,and 36-item Health Survey Scale(SF-36).SPSS statistical software was used for statistical analysis of the data.Results:There were no significant intergroup differences in preoperative baseline data,duration of operation,intraoperative blood loss,days in hospital,rate of immediate postoperative reduction loss,or complications.The time of fracture healing,the rate of secondary reduction loss,and the mean WOMAC score was significantly reduced compared with those in Group 1(P=0.024,0.015,and 0.024,respectively).There were significant intergroup differences in the mean HSS score(89.0±11.4 vs.94.4±6.7,P=0.042),the mean Lysholm score(83.8±9.6 vs.88.4±5.2,P=0.027),and the mean SF-36 score(82.8±12.5 vs.90.5±7.6,P=0.001).Additionally,there were similar significant differences in subgroup analysis(only included patients with Schatzker Ⅱ-Ⅲ),except for WOMAC score.Conclusions:Compared with unilateral locking plate fixation,unilateral locking plate combined with compressing bolt fixation can reduce the rate of secondary reduction loss,accelerate fracture healing and show better clinical outcomes for patients with Schatzker Ⅰ-Ⅳ tibial plateau fractures.Part Four Correlation between postoperative NLR and PLR and the magnitude of surgery-related trauma in young and middle-aged patients with bicondylar tibial plateau fracturesObjective:The purpose of this study was to investigate the value of the postoperative neutrophil to lymphocyte ratio(NLR)and platelet to lymphocyte ratio(PLR)as biomarkers in assessing the magnitude of surgery-related trauma in young and middle-aged patients with bicondylar tibial plateau fractures(TPFs).Methods:A total of 136 young and middle-aged patients with bicondylar TPFs who underwent surgical treatment between May 2016 and April 2020 were included.According to the different surgery programs,all patients were divided into two groups:group 1,which represented minimally invasive reduction and internal fixation(MIRIF),and group 2,which represented open reduction and internal fixation(ORIF).Univariate and multivariate logistic regression and ROC curve analyses were used.Patient demographics,preoperative and postoperative laboratory data,and details of surgery-related variables are available from our trauma Center’s electronic case database.Univariate analysis and multivariate logistic regression analysis were used to analyze the correlation of biomarkers or related indicators.Area under curve(AUC),sensitivity and specificity in ROC curve were used to evaluate the predictive ability of biomarkers or related indicators.Results:Through ROC curve analysis,the optimal cut-off values of related variables such as incision length,operation time,intraoperative blood loss,preoperative and postoperative NLR,PLR,and HCRP were determined.In univariate analysis,there were no significant differences in baseline characteristics and preoperative hematological parameters between the two groups;operation time,intraoperative tourniquet application or not,intraoperative blood loss,incision length,and NLR>10.1 on the first postoperative day,PLR>223.9 on the first postoperative day,RBC<lower limit on the first postoperative day,and HCRP>47.6 mg/L on the first postoperative day(P<0.05).Multivariate analysis showed that postoperative PLR≥223.9(OR 4.24,95%CI 1.20-14.93,P=0.025),surgical incision>19.0 cm(OR 14.71,95%CI 4.03-52.63,P<0.001),operation time>130 min(OR 6.94,95%CI 2.32-21.27,P=0.001)was closely related to the severity of surgery-related trauma.ROC curve analysis showed that postoperative PLR could predict the severity of surgery-related trauma with a specificity of 76.0%and a sensitivity of 55.7%,P<0.001.Conclusions:Postoperative PLR appears to be a useful biomarker that is closely associated with magnitude of surgery-related trauma in young and middle-aged patients with bicondylar TPFs.