BACKGROUND:During the treatment of posterolateral tibial plateau fractures through the fibular head approach,the gap between the fibular head and the lateral plateau cannot accommodate the posterior placement of a plate for all patients.OBJECTIVE:To analyze,via finite element analysis,the differences in fixation strength resulting from varying the angles and quantities of horizontal arm variable angle screws in the plate during the treatment of posterolateral tibial plateau fractures through the fibular head approach.METHODS:A finite element model was established based on CT images of the knee to ankle joints of a 30-year-old healthy adult male volunteer.The models were divided into two categories:posteriorly placed group and non-posteriorly placed group based on whether the lateral locking compression plate was posteriorly placed.The posteriorly placed group was further subdivided into groups A-D based on the offset angle of the two variable angle screws(0°,5°,10°,and 15°).The non-posteriorly placed group was subdivided into groups E and F based on offset angles(0° and 15°).Finite element analysis was used to evaluate the von Mises stress distribution,maximum von Mises stress,and compressive displacement under loads of 250,500,and 750 N,exploring the mechanical differences between the groups.RESULTS AND CONCLUSION:(1)Finite element analysis results showed that under a 750 N load,the maximum compressive displacement trend of the internal fixation device was D＜B=C=F＜A＜E.The trend for maximum von Mises stress was B＜C＜A＜D＜F＜E.The trend for maximum compressive displacement on the bone was C=D＜B＜A＜F＜E,and for maximum von Mises stress,it was B＜C＜A＜F＜D＜E.The displacement and stress trends for the six models were similar under loads ranging from 250 N to 750 N.(2)These results suggest that for posterolateral tibial plateau fractures fixed through the fibular head approach,posterior placement of the plate should aim to accommodate two screws.If only one screw can be fixed during surgery,variable angle screws should be offset in the range of 0-15° to increase the probability of securing two screws.

BACKGROUND:During the treatment of posterolateral tibial plateau fractures through the fibular head approach,the gap between the fibular head and the lateral plateau cannot accommodate the posterior placement of a plate for all patients.OBJECTIVE:To analyze,via finite element analysis,the differences in fixation strength resulting from varying the angles and quantities of horizontal arm variable angle screws in the plate during the treatment of posterolateral tibial plateau fractures through the fibular head approach.METHODS:A finite element model was established based on CT images of the knee to ankle joints of a 30-year-old healthy adult male volunteer.The models were divided into two categories:posteriorly placed group and non-posteriorly placed group based on whether the lateral locking compression plate was posteriorly placed.The posteriorly placed group was further subdivided into groups A-D based on the offset angle of the two variable angle screws(0°,5°,10°,and 15°).The non-posteriorly placed group was subdivided into groups E and F based on offset angles(0° and 15°).Finite element analysis was used to evaluate the von Mises stress distribution,maximum von Mises stress,and compressive displacement under loads of 250,500,and 750 N,exploring the mechanical differences between the groups.RESULTS AND CONCLUSION:(1)Finite element analysis results showed that under a 750 N load,the maximum compressive displacement trend of the internal fixation device was D＜B=C=F＜A＜E.The trend for maximum von Mises stress was B＜C＜A＜D＜F＜E.The trend for maximum compressive displacement on the bone was C=D＜B＜A＜F＜E,and for maximum von Mises stress,it was B＜C＜A＜F＜D＜E.The displacement and stress trends for the six models were similar under loads ranging from 250 N to 750 N.(2)These results suggest that for posterolateral tibial plateau fractures fixed through the fibular head approach,posterior placement of the plate should aim to accommodate two screws.If only one screw can be fixed during surgery,variable angle screws should be offset in the range of 0-15° to increase the probability of securing two screws.

Objective:To investigate the early clinical outcomes of a minimally invasive anterolateral approach (Orthopadische chirurgie munchen, OCM) versus a conventional (posterolateral approach, PLA) hemiarthroplasty in the treatment of senior femoral neck fractures.Methods:A retrospective analysis was performed on 90 elderly patients with femoral neck fractures who received anterolateral and posterolateral approaches for hemiarthroplasty in the Second Affiliated Hospital of Soochow University from December 2019 to June 2021 and were followed up. In the OCM group, there were 45 cases, including 18 males and 27 females, aged 83.33±5.29 years (range, 76-96 years); In the PLA group, there were 45 cases, including 13 males and 32 females, aged 81.87±5.00 years (range, 75-94 years). Postoperative, surgical indices, perioperative bleeding, and soft tissue injury were assessed; pain was assessed using the visual analogue scale (VAS), and hip function was evaluated using the Harris score and the University of California at Los Angeles (UCLA) score.Results:The incision length, postoperative hospital stay, hemoglobin reduction, and occult blood loss were lower in the OCM group than in the PLA group ( P<0.05), but there was no significant difference in intraoperative bleeding and postoperative transfusion rate ( P>0.05). Serum creatine kinase and C-reactive protein levels (232.98±83.70 IU/L and 81.67±48.85 mg/L) were lower in the OCM group than in the PLA group (296.93±124.58 IU/L and 104.79±36.75 mg/L) 1 day after surgery, and the differences were statistically significant ( t=2.86, P=0.005; t=2.54, P=0.013). Postoperative pain was significantly improved in all patients, and VAS scores were lower in the OCM group than in the PLA group at 12 h, 24 h, and 48 h postoperatively ( P<0.05). The time to get out of bed after surgery was 20.73±4.99 h in the OCM group compared with 41.69±13.58 h in the PLA group, with a statistically significant difference ( t=9.71, P<0.001). Harris scores (63.31±6.21 and 75.76±4.91) and UCLA scores (1.84±0.42 and 3.69±0.76) were higher in the OCM group on the day of discharge and at 1 month postoperatively than in the PLA group (52.69±10.01 and 71.33±3.66); (1.62±0.54 and 3.16±0.80) points, all with statistically significant differences ( P<0.05). However, the differences in Harris score and UCLA score between the two groups at 6 months postoperatively were not statistically significant ( P>0.05). There were two cases of intermuscular vein thrombosis in the OCM group, with a complication rate of 4% (2/45), and one case of dislocation in the PLA group, with a complication rate of 2% (1/45), there was no significant difference between the two groups ( P=1.000). Conclusion:The minimally invasive anterolateral approach is a more ideal procedure for elderly patients with femoral neck fractures undergoing hemiarthroplasty. It has the advantages of a short incision, small soft tissue damage, low occult blood loss, early removal from bed, a short postoperative hospital stay, an improvement in pain, and a good early recovery of hip function.