| Objective:1.To explore the related factors affecting the functional recovery of foot and ankle after calcaneal fracture surgery.2.Finite element analysis is used to study the biomechanical changes brought by different degrees of reduction of Bohler Angle to the subtalar articular surface.Mehtods:1.123 cases of calcaneal fracture in Fuyang People’s Hospital Affiliated to Wannan Medical College from September 2018 to December 2021 were retrospectively analyzed.Factors such as sex,age,BMI,side profile,fall height,preoperative preparation time,hospital stay,Sanders classification,operation time,amount of blood loss,operation method,internal fixation materials,whether there was concomitant injury,calcaneal length,width,calcaneal collapse degree,Bohler Angle and Gissane Angle were collected.Outpatient follow-up was performed according to the AOFAS scoring system,and patients were divided into good group and poor group according to the scoring results.Gender,age,BMI,flank,fall height,preoperative preparation time,length of hospital stay,Sanders classification,operation time,amount of blood loss,surgical method,internal fixation materials,whether there is concomitant injury,calcaneal length,width,calcaneal collapse degree,Bohler Angle and Gissane Angle were included in the univariate analysis.The factors with differences were further analyzed by multivariate logistic regression,and the independent risk factors affecting the functional recovery of foot and ankle after calcaneal fracture were identified.2.Firstly,X-ray film was performed on the ankle of a volunteer to confirm that there was no injury or deformity in the ankle of the volunteer.Secondly,the foot and ankle data of the volunteer were obtained through CT scan,and the CT scan data was imported into MIMICS 21.0 to establish normal calcaneus and talus models with tools.The model is repaired and three-dimensional materialized by Geomagic.Hypermesh was used to partition the mesh,and the model of calcaneal Bohler Angle reduced by 5 degrees,10 degrees,15 degrees and 20 degrees was established.The biomechanical effects of different Angle changes on the subtalar joint were analyzed by Abaqus finite element method.Results:1.A total of 123 feet were followed up in this study,and the average score of AOFAS was 79.18 ± 15.70,with an excellent and good rate of 65.9%.Univariate findings showed that the relevant factors affecting the functional recovery of foot and ankle after calcaneal fracture included BMI,fall height,Sanders classification,surgical method,internal fixation materials,posterior articular surface collapse degree,Gissane Angle and Bohler Angle.Multivariate Logistic regression analysis showed that BMI,Sanders classification,posterior articular surface collapse degree,Bohler Angle and Gissane Angle were independent risk factors affecting the functional recovery of foot and ankle after calcaneal fracture.2.The stress distribution of the normal calcaneus model was relatively uniform in the posterior medial surface of the posterior subtalar articular surface.When the Bohler Angle of calcaneal model was reduced by 5 degrees,the maximum stress was mainly distributed in the posterior and inner part of the articular surface below the posterior talar,and the maximum stress was 13.48 Mpa.When the Bohler Angle of calcaneal model was reduced by 10 degrees,the stress was mainly distributed in the medial and posterior sides of the subtalar articular surface,and the maximum stress value was 41.13 Mpa.When the Bohler Angle of calcaneal bone model was reduced by 15 degrees,the stress was mainly distributed in the medial and posterior side of the articular surface under the posterior talar,and the maximum stress value was 69.21 Mpa.When the Bohler Angle of the calcaneal model decreased by 20 degrees,the stress mainly distributed in the subposttalar articular surface and moved forward to the subcalcaneocuboid articular surface.The maximum stress mainly appeared in the subposttalar articular surface,and the maximum stress value was 250.30 Mpa,and the stress increased significantly.Conclusion:1.Factors related to functional recovery of foot and ankle after calcaneal fracture surgery include BMI,fall height,Sanders classification,surgical methods,internal fixation materials,collapse degree of posterior articular surface,Gissane Angle and Bohler Angle.2.Independent risk factors affecting functional recovery of foot and ankle after calcaneal fracture surgery included BMI,Sanders classification,posterior articular surface collapse degree,Gissane Angle and Bohler Angle.3.Under normal conditions,the stress is evenly distributed in the subposttalar joint surface.When the Bohler Angle is reduced by 5 ～ 15°,the stress in the subposttalar joint changes,and the maximum stress is mainly concentrated in the subposttalar joint.4.When the Bohler Angle decreased by 20 °,the stress mainly concentrated in the subtalar joint and moved forward to the calcaneocuboid joint.The stress on the subtalar articular surface and the calcaneocuboid articular surface increased significantly,resulting in significant changes in the biomechanics of the subtalar joint. |
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