Study On The Clinical Application Of Computer Virtual Technology To Assist In The Diagnosis And Treatment Of Distal Femur Fractures

Distal femoral fractures are fractures within 15cm of the articular surface of the distal femur,including intercondylar and supracondylar fractures of the femur.The incidence of fractures is low,accounting for only 0.5%of all fractures and approximately 3%to 6%of femoral fractures.Fractures are concentrated in young patients with high energy injuries and in older patients with low energy injuries with fracture laxity,with a bimodal distribution.These fractures are often comminuted and are likely to be accompanied by intra-articular fractures or severe soft tissue,vascular and neurological injuries,which may result in postoperative malunion,osteochondritis,traumatic osteomyelitis,knee dysfunction and infection.In addition,the incidence of periprosthetic femoral fractures tends to increase with the number of knee replacements,which,excluding operator and patient factors,may also be related to a mismatch in prosthesis size.Accurate diagnosis of distal femoral fractures,rational design of internal fixation devices and detailed preoperative planning to assist in surgical treatment are still a major challenge for orthopaedic surgeons and need to be addressed.In recent years,with the rapid development of computerized image processing technology,3D morphometry based on computed tomography(CT)data,fracture line mapping,volumetric rendering(VR)imaging,cinematic rendering(CR)imaging,and fracture treatment have been developed.The present study proposes to apply these techniques to femoral fracture data.In this study,we propose to apply these techniques to distal femur morphometry,fracture mapping,accurate fracture diagnosis and detailed preoperative planning,in order to try to establish a new treatment mode for distal femur fracture management based on computer-assisted virtual technology.As most imported prostheses are designed with reference to the anatomical features of the European and American populations,there is a mismatch with the anatomy of the Chinese population,which affects the clinical outcome of the surgery.The measurement of the relevant anatomical parameters of the distal femur can provide data for the design of femoral prostheses and internal fixation devices suitable for the Chinese population,which is important.In the past,direct cadaveric measurements have been used to obtain data,but the number of specimens is limited to meet the needs of large sample studies.The accuracy and reproducibility of X-ray based measurements have been questioned by various scholars.At present,morphological measurements based on CT 3D reconstruction have broken through this dilemma and are now the mainstream method for anatomical measurement studies.Therefore,in this paper,CT thin-section scans of 91 healthy femurs were reconstructed in 3D and various anatomical parameters of the distal femur were measured.The morphological parameters of the distal femur measured included the anteroposterior diameter of the femoral epicondyle(LAP),the anteroposterior diameter of the femoral medial condyle(MAP),the anteroposterior diameter of the distal femur(AP),the width of the femoral condyle(ML),the supracondylar axis of the femoral condyle(TEA),the width of the femoral epicondyle(LCW),the width of the femoral medial condyle(MCW),the posterior height of the femoral epicondyle(LPCH),the posterior height of the femoral medial condyle(MPCH)and the posterior condylar angle(PCA).The normality of the measured data was assessed using the Shapiro-Wilk test.The Levene test was used to determine the chi-square of each group of data.Unpaired t-tests were used for normally distributed quantitative data to compare differences between two groups.Otherwise,the Mann-Whitney test was used to assess.Correlations were assessed by calculating Spearman’s correlation coefficients between the parameters.Linear regression analysis was performed for strongly correlated parameter pairs.In addition,K-means clustering analysis was performed for ML and AP parameters to provide a reference for the design of different types of distal femoral prostheses.The results suggest that the method used in this study is reproducible.The differences between the measurements of the distal femur at different sides were not significant(all P values>0.05).Except for PCA(P>0.05),the values of anatomical and morphological parameters of the distal femur were significantly higher in men than in women(all P values less than 0.05).There were also significant differences in anatomical parameters between the national and foreign populations.The values of the distal femur parameters were greater in Chinese than in Koreans and slightly less than in Caucasians(all P values less than0.05).In addition,the results of the cluster analysis suggest that in order to reasonably design a distal femoral prosthesis that covers the anatomy of the national population,the prosthesis should contain at least four ML and AP sizes.This study provides a detailed reference of anatomical parameter data for the rational design of femoral prostheses for national men and women respectively.This has far-reaching implications for the optimisation of internal fixation devices and the improvement of clinical function in patients after surgery.Fractures of the distal femur are complex and varied,and it is difficult to deduce the distribution of all fractures from a single fracture feature alone.Based on the concept of big data and 3D reconstruction technology,the fracture line distribution map was created.This technique uses computer software to create a model of each fracture,reposition it virtually,extract the fracture lines,superimpose all the fracture lines on a standard 3D model of the skeleton and finally use the heat map to analyze the fracture line distribution pattern.This helps the orthopaedic surgeon to observe and analyze the fracture line origin,course,distribution,and fracture comminution in a more three-dimensional way.At present,there are few studies on fracture maps of the distal femur,and most of them focus on the distribution of fracture lines but neglect the morphological characteristics of the fracture comminution area.In this paper,based on CT 3D reconstruction and image segmentation,we depict the fracture distribution of the distal femoral fractures of the Arbeitsgemeinschaftfür Osteosynthesefragen Foundation and the Orthopaedic Trauma Association(AO/OTA)33A and 33C.33A and 33C fractures of the distal femur,the location and frequency of fracture lines and comminuted areas,and further analysis of their morphological characteristics,in order to provide more clinically relevant information for the treatment of distal femur fractures.In this paper,we reviewed and analyzed the clinical and imaging data of 74 cases of OTA/AO 33A and 33C type distal femoral fractures admitted from December 2013to December 2020,and performed 3D reconstruction,virtual division of the fracture block and virtual repositioning on the fractures included in the study.The reconstructed virtual repositioned fracture models were then aligned with the templates and the contours of each fracture block of the fracture models were copied in transparent mode using smooth curves.A fracture block area smaller than 1cm~3was also extracted and defined as the comminuted area.Finally,the virtual fracture lines and comminuted regions of all fracture models were assembled separately in the standard template and analyzed using the heat map technique.The results suggested that the fracture lines and comminuted areas of 74 fractures were mainly concentrated in the femoral epiphysis,intercondylar notch and around the patellofemoral joint.53 fracture lines and comminuted areas of type 33A fractures followed the medial-superior to lateral-inferior course,and the comminuted areas were mainly located in the anterior,lateral,and posterior aspects of the distal femur,with less involvement of the medial aspect.21 fracture lines and comminuted areas of type 33C fractures were concentrated in the anterior,medial and the fracture line and comminution area in the 21 33C fractures were concentrated in the anterior,medial,and lateral intercondylar notches of the femoral diaphysis and less frequently in the lateral aspect,resembling a"Y"shape.This study provides a reference for the selection of the surgical approach for 33A and 33C fractures of the distal femur,the placement strategy of the internal fixation and the optimization of the osteotomy plan for biomechanical studies.CR reconstruction has been reported to produce more realistic images than VR reconstruction and has a wide range of clinical applications.At present,there are no studies on the application of CR reconstruction in the classification of distal femoral fractures.In this paper,we propose to investigate the value of this emerging technique in OTA/AO classification of distal femoral fractures and compare it with the VR technique.We retrospectively analyzed the clinical and imaging data of patients admitted to hospital with distal femoral fractures from July 2013 to July2020.Two evaluators with different clinical experience successively classified distal femoral fractures according to OTA/AO criteria.Inter-and intra-observer agreement were assessed using Cicchetti-Allison weighted Kappa method.Correctness,precision,recall and F1 values were calculated to evaluate classification results.Differences between the diagnostic confidence scores of the two raters using different imaging techniques were assessed using the chi-square test or Fisher’s exact test,respectively.The results suggest an excellent degree of inter-and intra-observer agreement by using the CR reconstruction technique,with Cicchetti-Allison weighted Kappa values of 0.989 and 0.992 respectively,which is higher than the agreement using the VR technique(Kappa values were 0.941 and 0.905,respectively).In addition,the CR technique was more precision than the VR technique,but the difference was not significant(all P values were greater than 0.05).Similarly,the accuracy,recall and F1 value macro-and micro-means of CR technique were all higher than using the VR technique.The difference between the diagnostic confidence scores of the two imaging modalities was significant(P<0.05),with raters achieving higher diagnostic confidence scores when using CR technique for classification.CR imaging provides a more realistic and detailed representation of the distal femur fracture than conventional VR imaging,which helps orthopaedic surgeons to accurately classifing fractures and improves diagnostic confidence.In addition,the inter-and intra-observer agreement using this technique is excellent,and the results are reliable and easily reproducible,making it worthwhile to promote its use in clinical practice.What are the prospects for a treatment model based on computerized virtual technology-assisted preoperative planning for distal femoral fractures?Rarely reported.In this paper,we intend to evaluate the value of this technique in the treatment of distal femoral fractures and its clinical outcomes.We retrospectively analyzed 32 patients with distal femoral fractures who were admitted to hospital and underwent incisional internal fixation from February 2014 to May 2017 and were divided into a conventional group(17 patients)and a virtual surgery group(15patients)according to different preoperative planning methods.The time of fracture division,virtual reduction and virtual internal fixation were also reviewed for the virtual surgery group.The differences between the two groups were compared in terms of operative time,intraoperative bleeding,number of intraoperative fluoroscopies,days in hospital,postoperative complications,and postoperative functional outcome.The results suggest that the mean preoperative planning time for fractures of type 33A,33B and 33C in the virtual surgery group was 43.0±1.7,23.0±1.3 and 51.4±3.7 minutes,respectively.Intraoperative blood loss,number of intraoperative fluoroscopies,operative time and hospital days were all reduced in the virtual surgery group compared to the conventional surgery group(all P values less than 0.05).The differences in KSS,SF-36 and VAS scores between the two groups at the final follow-up were not statistically significant(all P values were greater than0.05).In this research,we found that computer-assisted virtual surgery technology can help clinicians to rapidly formulate surgical treatment plans,improve surgical efficiency,and provide satisfactory clinical and imaging results after distal femoral fractures.