The Exploration Of The Measurement Method Of The Heel Morphology And The Development Of Anatomical Calcaneal External Fixator

Objectives:1 Explore more accurate morphology measurement methods of the herl.2 Anatomical calcaneal external fixator self-designed according to the morphology of the heel.3 Clinical application of anatomical calcaneal external fixator.Methods:1 100 people's eligible stereoscopic data of the heel are measured by the direct measurement mode.This mode is developed according to ergonomics and local anatomy.The measurement mode is divided into two parts.The first part is the weight-bearing standing bone-marker by vernier caliper measurement method to measure and classify the average shoe size,the average length of heel,the average width of heel,the average height of heel,the average height of the medial ankle,the average height of the lateral ankle and the average of calcaneal pitch angle(CPA);the second part is the supine position 3D dot matrix measuring plate measuring method to measure the shape of the hind foot in the supine position.Using these stereoscopic data,a new anatomical calcaneus external fixator was designed with AutoCAD 2019 and other three-dimensional industrial design software.2 The measured morphological data results are used to calculate coordinates in AutoCAD 2019(Autodesk company,USA)to obtain point positions,and the points will be imported into Geomagic Wrap 2015(Geomagic,USA)by the binary data file recorded as.txt with Notepad(Microsoft,USA).and then,gets a point cloud chart.According to the data range of the point cloud chart and the different characteristics of the index values of men's and women's heels,SolidWorks 2016(Siemens,Germany)was used to draw the design chart.3 From September 2019 to March 2020,9 patients of calcaneal fractures with who had been treated at Depatment of Orthopaedic Surgery,920th Hospital of Joint Logistic Support Force.There were 7 males and 2 females,aged from 23 to 66 years,with an average age of 41.3 years.Among them,there were 6 cases of falling injury and 3 cases of traffic accident injury.According to Sanders classification,there were 2 cases of S ? B type,2 cases of S? AC type,3 cases of S? AB type,1 case of S? BC type and 1 case of S? type.According to the classification of AO closed soft tissue injury,8 cases of closed fracture were classified as G? 5 cases,G ? 3 cases;1 case of open fracture was classified as G? B according to Gustilo,and the wound was repaired by skin flap after debridement.All 9 patients were treated with anatomic external fixation device during the first or second operation.Results:1 The weight-bearing standing bone-marker by vernier caliper measurement method showed that the male group of indicators that shoe size,heel length,heel width,heel height,medial ankle height,lateral ankle height,CPA and other were significantly higher than the female group(P<0.05).Except that the medial ankle height of the left foot is significantly smaller than the right foot(t=-2.827,P=0.005),there is no statistically significant difference between the left and right feet of the other indicators(P>0.05).From the morphology point of view,the left and right feet can basically be regarded as a mirror-symmetric relationship.The supine position 3D dot matrix measuring plate measurement method showed that the heel is a non-circular arc edge,and the plurality of arc edges generally fluctuate within a limited range.2 According to the morphological data of the heels,we have successfully produced two kinds of metal templates,large and small.Based on the injury characteristics of calcaneus fracture,Sanders classification basis and Campbell's requirements of Orthopaedic Surgery,combined with the clinical experience of many senior doctors in trauma orthopaedic of foot and ankle surgery at depatment of Orthopaedic Surgery,920th Hospital of Joint Logistic Support Force,three configuration schemes of calcaneal anatomical external fixator were designed:ordinary configuration,compression configuration and orthodontic configuration.3 Through the comparative observation of X-ray films before and after operation,it can be seen that the anatomic external fixation device of calcaneus can firmly fix the calcaneus fracture after reduction,the fracture end is in good alignment,the accumulated calcaneus fracture on the articular surface can also be firmly fixed,the limited open reduction and fixation or non open prying reduction and fixation during operation,the operation incision is small,and the soft tissue can be protected to the maximum extent.Three days after the operation,the patients could get out of bed for rehabilitation exercise.There were no complications such as needle infection and osteomyelitis in 9 patients.The follow-up results were satisfactory.Conclusions:1 The weight-bearing standing bone-marker by vernier caliper measurement method can get the accurate data of morphological plane of heel.The supine position 3D dot matrix measuring plate measurement method can get the accurate data of morphological stereoscopic of heel.2 The external fixer designed based on the heel morphology is an anatomical type.The configuration of the external fixator based on the morphology can theoretically meet stable and flexible clinical needs3 The anatomical calcaneal external fixator is a kind of effective fixator,which is superior to the conventional surgical device in the handle of plant space occupation and the promotion of fracture healing.