| Objectives and SingificanceThe treatment of displaced intraarticular calcaneal fractures has long been an anathema to the orthopedic sugreon.Because of its unique shape,difficulties arose in understanding the pathoanatomy of the fracture.Because of its location,surgical treatment was fraught with difficulties and complications.Because of complex of operative intervention,results were poor and fraught with iatrogenic injuries to surrounding tissues.So far,there are many unresolved problems in treatment for displaced intraarticular calcaneal fractures,and researches on it are necessary.This research include three parts,(1)Anatomic study and its clinical application of calcaneus and its surrounding tissues and their relations.Our aim is to measure the optimal values and to boost the accuracy and safety of internal fixation of treatment for displaced intraarticular calcaneal fractures through extensile right-angled lateral incision.(2)Anatomic study and its clinical application of compartments of the foot. Our aim is to provide more information for diagnosis and treatment of compartment syndrome of the foot after displaced intraarticular calcaneal fractures.(3)Evaluate the significance of CT assesment for extraarticular pathoanatomy in treatment of displaced intraarticular calcaneal fractures.Our aim is to provides useful methods of measurement to treatment of displaced intraarticular calcaneal fractures and boost its outcome..Materials and methods1.Anatomic study and clinical application of internal fixation for displaced intraarticular calcaneal fractures1.1 Measurement of normal calcaneum 40 pieces of adult calcaneum specimen were measured,items of measurement were transverse diameter of the calcaneal cuboid articular surface,inner tilt angle of the calcaneal cuboid articular surface,anterior tilt angle of the sustentaculum,anterior tilt angle of anterior part of posterior facet, thickness of the middle part of calcaneum,maximal and minimal thickness of base of sustentaculum,width of tuberosity,height of lateral wall,height of medial wall.1.2 Observation of inner structures of normal calcaneum Through serial sagittal sections of 4 pieces of normal adult calcaneum specimen,the inner structures of normal calcaneum were observed.Through serial sections in the plane parallel to the longitudinal axial of the sustentaculum of 4 pieces of normal adult calcaneum specimen,bone trabeculae beneath the sustentaculum and the posterior facet were observed.1.3 Anatomic study of medial tissues of calcaneum Through anatomic study of 30 embalmed adult lower extremity specimens,the medial calccaneal nerves,the inferior calcaneal nerves,the posterior tibial arteries and veins,the posterior tibial nerves,the medial plantar nerves,the lateral planter nerves and their relations to calcaneum were observed.1.4 Observation and measurement of the model of interal fixation of middle part of calcaneum Through 40 pieces of model of the internal fixation of middle part of calcaneum,positions and angles of screws were selected and measured.1.5 Clinical evaluation of ORIF(open reduction and internal fixation)Seven patient of displaced intraarticular calcaneal fractures treated by ORIF through extensile fight-angled lateral incision were observed and followed up,accuracy of screws and functional outcome were assessed.2.Anatomic study and clinical application of compartments of foot2.1 Anatomic study of compartments of normal foot Through 30 embalmed adult lower extremity specimens,the boundary and content of each compartment were observed.2.2 Anatomic study of model of intraarticular calcaneal fracture Six fresh specimens of lower extremites were used to make experimental model of intraarticular calcaneal fractures,through those models,effects on soft tissues and compartments of intraarticular calcaneal fractures were observed.2.3 Clinical observation of compartment syndrome of foot after displaced intraarticular calcaneal fractures Decompressive fasciotomies of compartments were performed in 8 patients with compartment syndrome of foot after displaced intraarticular calcaneal fractures,results were evaluated by follow-up.3.Application of CT in assessement of displaced intraarticular calcaneal fractures3.1 Measurement of normal calcaneum 40 pieces of adult calcaneum specimen were measured,items of measurement included height of culmination of posterior facet and tuberosity,width of posterior edge of sustentaculum and tuberosity.3.2 CT measurement of calcaneum Transvers(axial)and coronal CT scanning were obtained from 20 feet with displaced intraarticular calcaneal and 20 normal feet as contral.Following items were measured in CT scanning:the height of culmination of posterior facet and tuberosity,the coronal talocalcaneal angle,in coronal scanning, the width of posterior edge of sustentaculum and tuberosity,the axial calcaneocuboid angle,in axial scanning.Results 1.Anatomic study and clinical application of internal fixation for displaced intraarticular calcaneal fractures1.1 Measurement of normal calcaneum transverse diameter of the calcaneal cuboid articular surface is(22.67±2.14)mm,inner tilt angle of the calcaneal cuboid articular surface is(60.4±7.1)°,anterior tilt angle of the sustentaculum is(50.23±4.64)°, anterior tilt angle of anterior part of posterior facet is(68.65±4.69)°,thickness of the middle part of calcaneum is(41.75±1.76)mm,maximal and minimal thickness of base of sustentaculum is(12.14±1.60)mm and(4.81±1.07)mm,width of tuberosity is(33.57±2.16)mm,height of lateral wall is(23.36±2.59)mm,height of medial wall is(28.33±2.44)mm.1.2 Observation of inner structures of normal calcaneum Through serial sagittal sections of normal adult calcaneum specimen,bone trabeculae beneath the the tuberosity,the posterior facet and the caleaneal cuboid articular surface were the most compacet,their thickness was about 5mm.The compact bone trabeculae beneath the sustentaculum and the posterior facet were consecutive.1.3 Anatomic study of medial tissues of calcaneum All the tissues positioned medially to calcaneum had intimate relations with calcaneum and should be considered when internal fixation used.Medially,the calcaneus was covered by a dense fibrofatty layer,the abductor hallucis,and the medial head of quadratus plantae muscle.The subcutaneous tissue had a lamellar configuration with the superficial veins and nerves coursing over the superficial fascia.The major portion of the neurovascular bundle lied within the tarsal turmel.Immediately posterior to the neurovascular bundle was the flexor hallucis longus,which ran in a fibroosseus tunnel beneath the sustentaculum tali.Just anterior to the neurovascular bundle lied the flexor digitorum longus,which coursed directly over the sustentaculum.1.4 Observation and measurement of the model of interal fixation of middle part of calcaneum Only implanted into the posterior half of sustentaculum,the screws were in safe position.In order to put the screws in safe position,we had to follow principles,1)implant screws parallel to the posterior facet through the compact trabeculae,2)the screws' angles was from(25±5)°to(3±3)°in coronal plane. 1.5 Clinical evaluation of ORIF Postoperatively,seven patients were followed up, excellent and good rate of functional outcome was 87.5%,and screws of one patient was in wrong position.2.Anatomic study and clinical application of compartments of foot2.1 Anatomic study of compartments of normal foot There was very thin sarolemma-like tissue between adductor hallucis and quadratus plantae and between quadratus plantae and flexor digitorum brevis as well.Both abductor halluvis brevis and flexor digitorum brevis arose from medial tuberosity,immediately latreal to medial tuberosity was abductor digit minimi.Flexor digitorum brevis inserted into flexor digitorum longus distally.Quadratus platae arose from medial margin of middle part of calcaneum and inserted into flexor digitorum longus and flexor hallucis longus.2.2 Anatomic study of model of intraarticular calcaneal fracture The primary fracture line coursed from anterolateral to posteromedial,and from anterosuperior to posteroinferior.It damaged all the soft tissue arosed from medial margin and medial tuberosity of the calcaneum.2.3 Clinical observation of compartment syndrome of foot after displaced intraarticular calcaneal fractures Wounds of all patients healed,and had no bad effect on internal fixation followed.One patient had clawfoot deformity.3.Application of CT in assessement of displaced intraarticular calcaneal fractures3.1 Measurement of height of calcaneum Height of culmination of posterior facet and tuberosity of calcaneal specimen were(43.07±2.85)mm and(44.69±3.67)mm respectively,and these two items from CT scanning of normal feet were(42.84±1.66) mm,(43.40±3.01)mm,and from CT scanning of feet with calcaneal fractures were (34.76±3.24)mm,(40.41±3.69)mm.There was a statistically significant different between these two items for normal calcaneal specimen and for CT scanning of feet with calcaneal fractures(P＜0.001),and between CT scanning of normal feet and of feet with calcaneal fractures as well.3.2 Measurement of width of calcaneum Width of posterior edge of sustentaculum and tuberosity were(30.53±2.06)mm and(33.57±2.17)mm respectively,and these two items from CT scanning of normal feet were(30.47±2.33)mm,(32.69±2.00)mm, and from CT scanning of feet with calcaneal fractures were(45.99±4.79)mm, (36.28±2.08)mm.There was a statistically significant different between these two items for normal calcaneal specimen and for CT scanning of feet with calcaneal fractures(P＜0.001),and between CT scanning of normal feet and of feet with calcaneal fractures as well.3.3 Measurement of the calcaneal varus angle in the normal and fractured hindfoot the coronal talocalcaneal angle and the axial calcaneocuboid angle from CT scanning of normal hindfoot were(13.33±0.75)°and(25.56±0.95)°respectively,these two items were(22.51±1.34)°and(30.15±1.62)°.There was a statistically significant different between these two items in the normal and fractured hindfoot(P＜0.001).Conclusions1 ORIF through extensile right-angled lateral incision was a effective treatment for displaced intraarticular calcaneal fractures.The suitable positions of screws anchorage for this type of internal fixation were beneath the tuberosity,the posterior facet and the calcaneal cuboid articular surface.Direction and length of screws in every position was different and determined according to anatomic characteristic of different position. 2 When screw was implanted in the calcaneal cuboid articular surface,its length was determined according to transverse diameter of the calcaneal cuboid articular surfac, and its direction according to inner tilt angle of the calcaneal cuboid articular surface.3 Implanted under the posterior facet,screws must be planted into the sustentaculum accuratedly,if not,they were not able to provide enough stablity and might injury the soft tissue medially.4 When screw was implanted beneath the tuberosity,its length was determined according to width of tuberosity,and it should be directed posteriorly to medial tuberosity.5 Sometimes,pins implaned longitudinally might be necessary.These pins' location was according to height of lateral and madial wall.6 Though data had been measured for internal fixation in order that we could plant the implants in precise and safe positions,but we had to remember there was individual difference in diffenent person.,and we had to confirm the position and length of screw introperatively by fluoroscopic or7 Compartments of foot were not absolutely isolated,all compartments usually were affected when compartment syndrome took place after displaced intraarticular calcaneal fractures.There was no significance of diagnosis to divide the foot into different compartment,but it is necessary to understand compartments' anatomy when performing decompressive fasciotomies of compartments.8 Decompressive fasciotomies of compartments was effective treatment for compartment syndrome of feet.9 Studies of compartment and compartment syndrome of foot we had done were anatomic,they were not enough,if study of pathophysiology could be done in the future,our understanding of compartment syndrome of foot could be improved largely. 10 An important feature of the calcaneal fracture is the charcateristic deformities produced in the extraarticular anatomy.These deformities must be corrected in the surgical treatment of this fracture and can give rise to late symptoms if a malunion develops.These deformities could be evaluated correctly by CT scanning. |
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