| The interosseous talocalcaneal ligament(ITCL) lies in the tarsal canal in the midle of the subtalar joint. The ITCL is just under the axis of the subtalar joint which is one of the main ligaments maintainning the subtalar joint stability. Therefore, injeries of the ITCL ligaments can lead to serious subtalar joint instability. In the past, few attentions were paid to this issue. The detailed anatomy of the anterior and posterior bundles of the ITCL and their funcitons are not understood totally and thoroughly. There are various views about the ITCL among different scholars. Routine examinations cannot guarantee satisfactory diagnosis of the injured ITCL. Magnetic Resonance Imaging(MRI) can demonstrates directly the ITCL. In order to obtain a more desirable image, this study selected a variety of 3D-MR sequences and scanning technique to test the ITCL. The images obtained with various MR sequences were compared and teh optimal MR sequence was identified. The course of the ITCL was observed and the widths and lengths of the ITCL on varous MR images were measured and analyzed. Based upon the MRI images of the ITCL, the position of the ITCL was determined to milling the specimens in the sectional anatomical study, aiming to obtain better cross-sections to demonstrate the intact course and the attachments of the ITCL. Digital photographs of the sectional images were taken and compared with the MRI images to study the ralationship between the MRI images and the sectional images of the ITCL. This can provide anatomical basis for the imageological identification and the diagnosis of the ITCL.At present, the measurements of the ITCL are included mainly in the anatomical study. However, these data cannot be applied into the clinics directly due to the individual discrepency and the difference between the specimens and the living body. Imageological examinations are the important resorts to diagnose the various injuries. MRI scan is one of the principal means to oberve the ligament injury.Few research exists regarding the comparision of the ITCL lengths and widths between the reconstructed MRI images and the anatomical studies. This study is to provide quantitative image data by observing and measuring the width and length of the ITCL on reconstructed saggital and oblique coronal MR images of the foot and ankle. X ray or CT scan is the commonly used means for quick examinations of the injuries of the foot and ankle. If the observations and measurements of the bone structure can reflect indirectly the course, dimensions and the injury severity, it will help to determine further examination and treatment. In this study, the length and width of the ITCL were measured on the sagittal and oblique coronal CT images of the volunteers and the data was compared with that obtained on MR images. On the basis of the above-mentioned study, various radiographs of the foot were taken following the X-ray beams in different directions. The gap where the ITCL lies was observed. The optimal radiograph was determined to show the intact ITCL gap on which the length of gap was measured. The gap length was compared with that measured on the corresponding saggital CT images. In short, we aim to explore the feasibility of oberving the course and the injury of the ITCL using X-ray films or CT images, and test their comparability regarding ITCL with the MRI images.Calcaneal fracture accounts for about 2% of all fractures and about 60% of tarsal bone fractures. Currently, the diagnosis and treatment of calcaneal fractures mainly focus on the fracture itself. The associated ligament injuries, especially the ITCL injuries, were involved in few study. Some patients with calcaneal fractures may sustain subtalar arthritis and other complications with regard to subtalar joint instability after either conservative treatment or surgical management. If severe symptoms occurred in these patients, subtalar arthrodesis is required to relieves the symptom. However, this procedure will cause the impairment of the function of the ankle joint and affects inevitably work or even daily life. There is little study with regard to whether the patients with calcaneal fractures are with associated ITCL injuries and the injured sites and morphous of the ITCL. The current study aims to investigate the incidence and the injured features of the ITCL in patients with calcaneal fracturs with the use of MRI.Part 1 The study of the MRI sequences on scanning the interosseous talocalcaneal ligamentObjective: To optimize the MRI sequences for interosseous talocalcaneal ligaments by evaluating and comparing quantitatively the quality of the reconstructed images of interosseous talocalcaneal ligaments scanned using a variety of 3D MRI sequences. By observing and measuring the course of the interosseous talocalcaneal ligaments, the relationship between the interosseous talocalcaneal ligament and the body surface symbol was invesgated, which can help guiding the selection of the sectional direction in the sectional anatomical study.Methods: There were 32 healthy volunteers in the study, including 17 men and 15 women with an average age of 35.6 years(ranged, from 15 to 69 years). No bone abnormality was detected on the the lateral calcaneal and axial radiographies. When taking MRI scans, the volunteers lay supine with foot advancing and the foot and ankle fixed at a natural state. The Siemens Avanto 1.5-T superconducting MR machine and Coil elements KN were used and 32 subtalar joints were scaned using 3D MRI sequences. Firstly, 10 subtalar joints were scanned by T1-MPR, T1-VIBE, 3D-VIBE+Fs, 3D-SPACE, 3D-Medic, 3D-True FISP, and 3D-FLASH sequences, and the saggital images, oblique coronal images and oblique horizontal images were reconstructed using the multi-plannar reconstruction technology. The optimal images were selected blindly and the sequences were divided into two groups, T1 group with 2 subgroups and T2 group with 5 subgroups. Three radiological physicians eveluated the images and assess quantitatively the interosseous talocalcaneal ligaments with 5.0 basis. The mean score of the three physicians on each image is defined as its score. The T1 and T2 groups were assessed with statistical analysis using the single factor analysis of variance, respectively. The subgroups of T2 group 5 subgroups were analyzed with the use of SNK method to identify the optimal scanning sequence. Meanwhile, the demonstration of the bone, joint, joint space, ligament, muscle and soft tissue and joint fluid on the images were assessed. Subsequently, the other 22 subtalar joints were scanned using the optimal MRI sequences and the sagittal, oblique coronal and oblique horizontal images were reconstructed. The angle between tha planta pedis of the hindfoot and the long axis of the interosseous talocalcaneal ligament was measured on each saggital image. The angle between tha articular surface of the ankle joint and the long axis of the interosseous talocalcaneal ligament was measured on each oblique coronal image.Results: The three physicians shared consistency on the eveluation of the quality of MR images demonstrating the subtalar joint(Kappa = 0.85). The mean score of each image was selected for analysis. In T1 group, the overall variance of the two subgroups was equal to each other after homogeneity test of variance. While, univariate analysis of variance revealed that T1-VIBE sequence was superior to T1-MPR sequences wiht F=113.01 and P<0.001. In T2 group, the overall variance of the five subgroups was equal to each other after homogeneity test of variance. While, univariate analysis of variance revealed that there was significant difference among the five subgroups with F=119.64 and P<0.001. SNK tests showed that the 3D-VIBE+Fs and 3D-FLASH sequences were better than 3D-SPACE, 3D-MEDIC and 3D-True FISP sequences, although no significant difference was found either between the 3D-VIBE+Fs and 3D-FLASH sequences or among 3D-SPACE, 3D-MEDIC and 3D-True FISP sequences. The angle between tha planta pedis of the hindfoot and the long axis of the interosseous talocalcaneal ligament was (61.19±4.65)°on each saggital image. The angle between tha articular surface of the ankle joint and the long axis of the interosseous talocalcaneal ligament was (46.59±4.37)°on each oblique coronal image.Conclusion: 1. T1 weighted T1-VIBE sequence is better than T1-MPR sequences in demonstrating the interosseous talocalcaneal ligament and the bone of the subtalar joint. 2. T2 weighted 3D-VIBE + Fs and 3D-FLASH sequences are much better than 3D-SPACE, 3D-MEDIC and 3D-True FISP sequences in demonstrating the bone, cartilage and synovial fluid. There is no significant difference between 3D-VIBE + Fs sequence and 3D-FLASH sequence. 3. On the saggital images, the course of the interosseous talocalcaneal ligament runs anterosuperiorly, and the angle between tha planta pedis of the hindfoot and the long axis of the ligament was (61.19±4.65)°. 4. On the oblique coronal images, the course of the interosseous talocalcaneal ligament runs medial-superiorly, and the angle tha articular surface of the ankle joint and the long axis of ligament the was (46.59±4.37)°.Part 2 The comparative study between digital sectional images and MRI images of the interosseous talocalcaneal ligamentObjective: To obtain digital images of thin sections and 3D reconstructed MR images of normal chinese adult feet, to observe the interosseous talocalcaneal ligament and its surrounding structures, and to compare MR images to their corresponding sectional digital images, providing anatomical basis for diagnosing and treating lesions of the interosseous talocalcaneal ligament.Methods: Six normal fresh feet specimens were selected and divided into three groups named A, B, and C. Specimens in three different groups which were embedded, fixed and frozen in different positions, were milled(thickness = 0.2mm, accuracy = 0.00lmm) to obtain sagittal, coronal oblique, and transverse oblique sections respectively. Digital images of all sections were taken by a digital camera (8.2 megapixel). Thirty-two adult volunteers with no trauma and surgery history and no complaints of foot/ankle were recruited, including 17 males and 15 females, aged from 15 to 69 years old(average 35.6), providing 32 ankle-subtalar joints. Bony abnormity were excluded in all volunteers using radiography before the MR examination. The subjects were placed in lateral position. T1-VIBE, 3D-VIBE+Fs and 3D-FLASH MR sequences were scanned using Coil element KN for All ankle-subtalar joints. Then multi-planar reconstruction images were created in sagittal, oblique coronal, oblique horizontal orientations. Sectional images and their corresponding MR images in three different planes were visualized and compared by 3 experienced radiologists, to explore anatomical and iconographic characteristics of the intersseous talocalcaneal ligament.Results: Both digital images of thin sections of fresh frozen cadaver feet and in vivo MRI images of healthy adult feet could distinctly displayed different tissues and structures such as ligament, fat, cartilage, bone, and tendon, while the former had higher resolution than the later did. However, orientations of thin sections were not accurate enough to achieve complete correspondence of certain structures between the two types of images. In sagittal planes which cut through central and lateral part of the neck of talus, the interosseous talocalcaneal ligament(ITCL) is located posterior to the cervical ligament, consisted of two bundles, anterior and posterior. The posterior bundle, whose shape is column or trapezoid, stands just anterior to the posterior subtalar joint in the posterolateral part of the tarsal tunnel. Its fibers are orientated anterosuperomedially. The anterior bundle, which is fusiform or cordlike, is found anteromedial to the posterior bundle. There necessarily are some fatty tissue in between the two bundles. Bundles of the ITCL both appear hypointense on the MRI image, and It is more difficult to distinguish them on these images than on images in coronal oblique plane. In coronal oblique planes which cut through the postmedian part of the neck of talus, the anterior bundle of the ITCL is seen running longitudinally. In coronal oblique planes just anterior to the posterior facet of the talus, the anterior bundle and the posterior bundle which is thicker, are both oblique bands with broader lower end. On their corresponding MRI images, the hypointense ITCL in the innermost of the tarsal canal runs from lateroinferior to mediosuperior. Its two bundles can be distinguished clearly from each other on these planes, between which the intermediate root of the inferior extensor retinaculum is located. In transverse oblique planes, the rhombic ITCL attaches to the sulcus calcanei and runs anterosuperiorly toward the sulcus tarsi. Its two bundles can also be distinguished clearly from each other on these planes. Conclusions: 1. Fibers of the ITCL are orientated obliquely anterosuperomedially and divided into two bundles. The posterior bundle is located anterior to the posterior subtalar joint in the posterolateral part of the tarsal tunnel, arising from the sulcus calcanei anterior to the posterior facet of the talus, inserting into the sulcus tarsi. The anterior bundle is located anteromedial to the posterior bundle and posterior to the anterior and middle subtalar joints, originating from the anterior floor of the tarsal tunnel, anterior and medial to the origin of the posterior bundle, and inserting into the roof of the tarsal tunnel. 2. In this study, excellent comparability is found between digital images of thin sections of fresh frozen cadaver feet and in vivo MRI images of healthy adult feet. Therefore, MRI examination is considered to be qualified for diagnosing ITCL injuries. The focused observation area, is between the lateral margin of talus and medial margin of the sustentaculum tali of calcaneus on sagittal images, between the fore-end of the anterior subtalar joint and the posterior border of the tarsal tunnel on coronal oblique images, and between the floor of the tarsal tunnel and the neck of talus on transverse oblique images.Part 3 The imageological measurement and the injured characterics of the interosseous talocalcaneal ligamentObjective: To investigate the characteristics of the injuries of interosseous talocalcaneal ligament in patients with calcaneal fractures and to explore the feasibility and comparability of magnetic resonance imaging(MRI), computed tomography(CT) scan and radiograph in demonstrating the interosseous talocalcaneal ligament and the gap where the ligament lies. Methods: 1. From February 2008 to march 2010, patients with calcaneal fractures who had undergone magnetic resonance imaging (MRI) were included in the study. The MRI images were studied to observe whether interosseous talocalcaneal ligament was disrupted. If injured, the site and injury pattern of disrupted ligametns were identified. Its incident rate was analysed. Concomitant injure were also identified on the images. 2. From February 2008 to March 2010 patients who had undergone MRI while without ?fractures and ligaments'injury were enrolled in the study. MRI scan of the ankle and foot following T1-vibe sequence, T2 3D VIBE sequence and 3D FLASH sequence were taken and the sagittal, oblique coronal planes were rebuilted. The length and width of interosseous talocalcaneal ligament were measured in the reconstructed imageds with the use of the measurement software on the workstation. The largest length was defined as the length of the interosseous talocalcaneal ligament. 3. Thirty healthy adults were selected in the group. The lengthes of the gap where the ITCL lies were measured on the consecutive reconstructed saggital and oblique coronal planes obtained from CT scans. The maximal length was defined as the length of the gap of interosseous talocalcaneal ligament. 4. The radiographs of the foot and ankle of 30 volunteers were taken with X-ray beam in various rotations. When taking radiographes, the volunteers lie on side and the line of position(LOP) runs through the gap between the talus and the calcaneus. adjust the rotation angle, set the tube vertical. The neutrol position was defined as the tube of the radiographic system being vertical to the radiographic table. The tube tilited distally is taken as cephalic rotation and the tube tilted proximally is considered as caudal rotation. Seven radiographes were taken on each foot at 15, 10, 5 degrees cephalic rotation, neutral position, 5, 10, and 15 degrees caudal rotation. The gap where the ITCL lies was observed and measured on each radiograph. The data was compared with thosed obtained from CT or MRI images.Results: 1. According to Sanders classification of calcaneal fractures,Ⅱfracture 11 sides,Ⅲfracture 37 side,Ⅳfracture 30 side were included in this group. 44 lateral calcaneal fracture (56.4%) with interosseous talocalcaneal ligament injured, the injury near the heel side, 36 sides (81.8%) with interosseous talocalcaneal ligament disrupted, , 8 sides (19.2%) with partly disrupted, 42 sides (95.5%)were in the calcaneal side of the 1/3, 2 sides (4.5%) were in the ligament of middle 1/3. thirty-four lateral in the group with cervical ligament injury, of which 29 sides (85.3%) cervical ligament disrupted, 5 sides (14.7%) cervical ligament stretch injury. 2. The length of interosseous talocalcaneal ligament was 13.2mm±3.0mm for male and 12.1mm±2.7mm for female on MRI saggital images, and 14.7mm±3.5mm for male and 13.8mm±3.2mm for female on MRI oblique coronal images. There is no significant difference between the lengths of the right and left interosseous talocalcaneal ligaments either on saggital or oblique coronal MRI images in the same gender(P>0.05). The length of interosseous talocalcaneal ligaments for male is longer than that for female on both saggital and oblique coronal MRI images(P>0.05). 3. The gap length of the interosseous talocalcaneal ligament was 13.1mm±2.9mm for male and 12.2mm±2.5mm for female on saggital CT images, and the gap length was 14.7mm±3.3mm for male and 13.7mm±2.9mm for female on the oblique coronal images. There is no significant difference between the lengths of the right and left interosseous talocalcaneal ligaments either on saggital or oblique coronal CT images in the same gender(P>0.05). The length of interosseous talocalcaneal ligaments for male is longer than that for female on both saggital and oblique coronal CT images(P>0.05). The length of interosseous talocalcaneal ligaments on saggital CT images is shorter than that on oblique coronal CT images(P<0.05). 4. The gap lengths of the interosseous talocalcaneal ligament on radiographs obtained from X-ray beam in different rotation angle are various. The gap length of the interosseous talocalcaneal ligament of the left side is similar with that of right side obtained from the same angle of X-ray beam rotation(P>0.05). The gap length of the interosseous talocalcaneal ligament for male is longer than that for female in the same side obtained from the same angle of X-ray beam rotation(P<0.05). The gap lengths on the lateral radiographs obtained from three caudal rotations and the neutral position is longer than that obtained from the saggital CT images(P<0.05). The gap lengths on the lateral radiographs obtained from 5 and 10 degrees cephalic rotation is similar with that obtained from the saggital CT images(P>0.05). The gap of the interosseous talocalcaneal ligament is demonstrated clearly on the 10 degrees cephalic rotation, which is rectangle and runs from posteroinferior to anteosuperior. The calcaneal and talar side of the gap is easily identified. Therefore the gap length measured on the radiographs obtained from 10 degrees cephalic rotation is defined as the length of the ligament measured on the lateral radiographs and the length is (14.2±3.1)mm for male and (12.3±2.3)mm female.Conclusion: The study reveals that the length of interosseous talocalcaneal ligament obtained from MRI and CT has no significant difference between the right side and the left side, while the length of interosseous talocalcaneal ligament of the male is larger than that of female. The length of the ligament measured on the both CT and MRI sagittal and coronal images are comparable, respectively. The 10 degrees cephalic rotation lateral radiographs of the foot can demonstrate clearly the gap where interosseous talocalcaneal ligament lies, on which the gap length measured has no significant difference when comparing with the length measured on the the CT and MRI sagittal images.
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