A New Classification of Talocalcaneal Coalitions Based On Computed Tomography For Operative Planning

A New Classification of Talocalcaneal Coalitions Based On Computed Tomography For Operative Planning | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article A New Classification of Talocalcaneal Coalitions Based On Computed Tomography For Operative Planning Anhong Wang, Weili Shi, Linxin Chen, Xing Xie, Feng Zhao, Yanbin Pi, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-422276/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 11 Aug, 2021 Read the published version in BMC Musculoskeletal Disorders → Version 1 posted 8 You are reading this latest preprint version Abstract Background Current classifications emphasize the morphology of the coalition, however, subtalar joint facets involved should also be emphasized. Objective The objective of this study was to develop a new classification system based on the articular facets involved to cover all coalitions and guide operative planning. Methods Patients were diagnosed with talocalcaneal coalition using a CT scan, between January 2009 and February 2021. We classified the coalition into four main types according to the shape and nature of the coalition: I, inferiorly overgrown talus or superiorly overgrown calcaneus; II, both talus and calcaneus overgrew; III, coalition with an accessory ossicle; (I-III types are non-osseous coalition) IV, complete osseous coalition. Then each type was further divided into three subtypes according to the articular facets involved. A, the coalition involving the anterior facets; M, the coalition involving the middle facets, and P, the coalition involving the posterior facets. Results There were 106 patients (108 feet) included in this study. Overall, 8 feet (7.5%) were classified as type I, 75 feet (69.4%) as type II, 7 feet (6.5%) as type III, and 18 feet (16.7%) as type IV. Twenty-nine coalitions (26.9%) involved the posterior facets only (subtype-P), 74 coalitions (68.5%) involved both the middle and posterior facets (subtype-MP), and five coalitions (4.6%) simultaneously involved the anterior, middle, and posterior facets (subtype-AMP). Type II-MP coalition was the most common. Conclusion A new classification system of the talocalcaneal coalition to facilitate operative planning was developed. Orthopedics talocalcaneal coalition classification articular facet computed tomography Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Introduction Talocalcaneal coalition is the abnormal bridge between talus and calcaneus. It is a type of tarsal coalitions and is attributed to the failure of differentiation and segmentation in the primitive mesenchyme.[ 1 – 3 ] Talocalcaneal coalition is a significant cause of hindfoot pain, limited motion, and a valgus heel.[ 4 – 6 ] The talocalcaneal coalition can be divided into syndesmosis, synchondrosis, and synostosis by its nature. A plain radiograph is still the first choice to evaluate talocalcaneal coalition. A weight-bearing anterior-posterior, lateral radiograph, and Harris-heel view are commonly used.[ 7 , 8 ] A feature of the C-sign, which formed by the outline of the talar dome and the inferior outline of the sustentaculum tali in the lateral radiograph may be indicated. However, the diagnosis of the talocalcaneal coalition is difficult depending on the plain radiograph and the C-sign lacks sensitivity.[ 9 ] The normal subtalar joint is divided into the anterior, middle, and posterior joint. The talocalcaneal coalition is thought to be most commonly developed in the middle part of the subtalar joint[ 10 – 12 ]. The middle and anterior facets were both concave on the calcaneus and fused anterior and middle articular facets were seen more frequently.[ 13 , 14 ] The bridged anterior and middle joint facets were considered an integration because they were continuous with the talocalcaneonavicular joint.[ 14 , 15 ] The tarsal sinus, lying lateral to open space the middle joint facet, separates the posterior and middle facet joints. It is the boundary to distinguish the middle from the posterior subtalar joint facets. For the complicated anatomy, plain radiographs cannot determine the type and location of the coalition, while computed tomography (CT) enables a good depiction of the subtalar anatomy, to effectively determine the size and shape, and also allows distinguishing between osseous and non-osseous coalitions.[ 2 , 10 , 14 – 16 ] CT has been regarded as the standard diagnostic modality and is helpful to preoperative planning. Rozansky et al.[ 17 ] in 2010 classified the talocalcaneal coalition into five types based on the coalition nature, location, and facet joint orientation. After that, Sanghyeok Lim et al.[ 18 ] in 2013 used CT and MRI to evaluate the coalition and developed a classification according to the coalition nature and shape. However, besides coalition nature and shape, subtalar joint facets involved should also be emphasized. The purpose of this study is to develop a new classification system for operative planning based on the morphology, nature of the coalition, and the subtalar articular facets involved. Methods And Materials The retrospective study was approved by the Board of Research Ethics. Patients were identified through the clinical medical record system in our hospital using the keywords of “talocalcaneal coalition”, “tarsal coalition” or “coalition”, between January 2009 and February 2021. One hundred and twenty-one subjects were identified. After that, patients with talocalcaneal coalition confirmed using CT scan were included. Exclusion criteria included talonavicular or calcaneonavicular coalition and patients without a CT scan. CT examinations were performed using a 64-slices helical CT (GE, USA). All the CT images were reviewed by the corresponding author (with 18 years of orthopedic sports medicine experience). We distinguished the middle from the posterior subtalar joint facet by the boundary of the tarsal sinus in the coronary planes of CT, in the Picture Archiving Communication System (PACS). Diagnosis criteria were as follows: osseous coalitions were confirmed by the presence of a bony bridge; nonosseous coalitions were confirmed by manifestations of narrowing of the facet with marginal cortical irregularity as Kumar et al. depicted[19] and overgrown talus or calcaneus was discovered. Besides, a 3D construction image was obtained to show the details of the abnormal bar.[17] The coalitions were classified into four main types according to the shape and nature of the coalition: I, inferiorly overgrown talus or superiorly overgrown calcaneus; II, both talus and calcaneus overgrew; III, a coalition with an accessory ossicle; (I-III types are non-osseous coalition) IV, complete osseous coalition. On the coronal images of CT, the shape and nature of the coalitions could be observed. Then each type was further divided into three subtypes according to the articular facets involved. A, the coalition involving the anterior facets; On the coronal images of CT, the coalition could only be found anterior to the images of the tarsal sinus for this subtype. M, the coalition involving the middle facets. The subtypes could be identified through the coronal images of CT of the tarsal sinus. P, the coalition involving the posterior facets. On the coronal images of CT, the coalition could only be found posterior to the images of the tarsal sinus. For the coalitions involving the posterior facets only, the open of the sinus tarsal was obvious on a 3D reconstruction image. While for the coalitions involving the middle and posterior facets, the open of the sinus tarsal could not be seen on a 3D reconstruction image (Fig. 1–9). Statistical analysis was conducted using the statistical software (Excel; Microsoft Corporation, USA). Results A total of 106 patients (108 feet) with talocalcaneal coalition were included in this study, of which 2 patients had bilateral coalitions. There were 76 male patients (70.4%) and 30 females (28.8%). Sixty-four right feet (59.3%) were affected while 44 coalitions (40.7%) were on the left feet. The average patient age was 29.8 ±11.0 years (range 12-60 years). Overall, 8 feet (7.5%) were classified as type I, 75 feet (69.4%) as type II, 7 feet (6.5%) as type III, and 18 feet (16.7%) as type IV. All coalitions involved the posterior facets. Twenty-nine coalitions (26.9%) involved the posterior facets only, 74 coalitions (68.5%) involved both the middle and posterior facets, and five coalitions (4.6%) simultaneously involved the anterior, middle, and posterior facets (Table 1). We didn’t find any coalition involving the anterior facets in type I, II, and III. Table 1 The classification of the talocalcaneal coalition Classification α Num. of feet Percentage I I-P 2 1.9% I-MP 6 5.6% II II-P 20 18.5% II-MP 55 50.9% III III-P 4 3.7% III-MP 3 2.8% IV IV-P 3 2.8% IV-MP 10 9.3% IV-AMP 5 4.6% Total 108 100% α Type I, inferiorly overgrown talus or superiorly overgrown calcaneus; II, both talus and calcaneus overgrew; III, coalition with an accessory ossicle; (I-III types are non-osseous coalition) IV, complete osseous coalition. Then each type was further divided into three subtypes according to the articular facets involved. A, the coalition involving the anterior facets; M, the coalition involving the middle facets, and P, the coalition involving the posterior facets. Discussion Based on the shape, nature of the coalitions, and the articular facets that coalitions involved, we devised a new classification system through analyzing the large sample of cases and found the coalition with both talus and calcaneus overgrew, involving the posterior and middle subtalar joint facets, was most common. Type II-MP was the most common type, comprising 50.9% of the coalitions, manifesting with both overgrown talus and calcaneus. We found only 8 coalitions (7.8%) of type I (two I-P types and 6 I-MP types). It was lower than 23 coalitions (33%) in Sanghyeok Lim et al’s study.[ 18 ] Type I and II showed the coalition orientation (sloping up or down, or horizontal) which was helpful to find the fibrocartilage or fibrous line between the talar part and calcaneal part to guide to operative resection, particularly during arthroscopic resection. Seong Jong Yun and his colleagues[ 20 ] reported that 15 of 54 (27.8%) feet showed talocalcaneal coalitions with an accessory ossicle. They regarded the accessory bone as os sustentaculum, forming when the accessory ossification center ossified, at the medial and posterosuperior aspects of the sustentaculum tali and they believed that the accessory bone may be a cause of bone marrow edema and pain in osteoarthritis. Sanghyeok Lim et al.[ 18 ] regarded this accessory ossicle as a fracture fragment and they found a coalition with a “fracture fragment” in 17 of 70 feet (24%). We found 7 coalitions (6.5%) with an accessory ossicle (Type III) in this study. We also thought the coalition might be an accessory ossicle but not a fracture fragment, because the sclerosis of nonunion was not found in the ossicle by CT. A complete osseous coalition may be difficult for resection for it’s hard to identify the borderline of the coalition, particularly in arthroscopic surgery. There were 18 feet (16.7%) identified as complete osseous coalitions (Type IV) in this study. This was in line with the study of Rozansky et al.[ 17 ]. However, Wael Aldahshan et al.[ 21 ] reported 8 complete bony coalitions (40%) while Amir Khoshbin et al.[ 22 ] also found 5 complete osseous coalitions(38.3%). But in Sanghyeok Lim et al.’s study[ 18 ], there were only 2 complete synostosis coalitions (3%) 18 . The difference may lie in the different sample sizes. The subtalar middle facet was most commonly involved while the posterior facet coalition was rare as reported in some studies[ 14 , 16 , 23 ]. Soon Hyuck Lee et al.[ 24 ] reported recently that the prevalence of the talocalcaneal coalition in the middle and posterior subtalar facets was 27%, while 68% of coalitions involved the posterior facet only. Seong Jong Yun et al.[ 20 ] reported that the prevalence of subtalar posterior facet coalition (34.6%) was higher than the middle facet coalition (9.9%) in 81 patients. Scranton, P. E. et al.[ 25 ] reported 10 posterior coalitions (55.6%) in 18 feet. These studies indicated that coalition in the posterior facet was not as rare as long believed and took up a great part of the talocalcaneal coalition. In the current study, we found that all coalitions (100%) involved the posterior articular facet, while 73.2% of coalitions involved both the middle and posterior articular facets. The finding that the coalition involving the posterior facets was more than the coalition involving the middle facets, was consistent with the studies of Soon Hyuck Lee et al.[ 24 ] and Seong Jong Yun et al.[ 20 ]. However, the coalition only involved the middle facet was not found in our case series. The studies about the coalition involving the anterior facets were rare[ 16 , 26 ], and we found only five coalitions (4.6%) that involved the anterior facets. Rozansky et al.[ 17 ] depicted the features of coalitions on the 3D construction image, however, they didn’t emphasize the open of the tarsal sinus. In the current study, the open of the tarsal sinus could be found in the subtype-P coalitions on a 3D construction image, while for subtype-MP and AMP, it could not be found. So, we can also distinguish the facets that the coalitions involve from a 3D construction image. The first-line strategy for symptomatic talocalcaneal coalitions is conservative treatment[ 8 , 11 ]. Coalition resection is recommended if non-operative treatment failed. Traditional open techniques may prolong hospitalization for wound management and pain control[ 27 ]. An open technique[ 28 , 29 ] is often performed with an incision over the sustentaculum tali, and then, identifying the bridge edge through the talonavicular joint anteriorly and the residual talocalcaneal joint. Finally, the coalition is resected until the articular cartilage is visible. Arthroscopy has gained popularity recently and several authors reported good results after endoscopic coalition resection[ 21 , 30 , 31 ]. For the subtype-P coalitions, the excision is enough until healthy cartilage of the posterior subtalar joint is visualized. While for subtype-MP coalitions, the excision should be extended anteriorly to the medial open of the tarsal sinus in an open technique. It is similar to arthroscopic surgery, in which the flexor hallucis longus (FHL) is an important landmark[ 32 , 33 ]. The excision under the arthroscope should be extended medially, according to the non-osseous coalitions of types I-III. In type IV (osseous coalition), an important landmark that can help identify the location of the subtalar joint is the posterior talofibular ligament[ 32 ]. Conclusion A new classification system of the talocalcaneal coalition to facilitate operative planning was developed. Limitations The limitation of this study lies in its retrospective nature. However, as we know, this is the largest sample size currently reported and may make up for this shortcoming. Some studies referred to the coalition that only involved the middle facet. However, the coalition only involving the anterior facet or middle facet was not found in this case series. Declarations Ethics approval and consent to participate This work was approved by the Institutional Review Board in Peking University Third Hospital. All methods were carried out in accordance with relevant guidelines and regulations of the Institutional Review Board. For the retrospective design of this study, and all of the clinical and radiological data were collected and analyzed anonymously, the Ethics Committee of Peking University Third Hospital waived this study from obtaining informed consent for patients. Acknowledgements Not applicable. Competing interests The authors declare that they have no competing interests. Availability of data and materials The dataset analysed during the current study is available from the corresponding author on reasonable request. Consent for publication Not applicable. Funding This study was funded by the National Natural Science Foundation of China (NO.81672153) Authors' contributions Anhong Wang, Weili Shi, Qinwei Guo, Dong Jiang, and Linxin Chen conceived the study and performed the data acquisition and statistical analysis. Xing Xie, Dong Jiang, Feng Zhao, Yanbin Pi, and CHEN JIAO wrote and edited the manuscript. Anhong Wang, Weili Shi, Qinwei Guo and Yuelin Hu reviewed and revised the paper (An hong Wang and Weili Shi contributed equally to this work; Qinwei Guo is the corresponding author and Dong Jiang is the co- corresponding author for this paper). All authors have read and agree with the final manuscript. References de Wouters S, Tran Duy K, Docquier PL. Patient-specific instruments for surgical resection of painful tarsal coalition in adolescents. Orthop Traumatol Surg Res 2014; 100:423-427 Zhou B, Tang K, Hardy M. Talocalcaneal coalition combined with flatfoot in children: diagnosis and treatment: a review. J Orthop Surg Res 2014; 9:129 Leonard MA. The inheritance of tarsal coalition and its relationship to spastic flat foot. J Bone Joint Surg Br 1974; 56B:520-526 Mahan ST, Spencer SA, Vezeridis PS, Kasser JR. Patient-reported Outcomes of Tarsal Coalitions Treated With Surgical Excision. J Pediatr Orthop 2015; 35:583-588 Umul A. MRI Findings of Talocalcaneal Coalition: Two Case Reports. Acta Inform Med 2015; 23:248-249 Cass AD, Camasta CA. A review of tarsal coalition and pes planovalgus: clinical examination, diagnostic imaging, and surgical planning. J Foot Ankle Surg 2010; 49:274-293 Murphy JS, Mubarak SJ. Talocalcaneal Coalitions. Foot Ankle Clin 2015; 20:681-691 Lemley F, Berlet G, Hill K, Philbin T, Isaac B, Lee T. Current concepts review: Tarsal coalition. 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Foot Ankle Int 2018; 39:1082-1088 Khoshbin A, Law PW, Caspi L, Wright JG. Long-term functional outcomes of resected tarsal coalitions. Foot Ankle Int 2013; 34:1370-1375 Staser J, Karmazyn B, Lubicky J. Radiographic diagnosis of posterior facet talocalcaneal coalition. Pediatric radiology 2007; 37:79-81 Lee SH, Park HJ, Yeo ED, Lee YK. Talocalcaneal coalition: A focus on radiographic findings and sites of bridging. Indian J Orthop 2016; 50:661-668 Scranton PE. Treatment of Symptomatic Talocalcaneal Coalition. Journal of Bone and Joint Surgery-American Volume 1987; 69a:533-539 Linklater J, Hayter CL, Vu D, Tse K. Anatomy of the subtalar joint and imaging of talo-calcaneal coalition. Skeletal Radiol 2009; 38:437-449 Sperl M, Saraph V, Zwick EB, Kraus T, Spendel S, Linhart WE. Preliminary report: resection and interposition of a deepithelialized skin flap graft in tarsal coalition in children. J Pediatr Orthop B 2010; 19:171-176 Di Gennaro GL, Stallone S, Olivotto E, et al. Operative versus nonoperative treatment in children with painful rigid flatfoot and talocalcaneal coalition. BMC Musculoskelet Disord 2020; 21:185 Wilde PH, Torode IP, Dickens DR, Cole WG. Resection for symptomatic talocalcaneal coalition. J Bone Joint Surg Br 1994; 76:797-801 Knorr J, Soldado F, Menendez ME, Domenech P, Sanchez M, Sales de Gauzy J. Arthroscopic Talocalcaneal Coalition Resection in Children. Arthroscopy 2015; 31:2417-2423 Nakazora S, Nishimura A, Ito N, Kato K, Sudo A. Endoscopic Resection for Talocalcaneal Coalition Using Posteromedial Approach: Report of Three Cases. Foot & Ankle Orthopaedics 2016; 1:2473011416S2473000064 Bonasia DE, Phisitkul P, Saltzman CL, Barg A, Amendola A. Arthroscopic resection of talocalcaneal coalitions. Arthroscopy 2011; 27:430-435 Bonasia DE, Phisitkul P, Amendola A. Endoscopic coalition resection. Foot Ankle Clin 2015; 20:81-91 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 11 Aug, 2021 Read the published version in BMC Musculoskeletal Disorders → Version 1 posted Editorial decision: Major revision 08 Jul, 2021 Reviews received at journal 12 Jun, 2021 Reviewers agreed at journal 11 Jun, 2021 Reviewers invited by journal 27 May, 2021 Editor assigned by journal 24 May, 2021 Editor invited by journal 24 May, 2021 Submission checks completed at journal 24 May, 2021 First submitted to journal 14 Apr, 2021 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-422276","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":28842459,"identity":"b42dca4d-cc14-4842-8906-9a73b025e6c8","order_by":0,"name":"Anhong Wang","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Anhong","middleName":"","lastName":"Wang","suffix":""},{"id":28842460,"identity":"acf3198c-b4eb-47a6-8437-7b8d68bd4ace","order_by":1,"name":"Weili Shi","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Weili","middleName":"","lastName":"Shi","suffix":""},{"id":28842461,"identity":"099f5150-5eb3-4462-811f-06b7584ca697","order_by":2,"name":"Linxin Chen","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Linxin","middleName":"","lastName":"Chen","suffix":""},{"id":28842462,"identity":"d9400ca4-5c1d-4e9d-bfd0-036009788fcf","order_by":3,"name":"Xing Xie","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Xing","middleName":"","lastName":"Xie","suffix":""},{"id":28842464,"identity":"bed86421-81fb-4712-8645-f77a77c633cb","order_by":4,"name":"Feng Zhao","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Feng","middleName":"","lastName":"Zhao","suffix":""},{"id":28842467,"identity":"e5e91e6e-4125-4c27-9bda-d241db665e23","order_by":5,"name":"Yanbin Pi","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yanbin","middleName":"","lastName":"Pi","suffix":""},{"id":28842466,"identity":"224036c1-cd01-4852-a231-96ed5cfcca65","order_by":6,"name":"Chen Jiao","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Chen","middleName":"","lastName":"Jiao","suffix":""},{"id":28842465,"identity":"795dc88d-973b-4027-ad44-c0daa01e1bb9","order_by":7,"name":"Yuelin Hu","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yuelin","middleName":"","lastName":"Hu","suffix":""},{"id":28842463,"identity":"f78ef62e-9238-465e-abca-d7ef3a1688d8","order_by":8,"name":"Dong Jiang","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Dong","middleName":"","lastName":"Jiang","suffix":""},{"id":28842468,"identity":"de365e6b-48e6-4d2b-bc23-f3dd1b65dff8","order_by":9,"name":"Qinwei Guo","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6UlEQVRIiWNgGAWjYLCCBCBmY29gOACkeUjQwnOAFC1gIJFApEL5iOSDNx7uOCzHJ/nG8HABQ52MOfsBxg8fc3BrMbyRlmyReOawMZt0jsHhGQyHeSx7EpglZ27Do2VGjplEYtvtxDbptITDPAwHeAwOJLAx8xKhpb5N8hhISx2PwfkH+LXIS0C0JLBJMB8AamHmMbhBwBYDnmdAv7T9N2zjST5weIbBYaCWh814/SLfnnzw5s+2NHn59oPNnwsq6uwNzicf/PARny0HgDEC4zAzGIAoxgbc6kG2NKBoGQWjYBSMglGABQAAFjBOhUPApd4AAAAASUVORK5CYII=","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":true,"prefix":"","firstName":"Qinwei","middleName":"","lastName":"Guo","suffix":""}],"badges":[],"createdAt":"2021-04-14 11:14:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-422276/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-422276/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12891-021-04567-0","type":"published","date":"2021-08-11T15:02:39+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":9630240,"identity":"e2ac0c37-67f0-4691-8e2e-c033898b636b","added_by":"auto","created_at":"2021-05-26 21:40:26","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":267808,"visible":true,"origin":"","legend":"25-year-old man with an I-P type coalition involving the posterior facet only. \n(A) Superiorly overgrown calcaneus (white arrow) covers the articular facet of the talus. \n(B) 3D construction image shows the open of sinus tarsal (black arrow) between the sustentaculum tali and the coalition (circle). ","description":"","filename":"fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-422276/v1/31f526e95a601ae352e94b5f.png"},{"id":9630353,"identity":"dc1bf7c7-8fae-4de6-a9be-25d0ca5ad18b","added_by":"auto","created_at":"2021-05-26 21:43:27","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":728112,"visible":true,"origin":"","legend":"35-year-old female with an I-MP type coalition involving both middle and posterior facets.\n(A) The tarsal sinus (black arrow) can be seen. A significantly overgrown talus (white arrow) covers the calcaneus. The marginal cortical irregularity of the calcaneus is also noted. \n(B) The tarsal sinus cannot be seen and only the posterior facet is shown (white arrow). The two images (A, B) indicate that the coalition involved both the middle and posterior facets. A significantly overgrown talus (white arrow) covers the calcaneus. The marginal cortical irregularity of the calcaneus is also noted. \n(C) 3D reconstruction image shows that the overgrown talus covers the calcaneus like a shingle (white oval) without the open of sinus tarsal. ","description":"","filename":"fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-422276/v1/5ab2e12f4ce5ea85bc076b73.png"},{"id":9630546,"identity":"56fc8bcf-e7ea-463a-abb7-add7125ae9df","added_by":"auto","created_at":"2021-05-26 21:46:27","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":558699,"visible":true,"origin":"","legend":"21-year-old man with an II-P type coalition involving the posterior facet only.\n(A) The tarsal sinus cannot be seen; both talus and calcaneus (white arrows) overgrow to adapt to each other. \n(B) 3D construction shows the open of sinus tarsal (black arrow); A significant coalition (oval) can be identified.","description":"","filename":"fig3.png","url":"https://assets-eu.researchsquare.com/files/rs-422276/v1/aaf477b8f86f71652e0cf75e.png"},{"id":9630351,"identity":"76f1c346-79f7-41b8-bc75-b77669b8b642","added_by":"auto","created_at":"2021-05-26 21:43:27","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":713943,"visible":true,"origin":"","legend":"34-year-old man with an II-MP type coalition involving both the middle and posterior facets.\n(A, B) Both the talus and calcaneus overgrow (white arrows) and cortical irregularity of the calcaneus and talus is obvious. The tarsal sinus (black arrow) can be seen, which indicates that the coalition involves the middle facet (fig.-A), however, the tarsal sinus is not shown behind that plane (fig.-B), indicating that the coalition affects the posterior facet.\n(C) 3D construction image shows that both the talus and calcaneus (oval) overgrow and cover each other. The open of sinus tarsal is not found.","description":"","filename":"fig4.png","url":"https://assets-eu.researchsquare.com/files/rs-422276/v1/515ab6c1eb33a7b2bc988bfe.png"},{"id":9630243,"identity":"5c112a3e-6fea-428c-bc37-03075d51416f","added_by":"auto","created_at":"2021-05-26 21:40:27","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":430930,"visible":true,"origin":"","legend":"24-year-old male with an III-P type coalition involving the posterior facet only.\n(A) An independent coalition with an accessory ossicle (white arrow) locates at the medial and inferior aspect of the talus and superior aspect of the calcaneus. The sclerosis was not found at the border between the ossicle and calcaneus or talus. \n(B) 3D reconstruction image shows the open of sinus tarsal (black arrow), and an accessory ossicle (oval). ","description":"","filename":"fig5.png","url":"https://assets-eu.researchsquare.com/files/rs-422276/v1/5a71123644b7457bde3e977b.png"},{"id":9630545,"identity":"1060ab22-60e2-4962-a02e-782ff08d0946","added_by":"auto","created_at":"2021-05-26 21:46:27","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":739237,"visible":true,"origin":"","legend":"35-year-old female with an III-MP type coalition involving both the middle and posterior facets.\n(A) The tarsal sinus (black arrow) can be seen and both overgrown talus and calcaneus (white arrows). \n(B) An accessory ossicle (white arrow) locates at the medial and inferior aspect of the talus and superior aspect of the calcaneus. The sclerosis is not found at the border between the ossicle and calcaneus or talus. \n(C) 3D reconstruction image shows that an accessory ossicle (circle) separates the talus and calcaneus. ","description":"","filename":"fig6.png","url":"https://assets-eu.researchsquare.com/files/rs-422276/v1/a6813043f626c1dc1ae59196.png"},{"id":9630245,"identity":"f49321d8-bf9b-4d35-9630-48089a4e58f3","added_by":"auto","created_at":"2021-05-26 21:40:27","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":480265,"visible":true,"origin":"","legend":"29-year-old female with an IV-P type coalition involving the posterior facet only.\n(A) Fused talus and calcaneus form a complete osseous coalition (white arrow) involving the posterior facet and cannot be torn apart. \n(B) 3D construction image shows a complete osseous (oval) bridge between talus and calcaneus. The open of sinus tarsal (black arrow) can also be seen.","description":"","filename":"fig7.png","url":"https://assets-eu.researchsquare.com/files/rs-422276/v1/6173a0c97beb821a6ed7f277.png"},{"id":9630354,"identity":"fdce8dfa-bcda-4d13-8ffd-ec6cbdfdcaec","added_by":"auto","created_at":"2021-05-26 21:43:27","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":676871,"visible":true,"origin":"","legend":"23-year-old man with an IV-MP type coalition involving both the middle and posterior facets.\n(A, B) The tarsal sinus (black arrow) can be seen and both the talus and calcaneus (white arrows) overgrow and cover each other (A). A complete osseous coalition (white arrow) can be seen in the posterior facet (B). \n(C) 3D construction image shows that the talus and calcaneus fuse together (oval) without the open of tarsal sinus.","description":"","filename":"fig8.png","url":"https://assets-eu.researchsquare.com/files/rs-422276/v1/e3ed5aa7c6f77e304d63be8a.png"},{"id":9630248,"identity":"4d74c34d-2fb1-4e57-bceb-8968be507bb5","added_by":"auto","created_at":"2021-05-26 21:40:27","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":676028,"visible":true,"origin":"","legend":"57-year-old man with an IV-AMP type coalition involving the anterior, middle and posterior facets.\n(A, B, C) Fused talus and calcaneus form a complete osseous coalition (white arrow) involving the anterior, middle and posterior facets. (B) The tarsal sinus (black arrow) can be seen. \n(C) 3D construction image shows that the talus and calcaneus fuse together (oval) without the open of tarsal sinus.","description":"","filename":"fig9.png","url":"https://assets-eu.researchsquare.com/files/rs-422276/v1/050195aa6c960b202e4176a8.png"},{"id":13695038,"identity":"c079118a-cbe0-40f0-910c-6492cdf1d456","added_by":"auto","created_at":"2021-09-17 12:55:30","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4953326,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-422276/v1/0cc61bd0-6b3b-43eb-b3d1-22e820c6794b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eA New Classification of Talocalcaneal Coalitions Based On Computed Tomography For Operative Planning\u003c/p\u003e","fulltext":[{"header":"Introduction","content":" \u003cp\u003eTalocalcaneal coalition is the abnormal bridge between talus and calcaneus. It is a type of tarsal coalitions and is attributed to the failure of differentiation and segmentation in the primitive mesenchyme.[\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] Talocalcaneal coalition is a significant cause of hindfoot pain, limited motion, and a valgus heel.[\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] The talocalcaneal coalition can be divided into syndesmosis, synchondrosis, and synostosis by its nature.\u003c/p\u003e \u003cp\u003eA plain radiograph is still the first choice to evaluate talocalcaneal coalition. A weight-bearing anterior-posterior, lateral radiograph, and Harris-heel view are commonly used.[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] A feature of the C-sign, which formed by the outline of the talar dome and the inferior outline of the sustentaculum tali in the lateral radiograph may be indicated. However, the diagnosis of the talocalcaneal coalition is difficult depending on the plain radiograph and the C-sign lacks sensitivity.[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe normal subtalar joint is divided into the anterior, middle, and posterior joint. The talocalcaneal coalition is thought to be most commonly developed in the middle part of the subtalar joint[\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The middle and anterior facets were both concave on the calcaneus and fused anterior and middle articular facets were seen more frequently.[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] The bridged anterior and middle joint facets were considered an integration because they were continuous with the talocalcaneonavicular joint.[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] The tarsal sinus, lying lateral to open space the middle joint facet, separates the posterior and middle facet joints. It is the boundary to distinguish the middle from the posterior subtalar joint facets. For the complicated anatomy, plain radiographs cannot determine the type and location of the coalition, while computed tomography (CT) enables a good depiction of the subtalar anatomy, to effectively determine the size and shape, and also allows distinguishing between osseous and non-osseous coalitions.[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan additionalcitationids=\"CR15\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] CT has been regarded as the standard diagnostic modality and is helpful to preoperative planning. Rozansky et al.[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] in 2010 classified the talocalcaneal coalition into five types based on the coalition nature, location, and facet joint orientation. After that, Sanghyeok Lim et al.[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] in 2013 used CT and MRI to evaluate the coalition and developed a classification according to the coalition nature and shape. However, besides coalition nature and shape, subtalar joint facets involved should also be emphasized.\u003c/p\u003e \u003cp\u003eThe purpose of this study is to develop a new classification system for operative planning based on the morphology, nature of the coalition, and the subtalar articular facets involved.\u003c/p\u003e "},{"header":"Methods And Materials","content":"\u003cp\u003eThe retrospective study was approved by the Board of Research Ethics. Patients were identified through the clinical medical record system in our hospital using the keywords of \u0026ldquo;talocalcaneal coalition\u0026rdquo;, \u0026ldquo;tarsal coalition\u0026rdquo; or \u0026ldquo;coalition\u0026rdquo;, between January 2009 and February 2021. One hundred and twenty-one subjects were identified. After that, patients with talocalcaneal coalition confirmed using CT scan were included. Exclusion criteria included talonavicular or calcaneonavicular coalition and patients without a CT scan.\u003c/p\u003e\n\u003cp\u003eCT examinations were performed using a 64-slices helical CT (GE, USA). All the CT images were reviewed by the corresponding author (with 18 years of orthopedic sports medicine experience). We distinguished the middle from the posterior subtalar joint facet by the boundary of the tarsal sinus in the coronary planes of CT, in the Picture Archiving Communication System (PACS). Diagnosis criteria were as follows: osseous coalitions were confirmed by the presence of a bony bridge; nonosseous coalitions were confirmed by manifestations of narrowing of the facet with marginal cortical irregularity as Kumar et al. depicted[19] and overgrown talus or calcaneus was discovered. Besides, a 3D construction image was obtained to show the details of the abnormal bar.[17]\u003c/p\u003e\n\u003cp\u003eThe coalitions were classified into four main types according to the shape and nature of the coalition: I, inferiorly overgrown talus or superiorly overgrown calcaneus; II, both talus and calcaneus overgrew; III, a coalition with an accessory ossicle; (I-III types are non-osseous coalition) IV, complete osseous coalition. On the coronal images of CT, the shape and nature of the coalitions could be observed. Then each type was further divided into three subtypes according to the articular facets involved. A, the coalition involving the anterior facets; On the coronal images of CT, the coalition could only be found anterior to the images of the tarsal sinus for this subtype. M, the coalition involving the middle facets. The subtypes could be identified through the coronal images of CT of the tarsal sinus. P, the coalition involving the posterior facets. On the coronal images of CT, the coalition could only be found posterior to the images of the tarsal sinus. For the coalitions involving the posterior facets only, the open of the sinus tarsal was obvious on a 3D reconstruction image. While for the coalitions involving the middle and posterior facets, the open of the sinus tarsal could not be seen on a 3D reconstruction image (Fig.\u0026nbsp;1\u0026ndash;9).\u003c/p\u003e\n\u003cp\u003eStatistical analysis was conducted using the statistical software (Excel; Microsoft Corporation, USA).\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 106 patients (108 feet) with talocalcaneal coalition were included in this study, of which 2 patients had bilateral coalitions. There were 76 male patients (70.4%) and 30 females (28.8%). Sixty-four right feet (59.3%) were affected while 44 coalitions (40.7%) were on the left feet. The average patient age was 29.8 \u0026plusmn;11.0 years (range 12-60 years).\u003c/p\u003e\n\u003cp\u003eOverall, 8 feet (7.5%) were classified as type I, 75 feet (69.4%) as type II, 7 feet (6.5%) as type III, and 18 feet (16.7%) as type IV. All coalitions involved the posterior facets. Twenty-nine coalitions (26.9%) involved the posterior facets only, 74 coalitions (68.5%) involved both the middle and posterior facets, and five coalitions (4.6%) simultaneously involved the anterior, middle, and posterior facets (Table 1). We didn\u0026rsquo;t find any coalition involving the anterior facets in type I, II, and III.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1 The classification of the talocalcaneal coalition\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eClassification\u003csup\u003e\u0026alpha;\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003eNum. of feet\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003ePercentage\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eI\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eI-P\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e1.9%\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eI-MP\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e6\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e5.6%\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eII\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eII-P\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e20\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e18.5%\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eII-MP\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e55\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e50.9%\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eIII\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eIII-P\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e3.7%\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eIII-MP\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e2.8%\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eIV\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eIV-P\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e2.8%\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eIV-MP\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e10\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e9.3%\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eIV-AMP\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e5\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e4.6%\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"125\"\u003e\n\u003cp\u003eTotal\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"117\"\u003e\n\u003cp\u003e108\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"106\"\u003e\n\u003cp\u003e100%\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003csup\u003e\u0026alpha;\u003c/sup\u003eType I, inferiorly overgrown talus or superiorly overgrown calcaneus; II, both talus and calcaneus overgrew; III, coalition with an accessory ossicle; (I-III types are non-osseous coalition) IV, complete osseous coalition. Then each type was further divided into three subtypes according to the articular facets involved. A, the coalition involving the anterior facets; M, the coalition involving the middle facets, and P, the coalition involving the posterior facets.\u003c/p\u003e"},{"header":"Discussion","content":" \u003cp\u003eBased on the shape, nature of the coalitions, and the articular facets that coalitions involved, we devised a new classification system through analyzing the large sample of cases and found the coalition with both talus and calcaneus overgrew, involving the posterior and middle subtalar joint facets, was most common.\u003c/p\u003e \u003cp\u003eType II-MP was the most common type, comprising 50.9% of the coalitions, manifesting with both overgrown talus and calcaneus. We found only 8 coalitions (7.8%) of type I (two I-P types and 6 I-MP types). It was lower than 23 coalitions (33%) in Sanghyeok Lim et al\u0026rsquo;s study.[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] Type I and II showed the coalition orientation (sloping up or down, or horizontal) which was helpful to find the fibrocartilage or fibrous line between the talar part and calcaneal part to guide to operative resection, particularly during arthroscopic resection. Seong Jong Yun and his colleagues[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] reported that 15 of 54 (27.8%) feet showed talocalcaneal coalitions with an accessory ossicle. They regarded the accessory bone as os sustentaculum, forming when the accessory ossification center ossified, at the medial and posterosuperior aspects of the sustentaculum tali and they believed that the accessory bone may be a cause of bone marrow edema and pain in osteoarthritis. Sanghyeok Lim et al.[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] regarded this accessory ossicle as a fracture fragment and they found a coalition with a \u0026ldquo;fracture fragment\u0026rdquo; in 17 of 70 feet (24%). We found 7 coalitions (6.5%) with an accessory ossicle (Type III) in this study. We also thought the coalition might be an accessory ossicle but not a fracture fragment, because the sclerosis of nonunion was not found in the ossicle by CT.\u003c/p\u003e \u003cp\u003eA complete osseous coalition may be difficult for resection for it\u0026rsquo;s hard to identify the borderline of the coalition, particularly in arthroscopic surgery. There were 18 feet (16.7%) identified as complete osseous coalitions (Type IV) in this study. This was in line with the study of Rozansky et al.[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. However, Wael Aldahshan et al.[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] reported 8 complete bony coalitions (40%) while Amir Khoshbin et al.[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] also found 5 complete osseous coalitions(38.3%). But in Sanghyeok Lim et al.\u0026rsquo;s study[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e], there were only 2 complete synostosis coalitions (3%)\u003csup\u003e18\u003c/sup\u003e. The difference may lie in the different sample sizes.\u003c/p\u003e \u003cp\u003eThe subtalar middle facet was most commonly involved while the posterior facet coalition was rare as reported in some studies[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Soon Hyuck Lee et al.[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] reported recently that the prevalence of the talocalcaneal coalition in the middle and posterior subtalar facets was 27%, while 68% of coalitions involved the posterior facet only. Seong Jong Yun et al.[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] reported that the prevalence of subtalar posterior facet coalition (34.6%) was higher than the middle facet coalition (9.9%) in 81 patients. Scranton, P. E. et al.[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e] reported 10 posterior coalitions (55.6%) in 18 feet. These studies indicated that coalition in the posterior facet was not as rare as long believed and took up a great part of the talocalcaneal coalition. In the current study, we found that all coalitions (100%) involved the posterior articular facet, while 73.2% of coalitions involved both the middle and posterior articular facets. The finding that the coalition involving the posterior facets was more than the coalition involving the middle facets, was consistent with the studies of Soon Hyuck Lee et al.[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] and Seong Jong Yun et al.[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. However, the coalition only involved the middle facet was not found in our case series. The studies about the coalition involving the anterior facets were rare[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e], and we found only five coalitions (4.6%) that involved the anterior facets.\u003c/p\u003e \u003cp\u003eRozansky et al.[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] depicted the features of coalitions on the 3D construction image, however, they didn\u0026rsquo;t emphasize the open of the tarsal sinus. In the current study, the open of the tarsal sinus could be found in the subtype-P coalitions on a 3D construction image, while for subtype-MP and AMP, it could not be found. So, we can also distinguish the facets that the coalitions involve from a 3D construction image.\u003c/p\u003e \u003cp\u003eThe first-line strategy for symptomatic talocalcaneal coalitions is conservative treatment[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Coalition resection is recommended if non-operative treatment failed. Traditional open techniques may prolong hospitalization for wound management and pain control[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. An open technique[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e] is often performed with an incision over the sustentaculum tali, and then, identifying the bridge edge through the talonavicular joint anteriorly and the residual talocalcaneal joint. Finally, the coalition is resected until the articular cartilage is visible. Arthroscopy has gained popularity recently and several authors reported good results after endoscopic coalition resection[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFor the subtype-P coalitions, the excision is enough until healthy cartilage of the posterior subtalar joint is visualized. While for subtype-MP coalitions, the excision should be extended anteriorly to the medial open of the tarsal sinus in an open technique. It is similar to arthroscopic surgery, in which the flexor hallucis longus (FHL) is an important landmark[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. The excision under the arthroscope should be extended medially, according to the non-osseous coalitions of types I-III. In type IV (osseous coalition), an important landmark that can help identify the location of the subtalar joint is the posterior talofibular ligament[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e "},{"header":"Conclusion","content":" \u003cp\u003eA new classification system of the talocalcaneal coalition to facilitate operative planning was developed.\u003c/p\u003e "},{"header":"Limitations","content":" \u003cp\u003eThe limitation of this study lies in its retrospective nature. However, as we know, this is the largest sample size currently reported and may make up for this shortcoming. Some studies referred to the coalition that only involved the middle facet. However, the coalition only involving the anterior facet or middle facet was not found in this case series.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was approved by the Institutional Review Board in Peking University Third Hospital. All methods were carried out in accordance with relevant guidelines and regulations of the Institutional Review Board. For the retrospective design of this study, and all of the clinical and radiological data were collected and analyzed anonymously, the Ethics Committee of Peking University Third Hospital waived this study from obtaining informed consent for patients.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe dataset analysed during the current study is available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was funded by the National Natural Science Foundation of China (NO.81672153)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors' contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAnhong Wang, Weili Shi, Qinwei Guo, Dong Jiang, and Linxin Chen conceived the study and performed the data acquisition and statistical analysis. Xing Xie, Dong Jiang, Feng Zhao, Yanbin Pi, and CHEN JIAO wrote and edited the manuscript. Anhong Wang, Weili Shi, Qinwei Guo and Yuelin Hu reviewed and revised the paper (An hong Wang and Weili Shi contributed equally to this work; Qinwei Guo is the corresponding author and Dong Jiang is the co- corresponding author for this paper). All authors have read and agree with the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003ede Wouters S, Tran Duy K, Docquier PL. Patient-specific instruments for surgical resection of painful tarsal coalition in adolescents. \u003cem\u003eOrthop Traumatol Surg Res\u003c/em\u003e 2014; 100:423-427\u003c/li\u003e\n\u003cli\u003eZhou B, Tang K, Hardy M. Talocalcaneal coalition combined with flatfoot in children: diagnosis and treatment: a review. \u003cem\u003eJ Orthop Surg Res\u003c/em\u003e 2014; 9:129\u003c/li\u003e\n\u003cli\u003eLeonard MA. The inheritance of tarsal coalition and its relationship to spastic flat foot. \u003cem\u003eJ Bone Joint Surg Br\u003c/em\u003e 1974; 56B:520-526\u003c/li\u003e\n\u003cli\u003eMahan ST, Spencer SA, Vezeridis PS, Kasser JR. Patient-reported Outcomes of Tarsal Coalitions Treated With Surgical Excision. \u003cem\u003eJ Pediatr Orthop\u003c/em\u003e 2015; 35:583-588\u003c/li\u003e\n\u003cli\u003eUmul A. MRI Findings of Talocalcaneal Coalition: Two Case Reports. \u003cem\u003eActa Inform Med\u003c/em\u003e 2015; 23:248-249\u003c/li\u003e\n\u003cli\u003eCass AD, Camasta CA. A review of tarsal coalition and pes planovalgus: clinical examination, diagnostic imaging, and surgical planning. \u003cem\u003eJ Foot Ankle Surg\u003c/em\u003e 2010; 49:274-293\u003c/li\u003e\n\u003cli\u003eMurphy JS, Mubarak SJ. Talocalcaneal Coalitions. \u003cem\u003eFoot Ankle Clin\u003c/em\u003e 2015; 20:681-691\u003c/li\u003e\n\u003cli\u003eLemley F, Berlet G, Hill K, Philbin T, Isaac B, Lee T. Current concepts review: Tarsal coalition. \u003cem\u003eFoot Ankle Int\u003c/em\u003e 2006; 27:1163-1169\u003c/li\u003e\n\u003cli\u003eTaniguchi A, Tanaka Y, Kadono K, Takakura Y, Kurumatani N. C sign for diagnosis of talocalcaneal coalition. \u003cem\u003eRadiology\u003c/em\u003e 2003; 228:501-505\u003c/li\u003e\n\u003cli\u003eKatayama T, Tanaka Y, Kadono K, Taniguchi A, Takakura Y. Talocalcaneal coalition: a case showing the ossification process. \u003cem\u003eFoot Ankle Int\u003c/em\u003e 2005; 26:490-493\u003c/li\u003e\n\u003cli\u003eDocquier PL, Maldaque P, Bouchard M. Tarsal coalition in paediatric patients. \u003cem\u003eOrthop Traumatol Surg Res\u003c/em\u003e 2019; 105:S123-S131\u003c/li\u003e\n\u003cli\u003eKulik SA, Jr., Clanton TO. Tarsal coalition. \u003cem\u003eFoot Ankle Int\u003c/em\u003e 1996; 17:286-296\u003c/li\u003e\n\u003cli\u003ePrasad SA, Rajasekhar S. Morphometric analysis of talus and calcaneus. \u003cem\u003eSurg Radiol Anat\u003c/em\u003e 2019; 41:9-24\u003c/li\u003e\n\u003cli\u003eHerzenberg JE, Goldner JL, Martinez S, Silverman PM. Computerized tomography of talocalcaneal tarsal coalition: a clinical and anatomic study. \u003cem\u003eFoot Ankle\u003c/em\u003e 1986; 6:273-288\u003c/li\u003e\n\u003cli\u003eWechsler RJ, Karasick D, Schweitzer ME. Computed tomography of talocalcaneal coalition: imaging techniques. \u003cem\u003eSkeletal Radiol\u003c/em\u003e 1992; 21:353-358\u003c/li\u003e\n\u003cli\u003eWarren MJ, Jeffree MA, Wilson DJ, MacLarnon JC. Computed tomography in suspected tarsal coalition. Examination of 26 cases. \u003cem\u003eActa Orthop Scand\u003c/em\u003e 1990; 61:554-557\u003c/li\u003e\n\u003cli\u003eRozansky A, Varley E, Moor M, Wenger DR, Mubarak SJ. A radiologic classification of talocalcaneal coalitions based on 3D reconstruction. \u003cem\u003eJ Child Orthop\u003c/em\u003e 2010; 4:129-135\u003c/li\u003e\n\u003cli\u003eLim S, Lee HK, Bae S, Rim NJ, Cho J. A radiological classification system for talocalcaneal coalition based on a multi-planar imaging study using CT and MRI. \u003cem\u003eInsights Imaging\u003c/em\u003e 2013; 4:563-567\u003c/li\u003e\n\u003cli\u003eKumar SJ, Guille JT, Lee MS, Couto JC. Osseous and non-osseous coalition of the middle facet of the talocalcaneal joint. \u003cem\u003eJ Bone Joint Surg Am\u003c/em\u003e 1992; 74:529-535\u003c/li\u003e\n\u003cli\u003eYun SJ, Jin W, Kim GY, et al. A Different Type of Talocalcaneal Coalition With Os Sustentaculum: The Continued Necessity of Revision of Classification. \u003cem\u003eAJR Am J Roentgenol\u003c/em\u003e 2015; 205:W612-618\u003c/li\u003e\n\u003cli\u003eAldahshan W, Hamed A, Elsherief F, Abdelaziz AM. Endoscopic Resection of Different Types of Talocalcaneal Coalition. \u003cem\u003eFoot Ankle Int\u003c/em\u003e 2018; 39:1082-1088\u003c/li\u003e\n\u003cli\u003eKhoshbin A, Law PW, Caspi L, Wright JG. Long-term functional outcomes of resected tarsal coalitions. \u003cem\u003eFoot Ankle Int\u003c/em\u003e 2013; 34:1370-1375\u003c/li\u003e\n\u003cli\u003eStaser J, Karmazyn B, Lubicky J. Radiographic diagnosis of posterior facet talocalcaneal coalition. \u003cem\u003ePediatric radiology\u003c/em\u003e 2007; 37:79-81\u003c/li\u003e\n\u003cli\u003eLee SH, Park HJ, Yeo ED, Lee YK. Talocalcaneal coalition: A focus on radiographic findings and sites of bridging. \u003cem\u003eIndian J Orthop\u003c/em\u003e 2016; 50:661-668\u003c/li\u003e\n\u003cli\u003eScranton PE. Treatment of Symptomatic Talocalcaneal Coalition. \u003cem\u003eJournal of Bone and Joint Surgery-American Volume\u003c/em\u003e 1987; 69a:533-539\u003c/li\u003e\n\u003cli\u003eLinklater J, Hayter CL, Vu D, Tse K. Anatomy of the subtalar joint and imaging of talo-calcaneal coalition. \u003cem\u003eSkeletal Radiol\u003c/em\u003e 2009; 38:437-449\u003c/li\u003e\n\u003cli\u003eSperl M, Saraph V, Zwick EB, Kraus T, Spendel S, Linhart WE. Preliminary report: resection and interposition of a deepithelialized skin flap graft in tarsal coalition in children. \u003cem\u003eJ Pediatr Orthop B\u003c/em\u003e 2010; 19:171-176\u003c/li\u003e\n\u003cli\u003eDi Gennaro GL, Stallone S, Olivotto E, et al. Operative versus nonoperative treatment in children with painful rigid flatfoot and talocalcaneal coalition. \u003cem\u003eBMC Musculoskelet Disord\u003c/em\u003e 2020; 21:185\u003c/li\u003e\n\u003cli\u003eWilde PH, Torode IP, Dickens DR, Cole WG. Resection for symptomatic talocalcaneal coalition. \u003cem\u003eJ Bone Joint Surg Br\u003c/em\u003e 1994; 76:797-801\u003c/li\u003e\n\u003cli\u003eKnorr J, Soldado F, Menendez ME, Domenech P, Sanchez M, Sales de Gauzy J. Arthroscopic Talocalcaneal Coalition Resection in Children. \u003cem\u003eArthroscopy\u003c/em\u003e 2015; 31:2417-2423\u003c/li\u003e\n\u003cli\u003eNakazora S, Nishimura A, Ito N, Kato K, Sudo A. Endoscopic Resection for Talocalcaneal Coalition Using Posteromedial Approach: Report of Three Cases. \u003cem\u003eFoot \u0026amp; Ankle Orthopaedics\u003c/em\u003e 2016; 1:2473011416S2473000064\u003c/li\u003e\n\u003cli\u003eBonasia DE, Phisitkul P, Saltzman CL, Barg A, Amendola A. Arthroscopic resection of talocalcaneal coalitions. \u003cem\u003eArthroscopy\u003c/em\u003e 2011; 27:430-435\u003c/li\u003e\n\u003cli\u003eBonasia DE, Phisitkul P, Amendola A. Endoscopic coalition resection. \u003cem\u003eFoot Ankle Clin\u003c/em\u003e 2015; 20:81-91\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"talocalcaneal coalition, classification, articular facet, computed tomography","lastPublishedDoi":"10.21203/rs.3.rs-422276/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-422276/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eCurrent classifications emphasize the morphology of the coalition, however, subtalar joint facets involved should also be emphasized.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eObjective\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eThe objective of this study was to develop a new classification system based on the articular facets involved to cover all coalitions and guide operative planning.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eMethods \u003c/strong\u003ePatients were diagnosed with talocalcaneal coalition using a CT scan, between January 2009 and February 2021. We classified the coalition into four main types according to the shape and nature of the coalition: I, inferiorly overgrown talus or superiorly overgrown calcaneus; II, both talus and calcaneus overgrew; III, coalition with an accessory ossicle; (I-III types are non-osseous coalition) IV, complete osseous coalition. Then each type was further divided into three subtypes according to the articular facets involved. A, the coalition involving the anterior facets; M, the coalition involving the middle facets, and P, the coalition involving the posterior facets.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e There were 106 patients (108 feet) included in this study. Overall, 8 feet (7.5%) were classified as type I, 75 feet (69.4%) as type II, 7 feet (6.5%) as type III, and 18 feet (16.7%) as type IV. Twenty-nine coalitions (26.9%) involved the posterior facets only (subtype-P), 74 coalitions (68.5%) involved both the middle and posterior facets (subtype-MP), and five coalitions (4.6%) simultaneously involved the anterior, middle, and posterior facets (subtype-AMP). Type II-MP coalition was the most common.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConclusion \u003c/strong\u003eA new classification system of the talocalcaneal coalition to facilitate operative planning was developed.\u003c/p\u003e","manuscriptTitle":"A New Classification of Talocalcaneal Coalitions Based On Computed Tomography For Operative Planning","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2021-05-26 21:40:24","doi":"10.21203/rs.3.rs-422276/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2021-07-08T13:01:58+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2021-06-12T13:00:44+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"f377f606-7aec-48fa-a30e-7d46b644f7bd","date":"2021-06-11T22:18:18+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2021-05-27T21:50:45+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2021-05-24T05:44:15+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2021-05-24T05:17:17+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2021-05-24T04:58:40+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Musculoskeletal Disorders","date":"2021-04-14T11:03:52+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"170babc2-f010-414f-ba5f-7904b09aa652","owner":[],"postedDate":"May 26th, 2021","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":4578906,"name":"Orthopedics"}],"tags":[],"updatedAt":"2021-08-22T15:14:07+00:00","versionOfRecord":{"articleIdentity":"rs-422276","link":"https://doi.org/10.1186/s12891-021-04567-0","journal":{"identity":"bmc-musculoskeletal-disorders","isVorOnly":false,"title":"BMC Musculoskeletal Disorders"},"publishedOn":"2021-08-11 15:02:39","publishedOnDateReadable":"August 11th, 2021"},"versionCreatedAt":"2021-05-26 21:40:24","video":"","vorDoi":"10.1186/s12891-021-04567-0","vorDoiUrl":"https://doi.org/10.1186/s12891-021-04567-0","workflowStages":[]},"version":"v1","identity":"rs-422276","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-422276","identity":"rs-422276","version":["v1"]},"buildId":"_2-kVJe1T_tPrBINL-cwx","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}