A dissection and computer tomograph study of tarsal coalitions in 100 cadaver feet

Cubonavicular Coalition: Magnetic Resonance Imaging Findings and Associated Pathology of a Rarely Reported Condition in 27 Patients

RATIONALE AND OBJECTIVES

(1) Describe multimodality imaging of cubonavicular coalition (CNC) with magnetic resonance imaging (MRI) focus, (2) evaluate CNC associated foot and ankle pathology, (3) examine clinical presentation/symptoms associated with CNC, (4) record CNC treatment.

MATERIALS AND METHODS

Retrospective Institutional Review Board (IRB) approved study. Picture Archiving and Communication System (PACS) databases searched for CNC. Final study population: 34 cases in 27 patients. Each CNC was reviewed for: coalition type (osseous versus non-osseous- cartilaginous versus fibrous), tendon and ligament pathology, bone marrow edema at CNC and adjacent joints, presence and severity of degenerative changes at CNC and adjacent joints, fractures, additional coalitions, laterality, and pes planus. MRI planes and radiographic views on which coalitions were best identified were recorded. Each CNC EMR was reviewed for: symptoms, trauma, management, patient demographics. Inter-reader reliability was performed for type of non-osseous coalition.

RESULTS

Final cohort included 34 cases in 27 patients (average age: 34.7, range: 10-76; 71% female). No CNC was completely osseous. On MRI, 89.5% of coalitions were non-osseous and 5.3% were partially osseous. 76.5% of patients had referable symptoms including pain, limited motion, inability to bear weight. 23.5% of patients were surgically managed/pathologically proven. On MRI, 36.8% of patients had tendon pathology, 52.6% had ligamentous pathology, 100% had bone marrow edema-like signal abnormality about the CNC, and 88.2% had CNC degenerative changes. There was bone marrow edema-like signal abnormality at bones adjacent to the CNC in 52.6% and adjacent joint degenerative disease present in 50%. CNC was best identified on oblique radiographs and axial MRI. Inter-reader reliability for non-osseous coalition type was poor, Cronbach's alpha 0.554.

CONCLUSION

CNC is subtle and findings of osteoarthritis or bone marrow edema-like about the cubonavicular articulation should raise suspicion for underlying coalition.

Tarsal coalition in adults

Adult tarsal coalition consists in abnormal union of two or more tarsal bones. Reported incidence ranges between 1 and 13%. It is generally a congenital condition, due to dominant autosomal chromosome disorder, but with some acquired forms following trauma or inflammatory pathology. Poorly specific clinical signs and the difficulty of screening on conventional X-ray may lead to diagnostic failure. The present review of tarsal coalition addresses the following questions: how to define tarsal coalition? How to diagnose it? How to treat it? And what results can be expected? There are 3 types of tarsal coalition, according to the type of tissue between the united bones: bony in pure synostosis, cartilaginous in synchondrosis, and fibrous in syndesmosis. Location varies; the most frequent forms are talocalcaneal (TC) and calcaneonavicular (CN), accounting for more than 90% of cases. Cuneonavicular, intercuneal and cuboideonavicular locations are much rarer, at less than 10%. Tarsal coalition is classically painful, often with valgus spastic flatfoot in young adults. The pain is caused by the biomechanical disturbance induced by the bone, cartilage or fibrous bridges which partially or completely hinder hindfoot and/or midfoot motion. Conventional imaging, with weight-bearing X-ray and CT, is standard practice. Weight-bearing CT is increasingly the gold standard, displaying abnormalities in 3 dimensions. Functional imaging on MRI and tomoscintigraphy assess direct and indirect joint impact at the affected and neighboring joint lines. Non-operative treatment can be proposed, with orthoses, rehabilitation and/or injections. But surgery is the most frequent option: either resection of the bony, cartilaginous or fibrous constructs to restore optimally normal anatomy, or arthrodesis in the affected joint line or the entire joint. Surgery can be open, arthroscopic or percutaneous, depending on the severity of the biomechanical impact on the affected and neighboring joints. Resecting the abnormality is the standard practice in all locations if it affects less than 50% of the talocalcaneal joint line and there is no osteoarthritis to impair the functional outcome. Otherwise, fusion is required. Level of evidence: V; expert opinion.

Racial differences in prevalence and anatomical distribution of tarsal coalition

Previous studies have reported a prevalence of tarsal coalition of 0.03-13%. Calcaneonavicular coalition is known as main anatomical type, and the bilateral occurrence of tarsal coalition is known to be 50% or more. These are the results of studies on Caucasians, there have been few studies targeting large number of East Asians so far. We hypothesized that the prevalence and characteristics of tarsal coalition in East Asians might differ from those in Caucasians. The medical records of 839 patients who underwent bilateral computed tomography on foot and ankle in our hospital from January 2012 to April 2021 were retrospectively reviewed. The overall prevalence was 6.0%, talocalcaneal coalition was the most common anatomical type. The overall bilateral occurrence was 56.5%, talocalcaneal coalition had the highest bilateral occurrence (76.0%) among anatomical types. Isolated union of the posterior facet was the most common subtype of talocalcaneal coalition (43.2%). Talocalcaneal coalition had a significantly higher proportion of coalition-related symptomatic patients than calcaneonavicular coalition (p = 0.019). Our study showed a similar trend to other East Asian studies, confirming the existence of racial differences. The possibility of tarsal coalition in foot and ankle patients in East Asians should always be considered, and bilateral examination is essential for diagnosis.

Tarsal coalition: Systematic review of arthroscopic management

INTRODUCTION

The standard of care in the treatment of symptomatic tarsal coalitions is open surgery. However, certain limitations exist with open surgery, which include limited visualization leading to an incomplete resection and possible recurrence of the tarsal coalition. Arthroscopic tarsal coalition resection (TCR) is an alternative that is gaining traction, primarily as the safety profile of posterior ankle and subtalar arthroscopy is more well understood. This study provides a systematic review of the outcomes of arthroscopic TCR.

METHODS

PubMed and Embase were searched independently by 2 reviewers for relevant articles based on predetermined criteria. The subject heading "tarsal coalition" and its related key terms were used.

RESULTS

A total of 416 studies were revealed by the initial search, out of which only 6 met our predetermined inclusion criteria. A total of 42 patients (average age: 17.6 years) were treated with arthroscopic TCR. Thirty-three (78.6%) and 9 (21.4%) patients had talocalcaneal and calcaneonavicular coalitions, respectively. The follow-up period ranged from 6 to 60 months (mean: 26 months), and no recurrence of the tarsal coalition was detected (0.0%). Complications occurred in two (4.8%) patients only, with one developing complex regional pain syndrome (CRPS), and another patient developing hyperesthesia on the medial aspect of the calcaneus.

CONCLUSION

Arthroscopic TCR is a feasible and effective surgery for both CNC and TCC with minimal complications and no disease recurrence at an average of 26 months follow-up. Future high-level of evidence studies are needed to compare the outcomes of open versus arthroscopic TCR.

Sustentaculum Tali Fracture Adjacent to Talocalcaneal Tarsal Coalitions: A Report of 2 Cases

CASE

An 11-year-old boy demonstrated chronic medial hindfoot pain. A 12-year-old boy experienced acute pain and swelling in his right medial ankle and hindfoot after a fall. This is the first report of sustentaculum tali fractures adjacent to a talocalcaneal tarsal coalition, likely resulting from a stress riser created by a rigid subtalar joint.

CONCLUSION

These 2 cases represent unique causes of foot pain in the setting of tarsal coalitions, never before described. Patient-reported outcome measures demonstrated expected improved outcomes after excision of tarsal coalition. Awareness to this possibility will help clinicians treating foot and ankle conditions in children optimize their care.

The C-sign in normal feet: a prospective study and novel imaging algorithm for subtalar joint tarsal coalition

OBJECTIVE

The C-sign on lateral radiographs has been subject to considerable debate with respect to its reliable association to subtalar joint tarsal coalition. The purpose of this study was to determine to what degree subtalar joint pronation factors into (a) the appearance of both complete and incomplete type A C-signs and (b) the conspicuity of the middle facet in both flatfeet and rectus feet.

STUDY DESIGN

Forty-seven normal adult volunteers were enrolled into the study with a total of 92 feet, of which 42 were flexible flatfeet and 50 were rectus feet with normal subtalar joint range of motion. Lateral weight-bearing radiographs were taken of each foot in a position of (a) standing and (b) maximum subtalar joint pronation. Investigators evaluated images for the visibility of the middle facet, and the presence or absence of a continuous or interrupted type A C-sign.

PRINCIPAL RESULTS

No continuous C-signs were produced with extreme pronation in either the rectus/normal or flatfoot populations. Three incomplete type A C-signs were produced with pronation, two of which were in rectus feet. Two absent middle facet signs were also produced with pronation. Absent visualization of the facet had high positive and negative predictive values (1.00 and 0.99 respectively) for the presence of an incomplete C-Sign.

MAJOR CONCLUSIONS

The standard, routine lateral foot/ankle radiographic image protocol for suspected talocalcaneal coalition should be modified routinely positioning the foot maximally supinated, thereby minimizing the possibility of producing C-signs (complete or type A incomplete) and/or absent middle facet signs with pronation in either normal or flatfeet. A novel algorithmic approach can then be simply applied to determine when ancillary CT scanning is warranted for suspected posterior facet coalition.

Incidence of Symptomatic Pediatric Tarsal Coalition in Olmsted County: A Population-Based Study

BACKGROUND

Tarsal coalitions are an important reason for foot pain in children. Early estimates placed the prevalence at up to 2%, while more recent data suggest that it is as high as 11% to 13%. To our knowledge, there have been no population-based studies to determine the true incidence of symptomatic tarsal coalitions in a pediatric population.

METHODS

A population-based database was used to identify all new diagnoses of symptomatic tarsal coalitions in children 18 years old or younger between 1966 and 2018. Patient records were reviewed for clinical data, and comparisons were made between the types and characteristics of the coalitions identified to determine differences in the affected populations. The annual age-specific, sex-specific, and type-specific incidence rates were estimated.

RESULTS

During the study period, 58 patients with a total of 79 symptomatic tarsal coalitions were identified (annual incidence = 3.5 per 100,000 children). There were 43 calcaneonavicular (CN) coalitions (annual incidence = 1.9 per 100,000 children), 27 talocalcaneal (TC) coalitions (annual incidence = 1.2 per 100,000 children), as well as 9 other coalitions (7 talonavicular, 1 naviculocuboid, and 1 naviculocuneiform) (annual incidence = 0.4 per 100,000 children). The overall incidence peaked between the ages of 10 and 14 years for both boys and girls (8.1 per 100,000 and 7.4 per 100,000 children, respectively). Statistical differences were identified between the types of tarsal coalitions. TC coalitions present at an older age relative to CN and other coalitions (mean,13.9, 12.7, and 11.4 years, respectively; p = 0.02). While CN and TC coalitions were similar in composition (23% and 30%, respectively, were osseous as opposed to fibrocartilaginous), other coalitions were more likely to be osseous (78%) (p = 0.0035). Other coalitions were also less likely to require surgery than CN and TC coalitions (11%, 74%, and 56%, respectively; p = 0.0015).

CONCLUSIONS

This population-based study demonstrates differences in the clinical presentation of tarsal coalitions and provides an estimate of the true incidence of symptomatic tarsal coalitions in a pediatric population.

Tarsal Coalition of the Cuneiforms in a Young Athlete: A Case Report

CASE

Tarsal coalitions are relatively common, but there are no reports of cuneiform-to cuneiform coalition in the English language literature. The authors present a case of medial-to-intermediate cuneiform coalition in a young female track athlete. Previous nonoperative treatments had been unsuccessful. Coalition release and medial-intermediate cuneiform arthrodesis enabled her to return initially to full athletic participation without pain, but she had return of pain that persists despite removal of hardware.

CONCLUSION

Medial-intermediate cuneiform coalition is rare. Surgery in this patient provided a short period of pain-free athletic participation, but long-term outcomes are not proven, and further research is needed.

Recently increased prevalence of the human median artery of the forearm: A microevolutionary change

The median artery has been considered as an embryonic structure, which normally regresses around the 8th week of gestation. However, various prevalences have been reported in adults since the 18th century. Furthermore, in a study by Henneberg and George (1995; Am J Phys Anthropol 96, 329-334), has suggested that increasing prevalence of the median artery during the 20th century was a 'possible secular trend'. The present study, conducted nearly a quarter of a century later, is a continuation of that study. A total of 26 median arteries were found in 78 upper limbs obtained from Australians aged 51 to 101 years, who died in the period 2015-2016, a prevalence rate of 33.3%. Analysis of the literature showed that the presence of the median artery has been significantly increasing (p = .001) over time, from approximately 10% in people born in the mid-1880s to approximately 30% by the end of the 20th century. The significance of the prevalence increased to a p value <.0001, when the results of the present study and other studies conducted by our research team were combined. After removal of the studies that were possibly biased, because of their specific focus on the evolutionary aspects of the median artery, the significance remained at p = .018. The present study provides an example of microevolutionary changes in the internal anatomy of the human body. Second-order polynomial regression of the median artery's prevalence on dates of birth shows that it is now present in 35% of people and predicts that people born 80 years from now will all carry a median artery if the trend continues. When the median artery prevalence reaches 50% or more, it should not be considered as a variant, but as a 'normal' human structure.

The radiological diagnosis of extra-articular posteromedial talocalcaneal coalition

OBJECTIVES

Extra-articular posteromedial talocalcaneal coalition (EA-PM TCC) accounts for approximately one-third of TCC, but its radiographic features are not well-described. The current study aims to compare the radiographic features of EA-PM TCC with normal ankles and with the commoner forms of TCC.

MATERIALS AND METHODS

A retrospective review of cases of TCC over 12 years for whom radiographs, CT, and/or MRI study were available. Radiographs were assessed by 2 radiologists for the presence of the C-sign, talar beak, dysmorphic sustentaculum, absent middle facet, and prominence of the posterior subtalar joint. TCC was classified by a third radiologist based on CT/MRI findings into 3 groups: no TCC, EA-PM TCC, and other TCCs. The radiographic findings for the 3 groups were compared.

RESULTS

The study included 50 patients, 28 males and 22 females with a mean age of 21.1 years (range 8-70 years). In 15 patients, both ankles had been imaged, resulting in a total of 65 cases. In 17 ankles, no TCC was identified, while 15 ankles were classified as EA-PM TCC and 33 as having other types of TCC. There were no statistically significant differentiating radiological features between the groups with no TCC and EA-PM TCC apart from prominence of the posterior subtalar joint, while only the C-sign allowed identification of patients with other types of TCC.

CONCLUSIONS

The study suggests that EA-PM TCC cannot be diagnosed based on the classical indirect radiological signs of TCC, but can be identified by prominence of the posterior subtalar joint.

Complete Cubonavicular Coalition Associated with Midfoot Osteoarthritis

Introduction. Cubonavicular coalitions represent a relatively rare condition with less than forty cases described in the literature, the majority of which are fibrocartilaginous. To our knowledge, cubonavicular osseous coalition associated with osteoarthritis of the midfoot has never been described.Case Presentation. We present the case of a 26-year-old man with bilateral Achilles tendinosis, in whom radiological studies show an incidental finding of a complete osseous cubonavicular coalition, as well as a partial osseous cubo-third cuneiform coalition and a fibrous band between the first and second cuneiforms of the right foot, associated with arthritic changes of the tarsometatarsal joint. A nonosseous calcaneocubonavicular coalition was found on the left foot. These multiples coalitions were asymptomatic in this case.Discussion. Cubonavicular coalition, even asymptomatic, can cause midfoot osteoarthritis in young patients. We may therefore suspect that the immobility of the cubonavicular joint causes additional stress on the midfoot.

Prevalence of Accessory Bones and Tarsal Coalitions Based on Radiographic Findings in a Healthy, Asymptomatic Population

Background

Accessory bones and tarsal coalitions are the most common developmental variations of the foot and ankle. However, their clinical implications are not well understood because there is no established prevalence data in the normal population and the reported prevalence varies widely. Therefore, we aimed to investigate the incidence of accessory ossicles and tarsal coalitions in a healthy, asymptomatic Korean population.

Methods

A total of 448 healthy, asymptomatic participants (224 men and 224 women; 896 feet) were enrolled and stratified by age and sex. To investigate the presence of accessory bones and tarsal coalitions in the foot and ankle, we obtained the weight-bearing standing radiographs (anteroposterior and lateral views) from each participant.

Results

Accessory ossicles were found in 49.2% of the healthy, asymptomatic Korean adults. The prevalence of accessory bones in adults was the highest with 34% for the accessory navicular, 5.8% for the os trigonum, 3.9% for the os peroneum, and 1.7% for the os subfibulare. The prevalence of tarsal coalitions in adults was 0.4% and that of symphalangism was 16% for the fourth toe and 80.6% for the fifth toe. The frequency of the accessory navicular and fifth toe symphalangism was significantly higher in women. Most of the accessory navicular and fourth and fifth toe symphalangism were bilateral, whereas the os subfibulare was mostly unilateral.

Conclusions

The prevalence of accessory bones and tarsal coalitions in the healthy, asymptomatic Korean population showed some variation according to age and sex.

Correlation between the accessory anterolateral talar facet, bone marrow edema, and tarsal coalitions

OBJECTIVE

The purposes of this study was to determine the prevalence of the accessory anterolateral talar facet (AALTF); to evaluate the relationship between AALTF, focal abutting bone marrow edema (FABME), and sinus tarsi edema; and to study the prevalence of tarsal coalitions in patients with the AALTF utilizing ankle MR images.

MATERIALS AND METHODS

5-T ankle MR images were reviewed for the presence of AALTF, FABME, sinus tarsi edema, tarsal coalition, and location and type of coalition (cartilaginous, fibrous, and osseous). Multivariate analysis was performed to examine the correlation between AALTF and the other variables.

RESULTS

Three hundred ninety-one consecutive patients were included (age range 5-86 years; mean age 45 years). An AALTF was present in 3.6% (14/391) of patients. The AALTF prevalence was 2% in women and 6.6% in men. There was a significantly association between AALTF and FABME (9/14, p < 0.05), sinus tarsi edema (13/14, p < 0.05), and tarsal coalition (4/14, p < 0.05).

CONCLUSION

AALTF is relatively often detected on MRI of the ankle and significantly associated with BME, sinus tarsi edema, and subtalar coalition. Patients with a tarsal coalition should be evaluated for the concurrent presence of an AALTF.

Operative versus nonoperative treatment in children with painful rigid flatfoot and talocalcaneal coalition

Background

The management of painful rigid flatfoot (RFF) with talocalcaneal coalition (TCC) is controversial. We aimed to compare operative and nonoperative treatment in children with RFF and TCC.

Methods

We retrospectively reviewed medical records and radiographs of children with RFF and TTC treated between 2005 and 2015. The nonoperative treatment consisted of manipulation under anesthesia, cast immobilization and shoe insert after cast removal. The operative treatment consisted of combined TCC resection, graft interposition and subtalar arthroereisis.

Results

Thirty-four children (47 ft) in the nonoperative group and twenty-one children (34 ft) in the operative group were included. No differences were found between groups, concerning baseline characteristics. The mean age at treatment was 11.8 years (9–17): 11.6 (9–17) for the nonoperative group, 12.2 (10–15) for the operative group. The mean follow-up averaged 6.6 (3–12) years and was significantly longer in the nonoperative group (7.8 versus 4.7 years; p < 0.0005), since the operative procedure was increasingly practiced in the latest years.

There were no complications in either groups, but 6 patients (7 ft) in the nonoperative group were unsatisfied and required surgery. At the latest follow-up, the AOFAS-AHS improved in both groups, although the operative group showed significantly better improvement. The operative group reported also significantly better FADI score, after adjustment for follow-up and baseline variables.

Conclusion

The operative treatment showed better results compared to the nonoperative treatment. Symptomatic RFF with TCC in children can be effectively treated in one step with resection, graft interposition and subtalar arthroereisis. Further prospective randomized studies are needed to confirm our findings and to identify the best operative strategy in this condition.

Diagnosing tarsal coalition in medieval Exeter

OBJECTIVE

The objective of this study is to estimate the frequency and types of tarsal coalition represented in medieval remains from Exeter, England.

MATERIALS

183 individuals from the Cathedral Green site in Exeter, England.

METHODS

Gross macroscopic analysis combined with radiographic examination and comparison with clinical and archaeological literature.

RESULTS

Eight coalitions of various forms were ultimately identified; these include five calcaneonavicular, one talocalcaneal, one calcaneocuboid, and one lateral cuneiform-third metatarsal coalition.

CONCLUSIONS

These frequencies are quite high for clinical imaging estimations, but consistent with other reported archaeological frequencies.

SIGNIFICANCE

This study contributes to known frequencies of tarsal coalition in the past. It also provides descriptive diagnostic criteria for identifying tarsal coalition in archaeological populations.

LIMITATIONS

Poor preservation of some of the individuals in this sample means that the true frequencies of tarsal coalition may be underrepresented.

SUGGESTIONS FOR FURTHER RESEARCH

This study should be expanded to include more archaeological sites, especially medieval British sites, to determine overall prevalence rates. Additionally, the diagnostic criteria should be compared with other examples of known tarsal coalition to further our understanding of this rare pathology.

Realignment Calcaneal Osteotomy for Bilateral Complete Talocalcaneal Synostosis: A Case Report

Talocalcaneal synostosis is a congenital failure of the segmentation between tarsal bones. It may be very difficult to differentiate from talocalcaneal coalition, known as the most common tarsal coalition, especially in cases with a large bone bridge. Complete talocalcaneal synostosis is very rare, and there are few references in the literature about the clinical outcomes and operative methods for symptomatic synostosis. We report a case of a 15-year-old female with bilateral complete talocalcaneal synostosis and heel varus deformity who has experienced good clinical results after lateral sliding calcaneal osteotomy for hindfoot realignment.

Coalitions of the Tarsal Bones

Tarsal coalitions are the result of impaired mesenchymal separation of the tarsal bones. The most common types include calcaneonavicular or talocalcaneal coalitions. Subtalar stiffness results in pathologic kinematics with increased risk of ankle sprains, planovalgus foot deformity, and progressive joint degeneration. Resection of the coalition yields good results. Tissue interposition may reduce the risk of reossification, and concomitant deformity should be addressed in the same surgical setting.

Postaxial limb hypoplasia (PALH): the classification, clinical features, and related developmental biology

Postaxial limb hypoplasia (PALH) is a group of nonhereditary diseases with congenital lower limb deficiency affecting the fibular ray, including fibular hemimelia, proximal femoral focal deficiency, and tarsal coalition. The etiology and the developmental biology of the anomaly are still not fully understood. Here, we review the previous classification systems, present the clinical features, and discuss the developmental biology of PALH.

Isolated Cuboid-Lateral Cuneiform Coalition A Rare Cause of Foot Pain

Tarsal coalitions represent a cohort of conditions characterized by bony, cartilaginous, or fibrous union of two or more tarsal bones. These disorders are often poorly understood by medical professionals, often leading to delays in diagnosis and treatment. They may be asymptomatic or cause hindfoot pain, stiffness, decreased range of motion, and foot deformities. Coalitions can be investigated by an ascending sequence of imaging including radiography, computed tomography, and magnetic resonance imaging. They may be managed conservatively with orthoses, activity modification, physiotherapy, anti-inflammatory medications, or definitive surgical intervention. To our knowledge, cuboid-lateral cuneiform coalition has not been reported in the orthopedic literature. We describe a 40-year-old woman with this condition who reported a 1-year history of left foot pain and stiffness. She was definitively diagnosed with magnetic resonance imaging and was managed conservatively with an aircast boot and hydrocortisone injection.

A Rare Combination of Ipsilateral Partial Talocalcaneal and Talonavicular Coalition

Tarsal coalitions refer to fibrous, cartilaginous or osseous fusion between two tarsal bones. Commonly seen are talocalcaneal coalitions and calcaneonavicular coalitions. Talonavicular, calcaneocuboid and cubonavicular coalition are very uncommonly seen. Talocalcaneal and calcaneonavicular coalitions are generally symptomatic whereas talonavicular coalitions are asymptomatic. Special view radiography, CT and MRI will be helpful in diagnosing coalitions depending on nature of coalitions. In this case report, we present 24-year-old male patient with rare combination of talocalcaneal and talonavicular coalition on ipsilateral side. Patient also showed talar beak sign and arthritic changes at subtalar joint. Considering first time presentation to hospital and milder symptoms, we treated patient conservatively with short leg cast and foot orthoses. With course of treatment, symptoms were relieved significantly.

Tarsal Coalitions--Calcaneonavicular Coalitions

Calcaneonavicular coalitions are an important cause of adolescent foot pain and deformity. The congenital condition is characterized by an aberrant osseous, cartilaginous, or fibrinous union of the calcaneal and navicular bones. Calcaneonavicular coalitions are the most common form of tarsal coalitions identified within epidemiologic studies. A thorough understanding of this clinically significant entity is important for restoring joint motion and preventing long-term disability.

Subtalar coalitions in the adult

Tarsal coalitions, while relatively uncommon, are typically identified in adult patients during an evaluation for ankle instability, sinus tarsus pain, and/or pes planovalgus. The true incidence of tarsal coalition is unknown with estimates ranging from 1% to 12% of the overall population. The most common area of involvement of the subtalar joint is the middle facet, and heightened awareness should be present in adult patients with limited motion of the subtalar joint. Standard radiographic imaging, to include a Harris heel view, is recommended initially, although computerized tomography scan and MRI are often necessary to confirm the diagnosis.

Tarsal Coalitions: Preliminary Results After Operative Excision and Silicone Sheet Interposition in Children

Symptomatic tarsal coalitions that begin in early adolescence are usually treated by resection and interposition (fat, muscle, or bone wax) to prevent recurrence. The purpose of the present retrospective study was to describe our operative technique and report our clinical and radiologic outcomes with sterile silicone sheet interposition after resection of painful tarsal coalitions in 4 children (4 feet). The present series included 1 case of talocalcaneal synchondrosis and 3 of synostosis (2 talocalcaneal and 1 cuboid-navicular). Two validated functional scales were used to assess the patients' overall outcome and satisfaction with the procedure: the American Orthopaedic Foot and Ankle Society ankle-hindfoot score and the Foot Function Index. Conventional radiography, computed tomography with 3-dimensional reconstruction, and magnetic resonance imaging were performed at the final follow-up visit. The mean follow-up period was 40 (range 12 to 80) months. The mean age at surgery was 10.5 (range 8 to 13) years. All patients had achieved their desired activity level at 6 months postoperatively. The mean American Orthopaedic Foot and Ankle Society ankle-hindfoot score was 93.5 (range 74 to 100), and the mean Foot Function Index was 3.25% (range 0% to 13%). No recurrence of the coalition on imaging at the final follow-up visit was observed in this patient series. Sterile silicone sheet interposition can be used to prevent recurrence of tarsal coalition in symptomatic tarsal coalitions after failure of conservative management.

Tarsal Coalitions: Radiographic, CT, and MR Imaging Findings

BACKGROUND

Tarsal coalitions affect up to 13% of the population and can be a cause of chronic ankle and hindfoot pain. They can be subdivided as osseous, cartilaginous, or fibrous types, each with unique radiographic, CT, and MR imaging findings. In particular, MR imaging offers the unique ability to determine the exact type of tarsal coalition that is present as well as whether any associated soft tissue abnormalities are present.

QUESTIONS/PURPOSES

The purposes of this paper were to (1) review the anatomy of the hindfoot; (2) review the radiographic, CT, and MR imaging findings of tarsal coalitions; and (3) review the imaging appearance of the specific types of tarsal coalitions.

METHODS

Online searches were performed using Google Scholar with the search criteria of "tarsal coalition," "hindfoot anatomy," and "subtalar coalition," and limiting the searches to papers published in the last 10 years in major radiology journals.

RESULTS

The anatomy of the hindfoot is complex but essential to understand. There are various radiographic, CT, and MR imaging findings that can be consistently noted in cases of tarsal coalition. The specific types of tarsal coalition demonstrate characteristic imaging findings.

CONCLUSIONS

Knowledge of the normal anatomy of the foot, in particular the hindfoot, combined with the knowledge of the imaging characteristics of different histologic subtypes of coalitions (osseous, cartilaginous, and fibrous) is essential for interpreting radiographic, CT, and MR images of the ankle and foot.

Imaging of tarsal navicular disorders: a pictorial review

The tarsal navicular is a bone within the midfoot that plays a critical role in maintaining the arch of the foot. This bone is clinically relevant because it may be affected by a wide array of pathologies. Our approach includes a detailed description of the imaging characteristics and disorders affecting the tarsal navicular. Organization includes (a) normal imaging, (b) accessory ossicles, (c) coalition, (d) fractures, (e) Kohler's disease, (f) osteonecrosis, (g) osteochondral lesions, (h) arthropathies, and (i) tumors. The purpose of this article is to discuss normal variants and pathological processes that can affect the tarsal navicular, with emphasis on the often-overlooked imaging findings.

An incidental talonavicular coalition in a diabetic patient: a podiatric perspective

A tarsal coalition is a pathological union of two or more tarsal bones. The authors present an incidental finding of a unilateral talonavicular (TN) coalition that was overlooked in a 57-year-old diabetic female with signs and symptoms of peripheral neuropathy. This case highlights the clinical implications and important teaching points in recognising a TN coalition. This is particularly relevant for new, upcoming clinicians who may have never been exposed to this diagnostic rarity during clinical training.

Botulinum Toxin Type A Injection Combined With Cast Immobilization for Treating Recurrent Peroneal Spastic Flatfoot Without Bone Coalitions: A Case Report and Review of the Literature

Peroneal spastic flatfoot is an uncommon condition. It often presents as a rigid and usually painful valgus deformity in the hindfoot with peroneal muscles spasms. Although tarsal coalition is an important cause, a few patients have not undergone bone coalitions. We describe a 27-year-old female who experienced recurrent peroneal spastic flatfoot after an injury. She was treated successfully with a combination of botulinum toxin type A and immobilization of the foot in a neutral position with a cast. After 3 years, the condition had not recurred, and she was pain free and walked normally, with no increase in muscle tone. This unique treatment could be of potential use to treat many patients with such conditions.

Middle subtalar osseous coalition with associated fusion of the sinus tarsi: a previously undescribed type of tarsal coalition

Tarsal coalitions affect up to 13% of the population and may cause chronic ankle and hindfoot pain. Coalitions can be subdivided as osseous, cartilaginous, or fibrous types. The most common type of tarsal coalition involvesthe talocalcaneal joint, where it usually affects the middle subtalar joint. In this article, we describe a previously unpublished form of talocalcaneal coalition with osseous coalition at the level of the middle subtalar joint with associated fusion of the sinus tarsi.

New perspectives on evolutionary medicine: the relevance of microevolution for human health and disease

Evolutionary medicine (EM) is a growing field focusing on the evolutionary basis of human diseases and their changes through time. To date, the majority of EM studies have used pure theories of hominin macroevolution to explain the present-day state of human health. Here, we propose a different approach by addressing more empirical and health-oriented research concerning past, current and future microevolutionary changes of human structure, functions and pathologies. Studying generation-to-generation changes of human morphology that occurred in historical times, and still occur in present-day populations under the forces of evolution, helps to explain medical conditions and warns clinicians that their current practices may influence future humans. Also, analyzing historic tissue specimens such as mummies is crucial in order to address the molecular evolution of pathogens, of the human genome, and their coadaptations.

An unusual cause of ankle pain: fracture of a talocalcaneal coalition as a differential diagnosis in an acute ankle sprain: a case report and literature review

BACKGROUND

The acute ankle sprain is one of the most common injuries seen in trauma departments. Ankle sprains have an incidence of about one injury per 10 000 people a day. In contrast tarsal coalition is a rare condition occurring in not more than one percent of the population.

CASE PRESENTATION

We present the case of a 23 year old male patient with pain and local swelling after an acute ankle sprain. Initial clinical and radiological examination showed no pathologies. Due to prolonged pain, swelling and the inability of the patient to weight bear one week after trauma further diagnostics was performed. Imaging studies (MRI and CT) revealed a fracture of a talocalcaneal coalition. To the knowledge of the authors no fracture of a coalition was reported so far.

CONCLUSION

This report highlights the presentation of symptomatic coalitions following trauma and furthermore, it points out the difficulties in the diagnosis and treatment of a rare entity after a common injury. A diagnostic algorithm has been developed to ensure not to miss a severe injury.

Talocalcaneal coalition in Muenke syndrome: report of a patient, review of the literature in FGFR-related craniosynostoses, and consideration of mechanism

Muenke syndrome is an autosomal dominant craniosynostosis syndrome resulting from a defining point mutation in the Fibroblast Growth Factor Receptor3 (FGFR3) gene. Muenke syndrome is characterized by coronal craniosynostosis (bilateral more often than unilateral), hearing loss, developmental delay, and carpal and/or tarsal bone coalition. Tarsal coalition is a distinct feature of Muenke syndrome and has been reported since the initial description of the disorder in the 1990s. Although talocalcaneal coalition is the most common tarsal coalition in the general population, it has never previously been reported in a patient with Muenke syndrome. We present a 7-year-old female patient with Muenke syndrome and symptomatic talocalcaneal coalition. She presented at the age of 7 with limping, tenderness and pain in her right foot following a fall and strain of her right foot. She was treated with ibuprofen, shoe inserts, a CAM walker boot, and stretching exercises without much improvement in symptoms. A computed tomography (CT) scan revealed bilateral talocalcaneal coalitions involving the middle facet. She underwent resection of the talocalcaneal coalitions, remaining pain-free post-operatively with an improvement in her range of motion, gait, and mobility. This report expands the phenotype of tarsal coalition in Muenke syndrome to include talocalcaneal coalition. A literature review revealed a high incidence of tarsal coalition in all FGFR related craniosynostosis syndromes when compared to the general population, a difference that is statistically significant. The most common articulation involved in all syndromic craniosynostoses associated with FGFR mutations is the calcaneocuboid articulation.

Stress fracture of the anterior process of the calcaneus associated with a calcaneonavicular coalition: a case report

Level of Evidence: V, Expert Opinion

Hamate-pisiform coalition: morphology, clinical significance, and a simplified classification scheme for carpal coalition

Hamate-pisiform coalition is characterized by the abnormal union of the pisiform bone and hamulus of the hamate. Because most reported cases are isolated, and literature on the subject is sparse, relatively little is known about this condition and its clinical significance. The purpose of this report is to discuss the occurrence, morphology, and frequency of hamate-pisiform coalition identified in a skeletal sample of native South Africans, and to conduct a metaanalysis of all known cases in order to clarify the sex distribution, laterality, form, and clinical significance of this condition. Five new cases (three male, two female) of hamate-pisiform coalition were identified in 527 native South Africans. Results indicate that hamate-pisiform coalition is infrequent (0.76%) but may be more likely encountered in individuals of African ancestry. Morphologically, non-osseous examples ranged in appearance from minor expressions involving pitting of an expanded hamulus base, to a variably pitted articulation between an elongated pisiform and hamulus. Osseous union between the two bones tends to extend beyond the hamulus base to adjacent areas of the hamate. Cases involving osseous union appear predisposed to fracture while ulnar neuropathy is significantly more frequent in individuals exhibiting non-osseous coalition. As both non-osseous and osseous cases can have clinical significance, awareness of the variable manifestations of this condition is necessary for hand specialists. A simplified classification system is suggested to more consistently characterize carpal coalitions.

Unilateral subtalar coalition: contralateral sustentaculum tali morphology

PURPOSE

To measure and compare the dimensions of the sustentaculum tali (ST) in pediatric patients with unilateral subtalar coalition to determine if the contralateral side has altered morphology.

MATERIALS AND METHODS

The institutional review board approved this study, which was HIPAA compliant. Informed consent was waived. Radiology records were reviewed to identify 35 patients with unilateral subtalar coalition undergoing computed tomography (CT) (21 male, 14 female; mean age, 14.54 years) and 33 control patients with triplane fracture (21 male, 12 female; mean age, 13.48 years). CT images were reviewed, and reformatted images through the subtalar joint (on the side opposite the coalition) were created. Anteroposterior measurements of the middle facet (MF) and the ST were recorded by two observers with electronic calipers. The MF/ST ratio and the ST length extending posterior to the MF were calculated. Measurements between groups were compared by using Wald tests based on linear regressions. Inter- and intraobserver variabilities were determined by means of a component of variance model.

RESULTS

The lengths of the MF and ST for the study and control groups were 12.86 and 16.82 mm (P < .001) and 23.83 and 22.06 mm (P = .053), respectively. Intra- and interobserver correlations for both measurements were 0.94 and 0.92 and 0.86 and 0.77, respectively. MF/ST ratio was 0.54 versus 0.76 (P < .001), and ST length extending posterior to the MF was 10.97 versus 5.24 mm (P < .001).

CONCLUSION

The MF is smaller and the ST extends further beyond the MF in patients with a contralateral subtalar coalition than in control patients. The morphology of the ST may provide insight into the origins and development of coalitions.

Tarsal coalitions

A tarsal coalition is an aberrant union between 2 or more tarsal bones and can be classified as osseous (synostosis) or nonosseous (cartilaginous [synchondrosis] or fibrous [syndesmosis]). This union may be complete or partial and the joints in the hindfoot and midfoot are most commonly affected. The resulting abnormal articulation presents as a noncorrectable flat foot, usually during adolescence, leading to accelerated degeneration within adjacent joints. An understanding of the condition and presenting symptoms enable the clinician to correctly diagnose and initiate appropriate treatment. This review discusses the evidence-based literature on the cause, diagnosis, and current management of tarsal coalition.

Endoscopic resection of a calcaneonavicular coalition

Calcaneonavicular coalition is a congenital anomaly characterized by a connection between the calcaneus and the navicular. Surgery is required in case of chronic pain and after failure of conservative treatment. The authors present here the surgical technique and results of a 2-portals endoscopic resection of a calcaneonavicular synostosis. Both visualization and working portals must be identified with accuracy around the tarsal coalition with fluoroscopic control and according to the localization of the superficial peroneus nerve, to avoid neurologic damages during the resection. The endoscopic procedure provides a better visualization of the whole resection area and allows to achieve a complete resection and avoid plantar residual bone bar. The other important advantage of the endoscopic technique is the possibility to assess and treat in the same procedure-associated pathologies such as degenerative changes in the lateral side of the talar head with debridement and resection.

A review of tarsal coalition and pes planovalgus: clinical examination, diagnostic imaging, and surgical planning

Pediatric pes planovalgus deformity may be classified as flexible or rigid. The rigid pes planovalgus is often a result of a tarsal coalition, which is typically characterized as a painful unilateral or bilateral deformity, frequently associated with peroneal spasm. However, many tarsal coalitions are asymptomatic and demonstrate no peroneal spasm or pes planovalgus deformity. Likewise, the severe pes planovalgus foot type can demonstrate some of the same clinical and radiographic features of a tarsal coalition, especially in the obese adolescent patient. Also, peroneal spasm may occur in the noncoalesced foot, making diagnosis and etiology more difficult to elucidate. The authors believe that many patients with a pes planovalgus deformity lie in this "gray zone": somewhere between the frank osseous coalition and the flexible pes planovalgus. The "step-forward Hubscher maneuver" is introduced as an effective means of evaluating the flexibility of a pes planovalgus foot by negating the effects of a gastrocnemius or gastrocnemius-soleus equinus. This article focuses on the clinical examination and findings of specific imaging studies to assist in an accurate diagnosis of these complicated patients. This will also help to reveal the various surgical options that are appropriate for the individual patient. Emphasis is placed on computerized tomography (CT) imaging and offers enhanced methods for ordering this test to specifically evaluate middle facet coalitions of the subtalar joint. The authors also introduce "lateral tarsal wedging," an image finding associated with severe deformities, the implications of this finding, as well as its impact on surgical planning.

Preliminary report: resection and interposition of a deepithelialized skin flap graft in tarsal coalition in children

Six tarsal coalitions in children were managed surgically using a deepithelialized skin flap for interposition after resection of the bony, fibrous or cartilaginous coalition. The advantage of this technique is that due to positioning the skin flap, joint motion can be preserved. The clinical results using the Ankle Hindfoot Scale of the American Orthopedic Foot and Ankle Society were excellent in two and good in four cases. The radiographs at follow-up showed no recurrences of the resected coalitions. This study shows that the use of deepithelialized skin flap interposition is effective in providing pain relief for the patients in symptomatic coalitions.

Tarsal coalitions: etiology, diagnosis, imaging, and stigmata

Tarsal coalition is a congenital condition characterized by the aberrant union (osseous or fibrous) between 2 bones in the rearfoot, most commonly talocalcaneal coalition, calcaneonavicular coalition, and talonavicular coalition, that results in a restriction or absence of motion. The association between tarsal coalition and a variety of coexisting conditions has been reported over the past 60 years and continues to be better understood. These coexisting conditions (the stigmata of tarsal coalition) have been believed to be secondary effects of the coalition and/or fixed rearfoot position. Advanced imaging has provided significant insights into the concomitant pathology and understanding of tarsal coalition that the symptoms associated with tarsal coalition can be present for a myriad of different reasons. One should consider all the stigmata of tarsal coalition when considering a surgical reconstruction.

Experimental model in cadavera of arthroscopic resection of calcaneonavicular coalition and its first in-vivo application: preliminary communication

Open surgical resection of calcaneonavicular coalition is indicated after the failure of conservative treatment. Our objectives are to develop the arthroscopic surgical technique and to check the feasibility of the arthroscopic resection of the calcaneonavicular coalition. We designed and performed endoscopic resection of the calcaneonavicular ligament and part of the anterior process of calcaneus as a simulation of the coalition resection on four cadaver specimens. After this procedure, we successfully performed the first resection in a 12-year-old girl, without any soft tissue interposition. American Orthopaedic Foot and Ankle Society Hindfoot Scale was 55 before surgery, 98 after 10 weeks, and 100 after 2 years without recurrence.

Anatomy of the subtalar joint and imaging of talo-calcaneal coalition

Talo-calcaneal coalitions may be intra-articular or extra-articular in position and may be classified as fibrous, cartilaginous or osseous in morphology. Fibrous coalitions, particularly extra-articular talo-calcaneal coalitions, may have cross-sectional imaging findings that resemble normal anatomic variants, particularly the medial talo-calcaneal ligament and to a lesser extent the presence of an accessory articular facet between the posterior margin of the sustentaculum and postero-medial process of the talus. Typically, in the adult fibrous coalition, there will be some osseous deformity at the entheses, allowing differentiation from a medial talo-calcaneal ligament. The anatomy of the subtalar joint and its ligamentous supports, normal anatomic variations and their corresponding imaging appearance are reviewed in the first part of this article. In the second part, the various forms of talo-calcaneal coalition and their imaging appearance are reviewed.

Non-osseous extra-articular anterolateral talocalcaneal coalition: a case report

We report a case of an extra-articular talocalcaneal coalition located anterolateral to the sinus tarsi. As non-osseous coalitions can be difficult to diagnose, physicians should keep this variant in mind in cases of a symptomatic hind foot with apparently equivocal radiological findings.

Imaging of the talus

There are numerous options for imaging talar pathology. Of these, radiography, CT, scintigraphy, and MRI are used most commonly. Advantages and limitations of these techniques should be considered when formulating an imaging algorithm for evaluation of the patient's clinical problem.

Imaging of the navicular

This article presented a rational approach to imaging of navicular pathology. The indications, techniques, and limitations of conventional radiographic imaging were discussed. In addition, the role of advanced imaging techniques, including MRI, CT, and NMI, in the diagnosis of navicular pathology was presented. By appropriately combining plain radiographic imaging with advanced imaging modalities, an accurate diagnosis is typically obtained.