Relationship between the ossification center and cartilaginous anlage in the normal hindfoot in children: study with MR imaging

Radiographic Impact on the Clinical Decision Making of Achilles Tenotomy in Clubfoot: In Search of an Objective Cut-Off Value

BACKGROUND

We tried to determine whether the indication of Achilles tenotomy (AT) in clubfoot patients based on clinical evaluation could be confirmed radiographically, and to find an objective radiographic cut-off value for its indication.

METHODS

Eighty-six clubfeet from 60 patients, (26 bilateral and 34 unilateral) were included. A standard Ponseti treatment regimen was applied. Group 1 comprised patients who underwent AT immediately after serial plaster casting (26 feet). Group 2 comprised patients who underwent AT during the follow-up period (48 feet). Group 3 comprised patients who were assumed to have a corrected foot and did not undergo AT (12 feet). Group 4 comprised the healthy sides of the unilateral cases (34 feet).

RESULTS

Both Group 1 and Group 2 showed significant improvement after tenotomy (p = 0.002). In order to differentiate between the normal and AT groups according to the pre-tenotomy angle, we obtained an optimal cut-off value of >85° according to the Youden index, a sensitivity of 96%, a specificity of 91.2%, a positive predictive value of 95.9%, a negative predictive value of 91.2%, and an accuracy rate of 94.4% (AUC: 0.983; p < 0.001).

CONCLUSIONS

Feet with a lateral tibio-calcaneal angle > 85° can be considered pathologic and accepted as candidates for AT.

The developing juvenile talus: Radiographic identification of distinct ontogenetic phases and structural trajectories

Trabecular bone architecture in the developing skeleton is a widely researched area of bone biomechanics; however, despite its significance in weight-bearing locomotion, the developing talus has received limited examination. This study investigates the talus with the purpose of identifying ontogenetic phases and developmental patterns that contribute to the growing understanding of the developing juvenile skeleton. Colour gradient mapping and radiographic absorptiometry were utilised to investigate 62 human tali from 38 individuals, ranging in age-at-death from 28 weeks intrauterine to 20 years of age. The perinatal talus exhibited a rudimentary pattern comparable to the structural organisation observed within the late adolescent talus. This early internal organisation is hypothesised to be related to the vascular pattern of the talus. After 2 years of age, the talus demonstrated refinement, where radiographic trajectories progressively developed into patterns consistent with adult trabecular organisation, which are linked to the forces associated with the bipedal gait, suggesting a strong influence of biomechanical forces on the development of the talus.

Magnetic resonance imaging of severe idiopathic club foot treated with one-week accelerated Ponseti (OWAP) technique

PURPOSE

This study aims to evaluate changes in tarsal bones relationship after the use of one week accelerated Ponseti method in the treatment of severe idiopathic clubfoot using MRI. We hypothesize that one-week accelerated Ponseti is at least as effective as standard techniques in achieving the desirable MRI parameters.

METHODS

This is a prospective study of 8 children with severe idiopathic clubfeet (Pirani 6) (4 unilateral and 4 bilateral) treated before the age of three months with one-week accelerated Ponseti technique, as described in a former study with minimum 2-year follow-up. The 8 corrected feet were compared with the 4 unilateral normal feet at clinical and radiological levels using a Pirani scoring system and an MRI, respectively.

RESULTS

Clinical results showed that Pirani score was 1.1 in the last follow up in comparison to Pirani 6 pretreatment (p < 0.05). MRI results indicated that the malleocalcaneal angle, axial malleocalcaneal index, coronal tibiocalcaneal angle, sagittal talocalcaneal angle, and talar head neck calcaneal rotation showed statistical difference between the two groups (p < 0.05). Sagittal malleocalcaneal index, sagittal tibiocalcaneal angle, talar head neck rotation related to talar body, and posterior calcaneal rotation showed no statistical difference between normal feet and clubfeet after correction (p value >0.05).

CONCLUSION

One-week accelerated Ponseti technique showed to be as effective and safe as other treatment methods through clinical and MRI follow up data. MRI role was to confirm the efficiency of this innovative accelerated technique, but not used as a routine follow up.

Dynamic Characteristics of Foot Development: A Narrative Synthesis of Plantar Pressure Data During Infancy and Childhood

PURPOSE

Quantifying plantar pressure throughout childhood enables clinicians to enhance knowledge of typical changes in foot function. This narrative review aims to describe existing research reporting plantar pressure analysis in infants and children developing typically, to advance understanding of foot development.

METHODS

A narrative approach was used; 263 articles were identified and 13 met inclusion criteria.

RESULTS

Plantar pressures during walking rapidly change in infancy and childhood. With development, pressures increasingly resemble those in adults with the development of initial heel contact, shift in pressure distribution from medial to lateral foot side, decreasing midfoot pressure magnitude. The literature has a variety of study designs, data collection protocols, and analysis.

CONCLUSION

This review describes plantar pressure changes occurring as walking develops, emphasizing the typical trajectory of foot function development in infancy and childhood. The present finding describes the complex biomechanical development of foot function in typically developing infancy and childhood.

Pitfalls in MRI of the Developing Pediatric Ankle

Normal skeletal development in the pediatric ankle is dynamic and often produces variable imaging appearances that are subject to misinterpretation. Radiologists must understand the underlying developmental phenomena, such as endochondral and membranous ossification and physeal fusion, and be familiar with their common and uncommon imaging manifestations unique to the pediatric ankle. This is especially true as the use of MRI in the evaluation of musculoskeletal trauma expands among younger populations. The authors focus on MRI evaluation of the skeletally maturing pediatric ankle and present pearls for accurately distinguishing normal findings and imaging pitfalls from true pathologic findings. The normal but often variable imaging findings of preossification, secondary ossification, and multiple ossification centers, as well as the range of bone marrow signal intensities that can be visualized within ossification centers, are described, along with tips to help differentiate these from true pathologic findings such as contusion, fracture, or tumor. The authors also review dynamic periosteal and physeal contributions to bone growth to highlight helpful distinguishing features and avoid misdiagnosis of common subperiosteal and periphyseal abnormalities. For example, the normal trilaminar appearance of the immature cortex and periosteum should not be mistaken for periosteal reaction, traumatic stripping, or subperiosteal hematoma. In addition, the physis can have several confusing but normal appearances, including normal physeal undulations (eg, Kump bump) or focal periphyseal edema, which should not be mistaken for pathologic findings such as physeal fracture, infection, or bar. ^©RSNA, 2020.

Bohler Angle and the Crucial Angle of Gissane in Paediatric Population

Bohler angle and the crucial angle of Gissane are used on the evaluation of calcaneus fractures. However, few authors have described the variation of the angles when the calcaneus is growing. In this study, Bohler angle and the crucial angle of Gissane in paediatric population were measured using lateral foot radiographs of 429 patients, from 0 to 16 years of age. The control group was composed of 70 adult patients. The sample had a mean Bohler angle of 35.4° ± 5.9° and a mean crucial angle of Gissane of 110.5° ± 7.4°. The greater mean difference was identified for Bohler angle (8°) in the age group of 5 to 8 years (39.6° ± 5.7°) and for the crucial angle of Gissane (5°-6°) in the age group of 0 to 4 years (115.8° ± 7.3) (P < .05). The influence of the ossification centres on the geometry of the calcaneus across age groups makes Bohler angle and the crucial angle of Gissane higher in young children. The increase in Bohler angle points out the relative development of the posterior facet in young children and the importance of the reconstruction of the posterior facet height in the intra-articular calcaneus fractures.

Level of Evidence: Diagnostic study; Level III.

Alteration in hypoplasia of the hindfoot structures during early growth in clubfeet treated using the Ponseti method

PURPOSE

Previous reports have demonstrated diminished size of the hindfoot bones in patients with idiopathic clubfoot deformity. However, no study has quantified the percentage of hypoplasia as a function of early growth, during the brace phase of Ponseti treatment.

METHODS

We measured the dimensions of ossified structures on radiographs in patients with unilateral Ponseti-treated clubfeet to determine changes in the percentage of hypoplasia between two and four years of age.

RESULTS

The degree of hypoplasia varied among the osseous structures in Ponseti-treated clubfeet at age two years, with greater hypoplasia being observed in the talus (7.3%), followed by calcaneus (4.9%) and the cuboid (4.8%). Overall, the degree of hypoplasia diminished by four years, such that the degree of hypoplasia was greatest in the talus (4.2%) and the calcaneus (4.2%) followed by the cuboid (0.6%). At four years of age, the greatest degree of hypoplasia persisted in the talus and calcaneus.

CONCLUSIONS

Changes occurred in the size of the ossification of hindfoot bones between two and four years of age, and the observed changes in the percentage of hypoplasia varied among the different structures. At four years of age, the greatest percentage of hypoplasia was observed in the talus and calcaneus at values similar to those previously reported in skeletally mature patients. The results suggested that the relative difference in size of the feet may be expected to remain constant in a child with a unilateral clubfoot after this age.

Eccentric Capitellar Ossification Limits the Utility of the Radiocapitellar Line in Young Children

BACKGROUND

The radiocapitellar line (RCL) has long been used for the radiographic evaluation of elbow alignment. In children, the capitellar ossific nucleus serves as a proxy for the entire capitellum, but this substitution has not been verified. Using magnetic resonance imaging (MRI), we sought to understand how maturation of the ossific nucleus of the capitellum affects the utility of RCL throughout skeletal maturation of the elbow.

METHODS

The RCL was drawn on coronal and sagittal MRIs in 82 children (43 boys, 39 girls; age range, 1 to 13 y) with at least 3 patients in each 1-year interval age group. The perpendicular distance of the RCL from the center of both the cartilaginous capitellum and the capitellar ossific nucleus was measured relative to its total width, and a percent offset for each measurement was calculated. Logarithmic regression analysis was performed to analyze the effect of age and sex on percent offset.

RESULTS

The RCL reliably intersected with the central third of the cartilaginous capitellum at all ages in both planes. Although the RCL intersected with the ossified capitellum in all but 3 measurements, it intersected with the central third of the ossified capitellum less often in younger children in both sagittal (B=0.47, P<0.001) and coronal (B=0.31, P=0.002) planes. Percent offset decreased significantly with age in a logarithmic manner in both sagittal (r=0.57, P<0.001) and coronal (r=-0.47, P<0.001) planes. 95% confidence intervals predict that the sagittal plane RCL will accurately intersect the central third of the ossified capitellum by age 10 years in girls and age 11 years in boys but not in the coronal plane.

CONCLUSIONS

Eccentric ossification of the capitellum explains RCL variability in young children. The RCL does not reliably intersect the central third of the ossified capitellum until ages 10 years in girls and 11 years in boys in the sagittal plane. The RCL should be used within its limitations in skeletally immature children and should be combined with advanced imaging if necessary.

MR imaging of capitellar ossification: a study in children of different ages

BACKGROUND

The capitellar ossification center is used routinely to evaluate elbow alignment on radiography. However, whether capitellar ossification is central and concentric to support this practice is unknown.

OBJECTIVE

To define the pattern of capitellar ossification at different ages of childhood.

MATERIALS AND METHODS

This HIPAA-compliant study was IRB approved. MR imaging examinations from 81 children (ages 1-13 years, at least 3 boys and 3 girls in each age group) were included. We determined the center points of the ossified capitellum and the cartilaginous capitellum on the sagittal and coronal sequences that best showed differentiation between cartilage and bone. Percentage offset of the center of the ossified capitellum from the center of the cartilaginous capitellum was calculated in anterior-posterior, proximal-distal and medial-lateral dimensions, and compared across age groups and between genders. Linear regressions were used to ascertain the effect of age on percentage offset for all patients and for each gender.

RESULTS

Capitellar ossification begins eccentrically with sagittal anterior proximal offset and coronal medial offset. With age, ossification proceeds posteriorly, distally and laterally. Percentage offset gradually diminishes with age. The ossified capitellum centralizes in the sagittal plane by 12-13 years. In the coronal plane, the capitellum ossifies medially beyond the proximal radioulnar joint and remains eccentric at 12-13 years. Centralization in boys lags in the anterior-posterior dimension.

CONCLUSION

Capitellar ossification is an eccentric process, with lag in anterior-posterior centralization in boys. Medial offset persists at 12-13 years. Recognition of this eccentric ossification may allow for more accurate assessment of elbow alignment on radiographs, especially in younger children.

Dynamic US study in the evaluation of infants with vertical or oblique talus deformities

BACKGROUND

Congenital vertical talus (CVT) is a rare foot deformity that is sometimes difficult to differentiate from oblique talus (OT) by physical examination and foot radiography.

OBJECTIVE

The purpose of this study was to summarize our experience with US in evaluation of CVT and OT deformities.

MATERIALS AND METHODS

We identified all children (2005-2011) younger than 6 months who underwent dynamic focused US of the foot at our tertiary-care facility to evaluate clinically equivocal cases of CVT. Diagnostic criteria for CVT were persistent talonavicular dislocation on forced plantar flexion of the foot. OT was diagnosed based on reduction of the talonavicular dislocation on forced plantar flexion. Medical and imaging charts were reviewed for diagnosis on US and plain radiographs (when available) and for underlying neuromuscular disorders, treatment and outcome on follow-up.

RESULTS

Ten patients (eight boys and two girls, mean age 33 days) were evaluated by US for CVT. Radiographs of the foot were obtained in only two children and were non-diagnostic. Thirteen feet were evaluated by US. Diagnosis of CVT was confirmed by surgery in seven children, three of whom had bilateral CVT. Diagnosis of OT in three children was supported by response to casting treatment.

CONCLUSION

Dynamic US can reliably distinguish between CVT and OT deformities.

Postnatal growth of the calcaneus does not simulate growth of the foot

BACKGROUND

In the absence of age and sex-specific normative data for postnatal growth of the calcaneus, it has been hypothesized that the growth of the calcaneus would simulate growth of the foot.

METHODS

A total of 860 normal lateral foot radiographs, 50 (25 female and 25 male) for each year of development from 1 to 18 years, and 10 radiographs from birth till 1 year, were measured for the length and height of the calcaneus, Bohler angle, the appearance, fusion and fragmentation of calcaneus apophysis, and the height and width of apophysis. Nonlinear curves were fit to a growth chart of the calcaneus, and the results were superimposed on the historical growth charts of the foot, stature, and long bones (femur, tibia). The ratio of calcaneus length to apophysis height was calculated.

RESULTS

Growth of the calcaneus does not simulate growth of the foot (which attains 50% of its mature dimension by the age of 1 y in girls and 1.5 y in boys), but simulates the growth of the long bones, which attain 50% of their mature length after the age of 3 years in girls and 4 years in boys. Bohler angle remains within normal limits across all ages. When the length of calcaneus is triple the height of its apophysis, 80% of calcaneus growth is complete.

CONCLUSIONS

We provide normative data for postnatal growth of the calcaneus. On the basis of these data, the assumption that growth disturbance in children affects the length of the calcaneus proportionately less than similar disturbances in the long bones, is false. Children <3 years have at least 50% of growth remaining. Bohler angle should be maintained at all ages.

CLINICAL RELEVANCE

This study of postnatal growth of the calcaneus provides age and sex-based normative data to predict growth pattern of calcaneus.

The paediatric Bohler's angle and crucial angle of Gissane: a case series

Background

Bohler's angle and the crucial angle of Gissane can be used to assess calcaneal fractures. While the normal adult values of these angles are widely known, the normal paediatric values have not yet been established. Our aim is to investigate Bohler's angle and the crucial angle of Gissane in a paediatric population and establish normal paediatric reference values.

Method

We measured Bohler's angle and the crucial angle of Gissane using normal plain ankle radiographs of 763 patients from birth to 14 years of age completed over a five year period from July 2003 to June 2008.

Results

In our paediatric study group, the mean Bohler's angle was 35.2 degrees and the mean crucial angle of Gissane was 111.3 degrees. In an adult comparison group, the mean Bohler's angle was 39.2 degrees and the mean crucial angle of Gissane was 113.8 degrees. The differences in Bohler's angle and the crucial angle of Gissane between these two groups were statistically significant.

Conclusion

We have presented the normal values of Bohler's angle and the crucial angle of Gissane in a paediatric population. These values may provide a useful comparison to assist with the management of the paediatric calcaneal fracture.

Complications of talus fractures in children

BACKGROUND

Pediatric talus fractures are rare with variable rates of posttraumatic complications reported in the literature. The purpose of this retrospective study was to evaluate posttraumatic complications in children after talus fracture and report injury characteristics.

METHODS

This study included 29 children with talus fractures sustained between 1999 and 2008 at an average age of 13.5 years (range, 1.2-17.8). Patient records and radiographs were reviewed to determine the mechanism of injury, fracture type, associated injuries, and treatment. Posttraumatic complications assessed were avascular necrosis, arthrosis, nonunion or delayed union, neurapraxia, infection or wound-healing problems, and the need for further unanticipated surgery. Clinical follow-up averaged 24 months (range, 6 mo-5 y).

RESULTS

Twenty-nine children sustained a major fracture of the talar body, neck, or head. Avascular necrosis occurred in 2 patients (7%), arthrosis in 5 (17%), delayed union in 1 (3%), neurapraxia in 2 (7%), infection in 0, and the need for further surgery in 3 (10%). Both high-energy mechanism and fracture displacement corresponded to a greater number of posttraumatic complications. The number and severity of talus fractures increased in older children.

CONCLUSIONS

In this case series, posttraumatic complications after pediatric talus fractures occurred more frequently after a high-energy mechanism of injury or a displaced fracture. Talus fractures occurred more commonly and with more severity in older children.

LEVEL OF EVIDENCE

Level IV. Retrospective case series.

Interobserver reliability of radiographic measurements of contralateral feet of pediatric patients with unilateral clubfoot

BACKGROUND

Radiographs have traditionally been used to describe and quantify foot deformities in infants and children. We hypothesized that the interobserver reliability of measurements obtained from radiographs of pediatric feet would be low, especially with regard to the infant foot, and that normal ranges and standard deviations would decrease in association with increasing patient age.

METHODS

We retrospectively reviewed 494 radiographs of 121 patients treated for unilateral clubfoot at our institution and studied the contralateral normal foot. All anteroposterior radiographs, lateral radiographs, and lateral radiographs made with the foot in maximum dorsiflexion were analyzed by three observers, and the values were recorded. The databases created by the three observers were statistically analyzed according to five predefined age groups (birth to less than three months, three months to less than twelve months, twelve months to less than three years, three years to less than seven years, and seven years to less than fourteen years).

RESULTS

The anteroposterior talocalcaneal angle was rated as having good interobserver reliability (i.e., an intraclass correlation coefficient of 0.61 to 0.80) for all patients in each age group. Other angles that were associated with good interobserver reliability were the anteroposterior calcaneus-fifth metatarsal angle in the twelve months to less than three-year age group, the three-year to less than seven-year age group, and the seven-year to less than fourteen-year age group; the lateral talocalcaneal angle in the three-year to less than seven-year age group; the lateral tibiotalar angle in the three-year to less than seven-year age group; and the lateral talus-first metatarsal angle in the seven-year to less than fourteen-year age group. All other angles were rated as having very good interobserver reliability (i.e., an intraclass correlation coefficient of 0.81 to 1). The mean difference and the maximum difference among the observers decreased for all angles in nearly all age groups.

CONCLUSIONS

Interobserver reliability with regard to the radiographic measurement of pediatric feet was higher than expected, although measurement discrepancies can be as great as 30° with the infant foot. Interobserver reliability tended to improve with increasing patient age. The standard deviation showed a trend toward a decrease as patient age increased, although the trend was less notable than expected.

Pediatric heel pain

Heel pain is a condition that is generally more common in the adult population. However, it is a condition that the foot and ankle specialist must be prepared to treat in pediatric patients. The insidious onset of heel pain in the pediatric patient can be an enigma to the foot and ankle specialist. Some of the more common etiologies for pediatric heel pain are discussed. The presenting signs and symptoms, as well as proper workup and treatment are discussed. Two case reports of unusual pediatric calcaneal fractures are also presented.

The natural history and pathophysiology of flexible flatfoot

The frequent occurrence of flexible flatfoot raises the question of its pathologic status. There may be cultural overtones resulting in the consideration that flat feet are always pathologic. Parents may believe that their own flat feet were successfully treated when they were children and wish the same for their offspring. Few studies attempt to answer the question of the natural history of this condition. This article reviews the available literature dealing with the natural history, comorbidities, recommendations for treatment, expansion of biomechanical theory, and classification of flatfoot. Issues associated with imaging of flatfoot and the design of studies to validate the effects of treatment are also reviewed.

Cartilage anlagen adapt in response to static deformation

Connective tissue adaptation, including the development of cartilaginous anlagen into bones, is widely believed to be related to dynamic, intermittent load and stress histories. Static stresses, on the other hand, are generally believed deleterious in tissue adaptation. Using serial MRI in a natural human experiment (manipulation and corrective casting of infant clubfoot), we have observed casting produces two effects: (1) the well recognized change in relative positions of the hindfoot anlagen; (2) a newly recognized immediate shape change in the anlagen. These changes seemingly enhance the rate of growth of the anlagen and of the ossific nucleus. The shape change or deformation in the anlagen would occur as a result of alterations in the magnitudes and directions of loading from soft tissue attachments and muscle activity and would necessarily be associated with changes in the stress states within the anlagen and, when present, the ossific nuclei. Given the known role of load and stress history in tissue adaptation, we presume the reduced stress histories influence the enhanced growth rates. These observations contradict some current theories of tissue adaptation since static, rather than dynamic stresses play a crucial role in accelerating the growth and development of anlagen in the infant clubfoot.

3D reconstruction of the skeletal anatomy of the normal neonatal foot using 3D ultrasound

Currently imaging plays a limited role in the assessment of the neonate with a foot deformity. The aim of this study was to establish a technique for examining the neonatal foot with three-dimensional ultrasound (3D US). 3D US was attempted on the normal feet of 20 infants (9 male, 11 female) under 6 weeks old (range 35-41 days). The data sets were obtained whilst the infants were feeding or asleep to minimize movement artefact. A high-resolution optically tracked freehand 3D US system (Diasus, 16 MHz transducer) was used with Stradx software to acquire and analyse the data sets. Manual segmentation of the non-ossified tarsi from the data sets was performed. Five infants were too restless to be examined. 107 data sets were recorded from 22 feet of the remaining 15 infants. 21 of the data sets were discarded due to movement artefact. 86 were suitable for manual segmentation. Surface interpolation of the segmented data sets produced surface rendered reconstructions illustrating the complex 3D anatomy of the foot. This new technique may offer a method of examining the deformed foot, e.g. congenital talipes equinovarus.

Assessment of the three-dimensional relationship of the ossific nuclei and cartilaginous anlagen in congenital clubfoot by 3-D MRI

PURPOSE

Radiographic measurement is the usual method used to objectively determine the extent of a congenital clubfoot deformity. Although radiographs have been used clinically to estimate the size and location of tarsal bones through measurements of the ossific nuclei, it is not clear to what extent these relationships are actually reflected in these measurements. So, we used a 3-D MRI system that could more objectively estimate sizes and positional relationships.

MATERIAL AND METHOD

We evaluated 5 patients with unilateral congenital clubfoot deformity. Magnetic resonance imaging was performed of both feet using 1.5-T magnet. Based on the resulting magnetic resonance imaging volume data, a three-dimensional surface bone model was reconstructed by the Marching Cubes method. We used this model to perform a comparative analysis of the volume and volume ratio of each cartilaginous anlage and ossific nucleus, the length of the talus and the calcaneus, and the position of the center of gravity of ossific nuclei within the cartilaginous anlagen. We measured the relationship between the ossific nuclei and cartilaginous anlagen in the talus and calcaneus of patients with unilateral clubfoot deformity.

RESULT

In clubfeet talus volume was reduced by 20.1% and calcaneal volume was reduced by 15.7%. Furthermore, the volume of the talar ossific nucleus was reduced by 42.6% and that of the calcaneal ossific nucleus was reduced by 12.1%. The length of the clubfoot talus was 8.2% shorter than normal, and that of the calcaneus was 4.8% shorter.

CONCLUSION

The assessment technique presented herein was shown to be useful in ascertaining the various pathological characteristics associated with clubfoot.

Evaluation of calcaneal malposition by magnetic resonance imaging in the infantile clubfoot

Magnetic resonance imaging (MRI) can clearly visualize both the ossification centers and surrounding cartilage of growing bones and enable a three-dimensional analysis of their positional relationships by using overlapping images. The calcaneal position was evaluated based on five newly proposed parameters of magnetic resonance images in 30 clubfeet of 18 infants with the bimalleolar and lower leg axes as reference lines. Sixteen unaffected feet in the unilateral cases were analyzed as normal feet. MRI showed that the calcaneus in clubfoot rotated internally, medially and posteriorly with reference to the bimallelar axis and that it took an equinus and a varus position with reference to the lower leg axis as compared with the normal foot. These five parameters and their normal values on the calcaneal position should be useful for the evaluation of infantile clubfeet.

Sonographic measurement of calcaneal volume for determination of skeletal age in children

PURPOSE

The purposes of this study were first to prospectively evaluate the feasibility of using sonographic measurements of volume of the ossified part of the calcaneus to determine skeletal age in healthy children and second, to provide normal ranges of this volume by sex and age up to 6 years.

METHODS

Four hundred normal girls and boys ranging in age from 1 day to 6 years were examined sonographically to determine the volume of the calcaneal ossification center. The children were randomly divided into 2 groups. The first group (300 children) was used to determine normal values for the mean calcaneal volume by age and sex. The second group (100 children) was used to validate those normal values.

RESULTS

The sonographically determined volume of the calcaneal ossification center correlated well with the chronologic age of the children. The calcaneal ossification centers of boys were larger than those of girls within the same age groups from ages 2 to 10 months, but from 11 months to 6 years old, they were larger in the girls. The differences, however, were not statistically significant. The volume of the calcaneal ossification center increased the most between the first and second years of life, reaching 183% and 140% in girls and boys, respectively. Using the normal values obtained from the first group, we correctly predicted the chronologic age in 91% of children in the validation group. Among the remaining 9%, the error in prediction of chronologic age never exceeded 1 age interval.

CONCLUSIONS

The use of sonography provides a quantitative means of measuring calcaneal volume, and its use is feasible for determining skeletal age in children. The normal values we obtained may be used as a baseline for sonographic assessment of skeletal maturation and diagnosis of growth retardation.

Assessment of the position of the navicular by three-dimensional magnetic resonance imaging in infant foot deformities

As the navicular is unossified in infants with foot deformities, until 5 years old (boys) and 3 years old (girls), it is difficult to give the exact position of hindfoot bones. Magnetic resonance imaging associated with three-dimensional reconstruction allows the visualization of the cartilaginous volume of the bones and the measurement of the relationships of the navicular with the talus. In normal feet, we noted that in the coronal plane the navicular was laterally situated (75%) relative to the talus. In club feet (17 patients), the navicular and the cuboid had a large medial displacement (77%) with a slight pronation movement in the sagittal plane. In suspected skewfoot (seven feet) we noted three cases with a lateral subluxation of the navicular. This objective technique of measurement may be of value for diagnosis and treatment of foot deformities.

Imaging of pediatric foot disorders

Imaging pediatric foot disorders is a challenging task. Optimally exposed and well-positioned radiographs can answer many questions. Because many bones may not be completely ossified, however, CT or MR imaging is often needed to provide additional information to assist in the management of congenital and acquired lesions in the foot.

Magnetic resonance imaging in follow-up of treated clubfoot during childhood

In this study, we evaluated the short-term results of surgically treated clubfoot with magnetic resonance imaging (MRI). T1- and T2-weighted MRI images with 4-mm slices in the standard anatomic sagittal, transverse, and coronal planes were obtained in seven cases of clubfoot aged 4--11 years (mean 5.6 years old). The mean follow-up period was 3.6 years (ranged between 2 and 6 years). Sagittal talocalcaneal angle, talar head and neck axis internal rotation, calcaneal axis internal rotation, transverse talar neck and head/calcaneus angle and posterior calcaneus external rotation were measured. Three cases with dorsal talonavicular subluxation and a case of calcaneocuboid luxation were demonstrated by MRI. It was concluded that MRI may help to understand results of surgically-treated clubfoot by revealing hindfoot articular relationships and many complications.

Talo-calcaneal relationship in clubfoot

Talo-calcaneal angles were measured on anteroposterior, stress dorsiflexion, and plantarflexion lateral radiographs of 75 normal feet and 145 clubfeet. The talus and calcaneum from 15 normal fetal limbs were dissected without disturbing the subtalar capsule. Anteroposterior and lateral radiographs of these specimens were also obtained. The long axes of the ossific nuclei and the long axes of the cartilaginous anlagen of the bones were marked, and the talo-calcaneal angles were measured. The talo-calcaneal angles were lower in clubfeet than in normal feet, but there was considerable overlap in the ranges of normal and clubfeet for all the angles measured. The lateral talo-calcaneal angles in normal feet were higher in dorsiflexion than in plantarflexion, whereas the converse was true in clubfeet. The talo-calcaneal angles measured from the axes of the ossific nuclei of the fetal specimens were higher than those measured from the axes of the cartilaginous anlagen. Using logistic regression analysis, a mathematical model was made to predict the probability of correction of clubfeet. A lateral talo-calcaneal angle difference (between the stress dorsiflexion and plantarflexion angles) of 20 degrees suggests that there is a 93% probability that the hindfoot deformity of clubfoot has been adequately corrected. A talo-calcaneal angle of 30 degrees or a talo-calcaneal index of 40 degrees does not ensure correction of clubfoot. A decrease of the talo-calcaneal angle by up to 10 degrees occurs as the child grows because of the alteration of the shape of the ossific nucleus of the talus that occurs normally with growth.

MR evaluation of talonavicular angle in congenital talipes equinovarus

The talonavicular relationship in 14 patients with talipes equinovarus was quantified using gradient echo sequences. The angle formed between the short axis of the navicular and the long axis of the talus was measured. There is a significant difference in the talonavicular angle between patients who had posteromedial release (PMR) and those who had posterior release (PR) or casting only (P=.0004). This method provides an objective assessment of residual deformity following surgical and conservative management of talipes equinovarus.

The ossification centre of the talus

The ossification of the talus was studied in plastinated and histological preparations of normal feet of eight newborn children. Quantitative data on the newborn talus were obtained with the IBAS image analysis system and by point counting methods. In the newborn talus up to 24 percent of the talar anlage already consists of bony tissue. The ossification centre is situated in the neck, which includes the non-articulating surfaces of the talus. Periosteal bone joins the endochondral centre below and, in well-differentiated specimens also above. The basal periosteal collar forms the surfaces of the sinus and canalis tarsi, whereas the cranial bony collar is included in the tibiotalar joint. The histological architecture of these periosteal collars differs. Four arteries contribute to the blood supply of the talar ossification centre.

Occult fracture of the calcaneus in toddlers

Five children 14-33 months of age were treated for calcaneal fractures. All had a history of trauma with limping or refusal to walk. Physical examination could not localize the fracture. Initial radiographs were negative. There were no signs of systemic illness. They were treated with long-leg casts. Radiographs after 2 weeks revealed an arc of sclerosis across the tuberosity of the calcaneus. In no case was a bone scan instrumental in making the diagnosis. Awareness of calcaneal fractures in the child younger than 36 months can prevent the routine use of bone scans to make the diagnosis.

Magnetic resonance imaging of skewfoot

Magnetic resonance imaging was used to visualize the ossified and unossified portions of the bones and soft tissues of the feet in order to evaluate the tarsometatarsal anatomy in sixteen children, three months to six years old (mean, fifteen months old), who were seen in the orthopaedic clinic with a suspected diagnosis of skewfoot. Twenty-seven feet were clinically abnormal and five were normal. Of the abnormal feet, twenty-six had a radiographic diagnosis of skewfoot and one, of simple metatarsus adductus. Of the skewfeet, seven had a talocalcaneal angle of 45 degrees or more as measured on the lateral radiograph and six had a talocalcaneal angle of 45 degrees or more as measured on the anterior radiograph. Valgus deformity of the hindfoot was not apparent on clinical examination in any of the children. The talocalcaneal angles measured on the magnetic resonance images corresponded poorly with those measured on the radiographs, possibly because it is not possible to simulate weight-bearing during magnetic resonance imaging or because the effect of partial volume averaging on thin sections. However, magnetic resonance imaging demonstrated the shapes of the bones and the positions of the unossified portions of the bones. Magnetic resonance imaging showed lateral subluxation of the navicular in twenty-four skewfeet, plantar subluxation in ten, and medial subluxation of the first metatarsal on the medial cuneiform in twenty-five. The alignment of the lateral margin of the calcaneus and cuboid on the magnetic resonance images was normal in all patients. Magnetic resonance imaging has the unique ability to show the cartilaginous and ossified portions of the developing bones of the foot.