Assessment of talus deformity by three-dimensional MRI in congenital clubfoot

Clubfoot: Congenital Talipes Equinovarus

Congenital talipes equinovarus (CTEV), also known as clubfoot, is a common musculoskeletal entity that affects one to two per 1000 live births worldwide. Imaging modalities including radiography, US, and MRI have emerged as valuable tools for the diagnosis, treatment, and monitoring of CTEV. The deformity is characterized by midfoot cavus, forefoot adductus, and hindfoot varus and equinus. The Ponseti method of manipulation and serial casting is the standard treatment of CTEV. Radiography shows the anatomy, position, and relationships of the different bones of the foot. US allows accurate assessment of cartilaginous and bony structures, in addition to its inherent advantages such as absence of ionizing radiation exposure. One of the indications for US is to monitor the response to Ponseti method treatment. MRI enables visualization of bones, cartilage, and soft tissues and allows multiplanar evaluation of deformities, providing a comprehensive imaging analysis of CTEV. An integrated approach that combines clinical examination and imaging findings is essential for effective management of CTEV. The authors provide a comprehensive overview of CTEV with a review of imaging modalities to help evaluate CTEV, focusing on radiography, US, and MRI. Using this article as a guide, radiologists involved in the assessment and treatment of CTEV can contribute to the management of the condition. ©RSNA, 2024 Supplemental material is available for this article.

Talar neck rotation angle in adults with clubfoot deformity: Observed values and intra- and inter-observer reliability using weightbearing CT

INTRODUCTION

Adults presenting with symptomatic clubfoot represent a challenging cohort of patients. An appreciation of the location and degree of deformities is essential for management. Talar anatomy is often abnormal with varus within the talar neck, however, there are few reproducible methods which quantify talar neck deformity in adults. We describe a technique of assessing talar neck deformity, and report on observed values and intra- / inter-observer reliability.

METHODS

This was a single-centre, retrospective study including 96 feet from 56 adult patients with clubfeet (82 feet had clubfoot deformity, 14 were normal). Mean age was 34.3 ± 16.9 years and 31 (55.3%) were male. Weight-bearing CT scans captured as part of routine clinical care were analysed. Image reformats were oriented parallel to the long axis of the talus in the sagittal plane. In the corresponding axial plane two lines were drawn (on separate slices): 1) a line perpendicular to the intermalleolar axis, 2) a line connecting the midpoints of the talar head and narrowest part of the talar neck. The talar neck rotation angle (TNR angle) was the angle formed between these lines. Intraclass correlation coefficients (ICC) were performed for intra- and inter-observer reliability.

RESULTS

Mean TNR angle in clubfeet was 27.6 ± 12.2 degrees (95%CI = 25.0 to 30.2 degrees). Mean TNR angle in normal feet was 18.7 ± 5.1 degrees (95%CI = 16.0 to 21.4 degrees) (p < 0.001). The ICC for clubfeet was 0.944 (95%CI = 0.913 to 0.964) for intra-observer agreement, and 0.896 (95%CI = 0.837 to 0.932) for inter-observer agreement.

CONCLUSION

This measurement technique demonstrated excellent intra- and inter-observer agreement. It also demonstrated that compared to normal feet, clubfeet had about 9 degrees of increased varus angulation of the talar neck. This technique and data may be used for future research into clubfoot deformity and in planning treatment.

LEVEL OF CLINICAL EVIDENCE

3.

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.

Are early antero-posterior and lateral radiographs predictive of clubfoot relapse requiring surgical intervention in children treated by Ponseti method?

Purpose

To investigate the value of antero-posterior and lateral radiographs in predicting clubfoot relapse after treatment with the Ponseti method.

Methods

This was a retrospective review of 104 children (157 feet) younger than 3 months of age with idiopathic clubfoot treated using the Ponseti method at our institution between January 2007 and December 2014. All patients underwent Achilles tenotomy and were divided into two groups according to the need for further surgery to correct the deformity: relapsed group (24 patients; 36 feet) and non-relapsed group (80 patients; 121 feet). All antero-posterior and lateral foot radiographs were performed less than 3 months after Achilles tenotomy. The talo-calcaneal (TC-AP) and talus-first metatarsal (TM-AP) angles were measured in the antero-posterior view, while the tibio-calcaneal (TIC-L), talus-first metatarsal (TM-L), and talo-calcaneal (TC-L) angles were measured in the lateral view. The multi-factor logistic regression model of the stepwise selection method was used to predict the relapse of clubfoot deformity from the potential predictive values.

Results

The mean age at initial plain radiography examination was 99.45 ± 21.54 days. Differences in TC-AP, TM-AP, TC-L, and TIC-L between the two groups were statistically significant. However, only TM-AP and TIC-L were included in the "risk of relapse" formula using the multi-factor logistic stepwise selection method.

Conclusion

Early antero-posterior and lateral radiographs in children younger than 3 months of age at initial Ponseti treatment have positive predictive value for relapse. Reduced TM-AP angle and increased TIC-L were associated with an increased risk of relapse.

Level of evidence

level III.

Muscle volume evaluation using 3DCT for congenital clubfoot

Background

In congenital clubfoot, the lower leg is very thin and the calf muscles are hypoplasic. However, there are few studies reporting real muscle volume.

Purpose

The purpose of this study is to assay the muscle volume in congenital clubfoot using 3DCT and to quantify the degree of the hypoplasia.

Material and methods

From January 2015 to December 2016, nine consecutive patients, seven male and two female, with unilateral congenital clubfeet were recruited for CT scans. Axial transverse sectional CT scans were acquired from the delineation of the fibular head to the tibial plafond. From the data, we rendered the entire muscle in 3D for muscle volume assay, and further segmented the posterior musculature for comparison between the normal and affected sides.

Results

The whole muscle volume on the normal side was 291.23 cm³ (181.23–593.49) and that on the affected side was 225.08 cm³ (120.71–429.08), for an affected side to normal side ratio of 0.79 (0.72–0.9), which was significantly smaller (p < .01). Posterior muscle volume on the normal side was 175.81 cm³ (103.72–376.32) and that on the affected side was 106.52 cm³ (58.3–188.39). The ratio of posterior muscle to whole muscle on the normal side was 0.62 (0.46–0.75), and that on the affected side was 0.48 (0.4–0.55), such that the affected side was significantly smaller (p < .01)

Conclusion

This study contributes quantitative data supporting the longstanding observations that the posterior calf muscles are significantly smaller on the affected side compared to the normal side in congenital clubfoot, and further underscores the importance of the extending the excursion of these muscles.

Clubfoot pathology in fetus and pathogenesis. A new pathogenetic theory based on pathology, imaging findings and biomechanics-a narrative review

Several studies have described the pathology of idiopathic congenital clubfoot (ICCF) in fetus. Numerous pathogenetic theories have been postulated on ICCF, but many of them lack any objective evidence. Pathologic studies in fetus together with MRI studies in patients with ICCF seem to favor the theory of a muscular imbalance of the foot activators during fetal growth as the main pathogenetic factor of ICCF. Our objectives were: (I) To support the theory of muscular imbalance as the primary pathogenetic factor of ICCF; (II) To clarify why atrophy and shortening affect the activator muscles of the foot unevenly, as reported by literature. A literature search based on MEDLINE and the COCHRANE database was performed to identify all published studies from 1929 to 2020 which report ICCF pathology in fetus, its etiopathogenesis, and imaging and biomechanical studies showing how the basic pathology may be addressed by Ponseti treatment. A manual search was also performed of the references cited in studies, reviews, and university libraries. Altered size, shape and articular relationships of the tarsal bones, and uneven atrophy and shortening of the leg muscles together with capsule and ligament abnormalities were the main pathologic findings reported in fetus with ICCF. Regarding ICCF pathogenesis, the main debate is between the advocators of a primitive blastemal defect of the tarsal bones leading to the skeletal abnormalities and those who hold that the latter are secondary to a deforming force generated by the soft tissues. Imaging studies have shown that the Ponseti method is able to address the skeletal abnormalities, the correction of which is maintained until adulthood, whereas leg muscle atrophy is not improved but tends to worsen with growth. Preliminary histochemical studies of the soleus-Achilles tendon junction have shown a decrease of the growth factors and the presence of myostatin, both down-regulators of muscle growth in patients with ICCF. The authors postulate that a defect of both the radial and the longitudinal growth unevenly affecting the leg muscles with a consequent imbalance of the foot activators might be the main pathogenetic factor of ICCF. Further studies are needed to confirm this theory.

Statistical shape modelling to analyse the talus in paediatric clubfoot

One fifth of idiopathic clubfoot deformities cannot be fully corrected by Serial Ponseti casting and deformity recurs in 20%-30% of cases. To avoid x-ray exposure, the joints with largely unossified bones are diagnosed with magnetic resonance images (MRI). Typically, geometric measurements are made in the MRI planes; however, this method is inaccurate compared to measurements on three-dimensional (3D) models of the joint. More accurate measurements using the 3D bone shapes may be better at identifying differences between groups; and therefore, improve diagnosis. The entire set of shape features from MRI can be analysed simultaneously through statistical shape modelling (SSM) which assesses bone morphology of clubfoot in a more sensitive way. A method for SSM of the talus is developed in this study and the shape of the normal talus is compared with the one in clubfeet with residual deformity through both geometric measurements and SSM. Significant differences between two groups were found by both methods; and therefore, might contribute to improve diagnosis of clubfoot.

Assessment of the talar deformity and alignment in congenital clubfoot using three-dimensional MRI after Ponseti method

BACKGROUND

Ponseti method have been widely accepted as the initial treatment of congenital idiopathic clubfoot because its excellent primary result. On the other hand, relapses after Ponseti method are not uncommon and the cause of relapses have not been fully elucidated. We investigated detailed morphology and alignment of tarsal bones in clubfoot after Ponseti method using three-dimensional MRI analysis.

METHODS

We performed MRI with 10 patients of unilateral clubfoot at three months after Achilles tenotomy. Based on the MRI volume data, we reconstructed three-dimensional bone surface model using the marching cubes method. We evaluated the volume of the talus and navicular bone, medial and planter deviation of the talar head and neck, medial deviation of the navicular bone, and internal rotation angle of the distal tibiofibular joint.

RESULTS

In clubfoot, the volume of talus and navicular bone were significantly smaller compared with the contralateral side. Deviation of the talar head and neck varied from medially to almost the same as that on the contralateral side. The degree of deformity of the talus and alignment of the navicular bone and distal tibiofibular joint showed correlations.

CONCLUSIONS

Patients with the medial deviated talar neck might have the alignment change of navicular bone and distal tibiofibular joint. Deformity of talar neck might to be compensated by talonavicular joint and distal tibiofibular joint through the manipulation of Ponseti method.

Delayed ossification and abnormal development of tarsal bones in idiopathic clubfoot: should it affect bracing protocol when using the Ponseti method?

PURPOSE

To point out the need to take into account the dysplastic nature of tarsal bones when treating idiopathic clubfoot (CF).

METHODS

Review the published evidence on the developmental abnormalities of tarsal bones in idiopathic CF.

RESULTS

The literature review provides abundant proof of the existence of delayed appearance and slower development of ossification centres of tarsal bones in idiopathic clubfoot.

CONCLUSION

Gentle manipulations and casting are the cornerstone of the Ponseti method. The biological response of all foot elements is critical for a successful outcome. Delayed ossification and abnormal development of tarsal bones in idiopathic CF may affect the results. Development of a personalized tailored bracing protocol based on severity assessment and response to casting treatment will improve results and quality of care in CF management.

LEVEL OF EVIDENCE

V.

The significance of foot length at the initiation of the Ponseti method: a prospective study

OBJECTIVES

We sought to evaluate foot length (FL) and forefoot circumference (FC) and their impact on the severity of idiopathic clubfoot (CF) and results of treatment. We hypothesized that a smaller foot size at birth that represents a lesser than term newborn may affect the response of the CF to the treatment.

METHODS

We conducted a prospective study documenting FL and FC of all neonates presented with idiopathic CF. Additional demographic information was collected. Outcome measures were number of casts needed for correction, need for recasting, additional surgery and functional score.

RESULTS

In all, 52 children with 73 CF with a minimum mean follow-up of two years (2.0 to 5.6; sd 1.08) were evaluated. Mean gestational age was 38.63 weeks and mean birth weight (BW) was 3184 g. The mean FL at presentation was 74 mm (5.70 to 9.00), initial Pirani score was 5.5 (2.5 to 6.0) while number of casts was 6.9 (4.0 to 11.0). The FL was significantly correlated both to initial Pirani score (r = -0.35; p < 0.01) and number of casts (r = -0.33; p < 0.05). Positive correlation was found between the number of casts to Pirani score and number of additional procedures (r = 0.39; r = 0.36; p < 0.01, respectively). A foot size of up to 8 cm, needed 7.3 casts (4 to 7) compared with a FL of 8 cm or longer who needed 4.7 casts (4 to 6; t = 7.11; p < 0.001).

CONCLUSION

FL is a simple approach to identify preterm babies. It can be used as part of the initial evaluation of CF and help in predicting the course of treatment. We recommend adding FL to the existing classification.

LEVEL OF EVIDENCE

I - Prognostic study.

Residual Equinus After the Ponseti Method: An MRI-based 3-Dimensional Analysis

BACKGROUND

Residual equinus deformity is present in up to 20% of clubfeet treated by the Ponseti method. These patients may require surgical release to restore dorsiflexion. Despite complete posterior release; persistent intraoperative equinus may be present and suggest concurrent joint incongruity. The purpose of this study was to characterize differences in ankle morphology in toddlers with residual equinus following the Ponseti method.

METHODS

Preoperative magnetic resonance imaging (MRI) data from 10 patients who underwent reconstruction (17 feet; 7 bilateral, 3 unilateral clubfeet) for persistent equinus were compared with 16 age-matched controls. Through reverse engineering software, MRI data were used to generate 3-dimensional (3D) models. Four talus-based measures were performed on both MRI data and 3D models-neck depth, neck angle, width, and length. Models were also used to calculate talus volume and arc of curvature (plafond and talar dome). Standard statistical analyses were performed.

RESULTS

Talus volumes, width, and length were less in clubfeet then in control feet. Although some measures were significant there was no mismatch with the ankle mortise dimensions or arc curvature that could account for any decrease in dorsiflexion. We found that from MRI measures the clubfoot neck depth was 2.3 versus 3.6 mm in controls (P<0.001) and from 3D modeling the clubfoot neck depth was 2.3 and 3.5 mm in controls (P=0.003). With 3D modeling talus clubfoot neck angle was 153.7 versus 140.4 degrees in controls (P=0.01). The clubfoot neck angle obtained from MRI measures were also different yet not significant [126.6 in clubfeet versus 122.5 degrees in controls (P=0.12)].

CONCLUSIONS

In comparison to age-matched feet; we have noted a decrease in talar neck depth and an obtuse talar neck angle in clubfeet treated in the manner of Ponseti. This may result in anterior ankle impingement and be the cause of residual equinus despite posterior release. In these procedures, the surgeon should recognize this possibility when the amount of dorsiflexion is less than expected.

LEVEL OF EVIDENCE

Level III-case control study.

Development of an orthosis for simultaneous three-dimensional correction of clubfoot deformity

BACKGROUND

Clubfoot is a three-dimensional deformity of the foot in which the foot is twisted in three mutually perpendicular planes from the normal shape of the foot. Of the various treatment methods that are available to manage clubfoot, non-operative approaches are preferred. The conventional non-operative method of treatment is to apply a series of casts to the infant's clubfoot to gradually manipulate its position. However, prolonged use of casts can result in skin rash, skin dehydration and ulcers on the soft skin of an infant. Treatment using orthosis represents an alternative non-operative and convenient technique because an orthosis can be put on and taken off at any time.

METHODS

In the present study, an orthosis was developed according to the rotation of three mutually perpendicular planes and was subsequently tested on five patients over the duration of one week.

FINDINGS

In all five cases, the desired incremental correction to the clubfoot was achieved through the one week intervention with the orthosis. No form of rash, dehydration, ulcers, and so on were observed on the skin of any baby involved in the study during or following application of the orthosis.

INTERPRETATION

By using the developed orthosis, partial correction of the clubfoot deformity was achieved over a short period of time. However the widespread use of this device for extended durations and with a larger number of patients will generate further evidence of the extent to which this orthosis can reliably treat clubfoot.

Prolonged use of foot abduction brace reduces the rate of surgery in Ponseti-treated idiopathic club feet

PURPOSE

There is conflicting evidence related to factors affecting the rates of recurrence of idiopathic club feet using the Ponseti method. We attempt to evaluate the predictors of success and failure in our physiotherapy-led Ponseti club foot clinic.

METHODS

We evaluated 189 children with 279 club feet with a mean follow-up of 6.3 years for the following: Pirani score at presentation, number of casts for correction, indication for Achilles tenotomy, and the duration of foot abduction brace (FAB) use, in relation to outcome. Outcome measures were the need for additional surgery and functional scores. Based on the pattern and rate of ossification of the tarsal bones in idiopathic club foot, a much longer FAB weaning protocol was designed and practiced since 2000. The objective of this study was to answer the question of whether a prolonged period of FAB use reduces the need for surgery in Ponseti-treated idiopathic club foot.

RESULTS

Thirty-six feet (12.9 %) underwent additional surgery. The Pirani score and the number of cast changes had no influence on the rate of surgery. The duration of FAB use had a significant effect on the outcome, i.e., the rate of surgery and functional scoring. Operated children used the FAB for 28 months versus 33 months in the non-operated group (p < 0.05). Only a minor delay in the attainment of walking age was noted (average 15 months).

CONCLUSIONS

The duration of FAB treatment was found to be the most influential on the functional results and on rate of surgery. Close follow-up and longer FAB weaning program reduced the rates of recurrence.

3D MRI analysis of the lower legs of treated idiopathic congenital talipes equinovarus (clubfoot)

Background

Idiopathic congenital talipes equinovarus (CTEV) is the commonest form of clubfoot. Its exact cause is unknown, although it is related to limb development. The aim of this study was to quantify the anatomy of the muscle, subcutaneous fat, tibia, fibula and arteries in the lower legs of teenagers and young adults with CTEV using 3D magnetic resonance imaging (MRI), and thus to investigate the anatomical differences between CTEV participants and controls.

Methodology/Principal Findings

The lower legs of six CTEV (2 bilateral, 4 unilateral) and five control young adults (age 12–28) were imaged using a 3T MRI Philips scanner. 5 of the CTEV participants had undergone soft-tissue and capsular release surgery. 3D T1-weighted and 3D magnetic resonance angiography (MRA) images were acquired. Segmentation software was used for volumetric, anatomical and image analysis. Kolmogorov-Smirnov tests were performed. The volumes of the lower affected leg, muscle, tibia and fibula in unilateral CTEV participants were consistently smaller compared to their contralateral unaffected leg, this was most pronounced in muscle. The proportion of muscle in affected CTEV legs was significantly reduced compared with control and unaffected CTEV legs, whilst proportion of muscular fat increased. No spatial abnormalities in the location or branching of arteries were detected, but hypoplastic anomalies were observed.

Conclusions/Significance

Combining 3D MRI and MRA is effective for quantitatively characterizing CTEV anatomy. Reduction in leg muscle volume appears to be a sensitive marker. Since 5/6 CTEV cases had soft-tissue surgery, further work is required to confirm that the treatment did not affect the MRI features observed. We propose that the proportion of muscle and intra-muscular fat within the lower leg could provide a valuable addition to current clinical CTEV classification. These measures could be useful for clinical care and guiding treatment pathways, as well as treatment research and clinical audit.

Value of the fetal plantar shape in prenatal diagnosis of talipes equinovarus

OBJECTIVES

The purpose of this study was to evaluate the value of the fetal plantar shape in prenatal diagnosis of talipes equinovarus.

METHODS

A case-control study was conducted between September 2009 and February 2011. We measured the width and length of 249 feet (156 fetuses) included in this study and then calculated the width to length ratio. All of the fetuses were followed to obtain the pregnancy outcomes and confirm whether the deformity existed; then the bimalleolar angle of each foot with talipes equinovarus was measured. Independent samples t tests were performed to compare the foot width, length, and width to length ratio between normal and talipes equinovarus groups. We also assessed the correlation between the width to length ratio and bimalleolar angle in the talipes equinovarus cases with the Pearson correlation coefficient.

RESULTS

Statistically significant differences were shown between the two groups (P< .001) for the three foot measurements, and a significant negative correlation was found between the width to length ratio and bimalleolar angle of the affected foot (r = -0.857).

CONCLUSIONS

The fetal plantar shape can provide valuable information for prenatal diagnosis of clubfoot. Compared with a normal foot, a clubfoot tends to be wider and shorter. A higher width to length ratio is associated with a smaller bimalleolar angle and indicates a more severe talipes equinovarus deformity.

The inter-relationship of clinical parameters in congenital talipes equinovarus: relevance to pathological anatomy and clinical classification

BACKGROUND

The clinical features that define congenital talipes equinovarus (CTEV) are the presence of four principal components, equinus, varus, adductus and cavus. Classification systems in CTEV often include a form of assessment of these components and also other concurrent clinical parameters which feature in the condition.

METHODS

Over a 14-year period from 1992 to 2006, 95 consecutive cases of CTEV were prospectively assessed and data recorded in order to investigate the relationships between the clinical parameters in CTEV and to compare these relationships with those that one would expect from our knowledge of the pathological anatomy and mechanics of the condition, relating these findings to the commonly used systems for classification.

RESULTS

Ninety-five cases of CTEV had failed conservative treatment and had undergone surgical release. The mean age at surgical release and assessment was 9 months. Cluster analysis demonstrated that there were, broadly, two groups of patients. The first group was those patients with a greater equinus deformity (greater than 31°). This group had a greater adductus deformity and the presence of other parameters indicating increased severity (multiplanar stiffness with the presence of cavus and medial skin crease). The second group was those patients with a smaller equinus deformity (less than 31°) who were more heterogenous with regards to the other parameters.

CONCLUSIONS

We analysed on a statistical basis the relevant aspects of the deformity in CTEV. We have demonstrated that there are certain parameters, namely, equinus and adductus, whose severity can reasonably predict the severity of other components of the deformity. With regards to hindfoot parameters, increased equinus is related to less sagittal plane reducibility and to stiff hindfoot varus (coronal plane stiffness). In terms of midfoot parameters, the degree of adductus is related to the presence of cavus deformity and the presence of a medial skin crease is associated with less reducibility of the adductus (axial plane stiffness). This is consistent with our current understanding of the pathological anatomy of CTEV and bears implications with regards to treatment and the design of proposed classification systems that are in use.

A model for clubfoot based on micro-CT data

The pathological anatomy of idiopathic clubfoot has been investigated for more than 180 years using anatomy, computed tomography (CT), histology and microscopy. Seven idiopathic clubfeet and two normal feet of aborted fetuses were dissected in the present study, with special emphasis on the shape of the cartilage and bones. A three-dimensional (3D) micro-CT system, which generates a series of X-ray attenuation measurements, was used to produce computed reconstructed 3D data sets of each of the separated bones. Based on the micro-CT data scans a high-definition 3D colour printing system was used to make a four times enlarged clubfoot model, precisely presenting all the bony malformations. This model reflects the complexity of the anatomy of this disease and is designed to be used in the workshops of orthopaedic surgeons and physiotherapists, for training in new surgical and manipulation techniques.

Magnetic resonance imaging of the congenital clubfoot treated with the French functional (physical therapy) method

The purpose of this study was to assess magnetic resonance imaging (MRI) changes that occur in clubfeet after nonoperative treatment with the French functional method, specifically pertaining to the chondro-osseous anatomy and the joint relationships. The magnetic resonance images were obtained in 6 infants before treatment and 3 months later. The MRI protocol described previously for clubfeet which were treated by the Ponseti method (J Pediatr Orthop. 2001;21:719) was closely adhered to, except that no sedation was allowed by our institutional review board. The severity of the clubfoot deformities before treatment made assessment of the tibiotalar, talonavicular, and talocalcaneal joint relationships difficult in some feet. Despite this, improvements were noted after treatment in tibiotalar plantarflexion, the talonavicular relationship, the calcaneocuboid relationship, and the varus position of the calcaneus. The wedge shape of both the navicular and distal end of the calcaneus that occasionally was noted on the MRI before treatment improved after therapy. Although improved clinically, persistent equinus of the calcaneus on MRI was significant in 2 feet and was associated with slight dorsal displacement of the cuboid on the calcaneus (MRI evidence of rocker bottom). As noted with use of the Ponseti nonoperative treatment method, the chondro-osseous abnormalities seen on MRI studies in congenital clubfoot improve after treatment with the French functional (physical therapy) method, with the exception of equinus.

Tarsal shape, size, and articulating surface morphology in adolescent surgically treated clubfoot and their contralateral normal foot

Despite the inability of radiographic measurements to quantify the 3-dimensional (3D) shape and size of the hindfoot bones affected by the clubfoot pathology, radiographs continue to be used to evaluate treatment efficacy. Advancements in imaging and image analysis allow new quantitative insights to be obtained into bone shape and size. Therefore, this study sought to quantify and compare the 3D size, shape, and articulating surface morphology of the tibia, talus, calcaneus, navicular, and cuboid bones in the adolescent surgically treated unilateral clubfoot and the contralateral normal foot. Anatomic measurements were obtained by geometrically modeling 3D reconstructed magnetic resonance images of the hindfoot tarsals in the feet of 7 adolescents (mean age, 13.0+/-2.8 years). The results showed that the tarsal bones in the surgically treated clubfoot were smaller in volume (20%-36%) and smaller in surface area (16%-28%) than those in the contralateral normal foot. Correspondingly, the size and shape of the articulating surfaces of these bones in the surgically treated clubfoot were also smaller and flatter than those in the contralateral normal foot. Specifically, the mean talar articular surface area was 25% to 40% smaller, the mean talar-tibiotalar articular surface length was 26% smaller, the mean tibiotalar articular surface length difference was 78% smaller, and the mean navicular "flattening index" was 86% larger in the surgically treated clubfoot. These data offer an objective standard that will advance the knowledge of the clubfoot pathology and aid treatment efficacy evaluation.

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.