Leg muscle atrophy in idiopathic congenital clubfoot: is it primitive or acquired?

Improving Prenatal Diagnosis Precision for Congenital Clubfoot by Using Three-Dimensional Ultrasonography

Prenatal diagnosis of clubfoot traditionally relied on two-dimensional ultrasonography. To enhance diagnosis and predict postnatal outcomes, we examined the parameters that differentiate pathological clubfoot using three-dimensional ultrasonography. In our retrospective study, we examined the findings of prenatal ultrasound and the postnatal outcomes of pregnancies with suspected congenital clubfoot between 2018 and 2021. Based on the three-dimensional perspective, we measured the angles of varus, equinus, calcaneopedal block, and forefoot adduction and compared the sonographic variables between the postnatal treated and non-treated groups. We evaluated 31 pregnancies (47 feet) with suspected clubfoot using three-dimensional ultrasonography. After delivery, a total of 37 feet (78.7%) underwent treatment involving serial casting only or additional Achilles tenotomy. The treated group showed significantly greater hindfoot varus deviation (60.5° vs. 46.6°, p = 0.026) and calcaneopedal block deviation (65.6° vs. 26.6°, p < 0.05) compared to the non-treated group. The calcaneopedal block had an area under the curve of 0.98 with a diagnostic threshold of 46.2 degrees (sensitivity of 97%, specificity of 90%, positive predictive value of 97%, and negative predictive value of 90%). During prenatal evaluation of clubfoot using three-dimensional ultrasonography, the calcaneopedal block deviation has the potential to predict postnatal treatment.

A prospective study on the role of foot evertor muscle activity in recurrence of clubfoot

BACKGROUND

Even after corrective casting and bracing, clubfoot recurrence is challenging throughout childhood, with around 14-40 % recurrence rates. Most of the literature on recurrence was attributed to various factors, and minimal research was conducted to know the role of foot evertor muscle activity and its stimulation benefits. This study aimed to assess the role of foot evertor muscle activity in idiopathic congenital clubfoot recurrence by using clinical, sonographic, and electromyographic parameters.

METHODS

A prospective cohort study was conducted at our tertiary care hospital from 2020 to 2022. The patient's demographic data, Pirani, Dimeglio, Clinical Evertor Muscle Activity scores, sonographic cross-sectional areas of leg muscle, and evertor motor activity using surface electromyography were recorded in adherence to the pre-defined intervals.

RESULTS

In total, 51 patients (51 feet) were included in the study, and the overall recurrence rate was 27.5 % (14/51). In this study, around 47 % (24/51) of children had mild or poor clinical evertor activity; among them, 58 % (14/24) children had a recurrence, and the insufficient clinical evertor activity and recurrence were strongly correlated (p = 0.01). Evertor muscle cross-sectional area ratio, motor unit potentials, and recruitment were comparatively less in the recurred group; however, only the cross-sectional area ratio was statistically significant (p = 0.02).

CONCLUSION

Early detection of evertor muscle weakness can help to individualize the treatment plans by predicting recurrence. Therefore, it should be included in routine clinical evaluations. Further research is required to determine the advantages of evertor muscle-strengthening activities in preventing idiopathic clubfoot deformity.

LEVEL OF CLINICAL EVIDENCE

A prospective cohort study, Level of evidence-II.

Three-dimensional gait analysis in children with recurrent idiopathic clubfoot undergoing complete tibialis anterior tendon transfer

This study was aimed to evaluate the kinetics and kinematics of the foot and ankle using three-dimensional gait analysis in children with recurrent clubfoot treated with tibialis anterior tendon transfer (TATT). Three-dimensional gait analysis of 17 children with dynamic supination (24 feet; 12 males; mean age: 6.34 years) was performed pre- and post-TATT. Spatial, temporal and kinematic parameters, as well as the gait deviation index (GDI), were recorded for all patients. Moreover, to evaluate the severity of dynamic supination during walking, we also measured the angle between the plane of the foot and the X-axis during the swing phase (V-angle-S). The postoperative step length (38.95 ± 8.36 cm) and stride length (76.73 ± 15.92 cm) were significantly smaller than their preoperative values (40.68 ± 9.35 cm and 80.57 ± 17.51 cm; P = 0.0316 and P = 0.0028, respectively). The postoperative peak internal ankle rotation angle in the frontal plane (20.45° ± 14.44) was significantly lower than the preoperative value (25.93° ± 9.84; P = 0.029). The postoperative peak internal foot progression angle in the transverse plane (0.96° ± 5.83) was significantly lower than the preoperative value (4.34° ± 8.88; P = 0.026). However, both the peak ankle varus moment and GDI were not significantly different between the pre- and postoperative data. Postoperative V-angle-S values (28.55° ± 7.56) were reduced compared to their preoperative values (32.52° ± 6.53; P = 0.0094). TATT to the lateral cuneiform can correct dynamic supination in patients with a recurrent clubfoot; however, it has limited or no effects on hindfoot varus deformity. Level of evidence: Level III.

Muscle-tendon properties and functional gait outcomes in clubfoot patients with and without a relapse compared to typically developing children

BACKGROUND

Altered muscle-tendon properties in clubfoot patients could play a role in the occurrence of a relapse and negatively affect physical functioning. However, there is a lack of literature about muscle-tendon properties of clubfoot relapse patients.

RESEARCH QUESTION

The aim of this study was to determine whether the muscle architecture of the medial gastrocnemius and the morphology of the Achilles tendon differ between typically developing children (TDC) and clubfoot patients with and without a relapse clubfoot and to determine the relationships between morphological and functional gait outcomes.

METHODS

A cross-sectional study was carried out in clubfoot patients treated according to the Ponseti method and TDC aged 4-8 years. A division between clubfoot patients with and without a relapse was made. Fifteen clubfoot patients, 10 clubfoot relapse patients and 19 TDC were included in the study. Morphologic properties of the medial head of the Gastrocnemius muscle and Achilles tendon were assessed by ultrasonography. Functional gait outcomes were assessed using three-dimensional gait analysis. Mean group differences were analysed with ANOVA and non-parametric alternatives. Relationships between functional and morphologic parameters were determined for all clubfoot patients together and for TDC with Spearman's rank correlation.

RESULTS

Morphological and functional gait parameters did not differ between clubfoot patients with and without a relapse, with exception of lower maximal dorsiflexor moment in clubfoot relapse patients. Compared to TDC, clubfoot and relapse patients did show lower functional gait outcomes, as well as shorter and more pennate muscles with a longer Achilles tendon. In all clubfoot patients, this longer relative tendon was related to higher ankle power and plantarflexor moment.

SIGNIFICANCE

In clubfoot and relapse patients, abnormalities in morphology did not always relate to worse functional gait outcomes. Understanding these relationships in all clubfoot patients may improve the knowledge about clubfoot and aid future treatment planning.

Determination of the Effective Site for Percutaneous Achilles Tenotomy in Ponseti Management of African Idiopathic Clubfoot

BACKGROUND

Percutaneous Achilles tenotomy is an essential step in the Ponseti treatment of idiopathic clubfoot, with reported complications such as injury to the surrounding neurovascular structures and incomplete division of the Achilles tendon (AT). Knowledge of AT thickness would guide tenotomy blade insertion depth, obviating these related complications. We embarked on this study to ultrasonographically determine AT thickness at its different levels from the calcaneal insertion in children with idiopathic clubfoot.

METHODS

This prospective comparative study consisted of two groups of children 4 years and younger: a study group of patients with clubfoot requiring tenotomy and a control group. Both groups underwent ultrasonographic evaluation of their AT. The ultrasonographic data collected include AT thickness 1 and 2 cm from the calcaneal insertion of the AT, thickness of the thinnest portion of the tendon, and the distance of this thinnest portion from the calcaneal insertion.

RESULTS

Twenty-seven children with idiopathic clubfoot constituted the study group, and 23 children with no musculoskeletal deformity were enrolled in the control group. Mean ± SD AT thicknesses 1 and 2 cm from the calcaneal insertion in the study group were 2.4 ± 0.7 mm and 2.1 ± 0.7 mm, respectively, and in the control group were 2.5 ± 0.7 mm and 2.3 ± 0.7 mm, respectively. The average thickness of the thinnest portion of the AT along its length was 2 mm at 1.8 cm from the calcaneal insertion in both groups.

CONCLUSIONS

Safe and complete percutaneous tenotomy would most likely be achieved when performed 1.8 cm from the calcaneal insertion, where the corresponding average AT thickness of 2 mm would be a guide to determine the insertion depth of the tenotomy blade.

Congenital Clubfoot - Is the Ponseti Method the Definitive Solution?

Congenital clubfoot is one of the most common deformities at birth. The inadequacy or absence of treatment causes serious limitations for people with this condition. The initial treatment using the Ponseti method ensures functional results superior to other treatment modalities previously proposed. However, recurrences and neglected feet are still a challenge today. An understanding of the pathophysiology of the disease, as well as of the anatomy and local biomechanics and a thorough clinical and radiological evaluation of patients are essential to understanding the limits of the method and choosing the best treatment.

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.

Peroneal Nerve Dysfunction in Patients with Clubfoot Deformity: Evaluation of Clinical Presentation and Treatment

Backgroud

Complete peroneal nerve dysfunction associated with congenital clubfoot is uncommonly reported. Our retrospective study highlights the recognition of clinical presentation and mid-term outcomes of treatment in these patients.

Methods

Eight out of 658 patients undergoing treatment for clubfoot were identified with unilateral complete peroneal nerve dysfunction associated with congenital clubfoot. Three patients presented primarily to our center; 5 were treated elsewhere initially. All patients were treated with Ponseti casts, Achilles tenotomy, and subsequent foot abduction bracing. Diagnosis of complete peroneal nerve dysfunction was confirmed using nerve conduction velocity studies in all patients. After full-time bracing, an insole polythene molded ankle foot orthosis was given. Three patients underwent tibialis posterior transfer to improve foot dorsiflexor power.

Results

The mean age at presentation was 1.3 years (range, 1 week–5 years). All patients had prominence of lateral 3 metatarsal heads and dimpling of intermetatarsal spaces. At a mean follow-up of 5.1 years, mean shortening of 1.2 cm in tibia (range, 1–2.5 cm) and mean calf wasting of 4.4 cm were observed. There was no relapse of any clubfoot deformity till the final follow-up.

Conclusions

Prominence of lateral metatarsal heads and dimpling of intermetatarsal spaces should raise early suspicion of peroneal nerve dysfunction. Standard Ponseti protocol is useful in treatment of these patients. Tibialis posterior transfer to dorsum partially restores the ankle dorsiflexion.

Genotype-phenotype correlation in clubfoot (talipes equinovarus)

Clubfoot (talipes equinovarus) is a congenital malformation affecting muscles, bones, connective tissue and vascular or neurological structures in limbs. It has a complex aetiology, both genetic and environmental. To date, the most important findings in clubfoot genetics involve PITX1 variants, which were linked to clubfoot phenotype in mice and humans. Additionally, copy number variations encompassing TBX4 or single nucleotide variants in HOXC11, the molecular targets of the PITX1 transcription factor, were linked to the clubfoot phenotype. In general, genes of cytoskeleton and muscle contractile apparatus, as well as components of the extracellular matrix and connective tissue, are frequently linked with clubfoot aetiology. Last but not least, an equally important element, that brings us closer to a better understanding of the clubfoot genotype/phenotype correlation, are studies on the two known animal models of clubfoot-the pma or EphA4 mice. This review will summarise the current state of knowledge of the molecular basis of this congenital malformation.

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.

Development of foot length in children with congenital clubfoot up to 7 years of age: a prospective follow-up study

Background

Clubfeet are typically shorter than normal feet. This study aimed first to describe the development of foot length in a consecutive series of children with congenital clubfoot and second to relate foot length to development of relapse and motion quality.

Methods

Foot length was measured every 6 months in 72 consecutive children with congenital clubfoot (29 bilateral) aged from 2 to 7 years. The initial treatment was nonsurgical followed by standardized orthotic treatment. Foot length growth rate was calculated every half year. In children with unilateral clubfeet, the difference in foot length between the clubfoot and the contralateral foot was calculated. Motion quality was evaluated by the Clubfoot Assessment Protocol (CAP). Student’s t test, the Mann–Whitney U test and Spearman’s correlation were used for group comparisons. Bonferroni correction was used when multiple comparisons were performed.

Results

Clubfeet were smaller (P < 0.001) than reference feet at all ages but had a similar growth rate up to age 7. Unilateral clubfeet with greater difference in size compared with the contralateral foot at the first measurement, relapsed more frequently (P = 0.016) and correlated with poorer motion quality (r = 0.4; P = 0.011).

Conclusions

As previously reported, clubfeet were smaller than reference feet at all ages. The growth rate, however, was similar between clubfeet and reference feet. Children with unilateral clubfeet and greater foot length difference at 2 years of age had a higher tendency to relapse and poorer motion quality at 7 years of age, indicating that foot length could be used as a prognostic tool.

Association Between TPM1 Gene Polymorphisms and Idiopathic Congenital Talipes Equinovarus Risk in a Chinese Population

Background: Idiopathic congenital talipes equinovarus (ICTEV) is one of the most common congenital deformities of children, and dysplasia of the striated muscle may be one of the causes of ICTEV. Previous studies have shown that polymorphisms of the rs4075583 SNP in the tropomyosin gene 1 (TPM1) were associated with ICTEV in Caucasian children. However, there are no studies investigating the correlations of TPM gene polymorphisms with the risk of ICTEV in Chinese children. Methods: We conducted a case-control study, including 430 children with ICTEV and 891 ICTEV-free children. We explored the potential correlations of three TPM gene polymorphisms (TPM1/rs4075583 G>A, tropomyosin gene 2 (TPM2)/rs2145925 C>T, and TPM2/rs2025126 G>A) with ICTEV risk. The three single nucleotide polymorphisms (SNPs) were genotyped using a TaqMan method. We calculated the odds ratios (ORs) and adjusted ORs and their 95% confidence intervals (CIs) to explore the associations between these selected SNP polymorphisms and ICTEV. Results: TPM1 rs4075583 A was found to be associated with an increased ICTEV risk (AA vs. GG: adjusted OR = 1.70, 95% CI = 1.15-2.49, p = 0.007; and GG/GA vs. AA: adjusted OR = 1.62, 95% CI = 1.14-2.31, p = 0.0071) after adjusting for age and sex. In addition, a risk effect of rs4075583 GA/AA with ICETV was observed for patients with affected right feet (adjusted OR = 1.62, 95% CI = 1.10-2.39, p = 0.014) in the stratified analysis. However, there were no significant differences in the risk for ICTEV associated with the rs2145925 and rs2025126 polymorphisms. Conclusion: These results indicate that the TPM1 rs4075583 G > A polymorphism is associated with ICTEV risk in a southern Chinese population; however, this finding needs to be confirmed in larger studies and through mechanistic studies.

Sport Ability during Walking Age in Clubfoot-Affected Children after Ponseti Method: A Case-Series Study

Background: The Ponseti method (PM) of manipulative treatment for congenital talipes equinovarus (CTEV) or clubfoot became widely adopted by pediatric orthopedic surgeons at the beginning of the mid-1990s with reports of long-term successful outcomes. Sports are crucial for children’s development and for learning good behavior. This study aimed to evaluate the sports activity levels in children treated with PM and to assess the different outcomes, according to gender and bilaterality. Methods: A total of 25 patients (44 feet) with CTEV treated by the PM were included in the study. The patients were clinically evaluated according to the Clubfoot Assessment Protocol, American Orthopedic Foot and Ankle Society, Ankle–Hindfoot score, the Foot and Ankle Disability Index (CAP, AOFAS, and FADI, respectively), and FADI Sport scores. Results: The overall mean CAP, AOFAS, FADI, and FADI Sport scores were 97.5 ± 6.4 (range 68.75–100), 97.5 ± 5.8 (range 73.00–100), 99.9 ± 0.6 (range 97.1–100), and 100, respectively. Gender and bilaterality did not affect outcome (p > 0.05). Conclusions: The data confirmed good-to-excellent outcomes in children with CTEV managed by PM. No limitations in sport performance or activity could be observed. In particular, male and female patients and patients with unilateral or bilateral involvement performed equally well.

Resistive index and peak systolic velocity for congenital talipes equinovarus: A color Doppler ultrasonography study

Objectives

This study aims to investigate whether resistive index (RI) and peak systolic velocity (PSV) are suitable parameters to determine if a clubfoot differs from feet of the normal population.

Patients and methods

Fifty-four feet of 27 clubfoot patients (22 males, 5 females; mean age 30.4±16.3 months; range, 5 to 72 months) were included in this retrospective study conducted between December 2017 and January 2019. Twenty-seven feet were conservatively treated, 19 had surgical treatment, and eight feet were healthy in patients with unilateral clubfoot. In addition, 22 feet of 11 normal controls (6 males, 5 females; mean age 33.4±15.3 months; range, 15 to 60 months) were studied. Color Doppler ultrasonography examinations were performed to evaluate the three major arteries of the leg and foot: dorsalis pedis (dp), tibialis posterior (tp), and popliteal (pop). Color filling, flow direction, spectral analysis, velocity, and RI were examined.

Results

With the exception of the dp artery RI, the PSV and RI values for all arteries differed significantly from those of the control group. There were no significant differences among the conservative, surgical, and healthy groups, while there were significant differences between each of the treated groups and the control group. Tibialis posterior artery PSV and pop artery RI were the best parameters to identify clubfoot and the cut-off points were 54 cm/second and 0.77, respectively.

Conclusion

Peak systolic velocity and RI may be accepted as important parameters for identification of clubfoot deformity. Tibialis posteriorartery PSV and pop artery RI are the best- detailed parameters for this examination.

HOXA9 rs3801776 G>A polymorphism increases congenital talipes equinovarus risk in a Chinese population

BACKGROUND

Congenital talipes equinovarus (CTEV) is the most common congenital deformity in children, and muscular dysplasia plays a potential role in the etiology of CTEV. Notably, previous studies have found that HOXA9 rs3801776 and TPM2 rs2025126 genetic polymorphisms play important roles in regulating muscle development in Caucasian children; however, there is a lack of investigations conducted in Chinese children.

METHODS

We conducted a hospital-based, case-control study of 189 children with CTEV and 457 CTEV-free children aiming to examine the associations between these two polymorphisms and CTEV susceptibility. The rs3801776 (G>A) and rs2025126 (G>A) polymorphisms were genotyped using TaqMan. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to measure the associations between the selected polymorphisms and CTEV susceptibility.

RESULTS

We found that rs3801776A was associated with increased CTEV risk (GA versus GG: adjusted OR = 1.81, 95% CI = 1.22-2.69, p = 0.0031; AA versus GG: adjusted OR = 2.19, 95% CI = 1.28-3.73, p = 0.0041; GA/AA versus GG: adjusted OR = 1.89, 95% CI = 1.29-2.76, p = 0.0010). In a stratified analysis, the risk effect of rs3801776 GA/AA was observed in both unilateral and bilateral patients.

CONCLUSIONS

The present study suggests that the rs3801776 G>A polymorphism is associated with CTEV risk in Chinese children; however, this conclusion should be validated in larger studies.

Does idiopathic congenital talipes equinovarus have an impact on attainment of developmental milestones? A multicentre international study

PURPOSE

The Ponseti method is a well-established approach to treating clubfoot. Potentially, both the underlying pathology and adherence to post-correction bracing can affect lower limb function and age of independent standing and walking. This cohort study investigates the age at which infants with idiopathic clubfoot treated using the Ponseti method achieved three selected developmental milestones and whether or not this correlated with treatment compliance.

METHODS

A prospectively collected database from four centres was visited. Inclusion criteria were patients with idiopathic clubfoot with no comorbidities or prior treatment. Age at attainment of independent standing, walking, nocturnal continence was compared across three groups: I) congenital talipes equinovarus (CTEV) children compliant with treatment; II) CTEV children non-compliant with treatment; and III) typically-developed siblings. Minimum follow-up was five years.

RESULTS

In all, 130 patients (198 feet) fitted the inclusion criteria: 43:87 (F:M). Standing was achieved by a mean 12.0 months in group I (sd 2.50); 12.0 months (sd 2.0) in II and ten months (sd 3.0) in III. Walking was achieved by a mean 15 months (sd 4.0) in group I, 14 months (sd 1.75) in II and 12 months (sd 3) in III, respectively. Both the compliant and non-compliant CTEV children were significantly slower at achieving standing and walking compared to sibling controls (p < 0.0001). There was no significant difference between age of nocturnal continence between the three groups.

CONCLUSION

Infants with idiopathic clubfoot treated according to the Ponseti method achieve independent standing and walking approximately two months later than their typically-developed siblings. The delay is not related to the use of the foot abduction brace.

LEVEL OF EVIDENCE

III.

Poor Evertor Muscle Activity Is a Predictor of Recurrence in Idiopathic Clubfoot Treated by the Ponseti Method: A Prospective Longitudinal Study With a 5-Year Follow-up

BACKGROUND

After successful primary correction of the deformity in idiopathic clubfoot with the Ponseti method, recurrence has been reported to affect up to 40% of children. So far, it has been difficult to predict which feet are at risk of recurrence, despite numerous studies investigating various potential risk factors. The foot abduction brace (FAB) has been the standard of care in preventing recurrence but, even with excellent compliance, recurrences still occur. Increasingly, evidence points to a congenital neuromuscular imbalance constituting the deforming forces present in clubfoot. Poor evertor muscle activity has been cited specifically as a potential risk factor for recurrence. The aim of this study is to evaluate whether poor evertor muscle activity on clinical examination can predict recurrence in idiopathic clubfoot at 5-year follow-up.

METHODS

Data were collected prospectively on patients treated at our tertiary physiotherapy-led Ponseti service between 2010 and 2015. Hospital ethical approval was obtained. Sex, age, laterality, Pirani score, number of casts, brace compliance, and evertor activity were recorded. Evertor muscle activity was scored in a semiquantitative repeatable manner: 0, 0.5, or 1 as previously described. Recurrence was defined as deterioration of any of the 4 components of the deformity following a previously complete correction.

RESULTS

In total, 104 patients (172 feet) were included in the study, 76 patients had good evertor activity, and 28 demonstrated poor evertor activity. The mean follow up was 62 months (range, 41 to 71 mo); 18.3% of the patients (19/104) had recurrence treated with repeat casting; 13.5% (14/104) of the patients required additional surgery following recasting. Recurrence was highly associated with poor evertor activity (P<0.01).

CONCLUSIONS

Results at 5 years confirm that a semiquantitative evertor muscle activity assessment can predict recurrence and should be added to the routine clinical assessment in order to assist with individualizing patient's treatment strategies.

LEVEL OF EVIDENCE

Level II.

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.

Use Of Ankle Immobilization In Evaluating Treatments To Promote Longitudinal Muscle Growth In Mice

INTRODUCTION

Difficulty in modeling congenital contractures (deformities of muscle-tendon unit development that include shortened muscles and lengthened tendons) has limited research of new treatments.

METHODS

Early immobilization of the ankle in prepuberal mice was used to produce deformities similar to congenital contractures. Stretch treatment, electrostimulation, and local intramuscular injection of a follistatin analog (FST-288) were assessed as therapeutic interventions for these deformities.

RESULTS

Ankle immobilization at full plantarflexion and 90 ° created tendon lengthening and muscle shortening in the tibialis anterior and soleus. Stretch treatment produced minimal evidence for longitudinal muscle growth and electrostimulation provided no additional benefit. Stretch treatment with FST-288 produced greater longitudinal muscle growth and less tendon lengthening, constituting the best treatment response.

DISCUSSION

Ankle immobilization recapitulates key morphologic features of congenital contracture, and these features can be mitigated by a combination of stretch and pharmacological approaches that may be useful in patients. Muscle Nerve 58: 718-725, 2018.

Sidestep-induced neuromuscular miswiring causes severe locomotion defects in Drosophila larvae

Mutations in motor axon guidance molecules cause aberrant projection patterns of motor nerves. As most studies in Drosophila have analysed these molecules in fixed embryos, the consequences for larval locomotion are entirely unexplored. Here, we took advantage of sidestep (side)-mutant larvae that display severe locomotion defects because of irreparable innervation errors. Mutations in side affected all motor nerve branches and all body wall regions. Innervation defects were non-stereotypical, showing unique innervation patterns in each hemisegment. Premature activation of Side in muscle precursors abrogated dorsal migration of motor nerves, resulting in larvae with a complete loss of neuromuscular junctions on dorsal-most muscles. High-speed videography showed that these larvae failed to maintain substrate contact and inappropriately raised both head and tail segments above the substrate, resulting in unique ‘arching’ and ‘lifting’ phenotypes. These results show that guidance errors in side mutants are maintained throughout larval life and are asymmetrical with respect to the bilateral body axis. Together with similar findings in mice, this study also suggests that miswiring could be an underlying cause of inherited movement disorders.

The etiology of idiopathic congenital talipes equinovarus: a systematic review

Background

Also known as clubfoot, idiopathic congenital talipes equinovarus (ICTEV) is the most common pediatric deformity and occurs in 1 in every 1000 live births. Even though it has been widely researched, the etiology of ICTEV remains poorly understood and is often described as being based on a multifactorial genesis. Genetic and environmental factors seem to have a major role in the development of this disease. Thus, the aim of this review is to analyze the available literature to document the current evidence on ICTEV etiology.

Methods

The literature on ICTEV etiology was systematically reviewed using the following inclusion criteria: studies of any level of evidence, reporting clinical or preclinical results, published in the last 20 years (1998–2018), and dealing with the etiology of ICTEV.

Results

A total of 48 articles were included. ICTEV etiology is still controversial. Several hypotheses have been researched, but none of them are decisive. Emerging evidence suggests a role of several pathways and gene families associated with limb development (HOX family; PITX1-TBX4), the apoptotic pathway (caspases), and muscle contractile protein (troponin and tropomyosin), but a major candidate gene has still not been identified. Strong recent evidence emerging from twin studies confirmed major roles of genetics and the environment in the disease pathogenesis.

Conclusions

The available literature on the etiology of ICTEV presents major limitations in terms of great heterogeneity and a lack of high-profile studies. Although many studies focus on the genetic background of the disease, there is lack of consensus on one or multiple targets. Genetics and smoking seem to be strongly associated with ICTEV etiology, but more studies are needed to understand the complex and multifactorial genesis of this common congenital lower-limb disease.

The developmental and genetic basis of 'clubfoot' in the peroneal muscular atrophy mutant mouse

Genetic factors underlying the human limb abnormality congenital talipes equinovarus ('clubfoot') remain incompletely understood. The spontaneous autosomal recessive mouse 'peroneal muscular atrophy' mutant (PMA) is a faithful morphological model of human clubfoot. In PMA mice, the dorsal (peroneal) branches of the sciatic nerves are absent. In this study, the primary developmental defect was identified as a reduced growth of sciatic nerve lateral motor column (LMC) neurons leading to failure to project to dorsal (peroneal) lower limb muscle blocks. The pma mutation was mapped and a candidate gene encoding LIM-domain kinase 1 (Limk1) identified, which is upregulated in mutant lateral LMC motor neurons. Genetic and molecular analyses showed that the mutation acts in the EphA4-Limk1-Cfl1/cofilin-actin pathway to modulate growth cone extension/collapse. In the chicken, both experimental upregulation of Limk1 by electroporation and pharmacological inhibition of actin turnover led to defects in hindlimb spinal motor neuron growth and pathfinding, and mimicked the clubfoot phenotype. The data support a neuromuscular aetiology for clubfoot and provide a mechanistic framework to understand clubfoot in humans.

Influence of muscle groups' activation on proximal femoral growth tendency

Muscle and joint contact force influence stresses at the proximal growth plate of the femur and thus bone growth, affecting the neck shaft angle (NSA) and femoral anteversion (FA). This study aims to illustrate how different muscle groups’ activation during gait affects NSA and FA development in able-bodied children. Subject-specific femur models were developed for three able-bodied children (ages 6, 7, and 11 years) using magnetic resonance images. Contributions of different muscle groups—hip flexors, hip extensors, hip adductors, hip abductors, and knee extensors—to overall hip contact force were computed. Specific growth rate for the growth plate was computed, and the growth was simulated in the principal stress direction at each element in the growth front. The predicted growth indicated decreased NSA and FA (of about \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$0.1 {^{\circ }}$$\end{document}0.1∘ over a four-month period) for able-bodied children. Hip abductors contributed the most, and hip adductors, the least, to growth rate. All muscles groups contributed to a decrease in predicted NSA (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim $$\end{document}∼0.01\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${^{\circ }}$$\end{document}∘–0.04\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${^{\circ }})$$\end{document}∘) and FA (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim $$\end{document}∼0.004\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${^{\circ }}$$\end{document}∘–\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$0.2{^{\circ }}$$\end{document}0.2∘), except hip extensors and hip adductors, which showed a tendency to increase the FA (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim $$\end{document}∼0.004\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${^{\circ }}$$\end{document}∘–\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$0.02{^{\circ }}$$\end{document}0.02∘). Understanding influences of different muscle groups on long bone growth tendency can help in treatment planning for growing children with affected gait.

The 2017 ABJS Nicolas Andry Award: Advancing Personalized Medicine for Clubfoot Through Translational Research

BACKGROUND

Clubfoot is one of the most common pediatric orthopaedic disorders. While the Ponseti method has revolutionized clubfoot treatment, it is not effective for all patients. When the Ponseti method does not correct the foot, patients are at risk for lifelong disability and may require more-extensive surgery.

QUESTIONS/PURPOSES

(1) What genetic and morphologic abnormalities contribute to the development of clubfoot? (2) How can this information be used to devise personalized treatment paradigms for patients with clubfoot?

METHODS

Human gene sequencing, molecular genetic engineering of mouse models of clubfoot, MRI of clubfoot, and development of new treatment methods all have been used by our group to understand the biological basis and improve therapy for this group of disorders.

RESULTS

We gained new insight into clubfoot pathogenesis from our discovery that mutations in the PITX1-TBX4-HOXC transcriptional pathway cause familial clubfoot and vertical talus in a small number of families, with the unique lower limb expression of these genes providing an explanation for the lack of upper extremity involvement in these disorders. MRI studies revealed corresponding morphologic abnormalities, including hypomorphic muscle, bone, and vasculature, that are not only associated with these gene mutations, but also are biomarkers for treatment-resistant clubfoot.

CONCLUSIONS

Based on an understanding of the underlying biology, we improved treatment methods for neglected and syndromic clubfoot, developed new treatment for congenital vertical talus based on the principles of the Ponseti method, and designed a new dynamic clubfoot brace to improve strength and compliance.

Development of congenital clubfoot during growth: a long-term study on the basis of pedobarography, biomechanics, and magnetic resonance imaging measurements of muscle volumes

The aim of this study was to clarify the degree to which the operated congenital asymptomatic clubfoot still shows malpositions or whether it approaches a physiological development with increasing age. Clubfeet of 12 children were examined repeatedly over up to 10 years using pedobarography. The muscle volumes of the lower legs were investigated with MRI and compared with those of a healthy control group. Although some characteristics of clubfoot remained in the plantar pressure distribution, a gradual decrease in the heel and metatarsus load accompanied by an increase in the forefoot load could be registered as is typical for a developing healthy child's foot. The MRI showed a reduced volume of all muscles of the affected lower leg. A correlation was detected between the measured moments in the upper and lower ankle joints and the volumes of the muscles that move these joints. Even though a functional and anatomical separation between the two groups existed, the general developmental changes during growth were similar. The combination of pedobarographic data and derived joint moments with MRI-measured muscle volumes indicated that higher ankle joint moments in clubfoot were associated with smaller muscle volume and were therefore generated by higher joint rigidity.

Evolution of clubfoot deformity and muscle abnormality in the Ponseti method: evaluation with the Dimeglio score

PURPOSE

The modality of progression of the correction along casting sessions of Ponseti method has been poorly investigated and information regarding evolution of muscular abnormalities is missing. The aim of the study was to investigate dynamics of correction of the different components of clubfoot deformity in a clinical setting.

METHODS

In a prospective study, 124 clubfeet consecutively treated by a single orthopaedic surgeon were evaluated with the Dimeglio system at each casting session and score progression was determined.

RESULTS

For each component a typical pattern was recorded. Cavus and medial crease showed a rapid correction. Rotation, adduction and varus corrected gradually and simultaneously. The posterior crease usually persisted until final cast was discontinued. Equinus improved progressively after each cast and then to a larger extent with Achilles tenotomy. The parameter describing poor muscular condition, reported at presentation in 39 feet (31.5%), was the only item showing extremely different dynamics of correction (from rapid and complete resolution to persistence at last cast removal), which could be explained by the large diversity of entities included (hypertonia, imbalance, fatty infiltration, fibrosis, aplasia).

CONCLUSIONS

This study confirmed that dynamics of correction in clinical setting correspond essentially to theoretical principles of Ponseti method. Muscle abnormalities are not uncommon in clubfeet and have great influence on the progression of correction. If abnormalities are recorded, their evolution along the treatment should be monitored. A more objective evaluation would be required.

What is the fate of clubfoot patients treated by posteromedial release?

INTRODUCTION

Management and long-term results of operatively treated clubfoot deformity still remains controversial. The aim of this study was to evaluate the radiological and clinical results of adult clubfoot patients treated with posteromedial release.

MATERIALS AND METHODS

Between 2005 and 2012, we evaluated patients with congenital foot deformities regarding clubfoot who were operatively treated with complete posteromedial release. Out of 320 patients evaluated, 29 patients (40 feet) were included the study. We also included foot radiographies of 40 healthy adults. Talocalcaneal angle on the dorsoplantar projection (TC-DP) and lateral projection (TC-L) and talus-first metatarsal angle on the dorsoplantar projection (TFM-DP) were measured for both clubfeet and control groups. Laaveg-Ponseti functional rating system was used for clinical evaluation and measurement of lower leg circumference was used for detection of atrophy.

RESULTS

The average age was 21.5 years (range 19-34). The mean TC-DP angle was 16.97 in the clubfeet group and 21.03 in the control group. The mean TC-L angle was 23.34 in the clubfeet group and 33.98 in the control group. The mean TFM-DP angle was 9.02 in the clubfeet group and 7.9 in control group. There were statistically significant difference between clubfoot and control groups regarding the TC-DP angle and the TC-L angle. The average Laaveg-Ponseti score was 74 points (range 42-96). While no significant correlations could be detected between the TC-DP angle, the TC-L angle, the TFM-DP angle and the functional score, a significant correlation was detected between circumferential measurement of lower leg and functional score (p = 0.04).

CONCLUSION

Functional outcome may be affected by lower leg muscular atrophy instead of foot alignment disturbance. Lastly we believe that results for treatment of clubfoot-a three-dimensional deformity-need to be evaluated with three-dimensional imaging techniques.

Soft-Tissue Abnormalities Associated with Treatment-Resistant and Treatment-Responsive Clubfoot: Findings of MRI Analysis

BACKGROUND

Clubfoot treatment commonly fails and often results in impaired quality of life. An understanding of the soft-tissue abnormalities associated with both treatment-responsive and treatment-resistant clubfoot is important to improving the diagnosis of clubfoot, the prognosis for patients, and treatment.

METHODS

Twenty patients with clubfoot treated with the Ponseti method were recruited for magnetic resonance imaging (MRI) of their lower extremities. Among these were seven patients (six unilateral cases) with treatment-responsive clubfoot and thirteen patients (five unilateral cases) with treatment-resistant clubfoot. Demographic information and physical examination findings were recorded. A descriptive analysis of the soft-tissue abnormalities was performed for both patient cohorts. For the patients with unilateral clubfoot, we calculated the percentage difference in cross-sectional area between the affected limb and the unaffected limb in terms of muscle, subcutaneous fat, intracompartment fat, and total area. With use of the Wilcoxon signed-rank test, we compared inter-leg differences in cross-sectional areas and the intracompartment adiposity index (IAI) between treatment-responsive and treatment-resistant groups. The IAI characterizes the cross-sectional area of fat within a muscle compartment.

RESULTS

Extensive soft-tissue abnormalities were more present in patients with treatment-resistant clubfoot than in patients with treatment-responsive clubfoot. Treatment-resistant clubfoot abnormalities included excess epimysial fat and intramuscular fat replacement as well as unique patterns of hypoplasia in specific muscle groups that were present within a subset of patients. Among the unilateral cases, treatment-resistant clubfoot was associated with a significantly greater difference in muscle area between the affected and unaffected limb (-47.8%) compared with treatment-responsive clubfoot (-26.6%) (p = 0.02), a significantly greater difference in intracompartment fat area between the affected and unaffected limb (402.6%) compared with treatment-responsive clubfoot (9%) (p = 0.01), and a corresponding higher inter-leg IAI ratio (8.7) compared with treatment-responsive clubfoot (1.5) (p = 0.01).

CONCLUSIONS

MRI demonstrated a range of soft-tissue abnormalities in patients, including unique patterns of specific muscle-compartment aplasia/hypoplasia that were present in patients with treatment-resistant clubfoot and not present in patients with treatment-responsive clubfoot. Correlations between MRI, physical examination, and treatment responsiveness may aid in the development of a prognostic classification system for clubfoot.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Etiopathogenesis of equinovarus foot malformations

Congenital talipes equinovarus (CTEV) is the most common musculoskeletal birth defect affecting approximately 1/700-1/1000 of liveborns. Even though extensive epidemiological and genetic studies have been carried out to address its causes, the precise mechanisms leading to this common birth defect remain elusive. CTEV is a multifactorial disorder, hence the combination of genetic and environmental factors are known contributors to this developmental abnormality. So far a handful of genes involved in limb patterning like PITX1, HOXA, HOXD, TBX4, and RBM10, as well as genes involved in muscle contraction, have been identified as possible players. Among many environmental factors investigated, maternal smoking seems to hold the strongest consistent association with this disorder. This article will review and discuss some of the most common genetic and environmental factors associated with the etiopathogenesis of CTEV.

Update on clubfoot

Congental talipes equinovarus, or clubfoot, remains one of the commonest congenital limb deformities. The genetics of this condition are not yet fully understood. It is increasingly being diagnosed on prenatal ultrasound with implications for prenatal counselling. With the widespread acceptance of the Ponseti method of clubfoot treatment major surgical interventions are needed much less frequently and long-term outcomes are improved.

The Ponseti method for the treatment of congenital club foot: review of the current literature and treatment recommendations

The Ponseti method has become the gold standard of care for the treatment of congenital club foot. Despite numerous articles in MEDLINE reporting results from around the globe there are still crucial details of the Ponseti method which seem to be less commonly known or considered. The Ponseti method is not only a detailed method of manipulation and casting but also of preventing and treating relapse. Recommendations on how to correct complex club foot have resulted in an almost 100 % initial correction rate. The foot abduction brace is crucial for preventing relapse and is still a challenge for families and sometimes doctors alike. Experience and knowledge on how to support the parents, how to set and apply the brace in the best possible way and how to solve problems that can be encountered during the bracing period are essential to ensure compliance. Regular follow-up visits are necessary to be able to detect early signs of recurrence and prevent full relapse by enforcing abduction bracing, recasting or performing tibialis anterior tendon transfer. Recent midterm outcome studies have shown that by following the Ponseti treatment regime in all aspects it is possible to prevent open joint surgery in almost all cases. The body of literature of the last decade has evaluated many steps and aspects of the Ponseti method and gives valuable answers to questions encountered in daily practice. This review of the current literature and recommendations on the different aspects of the Ponseti method aims to promote understanding of the treatment regime and its' details.

Effect of Achilles tenotomy on congenital clubfoot-associated calf-muscle atrophy: an ultrasonographic study

BACKGROUND

The Ponseti method for treating congenital clubfoot requires Achilles tenotomy to be performed toward the end of serial casting. However, it remains unclear if Achilles tenotomy has a negative effect on clubfoot-associated calf-muscle atrophy. We therefore investigated this issue by ultrasonographic examination.

MATERIALS AND METHODS

We studied 36 patients with congenital clubfoot who were treated with the Ponseti method and underwent Achilles tenotomy. Only unilateral cases were evaluated to enable comparison of the severity of atrophy and its changes over time between affected and unaffected sides. Tenotomy was performed at a mean age of 10.2 weeks after birth (range 8-16 weeks). The transverse and anteroposterior diameters of the calf muscles on the unaffected and affected sides were measured ultrasonographically by two examiners. The mean observation period was 27 months (range 24-34 months). Measurements were performed within 6 months after tenotomy, between 7 and 17 months after tenotomy, and at the final assessment. Differences between the diameters of the affected and unaffected sides at each time point, and changes in the diameters over time were determined. The data were analyzed by use of one-way ANOVA and repeated-measures ANOVA.

RESULTS

Tendon healing and gliding were achieved in all cases. There were significant differences between the diameters of the unaffected and affected sides at all measurement points (transverse p < 0.005, anteroposterior p < 0.01). The diameters of calf muscles on both sides increased significantly over time (p < 0.0001). The patterns of change in diameter were similar on both sides.

CONCLUSION

The transverse and anteroposterior diameters of the calf muscles differed significantly between the affected and unaffected sides after Achilles tenotomy, but there were no significant differences in changes over time. These results suggest that Achilles tenotomy had no negative short-term effects on calf-muscle atrophy associated with clubfoot.

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.

An MRI volumetric study for leg muscles in congenital clubfoot

PURPOSE

To investigate both volume and length of the three muscle compartments of the normal and the affected leg in unilateral congenital clubfoot.

METHODS

Volumetric magnetic resonance imaging (VMRI) of the anterior, lateral and postero-medial muscular compartments of both the normal and the clubfoot leg was obtained in three groups of seven patients each, whose mean age was, respectively, 4.8 months, 11.1 months and 4.7 years. At diagnosis, all the unilateral congenital clubfeet had a Pirani score ranging from 4.5 to 5.5 points, and all of them had been treated according to a strict Ponseti protocol. All the feet had percutaneous lengthening of the Achilles tendon.

RESULTS

A mean difference in both volume and length was found between the three muscular compartments of the leg, with the muscles of the clubfoot side being thinner and shorter than those of the normal side. The distal tendon of the tibialis anterior, peroneus longus and triceps surae (Achilles tendon) were longer than normal on the clubfoot side.

CONCLUSIONS

Our study shows that the three muscle compartments of the clubfoot leg are thinner and shorter than normal in the patients of the three groups. The difference in the musculature volume of the postero-medial compartment between the normal and the affected side increased nine-fold from age group 2 to 3, while the difference in length increased by 20 %, thus, showing that the muscles of the postero-medial compartment tend to grow in both thickness and length much less than the muscles of the other leg compartments.

Genetics of clubfoot

Modern advances in genetics have allowed investigators to identify the complex etiology of clubfoot. It has become increasingly apparent that clubfoot is a heterogeneous disorder with a polygenetic threshold model explaining its inheritance patterns. Several recent genetic studies have identified a key developmental pathway, the PITX1-TBX4 transcriptional pathway, as being important in clubfoot etiology. Both PITX1 and TBX4 are uniquely expressed in the hindlimb, which helps explain the foot phenotype seen with mutations in these transcription factors. Future studies are needed to develop animal models to determine the exact mechanisms by which these genetic abnormalities cause clubfoot and to test other hypotheses of clubfoot pathogenesis.

Pitx1 haploinsufficiency causes clubfoot in humans and a clubfoot-like phenotype in mice

Clubfoot affects 1 in 1000 live births, although little is known about its genetic or developmental basis. We recently identified a missense mutation in the PITX1 bicoid homeodomain transcription factor in a family with a spectrum of lower extremity abnormalities, including clubfoot. Because the E130K mutation reduced PITX1 activity, we hypothesized that PITX1 haploinsufficiency could also cause clubfoot. Using copy number analysis, we identified a 241 kb chromosome 5q31 microdeletion involving PITX1 in a patient with isolated familial clubfoot. The PITX1 deletion segregated with autosomal dominant clubfoot over three generations. To study the role of PITX1 haploinsufficiency in clubfoot pathogenesis, we began to breed Pitx1 knockout mice. Although Pitx1(+/-) mice were previously reported to be normal, clubfoot was observed in 20 of 225 Pitx1(+/-) mice, resulting in an 8.9% penetrance. Clubfoot was unilateral in 16 of the 20 affected Pitx1(+/-) mice, with the right and left limbs equally affected, in contrast to right-sided predominant hindlimb abnormalities previously noted with complete loss of Pitx1. Peroneal artery hypoplasia occurred in the clubfoot limb and corresponded spatially with small lateral muscle compartments. Tibial and fibular bone volumes were also reduced. Skeletal muscle gene expression was significantly reduced in Pitx1(-/-) E12.5 hindlimb buds compared with the wild-type, suggesting that muscle hypoplasia was due to abnormal early muscle development and not disuse atrophy. Our morphological data suggest that PITX1 haploinsufficiency may cause a developmental field defect preferentially affecting the lateral lower leg, a theory that accounts for similar findings in human clubfoot.

Vascular abnormalities correlate with decreased soft tissue volumes in idiopathic clubfoot

BACKGROUND

Lower extremity vascular anomalies have been described for patients with clubfoot but few imaging studies have investigated effects on soft tissues such as fat and muscle. To make these assessments we need noninvasive, noncontrast agents to more safely image children.

QUESTIONS/PURPOSES

We describe a novel noninvasive imaging protocol to identify vascular and soft tissue abnormalities in the lower limbs of patients with clubfoot and determine whether these abnormalities are present in patients who had recurrent clubfoot.

PATIENTS AND METHODS

Three-dimensional noncontrast-enhanced MR angiography was used to identify vascular, bone, and soft tissue abnormalities in patients with clubfoot. We determined whether these abnormalities were more common in patients who had experienced recurrent clubfoot.

RESULTS

Four patients with isolated unilateral clubfoot had arterial anomalies in the clubfoot limb. All patients had less muscle volume in the affected limb, and nine of 11 patients (82%) had less subcutaneous fat, with a mean difference of 0.56 cm(3) ± 0.36 cm(3) (range, 0.08-1.12 cm(3)). Vascular anomalies and decreased fat and muscle volumes were present in all three patients with recurrent clubfoot.

CONCLUSIONS

We found a high frequency of vascular and soft tissue anomalies in the affected limbs of patients with unilateral clubfoot that may correlate with response to treatment.

Micro-magnetic resonance imaging and embryological analysis of wild-type and pma mutant mice with clubfoot

Gross similarities between the external appearance of the hind limbs of the peroneal muscle atrophy (pma) mouse mutant and congenital talipes equinovarus (CTEV), a human disorder historically referred to as ‘clubfoot’, suggested that this mutant could be a useful model. We used micro-magnetic resonance imaging to visualize the detailed anatomy of the hind limb defect in mutant pma mice and performed 3D comparisons between mutant and wild-type hind limbs. We found that the pma foot demonstrates supination (i.e. adduction and inversion of the mid foot and fore foot together with plantar flexion of the ankle and toes) and that the tibiale and distal tarsals display 3D abnormalities in positioning. The size and shape of the tibia, fibula, tarsal and metatarsal bones are similar to the wild-type. Hypoplasia of the muscles in the antero-lateral (peroneal) compartment was also demonstrated. The resemblance of these features to those seen in CTEV suggests that the pma mouse is a possibly useful model for the human condition. To understand how the observed deformities in the pma mouse hind foot arise during embryonic development, we followed the process of foot rotation in both wild-type and pma mutant mice. Rotation of the hind foot in mouse embryos of wild-type strains (CD-1 and C57/Black) occurs from embryonic day 14.5 onwards with rotation in C57/Black taking longer. In embryos from both strains, rotation of the right hind foot more commonly precedes rotation of the left. In pma mutants, the initiation of rotation is often delayed and rotation is slower and does not reach completion. If the usefulness of the pma mutant as a model is confirmed, then these findings on pma mouse embryos, when extrapolated to humans, would support a long-standing hypothesis that CTEV is due to the failure of completion of the normal process of rotation and angulation, historically known as the ‘arrested development hypothesis’.