A histochemical study of muscle in club foot

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.

Congenital Talipes Equinovarus: Results of Treatment and Are We Bracing Effectively?

The aim of this retrospective study was to assess our management of Congenial Talipes Equinovarus (CTEV) in relation to national standards published by the British Society for Children's Orthopaedic Surgery (BSCOS). A secondary aim was to evaluate if a more tailored bracing regime than advocated in the traditional Ponseti technique, would be appropriate for some cases of CTEV. One hundred and thirty-three feet in 96 patients were treated between June 2006 and January 2016. All patients were clinically assessed prospectively by the senior author at initial presentation using the Harrold & Walker classification system. A combination of the senior author's database, Elogbook and trust IT systems were used for data collection. The results of Ponseti surgical procedures such as tendoachilles release and tibialis transfer fell within the BSCOS guidelines. The rate of radical subtalar surgical release was higher than advocated (12.3%) which was partly due to the number of primary syndromal patients in the series. There was a significantly lower mean time spent in bracing of 14.3 months (95% confidence interval 14.8-19.3) compared to recommended national guidelines. There was a clinically significant difference in the lower relapse rate of female patients compared to male patients and also a higher propensity of surgical intervention in male patients. In addition, there was a statistically significant difference in both time spent in bracing, between H&W classifications and between patients who had bracing removed pre walking age or post walking age. This potentially demonstrates a more tailored bracing regime may be possible when applied to less severely affected feet and the condition may be more benign in female cases.

Early ultrasonographic evaluation of idiopathic clubfeet treated with manipulations, casts, and Botox(®): a double-blind randomized control trial

BACKGROUND

The manipulations, casts, and Botox(®) method for treating idiopathic clubfoot is an alternative non-surgical treatment method. Botox(®)-induced reversible muscle paralysis of the gastrocsoleus enables a physician to manipulate and cast the clubfoot in greater dorsiflexion. Ultrasound is incorporated during the early treatment stages to monitor the underlying physiology of the muscle-tendon unit following Botox(®).

METHODS

Ultrasonographic evaluation was performed parallel to a double-blind randomized control trial administering Botox(®) or placebo to correct clubfoot. Patients underwent two-dimensional ultrasound to monitor the length changes to the gastrocsoleus and Achilles tendon unit at two time points: pre-injection (baseline) and 6 weeks post-blinded injection. Gastrocsoleus and Achilles tendon length measurements were analyzed among placebo, Botox(®) and contralateral controls using repeated measures ANOVA.

RESULTS

The baseline gastrocsoleus length of the clubfoot (322.4 pixels) before blinded injection appears shorter than controls (337.5 pixels), but fails to reach significance (p = 0.05). The complex length within each of the three treatment groups displayed no significant change between baseline and 6 weeks. The complex-tendon ratio and muscle-tendon ratio of the Botox(®) treatment group was significantly decreased compared to controls (p = 0.049 and 0.042, respectively). Briefly, when expressed as a proportion, an increase in Achilles tendon length and decrease in gastrocsoleus is observed when clubfeet are treated with Botox(®).

CONCLUSIONS

Only in the Botox(®) treatment cohort did the muscle shrink to uncover tendon (seen as a decreased complex-tendon ratio and muscle-tendon ratio) over the 6-week interval to effectively increase tendon length with respect to the unit as a whole.

Walking capacity of children with clubfeet in primary school: something to worry about?

Although the main aim of clubfoot correction is to create a foot without limitations in daily activities and sport, studies on the walking capacity of children with corrected clubfeet are rare. In this cross-sectional study, the outcome of the six-minute walking test in 44 children with clubfeet (16 unilateral and 28 bilateral, mean age 8.57±2.45 years) was compared with the reference values of Geiger, clinical status measured with the Clubfoot Assessment Protocol (CAP), and regression analysis used to calculate which CAP subgroup predicts walking capacity. The mean walking capacity was decreased to 79% (P<0.001) and was not influenced by unilaterality or bilaterality (P=0.437). The subgroup CAP morphology was a significant predictor (R=0.103; P=0.034). Knowing that walking capacity is only slightly decreased can help adjust expectations and set goals for training.

Pé torto congênito

Embora o pé torto congênito seja uma das deformidades congênitas mais comuns dos membros inferiores, ainda há controvérsias com relação à etiologia e ao tratamento. Apesar da frequência relativamente alta, o tratamento é desafiador, pois objetiva a obter um pé funcional, flexível, plantígrado e indolor, com resultados permanentes. O método de Ponseti destaca-se por propiciar resultados mais satisfatórios e diminuir a necessidade de cirurgias. Entretanto, o tratamento cirúrgico deve ser indicado após falha do tratamento conservador adequadamente realizado. A tendência atual consiste em evitar as extensas liberações cirúrgicas e, quando houver necessidade de cirurgia, preconizam-se correções localizadas, também conhecidas por liberações "à la carte". A perspectiva futura fundamenta-se em conhecer resultados de tratamento a longo prazo e novos conhecimentos sobre a etiologia do pé torto congênito, especialmente do ponto de vista genético, que poderão, eventualmente, auxiliar na determinação do prognóstico e até no tratamento. Nível de Evidência: Nível II, revisão sistemática.

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

PURPOSE

To investigate whether atrophy of the leg muscles present in congenital clubfoot (CCF) is primitive or secondary to treatment of the deformity.

METHODS

Magnetic resonance imaging (MRI) of both legs was taken in three cohorts of patients with unilateral congenital clubfoot (UCCF): eight untreated newborns (age range 10 days to 2 weeks); eight children who had been treated with the Ponseti method (age range 2-4 years); eight adults whose deformity had been corrected by manipulation and casting according to Ponseti, followed by a limited posterior release performed at age 2-3 months (age range 19-23 years). All of the treated patients wore a brace until 3 years of age. Muscles were measured on transverse MRI scans of both legs taken midway between the articular surface of the knee and the articular surface of the ankle, using a computer program (AutoCAD 2002 LT). The same program was used to measure leg muscles in the histologic cross sections of the legs of two fetuses with UCCF, spontaneously aborted at 13 and 19 weeks of gestation, respectively. Measurements of the whole cross section of the leg (total leg volume: TLV), of the muscular tissue (muscular tissue volume: MTV), and of the adipose tissue (adipose tissue volume: ATV) of the tibia, fibula, and of the other soft tissues (tendons, nerves, and vessels) were taken by using an interactive image analyzer (IAS 2000, Delta System, Milan, Italy).

RESULTS

Marked atrophy of the leg muscles on the clubfoot side was found in both fetuses and untreated newborns, with a percentage ratio of MTV between the normal and the affected leg of 1.3 and 1.5, respectively. Leg muscle atrophy increased with growth, and the percentage ratio of MTV between the normal and the affected leg was, respectively, 1.8 and 2 in treated children and adults. On the other hand, fatty tissue tended to increase relatively from birth to adulthood, but it could not compensate for the progressive muscular atrophy. As a result, the difference in TLV tended to increase from childhood to adulthood.

CONCLUSIONS

Our study shows that leg muscular atrophy is a primitive pathological component of CCF which is already present in the early stages of fetal CCF development and in newborns before starting treatment. Muscular atrophy increases with the patient's age, suggesting a mechanism of muscle growth impairment as a possible pathogenic factor of CCF.

Tibialis anterior tendon transfer after clubfoot surgery

Recurrent dynamic and structural deformities following clubfoot surgery are commonly due to residual muscle imbalance from a strong tibialis anterior muscle and weak antagonists. We asked whether subcutaneous tibialis anterior tendon transfer effectively treated recurrent deformities following clubfoot surgery and whether the presence of structural deformities influenced the outcome. The patients were divided into two groups: Group I, dynamic supination deformity only (51 patients, 76 feet); and Group II, dynamic supination with other structural deformities (44 patients, 61 feet). The mean age at surgery was 4.3 years (range, 1.4-10.7 years); the minimum followup was 2 years (mean, 5.2 years; range, 2-12.5 years) for both groups. The results were graded according to our subjective rating system of restoration of muscle balance: good, restoration of muscle balance; fair, partial restoration of muscle balance; and poor, no improvement. The two groups had similar outcomes: in Group I, there were 65 good (87%), 11 fair (13%), and no poor results and in Group II, there were 54 good (88%), seven fair (12%), and no poor results. Our data suggest the tibialis anterior tendon transfer restores muscle balance in recurrent clubfeet; we observed no recurrences. This transfer improves function and may prevent secondary osseous changes. We believe the muscle imbalance supports, at least in part, the neuromuscular etiological aspects of congenital clubfeet.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

The incidence and treatment of rocker bottom deformity as a complication of the conservative treatment of idiopathic congenital clubfoot

Rocker bottom deformity may occur during the conservative treatment of idiopathic congenital clubfoot. Between 1975 and 1996, we treated 715 patients (1120 clubfeet) conservatively. A total of 23 patients (36 feet; 3.2%) developed a rocker bottom deformity. It is these patients that we have studied. The pathoanatomy of the rocker bottom deformity is characterised by a plantar convexity appearing between three and six months of age with the hindfoot equinus position remaining constant. The convexity initially involves the medial column, radiologically identified by the talo-first metatarsal angle and secondly by the lateral column, revealed radiologically as the calcaneo-fifth metatarsal angle. The apex of the deformity is usually at the midtrasal with a dorsal calcaneocuboid subluxation. Ideal management of clubfoot deformity should avoid this complication, with adequate manipulation and splinting and early Achilles’ percutaneous tenotomy if plantar convexity occurs.

Adequate soft-tissue release provides satisfactory correction for rocker bottom deformity. However, this deformity requires more extensive and complex procedures than the standard surgical treatment of clubfoot. The need for lateral radiographs to ensure that the rocker bottom deformity is recognised early, is demonstrated.

Congenital talipes equinovarus: a review of current management

Talipes equinovarus is one of the more common congenital abnormalities affecting the lower limb and can be challenging to manage. This review provides a comprehensive update on idiopathic congenital talipes equinovarus with emphasis on the initial treatment. Current management is moving away from operative towards a more conservative treatment using the Ponseti regime. The long-term results of surgical correction and the recent results of conservative treatment will be discussed.

Histologic and histochemical analysis of muscle specimens in idiopathic talipes equinovarus

Congenital idiopathic talipes equinovarus is a relatively common disorder of uncertain etiology with a wide variance of clinical severity. Many theories have been postulated over the years without universal agreement in regard to the cause of this disorder. These hypotheses include vascular, viral, genetic, anatomic, compartment syndrome, environmental, and positioning considerations. A great deal of recent discussion has focused on a neuromuscular etiology for this condition. Muscle biopsies from the gastrocnemius, abductor hallucis, flexor digitorum longus, flexor hallucis, and tibialis posterior were obtained during posteromedial surgical release for idiopathic talipes equinovarus from September 1994 to October 2000 at the authors' institution. Ninety-five feet in 68 patients yielded a total of 431 muscle specimens. All of the specimens were processed and examined by light microscopy by an expert neuromuscular pathologist. In addition, 95 tissue samples were further processed for histochemical studies and electron microscopy. Three hundred seventy-two specimens (86.3%) showed no evidence of a pathologic diagnosis with normal fiber-type ratios and no type I fiber grouping indicative of neuromuscular pathology. Only 4 specimens (0.9%) showed type I fiber predominance, and 55 specimens (12.8%) revealed muscle fiber atrophy. The results of this study do not support the theory that a neuromuscular abnormality may be significant in the etiology of idiopathic talipes equinovarus.

The management of congenital talipes equinovarus

Congenital talipes equinovarus is a common deformity that is present at birth. It can be treated conservatively. Of the techniques available, the Ponseti method is effective in correcting most of these foot deformities and is best started early. Some of the stiffer "teratological" foot deformities may require surgical releases. Other conservative methods may be applied to correct deformity, but they have not been demonstrated to be as effective as the Ponseti method, although they may reduce the extent of subsequent surgical releases. Surgery can be undertaken to correct deformity, but some loss of motion is inevitable with extensive open procedures. Complications of treatment can be divided into: failure to correct, recurrence and overcorrection. Outcome can be assessed clinically and radiologically. Radiological outcome does not necessarily correspond to clinical results. The best long-term clinical outcome has been reported using the Ponseti method, for which there is great and increasing demand, largely driven by parents and facilitated by the Internet.

Centrally adaptations in unilateral idiopathic clubfoot children following conservative treatment

Adaptations in tiptoe rising were studied in unilateral idiopathic clubfoot (ICF) children, who underwent conservative treatment. The current study concerned 10 ICF children and 10 healthy children of the same range of ages (8-12 year). All ICF children were rated "good" or "very good" treatment results, but showed residual m. Triceps surae atrophy and mild foot alignment flaws. Tiptoe rising task was performed with subjects standing quietly with the feet on separate force platforms. Subjects were instructed to rise onto tiptoes as fast as possible and to maintain the tiptoe erect posture for a few seconds. Surface EMG of muscles Gastrocnemius, Tibialis anterior, Peroneus longus were recorded on both sides, simultaneously with vertical reaction forces (RZ) and centres of pressure (CP) displacements, during a series of 10-15 trials. Foot preferentiality was without influence on the EMG and biomechanical activities of the control group. Although not aware of a deficit in performance, ICF children show less vertical acceleration than healthy children. Timing and magnitude of muscular activities, and Cp and RZ variables of ICF children, evidenced alterations in both affected and sound side, when compared to healthy subjects. Alterations in the affected side activities were well explained by Triceps surae atrophy. Alterations in the sound side were considered as adaptations of central nervous system (CNS), preserving a global symmetry of the task. These results highlight the CNS capacity to adapt even for mild deficiencies. They stressed that it is mandatory to follow ICF children, even if they recovered a normal life.

Club feet with congenital perisylvian polymicrogyria possibly due to bifocal ischemic damage of the neuraxis in utero

Club foot is a common congenital deformity, for which a neurogenic process in utero has been proposed in some severe forms, but in most cases its cause remain uncertain. We report on four patients with an unilateral (three cases) or bilateral (one case) clubfoot and a bilateral perisylvian cortical dysplasia. All had severe dysarthria with mild mental retardation, epilepsy occurred in three cases. Direct evidence of fetal lesions of the spinal cord was occasionally present, such as signs of motor axonopathy in two cases analyzed by electrophysiological methods and syringomyelic cavitation at the thoracic level in one case. Even though the sensitivity of the investigations to demonstrate microcopic scars in the spinal cord remains weak, the presence of polymicrogyric rearrangements in the perisylvian cortex, known to proceed from a transient ischemic process occurring in the carotid territory during mid-gestation, strongly suggests that a similar mechanism occurred in the spinal cord. In fact, the foot deformity cannot be viewed as the consequence of lesions to brain regions that do not control the foot motility in the fetus. Extraneurological lesions such as jejunal atresia, possibly proceeding from localized vascular compromise, were also encountered. In one sibship, one sister was found to have a severe developmental anomaly of one foot, suggesting that genetic factors may be involved.

Improving the clinical assessment of leg muscle in adult clubfoot using magnetic resonance imaging: a case report

We report on a 37-year-old woman with a left clubfoot with a progressive decrease in ambulatory distance resulting from fatigue of her left calf muscles. She had multiple surgeries for correction of the clubfoot deformity in early childhood and uses an ankle-foot orthosis (AFO) during gait. Physical examination revealed a decrease in left calf girth. T1-weighted spin echo magnetic resonance imaging (MRI) of her legs distal to the knees showed a marked decrease in leg muscle volume in the clubfoot limb. There was increased subcutaneous fat overlying the leg muscles in the clubfoot limb, and the muscles of the clubfoot limb were infiltrated with fatty tissue. The extent of atrophy of the leg muscles on MRI was significantly greater than expected from the clinical examination. In conclusion, MRI provides a true measure of leg muscle volume in the adult clubfoot and offers an explanation for leg muscle fatigue during ambulation.

Histological abnormalities of the calcaneum in congenital talipes equinovarus

Six calcaneal fragments from patients aged 2, 3, 4, and 5 years with relapsed talipes, and two normal feet from a 40-week-old stillborn fetus were studied. All tissue was sectioned in the sagittal or coronal plane and stained using alcian blue and sirius red to distinguish cartilage and bone. Immunocytochemistry was performed to illustrate collagen types I and II. Within the clubfoot calcaneum, there were fewer chondrocytes and a diminished number of cartilage canals. Although a growth plate was present, the zones of differentiated chondrocytes were not apparent and the chondrocytes were smaller and flatter. The alcian blue staining within the spherical physis was paler than normal, suggesting that the amount of extracellular proteoglycans was reduced. Overall, the growth plate region of the talipes calcaneum resembled that of a permanent cartilage, like articular cartilage. Abnormalities were also seen in the ossification center. Cartilage spicules were rare, and developing bone frequently abutted directly onto the growth plate cartilage. The relative absence of a primary spongiosa suggested that the physis was virtually inactive and endochondral bone formation was retarded. These findings are consistent with the hypothesis that an intrinsic primary growth disorder causes the formation of a small hypoplastic bone and, subsequently, a smaller foot.

Congenital clubfoot. Month of conception

The medical records of 330 children who were born with uncomplicated congenital clubfoot were reviewed retrospectively. To determine their months of conception, the duration of gestation was extrapolated and those which were less than 40 weeks were noted. The years of conception for the studied children were from 1956 to 1994. Months of the year were ascribed angle values and the distribution of conceptions per month were grouped in radial manner. Using a circular analysis for variance a lack of uniform circular distribution was found for the grouped months of conception. There is a significant seasonal variation in the data. The mean month of conception was June. This finding is at variance with the peak months of conception for the population of the United States for the years 1989 through 1993. The theory that congenital clubfoot is caused by an intrauterine Enterovirus may be supported by this data. The summer and fall peak of Enterovirus infections in temperate climates coincide with the stage of embryologic development (> 8 weeks) which would allow an anterior horn cell lesion to lead to a deformity such as congenital club foot.

Epileptic seizures, arthrogryposis, and migrational brain disorders: a syndrome?

INTRODUCTION

Arthrogryposis multiplex congenita (AMC) may be associated with multiple developmental defects. In some severely affected newborns with AMC, autopsy studies have suggested a common mechanism of malmigration at the spinal and cerebral levels. To our knowledge, a constellation of arthrogryposis, epileptic seizures, and brain migrational anomalies in adult patients has not previously been described in a clinical material.

MATERIAL AND METHODS

Six consecutive adult patients with arthrogryposis multiplex congenita and epileptic seizures form the basis of the present study. Five patients had joint contractures and reduced muscle volume restricted to the lower extremities, whereas one patient had predominantly upper extremity affection. They were studied with magnetic resonance imaging (MRI), EEG, EMG, a neuropsychological test battery, and chromosome analysis.

RESULTS

Four of them had clear evidence of migrational brain disorders, demonstrated by MRI, in three of them roughly corresponding to the focal epileptiform EEG activity. Five of the patients had partial seizures, whereas one only had generalized tonic-clonic seizures. The MRI findings included polymicrogyria, pachygyria, and fused schizencephaly. Four had neurogenic EMG changes, one had myopathic EMG features, and one had an unremarkable EMG pattern in affected muscles. All patients with demonstrable migrational disorders showed abnormal neuropsychological features. Three patients were mentally retarded. A chromosome abnormality in the form of a ring chromosome 18 was present in one patient.

CONCLUSION

We suggest that AMC, epileptic seizures, and migrational brain disorders may form the integral parts of a hitherto undescribed syndrome in adults. A wide-spread defect in neuronal migration along the entire neural axis may be the underlying mechanism of the cerebral and the peripheral symptoms.

Calf-tendon jerks are altered in congenital equinovarus deformity

Stretch reflexes of posterior tibial (PT) and triceps surae (TS) muscles were studied electrophysiologically in 27 children with unoperated unilateral congenital equinovarus deformity, in an attempt to evaluate changes in tone of the leg muscles as a possible pathogenetic factor. Significantly reduced latency of the PT responses on the affected side was recorded in a majority of patients. In most patients the amplitudes of the PT responses were asymmetrical; however, lateralization was inconsistent. The TS responses were asymmetrical in a smaller proportion of the patients, though still significantly different from the controls. The findings suggest an asymmetrical increase in excitability level of the PT motoneuron pool on the affected side.

Histochemistry of the triceps surae muscle in idiopathic congenital clubfoot

The histochemical composition of the triceps surae muscle was investigated in 13 previously unoperated children (age 9-24 months) with unilateral idiopathic clubfoot. On both the normal and the affected side, the percentage of type I fibers was significantly higher than that of the other fiber types. The muscle biopsies from the clubfoot side showed an increase in their connective tissue content. The affected side showed a nonsignificant higher percentage of type I fibers, whereas the average capillary density and capillary to fiber ratio were significantly lower.

Morphometric study of muscle in congenital idiopathic club foot

In congenital idiopathic club foot gross morphological changes cannot be assessed in muscle tissue by conventional histopathological techniques. Since, however, recent studies have indicated the presence of neuromuscular anomalies with preponderance of Type 1 fibres in this condition, we have performed histochemical, morphometric and electron microscopic examinations in muscle biopsies of 23 patients with congenital idiopathic club foot deformity. The age of the patients varied between 6 weeks and 12 years, respectively. Muscle biopsy was taken mainly from the flexor group of the affected leg(s) during the surgical correction of the anomaly. No gross pathological changes could be found by histochemical analysis. Morphometric study, however, disclosed abnormalities in the composition of the fibre types. The most prominent change was the percentual increase in Type 1 and decrease in Type 2 fibres in almost all the cases. Electron microscopically, only minor fine structural changes could be found. Since these changes could be assessed soon after birth just as in the later course, they cannot be regarded as the consequence of the abnormal position of the leg. More probably, Type 1 fibre predominance is related etiologically to the congenital club foot deformity.

Effect of denervation on limb growth

This study used Rana pipiens tadpoles to assess the effect of complete and partial sciatic denervation on tibial bone growth and foot growth. Complete sciatic denervation was performed in R. pipiens at Stages XIV, XVII, and XX and they were killed at Stages XVII, XX, and XXIV. Partial denervation consisted of peroneal or tibial nerve sectioning at Stages XVII and XX with killing at Stages XX and XXIV. Analysis of experimental animals and controls consisted of (a) quantitative axon counts, (b) tibial length, (c) midtibial cross-sectional area, (d) midtibial cortical thickness, (e) midtibial cartilage anlage cross-sectional area, (f) foot silhouette area, and (g) osteocyte number and osteocyte density. Both complete and partial denervation resulted in significant effects on bone and foot growth: (a) decreased bone length, (b) decreased cross-sectional bone area without cortical thinning, (c) increased cartilage anlage cross-sectional area, and (d) decreased foot size. This experiment demonstrated a trophic effect of nerve on bone growth and development and foot growth. The mechanism of this action is unknown but the data suggests a slowed rate of maturation in denervated bones. The possibility exists that defective peripheral nerve-limb tissue interactions may cause human deformities such as idiopathic clubfoot and idiopathic limb length discrepancy.

Arthrogryposis multiplex congenita: spectrum of pathologic changes

The pathologic features of muscle and/or spinal cord were studied in 96 infants and children with contractures of multiple joints (arthrogryposis multiplex congenita), usually in association with other congenital abnormalities. Ninety of these infants had a neurogenic form of arthrogryposis, and six had primary muscle disease. The neurogenic form, unlike the myopathic form, was usually associated with other congenital abnormalities. The most frequently associated congenital changes were low-set ears, micrognathia, wide flat nose, short neck, congenital heart disease, high-arched palate, hypoplastic lungs, and cryptorchidism. Some of the associated abnormalities could be attributed to muscle weakness, occurring during intrauterine development. A variety of skeletal muscle changes were observed, including primary myopathic alterations, fiber type predominance and disproportion, hypoplasia, aplasia, and denervation atrophy. When the primary alterations were in the spinal cord, abnormalities of anterior horn cells of several distinct types were recognized--absence of cells, diminution, dysgenesis, degeneration, and axonal reaction. The changes in anterior roots corresponded to those of the anterior horn cells.

Arthrogryposis multiplex congenita: histochemical study of biopsied muscles

Morphometric analysis was performed after histochemical staining on 12 biopsied muscles of the affected limbs from 12 patients with arthrogryposis multiplex congenita. Except for one muscle, samples demonstrated variation in fiber size associated with abnormal fiber type distribution suggesting abnormal innervation: large groups of atrophic fibers in one muscle, either type 1 or 2 fiber predominance with occasional fiber type grouping in five, a complete lack of type 2 fibers in one, type one fiber atrophy in one, both type 2A and 2B fiber atrophy in two, and increased number of type 2C fibers in four. In most patients with arthrogryposis multiplex congenita, a defect in neural influence on the developing muscles may be responsible for the absence or maldevelopment of some muscle groups. Underdeveloped muscles are then assumed to induce imbalance of agonists and antagonists resulting in permanent contractures.

Neuromuscular arthrogryposis multiplex congenita in a thoroughbred foal

Arthrogryposis multiplex congenita was studied in a newborn thoroughbred foal. The syndrome affected only the left hind limb allowing the right hind limb to serve as a reference. There was a significant depletion of large motor neurons from the ventral horn of the spinal cord from L3 to S4 on the affected side. Hypoplasia of nerves, muscles, and bones was present in the affected limb. Histologically, hypoplasia and degeneration of myofibers and nerve bundles were seen. No cause of the syndrome, which corresponds to most human cases, was determined. Neuromuscular arthrogryposis was diagnosed because of the difficulty in distinguishing primary neuropathic from primary myopathic forms of the disease.

Features resisting primary treatment of congenital club foot

The aims of this study were: (1) to see whether the number of relapses of hindfoot deformity in congenital club foot in the first year of life could be reduced by operative treatment, and (2) to try by surgery to pinpoint features of congenital club feet that make them resistant to treatment. As compared to treatment of 95 feet with manipulation and plaster cast only or with heel cord tenotomy added, early tenotomy of both the heel cord and the tibialis posterior tendon in 23 feet markedly reduced the number of relapses of hindfoot deformity, and the need for additional treatment. The results indicate that the achilles and the tibialis posterior tendons, and their corresponding muscles, are the main dynamic features that need to be dealt with when treating the hindfoot deformity in congenital club foot.