Introduction

Talipes equinovarus (TEV) is a congenital disorder affecting a large portion of the global population leading to decreased quality of life, disability, and mobility limitations.[1] TEV is characterized by deformities of the foot, including cavus midfoot arch, adduction of the forefoot, hindfoot varus, and equinus.[2] It is estimated to have an overall incidence of 1-2 in 1000 live births. Left untreated, TEV will persist into adulthood, causing loss of mobility and decreased quality of life. Currently, no known cause exists for TEV, though multiple genetic associations have been found. TEV has an increased risk associated with a family history of TEV and maternal smoking. However, studies have not shown associations with TEV and oligohydramnios, the season of birth, parental age, or parity.[3] Typical management of TEV is non-operative and utilizes serial manipulation, casting, and bracing following the Ponseti method. For cases unresponsive to non-surgical methods, a variety of surgical approaches may be used to address TEV.

Etiology

TEV is a multifactorial disorder. Causes are structural and genetic. Historically, risk factors for TEV have been described to include maternal smoking, oligohydramnios, and a family history of TEV.[4] Multiple studies have linked maternal smoking to increased risk of TEV.[3][5][6] A Norwegian study reports that other risk factors for TEV include a parental history of TEV and exposure to solvents.[3] A recent systematic review showed risk factors for TEV included paternal smoking, maternal smoking, maternal BMI >30, amniocentesis, family history, SSRI exposure, gestational diabetes, nulliparity, and aboriginal Australian race.[7] However, studies have found no statistically significant increased risk for TEV associated with parental age, parental education level, oligohydramnios, parity, the season of birth, parental alcohol use, or maternal anxiety or depression.[3][4]

Many genetic studies have been performed looking for causes of TEV. No single genetic cause has been found. However, multiple genes have been associated with increased risk of TEV. It has been proposed that homeobox A and D (HOXA and HOXD) genes, which are involved in apoptosis and muscle contraction, contribute some genetic risk of TEV.[8][9][10] Another recent study has shown there may be an association with the PITX1-TBX4 pathway as well, which is part of the limb development mechanism.[10]

Epidemiology

TEV has a variable penetrance within global populations. On the low end of the spectrum, the incidence in the Chinese population is 0.39 per 1000 live births, whereas, in native Hawaiian and Maori communities, the incidence is 7 per 1000 live births.[11] Estimates within populations of European descent and the United States are 1-2 per 1000 live births.[10][12] Multiple studies have shown a preference for males with a ratio of approximately 2:1. There is no significant difference across ethnicities.[4]

Pathophysiology

Lower limb development occurs due to interactions between the lateral plate mesoderm and outer ectoderm. Multiple signaling pathways exist as part of this development. The exact pathogenesis of the development of TEV has not been found to date. The lack of evidence may be due to variations in genetic codes associated with limb and muscle development, environmental exposure to smoking, and family history of TEV, among other potential risk factors. Ultimately, the characteristic finding of TEV if forefoot adduction, hindfoot varus, midfoot cavus, and hindfoot equinus.[7][10][11]

History and Physical

A thorough history should be taken, including prenatal and birth history and any maternal risk factors, including smoking, alcohol, or drug use. There is an increased risk of TEV with maternal smoking. However, no association has been seen with alcohol use.[10] It is also essential to obtain family history as there is an increased risk for TEV with a family history positive for TEV.[13] One study has suggested solvent exposure as a possible risk factor as well. Thus, the mother should be asked if she had any personal or industrial exposure to solvents during pregnancy.[3]

On the physical exam of the newborn, the foot will assume a position of equinus and varus. Many times a prenatal ultrasound may indicate the possibility of TEV before the birth of the infant. The acronym CAVE (cavus, adduction, varus, equinus) is useful to recall the position of the affected foot. The midfoot arch is in cavus. The forefoot metatarsals are adducted, while the calcaneus is in varus and equinus.[2][14] Other findings on the physical exam include a small foot and calf, shortened tibia, and posterior and medial foot creases. A physical exam must be complete and inclusive of the whole body due to an increased incidence of associated disorders.[15] Of particular importance is the need to document leg length, skin creases, and calf circumference. Assessment of neurologic status should also be performed. The clinician must also assess the flexibility of the TEV deformity as this provides an idea of prognosis and potential for a non-operative correction.[15]

Evaluation

TEV is typically a clinical diagnosis. However, it is crucial to obtain appropriate imaging studies to assess the patient fully. Due to incomplete ossification in the newborn, the clinical utility of routine radiographs is questionable.[15] Anterior-posterior (AP) and lateral radiographs of the foot and tibia/fibula will aid in the assessment and management of TEV. Radiographic measurement should include the talocalcaneal angle, which will show parallelism in TEV.[15] Routine prenatal ultrasound may indicate a potential TEV deformity. However, this imaging modality is not 100 percent sensitive or specific to diagnose TEV, and clinical exam after birth is the most important clinical diagnostic evaluation. It has been suggested that there is a link between TEV and developmental dysplasia of the hip. However, recent studies have shown that routine imaging to screen the hips of a patient with TEV is not necessary.[16]

Differential Diagnosis

TEV has a classic appearance, and it is unlikely to be confused with any other diagnosis. However, it is essential to rule out a correctable deformity. Correctable deformities that have the appearance of TEV may be postural and often will self-correct with time. Thus, when planning treatment, one must differentiate between correctable and non-correctable TEV.

Prognosis

The prognosis for TEV is excellent. The vast majority of TEV can be corrected utilizing the Ponseti method of manipulation and sequential casting, followed by foot abduction orthosis. For cases with relapse or incomplete correction, a variety of surgical methods exist that can assist in the correction of the deformity. Multiple studies reports >90% success with the use of the Ponseti method for TEV correction.[17]

Complications

Complications that may occur with TEV include loss of mobility, disability, and decreased quality of life. Treatment complications can include typical cast complications, including skin breakdown, and nerve injury related to pressure over superficial nerves. These are mitigated by the frequent cast changes utilized with the Ponseti method. Weakness in eversion with inversion while dorsiflexing the foot can be seen after non-operative management. Weakness is typically managed with an anterior tibialis tendon transfer. Rocker-bottom foot deformity can also occur, typically this happens as a result of trying to correct the equinus deformity before the adduction and varus deformities.[15] Surgical complications include those related to anesthesia risks, as well as typical surgical risks of pain, infection, wound complications, and blood loss. Complications and failures with surgical care are reported at 13-50%.[17] One study reported 2% of their patients had serious bleeding complications following percutaneous Achilles tenotomy, most often related to inadvertent injury to the peroneal artery.[20] The greatest complication risk is the recurrence of TEV despite treatment. Reoccurrence typically occurs with the Ponseti method due to poor compliance with orthosis use at home.[17][20]

Deterrence and Patient Education

It is vital to educate parents about the treatment and expectations for home participation in treatment. Parents should understand the risks and benefits of surgical and non-surgical treatment of TEV. As the child will be required to be in the foot orthosis after serial casting with the Ponseti method, parents should be well educated in the use and care of the orthosis, as well as being educated regarding the risk for relapse with poor orthosis adherence.[17][20]

Pearls and Other Issues

Parent or guardian buy-in with non-operative treatment is vital to successful outcomes. Due to the burden of the home orthosis, many families may struggle with adherence. However, when issues arise, it is important not to scold or make the family feel as though they are failing. Instead, continued education and encouragement are crucial to success and will likely lead to better adherence in the future.

Enhancing Healthcare Team Outcomes

Talipes equinovarus is a disorder that can be treated without surgical intervention in most cases. Management of TEV requires an interprofessional team approach that includes:

• Evaluation by a skilled pediatrician or family medicine provider and referral to a pediatric orthopedic specialist
• Education and follow-up by nursing staff to ensure adherence to the treatment regimen
• Possible geneticist consultation for genetic counseling 
• Skilled long leg casting by cast technician

All involved in the patient's care needs to communicate well to optimize outcomes. Improving outcomes includes communication between primary care providers and orthopedists, as well as between nursing staff and clinicians. When an interprofessional team approach and appropriate management is undertaken, the Ponseti method is highly successful for non-operative care of talipes equinovarus.[21][22] [Level 5]