https://orcid.org/0000-0003-2513-5297
Dear Editor,
We recently read with interest the article published in March 2023 in the Journal of Maternal, Fetal and Neonatal Medicine by Xiu, Yun, et al. titled “Prenatal ultrasound diagnosis of congenital vertical talus” [Citation1].
We are writing to address a crucial matter related to the diagnosis of congenital vertical talus (CVT) and oblique talus during the intrauterine period, as discussed in the recent article.
Congenital vertical talus is a rigid rocker-bottom flatfoot deformity. Hindfoot valgus, hindfoot equinus, and forefoot abduction are observed. The talus is in a vertical position, and the navicula is in a dorsolateral luxated position. There is a co-occurrence of up to 50% with conditions such as meningomyelocele, arthrogryposis, certain chromosomal disorders, and malformations. While the article claims that CVT can be reliably and feasibly diagnosed, it is essential to clarify that the distinction between CVT and oblique talus in the intrauterine period remains challenging and unreliable. Both CVT and oblique talus share some similarities in their presentation during the intrauterine period. This overlap further complicates the differentiation process and can potentially lead to misdiagnosis or uncertainty. However, unlike in vertical talus, when placed in plantar flexion, there is no reduction of the navicular, whereas in oblique talus, reduction occurs. Therefore, it is not a rigid deformity. Their treatment is also completely different. The current and more widely applied approach for CVT involves initial serial manipulations and casting, followed by talonavicular reduction and stabilization with Kirschner wires, along with Achilles tenotomy as part of a minimally invasive approach [Citation2,Citation3]. The treatment for oblique talus is generally conservative including serial casting. Surgical intervention may be required very rarely, especially in a patient group with Achilles tendon contracture [Citation4].
Congenital vertical talus and oblique talus deformities pose challenges in clinical distinction during the prenatal period. The nuanced differences between CVT and oblique talus are often challenging to discern accurately [Citation5]. Prenatal imaging techniques, such as ultrasound, although valuable, may not offer the necessary clarity to differentiate between subtle deformities of the foot and ankle. To differentiate between these conditions, the foot must be evaluated in plantar flexion using lateral radiographs or ultrasonography [Citation6]. In CVT, the talonavicular joint remains unreduced in plantar flexion, while in oblique talus deformities, reduction occurs. Employing these imaging modalities facilitates accurate differential diagnosis and aids in developing an appropriate treatment algorithm. However, during the intrauterine period, obtaining a true lateral image of the foot in plantar flexion is unfeasible, thereby hindering the possibility of a differential diagnosis. The navicular bone, which is a crucial bone structure for this differential diagnosis, does not ossify until the age of 9 months to 5 years. Therefore, in radiographs, an attempt is made to diagnose by assessing the parallelism between the talus’s longitudinal axis and the metatarsal axis. In the neonatal period, the cartilaginous navicular bone can be observed with the assistance of dynamic ultrasound, and diagnosis can be made using this method [Citation7]. However, making this distinction during the prenatal period would be even more challenging, leading to limited information that can be obtained from a prenatal diagnostic perspective.
Consequently, there is a concern that the ultrasonographic findings mentioned in this article might lead to an increase in false-positive cases of CVT. Therefore, suspicion of CVT during the intrauterine period should prompt obstetricians to guide pediatric orthopedists and refer the patient for postnatal evaluation. Family meetings should be conducted to discuss potential diagnoses and situations. Thus, parental anxiety should be alleviated, and the family should be involved in the process to outline a roadmap [Citation8]. It is crucial to subject the diagnosis to a double-check mechanism and ensure that these procedures are carried out in experienced centers to minimize false positive results. Minimizing false-positive results will reduce both advanced anatomical or genetic investigations during the pregnancy period and potential further invasive examinations [Citation9]. Incorrect diagnosis of CVT can lead to misinformation about the treatment and the presence of probable additional anomalies and genetic disorders, potentially resulting in misguided advice regarding the challenges of postnatal treatments. This misinformation may lead to the formation of the family’s desire for abortion. Such a situation can increase the abortion rate due to both the physician and the families making an erroneous decision.
As the field of prenatal imaging and diagnostics continues to advance, researchers and medical professionals should work collaboratively to develop more accurate and reliable methods for identifying and distinguishing various congenital foot and ankle deformities. Until then, it is essential to recognize and communicate the limitations and uncertainties surrounding the prenatal diagnosis of CVT and oblique talus.
For this reason, we wanted to draw attention to the difficulties in the differential diagnosis of CVT and oblique talus in the prenatal period. We believe that the definitive diagnosis can only be made by an orthopedic and traumatology specialist in the postnatal period. However, we hope this letter sheds light on the complexities involved in diagnosing CVT and oblique talus during the intrauterine period. Further research and awareness will undoubtedly contribute to improved prenatal detection and management of these conditions.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Data availability statement
Data sharing is not applicable to this article as no new data were created or analyzed in this study.
Additional information
Funding
References
- Xiu Y, Wang Y, He F, et al. Prenatal ultrasound diagnosis of congenital vertical talus. J Matern Neonatal Med. 2023;36:1.
- Miller M, Dobbs MB. Congenital vertical talus: etiology and management. J Am Acad Orthop Surg. 2015;23(10):604–2. doi: 10.5435/JAAOS-D-14-00034.
- Dobbs MB, Purcell DB, Nunley R, et al. Early results of a new method of treatment for idiopathic congenital vertical talus. J Bone Joint Surg Am. 2006;88(6):1192–1200. doi: 10.2106/JBJS.E.00402.
- Riemen AHK, Gabrani A, Lumsden M, et al. Understanding congenital vertical talus. Orthop Trauma. 2022;36(6):304–310. doi: 10.1016/j.mporth.2022.09.002.
- Shiels WE, Coley BD, Kean J, et al. Focused dynamic sonographic examination of the congenital clubfoot. Pediatr Radiol. 2007;37(11):1118–1124. doi: 10.1007/s00247-007-0581-3.
- Chalayon O, Adams A, Dobbs MB. Minimally invasive approach for the treatment of non-isolated congenital vertical talus. J Bone Joint Surg Am. 2012;94(11):e73. doi: 10.2106/JBJS.K.00164.
- Supakul N, Loder RT, Karmazyn B. Dynamic US study in the evaluation of infants with vertical or oblique talus deformities. Pediatr Radiol. 2013;43(3):376–380. doi: 10.1007/s00247-012-2529-5.
- Oetgen ME, Kelly SM, Sellier LS, et al. Prenatal diagnosis of musculoskeletal conditions. J Am Acad Orthop Surg. 2015;23(4):213–221. doi: 10.5435/JAAOS-D-14-00004.
- Cavoretto PI, Castoldi M, Corbella G, et al. Prenatal diagnosis and postnatal outcome of fetal congenital knee dislocation: systematic review of literature. Ultrasound Obstet Gynecol. 2023;62(6):778–787. doi: 10.1002/uog.26283.