We know that the foot grows normally for the first several weeks in the pregnancy and then something happens that we don't understand yet, and the foot twists.
WHEN DOES CLUBFOOT "DEVELOP"?
Congenital clubfoot develops after the 12th week of pregnancy, which is why it is difficult to detect the condition earlier through ultrasound. Moreover, it may not be visible at all, even in later stages of pregnancy. However, it is most commonly diagnosed between the 16th and 23rd week of fetal life.
It is important to emphasize that suspicion of clubfoot in the second trimester should be followed by further assessment in the third trimester to confirm a true foot deformity, unrelated to improper leg positioning. Observing fetal leg movements during the ultrasound examination is essential to demonstrate foot rigidity.
EXPERIENCE
You must be aware that not every doctor will be able to diagnose the condition, even when performing an ultrasound examination, as they primarily assess the correctness of basic skeletal structures and internal organs. It is also important to remember that even an experienced doctor may not detect the condition during the examination. They should not be blamed for "not seeing it" because an accurate diagnosis depends not only on their skills and equipment but also on the gestational age and the baby’s position, which cannot be adjusted as needed.
Ultrasound of the foot at 22 weeks of pregnancy
Ultrasound of the foot at 22 weeks of pregnancy
TWO, THREE, FOUR
Clubfoot can be diagnosed during a routine 2D ultrasound examination. If there is suspicion that your baby may have this condition, the use of 3D (three-dimensional) or even 4D (four-dimensional) imaging can be highly beneficial. However, it is not a necessary requirement for diagnosis, but it can be extremely helpful.
During a 3D ultrasound, the baby appears on the monitor as a three-dimensional, static image placed in space. Thanks to the added depth, it becomes much easier for the doctor to examine the fetus externally, including the feet, which—depending on the baby’s position—can be observed and measured. A 4D ultrasound allows for real-time visualization of the baby in motion within a three-dimensional space. This dynamic view can further enhance the accuracy of diagnosing the condition. Clubfoot is particularly visible during movement, and in most cases, it leaves little room for doubt.
Ultrasound 3D
FALSELY?
Despite increasingly sensitive diagnostic probes, improved ultrasound machines, and significant advancements in medicine and imaging diagnostics, many children initially diagnosed with clubfoot do not actually have the congenital condition. Some studies suggest that the risk of detecting a "false-positive" (FP) case—meaning an incorrectly diagnosed clubfoot—can be as high as 30%, which is a considerable percentage.
This occurs because ultrasound imaging does not always allow for precise differentiation between true structural clubfoot, which requires treatment, and POSITIONAL CLUBFOOT, which does not require Ponseti treatment. Additionally, it can be challenging to distinguish isolated clubfoot from a more complex condition or to differentiate clubfoot from simple metatarsus adductus.
Attempts are being made to develop a scale that would allow for a more precise diagnosis of foot type and the severity of the deformity. However, these efforts still face limitations. Nevertheless, in Glotzbecker’s 2010 study, a classification scale was introduced, forming the basis for an ultrasound scoring system dependent on the angle between the long axis of the lower leg and the long axis of the foot. The categories were defined as follows:
- Normal: no angle between the long axis of the lower leg and the long axis of the foot.
- Mild: angle greater than 0 but less than or equal to 80 degrees between the long axis of the lower leg and the long axis of the foot.
- Moderate: angle greater than 80 but less than or equal to 100 degrees between the long axis of the lower leg and the long axis of the foot.
- Severe: angle greater than 100 degrees between the long axis of the lower leg and the long axis of the foot.
Sonographic scoring system based on the angle between the long axis of the foot and the long axis of the lower leg (Glotzbecker M.P et al.: "Prenatally diagnosed clubfeet: comparing ultrasonographic severity with objective clinical outcomes.").
In Mariano Lanna’s 2020 study, a strong correlation was found between the degree of the angle between the long axis of the foot and the long axis of the lower leg and the postnatal confirmation of the condition. All cases with an angle greater than 80° had a higher likelihood of being true cases of clubfoot. This false-positive rate can be significantly reduced by measuring the angle between the foot and the lower leg. As a result, treatment planning can be more effective, reducing the risk of unnecessary stress for mothers due to an incorrect diagnosis.
FINALLY!
The increasing capabilities of equipment and advanced research in prenatal diagnostics allow for more accurate diagnosis of the condition. 60-73% of clubfoot cases are diagnosed during ultrasound. Thanks to scales developed by doctors worldwide, it is possible to determine the type of foot, the degree of deformity, and forecasts regarding further treatment, especially when the clubfoot is a result of other, much more serious conditions. However, this is still under development and is not widely accepted. It also has many limitations. Prenatal diagnosis of clubfoot still faces many questions that doctors are seeking answers and solutions for.
The conclusion is that confirmation of a diagnosis will ultimately occur only after birth. This means that based on ultrasound, doctors cannot definitively determine whether the feet are truly clubfeet or if it might be a positional deformity, or whether the feet are "standard" or atypical. It is also difficult to correlate the "degree" of the deformity diagnosed during the ultrasound with the real image after birth, as it is often not determined or noted.
MORE?
Congenital clubfoot can be the result of or accompany other defects and syndromes.
Therefore, if a foot deformity is detected during the examination, it is the doctor's duty to thoroughly examine the child and take more precise measurements of the relevant structures. Of course, these measurements are not always conclusive. If it turns out that the clubfoot is a result of something more serious, such as Down syndrome, it is advisable to conduct a series of additional tests, such as the PAPP-A test, NIFTY test, karyotype, or amniocentesis. A detailed family history is also crucial for the accurate diagnosis of any defects. Some of these tests are invasive and carry the risk of miscarriage, so this risk should be kept in mind.
In most cases, the defect is isolated, meaning the cause of its occurrence is unknown. In such cases, performing additional tests is not necessary and is even debatable.
AMNIOCENTESIS
Some doctors believe that having an amniocentesis gives a partial answer confirming that the defect exists. However, when viewed realistically through the research, it does not contribute much when it comes to idiopathic clubfoot. An amniocentesis is an invasive test in which you take a sample of the amniotic fluid and test it. It is justified when there is a risk of other defects, because non-invasive prenatal examinations (e.g. the ultrasound scan between 11 and 14 weeks of pregnancy did not show the nasal bone of the child or the nuchal translucency index was very high) indicated the possibility of the occurrence of birth defects. The risk associated with amniocentesis is miscarriage, but – here is a paradox- the risk is also the formation of clubfoot with neurological background, when as a result od collecting the sample, the anterior peroneal nerve of the child was paralyzed (the test needle stuck in the front part of the shin), resulting in paralysis and deformity of the foot.
KARYOTYPE EXAMINATION
A karyotype is the complete set of chromosomes found in every cell in the body that has a nucleus. Each such cell (with the exception of reproductive cells) contains a set of 46 paired chromosomes. The karyotype test is performed on the basis of the patient's blood sample, and its evaluation is made during the cytogenetic test. The sample is tested by analyzing genetic material from one of the lymphocyte (white blood cell) populations, but it can also be performed by analyzing cells derived from amniotic fluid (obtained through amniocentesis) or from tumor cells. Regardless of the type of material obtained from the patient, cells are grown in vitro. During the test, not only the number of chromosomes is assessed, but also their location and shape. Karyotype testing is not routine. For the examination by the mother, specific indications are necessary:
- previous experience of miscarriage (including recurrent miscarriages);
- the occurrence of miscarriages among close relatives of parents;
- previous deliveries of a stillbirth;
- already having a child with genetic defects related to chromosomal disorders.
There are indications for the examination of the fetus:
- abnormal results of non-invasive prenatal tests;
- the age of the mother over 35;
- diagnosis of chromosomal disorders in the child's parents;
- the presence of genetic defects (related to chromosomal disorders) in the previous pregnancies of a given couple.
MAGNETIC RESONANCE IMAGING
The defect can be diagnosed more accurately by performing MRI or magnetic resonance imaging. It is not indispensable due to the strong radiation which is not insignificant for the mother and child and is not well understood. Performing magnetic resonance imaging as a routine examination, while no other abnormalities have been found in ultrasound, is highly debatable mainly because of its yet unknown effects on the fetus and the mother .
DISPUTES
Ultrasound of the foot at 35 weeks of pregnancy
There is ongoing debate among clinicians regarding the necessity of performing MRI, amniocentesis, and karyotype testing during the diagnosis of idiopathic clubfoot.
Some believe that, for example, karyotype testing is essential due to the potential of identifying other damaged genes that might indicate a possible connection between the deformity and other, more advanced conditions.
Others argue that karyotype testing is not of great significance, as in most cases, changes in individual genes still occur. Some studies suggest that performing this test on mothers and children with the deformity has not provided significant additional information for diagnosis.
CERTAINTY
Prenatal diagnosis of clubfoot is helpful in planning treatment after birth, but it should be as accurate as possible: a wrong diagnosis can cause excessive stress for parents and may lead to unnecessary invasive tests. On the other hand, well-executed diagnostics can alleviate parents' anxiety, eliminate the need for invasive testing, and help them better understand the condition and prepare for its treatment.
The ability to provide proper advice to patients requires the doctor to accurately diagnose both the foot deformity itself and any other associated abnormalities.
IF YOU ALREADY KNOW THAT YOUR CHILD MAY HAVE CONGENITAL CLUBFOOT,
ACQUIRE THE KNOWLEDGE YOU NEED:
START BY UNDERSTANDING WHAT THE CONDITION IS,
THEN LEARN ABOUT ITS TREATMENT METHODS, AND FINALLY,
GATHER INFORMATION ON POTENTIAL DIFFICULTIES ARISING FROM THE SPECIFICS OF THIS DEFORMITY.
- Bar-On E., Mashiach R. et al.: „Prenatal ultrasound diagnosis of club foot: outcome and recommendations for counselling and follow-up.”
- Faldini C., Fenga D. et al.: „Prenatal Diagnosis of Clubfoot: A Review of Current Available Methodology.”
- Glotzbecker M.P et al.: „Prenatally diagnosed clubfeet: comparing ultrasonographic severity with objective clinical outcomes.”
- Mahan S.T., Yazdy M.M. et al.: „Prenatal screening for clubfoot: what factors predict prenatal detection?”
- Radler C., Herzenberg J. E. et al.: „Maternal attitudes towards prenatal diagnosis of idiopathic clubfoot.”
- Nemec U., Nemec S.F. et al.i: „Clubfeet and associated abnormalities on fetal magnetic resonance imaging.”
- Luzzini L. et al.: „Prenatal Diagnosis of Clubfoot: Where Are We Now? Systematic Review and Meta-Analysis.”
- Glotzbecker M.P. at al.: „Prospective evaluation of a prenatal sonographic clubfoot classification system.”
- Lanna M. et al.: „Congenital isolated clubfoot: Correlation between prenatal assessment and postnatal degree of severity.”
- Castro A.A.E. et al.: „Clubfoot: Congenital Talipes Equinovarus.”
- Keret D. et al.: „Efficacy of prenatal ultrasonography in confirmed club foot.”
- Cady R. et al.: „Diagnosis and Treatment of Idiopathic Congenital Clubfoot.”
- Kim Y. et al.: „Improving Prenatal Diagnosis Precision for Congenital Clubfoot by Using Three-Dimensional Ultrasonography.”
In the order of appearance on the page:
- Image by serhii_bobyk on Freepik
- 2-4: own
- 4-5: Glotzbecker M.P et al.: "Prenatally diagnosed clubfeet: comparing ultrasonographic severity with objective clinical outcomes."
- 6: own