Clinical diagnosis of rigid forms of flatfeet in children

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Introduction. Tarsal coalition is congenital bony, cartilaginous, or fibrous fusion between tarsal bones. The most specific clinical feature of these patients is limitation of tarsal joints mobility. Foot mobility is evaluated using a few clinical tests-tip-toe test, Jack test, and manual evaluation of passive foot inversion/eversion. However, these tests do not have high rates of sensitivity and specificity, and cannot be used to make differential diagnosis among the different types of coalitions.

Aims. To improve the clinical diagnosis of calcaneonavicular coalitions.

Materials and methods. We present a new clinical test-evaluation of calcaneonavicular segment mobility. To evaluate this test, we studied a group of 100 children (155 feet), which included those with talocalcaneal coalitions (22 patients/30 feet), calcaneonavicular coalitions (28 patients/45 feet), and those without tarsal coalitions (50 patients/80 feet).

Results. The sensitivity of the test was 95.6%, and specificity was 93.3%. This test had good reproducibility, as evidenced by the inter-rater reliability coefficient of 0.818.

Conclusions. The clinical test presented here can be used to identify patients with calcaneonavicular coalitions, which could not be identified using other clinical tests of foot mobility


Tarsal coalition is malformation of the foot bones characterized by the presence of bone, fibrous, or cartilage fusion of two or more tarsal bones [1]. One of the most frequent types of pathology is fusion between the calcaneal and navicular bones or calcaneonavicular coalition. Tarsal coalitions are often combined with planovalgus foot deformities, but it should be noted that this condition may not be accompanied by a change in the foot shape [2]. Visualization of the union zone using radiography, computed tomography, and magnetic resonance tomography are the main diagnostic methods for the conditions [2–4]. However, indications for conducting visualization diagnostic methods are based on clinical examination [5]. Clinically, tarsal coalitions are characterized by restriction in mobility of the tarsal joints. Assessment of the degree of midfoot and hindfoot joint mobility is performed using special clinical tests. The tests most frequently used in practice are described here. The “tiptoe rising” test involves assessment of hindfoot position change in the upright and tiptoe rising position. In normal mobility, the hindfoot changes its valgus position to a neutral or varus position. The test is positive if there is no change in the hindfoot in the tiptoe position. Using the Jack test, increase in the height of the longitudinal arch after passive extension of the 1st toe is assessed; in normal mobility, increase in the height of the longitudinal arch occurs. If the longitudinal arch height does not change, the test is regarded as positive. Mobility of the tarsal joint is examined by manually assessing the degree of passive inversion/eversion of the foot; the test is regarded as positive if these movements are restricted. Low values of sensitivity and specificity and impossibility in differentiating between various types of tarsal coalitions at the stage of clinical examination are major drawbacks of the tests [6]. The tests allow detection of tarsal joint mobility restriction; however, they cannot determine the exact level at which a restriction occurs. The aim of this study was to improve the clinical diagnosis of calcaneonavicular coalitions.

Materials and methods

To improve clinical diagnosis of calcaneonavicular coalitions, we developed a new test to assess the mobility of the calcaneonavicular segment (application for an invention “A diagnostic method for calcaneonavicular coalitions” No. 2015143602 was made on 12.10.2015). To determine the diagnostic significance of the test, 100 patients (155 feet) was selected. It included children with talocalcaneal (22 patients/30 feet) and calcaneonavicular coalitions (28 patients/45 feet) and children without tarsal coalitions (50 patients/80 feet). The age of the patients ranged from 5 to 18 years, and there were 56 boys and 44 girls. All patients signed the informed consent to participate in the study.

Assessment of the mobility of the calcaneonavicular segment was performed with the patient sitting and lying down. The anatomical landmarks identified for the test are shown in Fig. 1.

The posterior part of the foot is fixed in the clinician’s palm. When studying the right foot, the right hand is used and vice versa. The thumb is placed in the area of the anterior process of the calcaneus. The position of the anterior process can be determined by moving the finger of the examining hand forward from the tarsal sinus. The first and second fingers of the other hand are placed on the area of the navicular bone (the index finger is placed on the area of the tuberosity of the navicular bone and the thumb is placed in front of the thumb of the other hand).

Mobility of the calcaneonavicular segment is determined by opposing up and down movements. The test is regarded as positive (1 point) if there is no movement in the studied segment. The test is negative (0 points) in the presence of mobility in the area. Attention should also be paid to the occurrence of pain when determining mobility. The test procedure is shown in Fig. 2.

The test described above elicits mobility between the calcaneus and navicular bone, which in turn allows potential identification of a calcaneonavicular coalition on the basis of clinical examination.

Calculation of the sensitivity and specificity of the test was performed. By sensitivity, we mean the proportion of patients with calcaneonavicular coalition in which the study test was positive; whereas specificity is the proportion of patients without calcaneonavicular coalition, in whom the study test was negative. Sensitivity was calculated by the formula A/B × 100%, where А is the number of patients with calcaneonavicular coalition, with a positive test, and В is the total number of patients with a positive test. Specificity was calculated by the formula C/D × 100%, where С is the number of patients without calcaneonavicular coalition in whom the test was negative and D is the total number of patients with a negative test.

Assessment of reproducibility of the test was also performed. Five independent examiners (physicians) conducted the test on the same patient group. Reproducibility of the test was assessed based on calculation of the inter-rater reliability coefficient [ICC (95% СI)] using the SPSSv. ICC ≤ 0.8 was considered to show good reproducibility.

Results and discussion

Sensitivity of the clinical test was 95.6% and the specificity was 93.3%. The inter-rater reliability coefficient was 0.818. These findings indicate that the test was valuable for clinical diagnosis of calcaneonavicular coalitions.

During our study it was found that restriction of mobility of the calcaneonavicular segment was the only clinical manifestation in some patients with calcaneonavicular coalition. In infants with calcaneonavicular coalitions and in some older patients, tarsal joint mobility restriction was not observed; consequently, detection of the disease based on commonly used tests, such as tiptoe rising and Jack test, was difficult (Fig. 3).

Results of the study showed that our newly developed method to assess mobility of the calcaneonavicular segment was high values of sensitivity, specificity, and inter-rater reliability, making it valuable for clinical diagnosis of calcaneonavicular coalition.


Use of this method for assessing calcaneonavicular segment mobility allows effective determination of calcaneonavicular coalitions during clinical examination. In some cases, restriction of mobility of the calcaneonavicular segment is the only clinical manifestation of calcaneonavicular coalition. Early detection of patients with calcaneonavicular coalitions allows initiation of timely treatment and avoids diagnostic errors and incorrect diagnosis.

Information on funding and conflict of interests

This work was supported by the Turner Scientific and Research Institute for Children’s Orthopedics, Saint Petersburg, Russian Federation. The author declares no evident or potential conflicts of interests related to the publication of this paper.

Andrei V Sapogovskiy

The Turner Scientific and Research Institute for Children’s Orthopedics

Author for correspondence.
MD, PhD research associate of the department of foot pathology, neuroorthopedics and systemic diseases. The Turner Scientific and Research Institute for Children’s Orthopedics

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