Development of foot length in children with congenital clubfoot up to 7 years of age: a prospective follow-up study

Symmetry of Shoe Size and Calf Girth in Children With Treated Idiopathic Clubfoot: A Longitudinal Study

BACKGROUND

Treatments for idiopathic clubfoot focus on obtaining a functional foot, typical gait pattern, and activity participation. Patients and families are also concerned about practical considerations regarding shoe wear and the appearance of the calf. The purpose of this study was to quantify whether children treated for idiopathic clubfoot have symmetry differences in shoe size and calf girth when presenting with unilateral versus bilateral involvement.

METHODS

Participants with a diagnosis of idiopathic clubfoot (treated with Ponseti or French functional methods) were prospectively recruited along with children who are typically developing. Shoe size and calf girth were measured at 5, 7, and 10 years of age.

RESULTS

Sixty-five participants, 45 with a diagnosis of idiopathic clubfoot (26 unilateral and 19 bilateral) and 20 who were typically developing, began the study at age 5. Children with clubfoot treated with the Ponseti versus French methods showed no differences in shoe size asymmetry, calf girth asymmetry, or absolute calf girth at age 5. Participants with unilateral clubfoot demonstrated an average of 1.5 size smaller shoes for the involved side at all 3 ages. Participants with bilateral clubfeet had a significantly smaller, <0.75 size difference between both feet. Participants with unilateral clubfoot demonstrated about a 2 cm smaller calf girth on the involved side compared with the uninvolved side at all 3 ages. Participants with bilateral clubfeet had a smaller, <0.5 cm calf difference between sides. Calf girths for involved limbs were significantly smaller than for uninvolved limbs.

CONCLUSIONS

Children with unilateral clubfeet can expect to need a smaller shoe on their involved side. Children with bilateral clubfeet can expect a minimal shoe size discrepancy between limbs. All limbs with clubfoot involvement can expect to have a smaller calf girth than limbs that are typically developing.

LEVEL OF EVIDENCE

Level II. This is considered a prognostic study-investigating the effect of a treated clubfoot on shoe size and calf girth. This is a lesser-quality prospective study in which <80% of persons completed follow-up.

The foot drawing method: reliability of measuring foot length and outward rotation in children with clubfoot

Background

The Ponseti method is the gold standard for clubfoot treatment. However, relapse and residual gait deviations are common, and follow-up until 7 years of age is recommended. We evaluated the reliability of the foot drawing method, a new instrument for the follow-up of clubfoot. The method uses drawings of the foot in the neutral position and external rotation to measure foot length and outward rotation.

Methods

Nineteen children aged 2.5–7 years who were treated with the Ponseti method for congenital clubfoot were included. Two raters made the drawings twice (D1 and D2). Each rater measured foot length, foot rotation, and foot–tibial rotation independently (D1). Later, the raters repeated the measurements (D2). Interrater reliability was assessed using the D1 from each rater. Intrarater reliability was assessed using the measurements from each rater’s D1 and D2. Bland–Altman plots were used to visualize the limits of agreement (LoA). The mean, 95% confidence interval, and one standard deviation of the differences in all measurements were calculated.

Results

The mean differences between and within raters were: foot length < 1 mm, foot rotation < 1°, and foot–tibia rotation < 2°, which indicated no systematic differences. The LoA for foot length were: 4.5 mm and 5.9 mm between raters for D1, − 4.8 mm and 5.9 mm for rater 1 (D1–D2), and − 5.1 mm and 5 mm for rater 2 (D1–D2). The LoA for foot rotation: were − 12° and 10.6° between raters (D1), − 8.4° and 6.6° for rater 1 (D1–D2), and − 14° and 14.1° for rater 2 (D1–D2). The LoA for foot–tibia rotation were: − 17.8° and 14.3° between raters (D1), − 12° and 12.2° for rater 1 (D1–D2), and − 12.7° and 13.6° for rater 2 (D1– D2).

Conclusions

The absence of systematic differences between and within raters, and LoA observed indicate that the foot drawing method is applicable in clinical practice and research. However, the results of the foot and foot–tibia rotation analyses imply that caution is needed when interpreting changes in foot rotation in feet with higher degrees of rotation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05465-9.