Are bilateral idiopathic clubfeet more severe than unilateral feet? A severity and treatment analysis

Abstract

Introduction:

Evidences suggest that different subgroups of idiopathic clubfoot exist with differences in severity and treatment outcomes. This study compares the severity and treatment outcomes of unilateral and bilateral clubfoot.

Material and methods:

We retrospectively studied 161 patients (bilateral 66, unilateral 95) with primary idiopathic clubfeet to evaluate the differences in severity and treatment. The parameters analyzed were precasting Pirani score, number of casts required, pretenotomy Pirani score, pretenotomy dorsiflexion, rate of tenotomy, and post-tenotomy dorsiflexion achieved. A Pirani score of at least 5 was classified as very severe and 4.5 or less was classified as less severe.

Results:

There were 49=(74.24%) male and 17 (25.75%) female patients in the bilateral group and 76 (80%) male and 19 (20%) female patients in the unilateral group. Out of 95 unilateral patients, 34 were left sided (35.8%). Comparing severity, the mean precasting Pirani score in bilateral patients (5.4 ± 0.6) was statistically more than the unilateral patients (4.9 ± 0.7). The number of casts required was significantly more in bilateral feet compared to unilateral (bilateral 5.3 ± 1.7, unilateral 4.7 ± 1.7; p < 0.011). Achilles tenotomy was required in all feet. Post Ponseti treatment, the foot deformity correction achieved (pretenotomy Pirani score, pretenotomy, and post-tenotomy dorsiflexion) was statistically similar in both unilateral and bilateral feet.

Conclusions:

Idiopathic bilateral clubfoot was more severe than unilateral foot at initial presentation and required more number of corrective casts. Post Ponseti treatment, the deformity correction in bilateral foot was similar to unilateral foot.

Introduction

It has been postulated for long that several subgroups of clubfoot might exist as there is variable severity and response to treatment. ¹ Traditionally, idiopathic unilateral and bilateral clubfoot are considered to have similar characteristics and have been classified within the same group for scientific research. ² One Australian study group pointed out the differences in severity even between the above two groups and cautioned researchers on this potential pairing. ³ It is known that the incidence of clubfoot varies around the world and as such the severity of clubfoot may vary between different ethnic subgroups. We considered it worthwhile to study bilateral and unilateral clubfeet to evaluate the difference between them, if any, in our region too. The parameters we included in our study were precasting Pirani score, number of Ponseti casts required, pretenotomy Pirani score, pretenotomy dorsiflexion, rate of tenotomy, and post-tenotomy dorsiflexion achieved. Thus, the study included both pre- and post-intervention comparisons.

Material and methods

This study was conducted at a CURE Clubfoot Clinic at a pediatric superspecialty center located in a suburb of a low-income country. Patients’ case files were used for chart review (January 2016 to October 2016). Being a retrospective study, ethical clearance was not required. A total of 161 patients (bilateral 66, unilateral 95) with primary idiopathic clubfoot were analyzed. Patients who had taken prior treatment elsewhere, atypical clubfeet, syndromic, or with any comorbidities were excluded. All the included patients were treated with Ponseti technique of weekly casting followed by tenotomy, if required.

The Pirani scoring system was used for pretreatment and pretentomy severity evaluation. A Pirani score of 5 or more was classified as very severe and 4.5 or less was classified as less severe. ³ The nonparametric Mann–Whitney U test was used for Pirani score analysis. Independent samples t-test was used to compare the number of Ponseti casts required and dorsiflexion between unilateral and bilateral feet.

Results

There were 49 (74.24%) male and 17 (25.75%) female patients in the bilateral group with bilateral feet affection (132 feet) and 76 (80%) male and 19 (20%) female patients in the unilateral group with unilateral feet affection (95 feet). Out of 95 unilateral patients, 34 were left sided (35.8%). The average age at the initiation of treatment was 5.1 months (range 0.26–60 months) for bilateral patients and 7.9 months (range 0.26–84 months) for unilateral patients. Comparing severity at the initiation of treatment, the feet were very severe in 114 (86.4%) out of 132 in bilateral patients. In unilateral patients, very severe deformity was present in 57 (60%) out of 95 feet. The various other parameters recorded are described in Table 1. In bilateral group, 46 (34.8%) out of 132 feet required less than five casts pretenotomy, while in the unilateral group, 48 (left 22, right 26; 50.5%) out of 95 feet required casts less than five. Achilles tenotomy was required in all feet. Post Ponseti treatment, the foot deformity correction achieved (pretenotomy Pirani score, pretenotomy, and post-tenotomy dorsiflexion) was statistically similar in both unilateral and bilateral feet.

Table 1.

Comparisons of various parameters in bilateral and unilateral feet.

Characteristics	Bilateral feet (n = 132)	Unilateral feet (n = 95)			p Value
		Left	Right	Combined
Precasting Pirani score (out of 6)a	5.4 ± 0.6	4.8 ± 0.8	5.0 ± 0.7	4.9 ± 0.7	Significant
Casts before tenotomyb	5.3 ± 1.7	4.3 ± 1.8	5.0 ± 1.7	4.7 ± 1.7	<0.011
Pretenotomy dorsiflexion (degrees)b	−9.8 ± 8.7	−7.9 ± 10.9	−10.7 ± 9.1	−9.7 ± 9.8	0.96
Pretenotomy Pirani score (out of 6)a	1.7 ± 0.4	1.6 ± 0.5	1.7 ± 0.5	1.7 ± 0.5	Not significant
Post-tenotomy dorsiflexion (degrees)b	22.1 ± 7.8	22.4 ± 9.4	21.0 ± 9.6	21.5 ± 9.5	0.58

^a Mann–Whitney U test.

^b Independent samples t-test.

Discussion

There is increasing evidence that different subgroups of idiopathic clubfoot might exist influencing the severity and treatment outcome. ¹ One research group from a high-income country reported the odds of bilateral feet being very severe as 2.6 (95% confidence interval 1.3–5.1) times higher compared with unilateral cases (p = 0.007). ³ They undertook a review of 66 unilateral and 75 bilateral clubfoot patients at an average age of 12.9 days. In their series, 53 of 75 (71%) bilateral cases and 37 of 66 (56%) unilateral cases were classified as very severe. The precasting Pirani score in bilateral feet (left 5.2 ± 0.8, right 5.3 ± 0.7) was higher than unilateral feet (left 4.7 ± 1.2, right 4.9 ± 1). Our study replicated similar findings supporting more severity for bilateral feet compared to unilateral ones. An interesting finding of our study was despite an increased precasting severity and increased cast numbers in bilateral feet, post-treatment behavior in terms of the foot deformity correction (pretenotomy Pirani score, pretenotomy, and post-tenotomy dorsiflexion) was statistically similar to unilateral feet.