Significance Of Pirani Score at Bracing-Implications for Recognizing A Corrected Clubfoot

Abstract

Background:

The aim of clubfoot treatment by Ponseti method is to achieve a corrected foot, with at least 15° dorsiflexion and 70° abduction, and fit comfortably into a brace at the recommended setting. This study aimed to acknowledge the validity and reliability of the Pirani scoring system, while investigating if a corrected clubfoot has a Pirani score of zero. The study hypothesized that a corrected clubfoot may or may not have a Pirani score of zero.

Methods:

706 patients with clubfoot were treated by Ponseti’s method of weekly manipulations and casting, from November 2011 to May 2016, at a tertiary care hospital, making a total of 1055 feet. All data was entered into the International Clubfoot Network Database, along with Pirani scoring. Tenotomy was performed in eligible patients.

Results:

The mean Pirani score at the end of treatment phase of casting and initiation of the maintenance phase of bracing for the right foot was 1.1 (SD=0.55) and left foot was 1.2 (SD=0.58). These feet not only fit the criteria of a corrected clubfoot, 70° abduction and 15° dorsiflexion, but also fit well in a foot abduction brace.

Of the 1055 diagnosed Clubfeet, 643 required tenotomy (60.9%).

Conclusion:

The study shows that the affected foot does not need to have a Pirani score of zero to be considered a corrected foot. Pirani score is an excellent tool used over the years to evaluate clubfoot. Pirani score does not assess adequately the transition from the treatment phase of casting to the maintenance phase of bracing. The use of the International Clubfoot Database-Treatment visit form, including all components of clubfoot and the Pirani score, provides a clear understanding of whether the patient has achieved foot correction or not.

Level of Evidence: Level IV

Introduction

Clubfoot, also known as Congenital Talipes Equinovarus, is a common congenital deformity that affects more than 100,000 infants worldwide each year¹, with an incidence of one to two per 1000 live births². It is a complex deformity with four components: Ankle Equinus, Hindfoot Varus, Forefoot Adductus, and Midfoot Cavus. Over the years there have been a number of scoring systems described for clubfoot. These include the Ponseti-Laaveg classification³, The Dimeglio classification⁴ etc. These are quite cumbersome to use and have not proved popular. In order to assess the level of severity of each of the components of Clubfoot effectively, Shafique Pirani MD, designed a convenient and easy tool known as the ‘Pirani Score’⁵. The Pirani score demonstrates its importance with regards to assessing the severity of clubfoot, mainly at presentation and for monitoring patient’s progress. The Pirani scoring system works by assessing six clinical signs of contracture, which may score 0 (no deformity), 0.5 (moderate deformity) or 1(severe deformity)^6,7. The total score is recorded after every visit. Pirani scoring is known to be valid and reliable⁸ for providing a good forecast about the potential treatment for an individual foot, such that a higher score at presentation may indicate the requirement of a higher number of casts to correct the deformity. By logical extension it can be assumed that the Pirani score of six means the most severe deformity and the Pirani score of zero would be a corrected clubfoot.

Initial, gold standard, treatment of congenital idiopathic clubfoot is considered to be Ponseti’s method of manipulation^9,10. It has two stages; our study was based on the critical transition from the treatment phase of manipulation and casting to the maintenance phase of bracing. According to Ponseti, a corrected clubfoot is one that achieves at least 15° dorsiflexion and 70° abduction¹¹, moreover it fits comfortably into a brace at the recommended setting. It would naturally be assumed that this position, as described by Ponseti, would be a corrected clubfoot at a Pirani score of zero. Clinical experience has shown that in order to achieve a Pirani score of zero, clinicians tend to overcast the affected foot, even if it has reached the desired corrected position as described by Ponseti. The rationale of the study is to elaborate on the transition between the treatment phase of manipulation and casting, and the maintenance phase of bracing.

This study acknowledges the validity and reliability of the Pirani scoring system, while investigating if a corrected clubfoot has a Pirani score of zero. We hypothesized that the mean Pirani score of a clinically corrected clubfoot, after Ponseti’s method of manipulation and casting, may or may not be zero. Our aim is to raise understanding that clubfoot scoring system is not accurate for the initiation of bracing.

Methods

We reviewed the data of clubfoot patients at a clinic in a tertiary care hospital, where they received free of cost treatment from November 2011 to May 2016. The inclusion criteria were: All children identified in the clinic less than 5 years of age at enrolment (with parental consent) while the exclusion criteria were: children more than 5 years old, consent refusal by parents, children with neurologic clubfoot or clubfoot part of other syndromes. The study included 706 children, who were diagnosed with clubfoot. 357 had unilateral clubfoot and 349 were bilateral leading to a total of 1055 feet.

Parents or guardians of patients who were enrolled were given information about the nature and duration of treatment, and their signatures/thumb prints were taken. Patients were assessed through comprehensive history and physical examination. Correction was achieved using Ponseti ‘s technique of weekly serial manipulation and casting, followed by Abduction bracing, Pirani scoring was obtained and pictures of the affected foot/feet were taken at every visit. Tenotomies were performed in eligible patients only. The aim of the program was to accomplish a corrected clubfoot according to Ponseti’s criteria, at least 15° dorsiflexion and 70° abduction. All data was entered into the International Clubfoot Network Database¹².

The records were studied in relation to Pirani Score at the time of bracing. The study includes the following variables:

Descriptive statistics include frequencies for mean and standard deviation for variables such as total score of right and left foot and the number of unilateral and bilateral feet (Figure 1).

Figure 1.

Variables in the study.

In addition to Pirani score, changes in foot abduction and dorsiflexion were recorded using the International Clubfoot Network Database-Treatment Visit Form. Records were studied in relation to improvement of Pirani Score and the degree of abduction and dorsiflexion (Figure 2).

Figure 2.

International Clubfoot Network Database- Dorsiflexion and Abduction assessment¹²

Results

Out of the 1055 feet diagnosed with clubfoot, 357 were unilateral and 349 were bilateral clubfeet (Figure 3).

Figure 3.

The bar graph illustrates the number of feet diagnosed with clubfoot.

Of the 1055 diagnosed Clubfoot, 643 required tenotomy (60.9%) (Table 1). The mean Pirani score at the initiation of bracing for the right foot was 1.1 (SD=0.55).

Table I.

Summary of Patients Enrolled

Years	Enrolled Children n (%)	Feet Under Treatment n (%)	Cast n (%)	Tenotomy n (%)	Children Progressed to Brace n (%)
1	104 (15)	138 (13)	739 (10)	72 (11)	83 (14)
2	140 (20)	212 (20)	1749 (25)	97 (15)	101 (17)
3	176 (25)	271 (26)	2057 (39)	140 (22)	154 (24)
4	170 (24)	247 (23)	1592 (23)	197 (31)	166 (27)
5 (7.5 months)	116 (16)	187 (18)	915 (13)	137 (21)	100 (17)
OVERALL	706	1055	7052	643	604

The mean Pirani score at the initiation of bracing for the left foot is 1.2 (SD=0.58) (Table 2). The range for the average Pirani score for both feet was 0 to 3 and the average number of casts required for correction was 5-6.

Table II.

Descriptive analysis of right and left Pirani score, at the beginning of bracing

Total Number of Feet	Left Foot	Right Foot
N= 1055	1.2±0.58	1.1±0.55

Of the 865 feet that were assessed at the time of bracing, 99.1% feet had a Pirani score of more than zero at the end of the treatment phase of casting and initiation of maintenance phase of bracing.

Discussion

Congenital talipes equinovarus (CTEV), also known as clubfoot, is the most common congenital orthopedic anomaly requires intensive treatment immediately or very soon after birth to guarantee high success rates^{13, 14}. In 1963, Ignacio Ponseti proposed treating clubfoot by serial manipulations and casting¹¹, which is the gold standard non-surgical method of treatment^9,10. The Ponseti treatment of clubfoot has two stages; our study was based on the critical transition from the treatment phase of manipulation and casting to the maintenance phase of bracing. Our study hypothesized that at the end of the treatment phase of manipulation and casting, the mean Pirani score may or may not be zero. In order to achieve a Pirani score of zero, medical personnel tend to overcast the foot. This leads to unnecessary tenotomy procedures and is a mindless dissipation of natural resources.

It has excellent long term results and benefits for clubfoot^8,15 with a low relapse rate. Due to the large number of patients, it was substantiated that it is impractical to expect the demand for treatment to be met by the physicians. For this particular reason, Ponseti’s method of casting and manipulation has been proved valuable because it requires relatively lower level of skills and can be successfully managed by non-specialist personnel¹⁶. It’s non-invasive and less expensive, factors that are very crucial for developing countries. Pirani score has been used worldwide by not only clinicians but Allied Health Professionals like cast technicians as an effective tool for diagnosis and follow up of clubfoot treatment by Ponseti method¹⁶. Several authors have shown the benefit of using the Pirani score in predicting the course of treatment and the likely number of casts required to correct the deformity⁶. It also predicts the need for tenotomy in the patient¹⁷. Our study hypothesized that at the end of the treatment phase of manipulation and casting, the mean Pirani score may or may not be zero. In order to achieve a Pirani score of zero, medical personnel tend to overcast the foot. This leads to unnecessary tenotomy procedures and is a mindless dissipation of natural resources.

In our study, the mean Pirani score at the end of the treatment phase of manipulation and casting, and maintenance phase of bracing was 1.1 in the right foot, and 1.2 in the left foot. These feet were pain free and clinically corrected with good mobility. We did not continue to cast the foot, in search of a Pirani score of 0 (Figure 4).

Figure 4.

Photographs show corrected clubfoot after manipulation and casting

Lack of understanding and poor compliance of patients’ parents due to poor socio-economic status, improper casting technique, failure to perform a tenotomy, under-corrected deformity, ill-fitting splints can all affect a positive outcome and are the most common problems experienced during clubfoot studies¹⁸.

When we started our clubfoot program and used the Pirani score to assess patients, in our experience, the patients who we casted reached a corrected foot according to Ponseti’s criteria but the Pirani score did not reach zero (Table 3). This is in contrast to the majority of clinical scoring systems that show strong relation between the clinical score and patient’s outcome. Towards the bottom end of the scoring scale, the Pirani score and the clinical picture does not correlate in all patients. For example, a widely used clinical scale is the VAS scale to measure pain intensity, is most commonly anchored by “no pain” (score of zero) and “worst imaginable pain” (score of 100)¹⁹. Similarly, it is assumed that a Pirani score of zero is a corrected clubfoot, when in some patients it does not reach zero.

Table III.

Pirani Score⁷

Pirani Score
1	Posterior Crease
2	Empty Heel
3	Rigid Equinus
4	Medial Crease
5	Curvature of Lateral Border
6	Position of Talar Head

Minimum total score is 0 and the maximum total score is 6. A high Pirani score indicates a severe deformity.

At the lower end of the Pirani score, the only weakness is its inability to assess the four components of Clubfoot: cavus, adductus, varus and equinus. In the present study, 1055 feet with clubfoot were studied. The mean Pirani scoring at the end of treatment phase with casting and initiation of maintenance phase with bracing was 1.1 for right foot and 1.2 for left foot. These feet were clinically corrected and fit well in a foot abduction brace (Figure 5).

Figure 5.

The photograph shows a foot-ankle abduction brace. In this patient, feet were clinically corrected, had a Pirani score of greater than zero and fit well in the brace. Three straps present on the brace holds the foot firmly in the shoe.

The present study concluded that as per the Ponseti criteria of a corrected clubfoot, the Pirani score of a corrected clubfoot may or may not be 0. According to the study, the Pirani does not assess the degree of foot abduction and dorsiflexion in all patients, which defines corrected clubfoot according to Ponseti’s criteria¹¹. A foot can easily fit in foot abduction brace and may not have a Pirani score of zero. Pirani score at initiation of bracing, in clinically corrected feet, in our research was ranging from 0.5-1.5. A score greater than two cannot justify correction. These findings provide a platform for clinicians to understand the importance of Pirani scoring system and its relevance to the number of casts. This is why the International Clubfoot Registry Database includes the Pirani score as well as foot position as measured by angles of cavus, abduction, varus, and equinus as the Pirani score may not capture them in all patients.

Pirani score is considered very effective for the assessment of clubfoot⁷. It is useful for the evaluation of severity, progress of Ponseti treatment and the need for tenotomy. We are not trying to invalidate the significance of Pirani score as it is hugely important for clubfoot care. It, however, does not reflect adequately the critical transition from treatment phase of casting to maintenance phase of bracing in all patients. The use of the International Clubfoot Database-Treatment visit form includes all components of clubfoot and thus provides a clear understanding of whether the patient has achieved foot correction or not.

Low tenotomy rate and restrospective analysis of data are our two major limitations. It is essential to understand that with the aim to achieve a Pirani score of zero, excessive casting is not required. This is because, as concluded by the study, a corrected clubfoot may not have a Pirani score of zero in all patients.