Paediatric Orthopaedics and Related Sciences

ORIGINAL ARTICLE
Year
: 2017  |  Volume : 3  |  Issue : 2  |  Page : 55--59

The Role of Pirani Scoring in Predicting the Frequency of Casting and the Need for Percutaneous Achilles Tenotomy in the Treatment of Idiopathic Clubfoot Using the Ponseti Method


Chukwuemeka O Anisi1, Joseph E Asuquo1, Innocent E Abang1, Michael E Eyong2, Onyebuchi G Osakwe1, Ngim E Ngim1,  
1 Department of Orthopaedics and Traumatology, University of Calabar, Cross River State, Nigeria
2 Department of Paediatrics, University of Calabar, Cross River State, Nigeria

Correspondence Address:
Chukwuemeka O Anisi
Department of Orthopaedics and Traumatology, University of Calabar Teaching Hospital, PMB 1278-Calabar, Cross River State
Nigeria

Abstract

Background: The Pirani scoring system is a simple tool widely used for grading the severity of clubfoot. This study was designed to objectively assess its value in predicting the total number of casts required, and the need for percutaneous Achilles tenotomy to achieve correction of the idiopathic clubfoot treated by the Ponseti method. Patients and Methods: All patients with idiopathic clubfoot, who attended our clubfoot clinic between January, 2013 and December, 2015, were prospectively studied. Each clubfoot was scored at presentation and at each visit by the first and second authors, using the Pirani scoring system. All patients were treated by the first and second authors by weekly stretching and cast application following the Ponseti treatment protocol until correction was achieved (with or without percutaneous Achilles tenotomy). Chi-square tests were applied to establish any existing relationship between the Pirani scores and the need for percutaneous tenotomy as well as the number of casts required to achieve correction. Results: A total of 69 patients with 108 idiopathic clubfeet were recruited into the study. In that, 14 patients defaulted, leaving the study with 81 clubfeet belonging to 55 patients. The median total Pirani score (TPS), midfoot contracture score and hindfoot contracture score at presentation were 4.0, 2.0 and 2.0, respectively. A total of 57 (70.4%) feet required percutaneous Achilles tenotomy to achieve correction. The average number of casts (including casts after tenotomy) required to achieve correction was 4.9 (2–10). The average number of casts required to achieve correction was 4.1 (2–10) for the no tenotomy group and 5.4 (3–10) for the tenotomy group. Statistically significant relationship was established between the TPS and number of casts required to achieve correction for both the tenotomy group (P = 0.039) and no tenotomy group (P = 0.05). Conclusion: High Pirani scores were associated with increased number of casts and percutaneous Achilles tenotomy for the correction of idiopathic clubfoot using the Ponseti method.



How to cite this article:
Anisi CO, Asuquo JE, Abang IE, Eyong ME, Osakwe OG, Ngim NE. The Role of Pirani Scoring in Predicting the Frequency of Casting and the Need for Percutaneous Achilles Tenotomy in the Treatment of Idiopathic Clubfoot Using the Ponseti Method.Paediatr Orthop Relat Sci 2017;3:55-59


How to cite this URL:
Anisi CO, Asuquo JE, Abang IE, Eyong ME, Osakwe OG, Ngim NE. The Role of Pirani Scoring in Predicting the Frequency of Casting and the Need for Percutaneous Achilles Tenotomy in the Treatment of Idiopathic Clubfoot Using the Ponseti Method. Paediatr Orthop Relat Sci [serial online] 2017 [cited 2019 Mar 23 ];3:55-59
Available from: http://www.pors.co.in/text.asp?2017/3/2/55/236714


Full Text

 Introduction



Congenital clubfoot is a deformity of the foot and ankle characterised by equinus, internal rotation and varus of the hindfoot, with adduction and supination of the forefoot.[1],[2] It is the most common congenital deformity of the lower limb with an incidence of approximately 1 in 1000 life births.[1],[2],[3],[4],[5],[6] Conservative treatment by serial manipulation and cast application as described by Ponseti[7] has been largely adopted as the treatment method of choice.[8],[9],[10],[11] Percutaneous Achilles tenotomy is considered an integral part of the Ponseti method of treatment, with 60% or more of affected feet requiring the procedure to achieve correction.[7],[12],[13],[14],[15] The goal of treatment is to correct all components of the deformity, such that the patient will have a functional, supple, plantigrade and pain-free foot.[7],[16],[17],[18] Success rates above 90% using the Ponseti treatment method have been largely reported.[19],[20],[21],[22],[23]

The Pirani scoring system is a simple tool, which is used to grade the severity of each component deformity of the clubfoot.[13] It has an excellent record of inter-observer reliability, with a significant correlation coefficient of 0.90.[24] The total Pirani score (TPS) comprises two sub-scores, the midfoot contracture score (MFCS) and the hindfoot contracture (HFCS), each assessing three component deformities. The MFCS assesses severity of the medial crease, prominence of the lateral head of Talus and degree of curvature of the lateral border of the foot. The HFCS assesses severity of the posterior crease, rigidity of equinus and emptiness of the heel. Each component deformity is scored 0.0 for no deformity, 0.5 for moderate deformity and 1.0 for severe deformity. Each sub-score is assigned a maximum score of 3.0 and the TPS, being the sum of the two sub-scores is assigned a maximum score of 6.0.

The Pirani scoring system is widely incorporated into the Ponseti method of idiopathic clubfoot treatment for grading the clubfoot at presentation, monitoring its progress during treatment and assessing the outcome of treatment. High scoring feet are likely to require percutaneous Achilles tenotomy as well as more sessions of manipulation and cast application to achieve correction.[25],[26],[27] This study was designed to objectively assess the predictive value of Pirani scores of idiopathic clubfeet at presentation, with respect to their relationship with the need for percutaneous Achilles tenotomy as well as the number of casts required to achieve correction.

 Patients and Methods



All patients with congenital clubfoot who attended our clubfoot clinic from January, 2013 to December, 2015 were prospectively studied. Patients who had any form of treatment for their clubfeet prior to presentation, as well as those with syndromic clubfeet were excluded from the study. Ethical clearance was obtained from the health research and ethical committee of the hospital, while informed consent was obtained from parents of the patients.

Each clubfoot was scored at presentation and at each visit, using the Pirani scoring system. Each foot was treated by serial manipulation and cast application by the first and second authors according to the Ponseti protocol until correction was achieved. The final cast was applied with the foot in 15° of dorsiflexion and about 50–70° of abduction, and retained for 3 weeks. Percutaneous Achilles tenotomy was performed for feet with persistent deformity prior to application of the final cast. Following removal of the final cast, correction was maintained using locally produced Steenbeck foot abduction brace, and follow-up was commenced beyond the period of this study.

Using the Statistical Package for Social Sciences software (SPSS Inc., Chicago, IL, United States), data of initial Pirani scores, number of casts required to achieve correction and percutaneous Achilles tenotomy were analysed. The relationship between the initial Pirani scores and total number of casts required to achieve correction was assessed using the chi-square test, and the level of significance was set at P = 0.05. Similarly, the relationship between the initial Pirani scores at presentation and the need for percutaneous Achilles tenotomy was assessed using the chi-square test, and the level of significance was set at P = 0.05.

 Results



A total of 69 patients with 106 clubfeet were recruited into the study. Fourteen patients defaulted, leaving the study with 81 clubfeet (11 right, 18 left and 26 bilateral) belonging to 55 patients (36 male, 19 female, M:F = 1.9:1) aged 3 days to 7 years. The median TPS, MFCS and HFCS were 4.0, 2.0 and 2.0, respectively [[Figure 1] and [Table 1]].{Figure 1}{Table 1}

Percutaneous Achilles tenotomy was performed on 57 (70.4%) feet. A total of 80 (98.8%) feet were successfully corrected (including those that required percutaneous Achilles tenotomy). One foot required elongation of Achilles tendon and posteromedial release. The average number of casts required to achieve correction (including casts applied following percutaneous Achilles tenotomy) was 4.9 (2–10) casts [[Figure 2] and [Table 2]]. Twenty-four (61.5%) out of 39 clubfeet with initial TPS of 4.5 and above required six casts or more, while all clubfeet with initial TPS of 4.0 and below required five casts or less to achieve correction (P = 0.05).{Figure 2}{Table 2}

Twenty-two (61.1%) out of 36 clubfeet with initial MFCS of 2.0 and above required six casts or more, while all clubfeet with MFCS of 1.5 and less required five casts or less to achieve correction (P = 0.002). Twenty-two (61.1%) out of 36 clubfeet with initial HFCS of 2.0 and above required six casts or more, while only 2 (5.6%) out of 45 clubfeet with HFCS of 1.5 and less required five casts or less to achieve correction (P = 0.001).

Forty-four (66.7%) out of 66 clubfeet with initial TPS of 3.0 and above required percutaneous Achilles tenotomy to achieve correction (P = 0.05). Forty-six (70.8%) out of 65 clubfeet with initial MFCS of 1.5 required percutaneous Achilles tenotomy to achieve correction (P = 0.032). Fifty-two (76.5%) out of 68 clubfeet with initial HFCS of 1.5 or more required percutaneous Achilles tenotomy to achieve correction (P = 0.004).

For clubfeet which did not require percutaneous Achilles tenotomy to achieve correction (no tenotomy group), the median initial TPS, MFCS and HFCS were 2.5, 1.5 and 1.5, respectively. The average number of casts required to achieve correction in this group was 4.1 (3–10). Fourteen (66.7%) out of 21 clubfeet with initial TPS of 2.0 and above, required four casts or more to achieve correction (P < 0.05). Fourteen (60.9%) out of 24 clubfeet with initial MFCS of 1.0 or more, required four casts or more to achieve correction (P = 0.078). Twelve (70.6%) out of 17 clubfeet with initial HFCS of 1.0, required four casts or more to achieve correction (P = 0.004).

For clubfeet which required percutaneous Achilles tenotomy to achieve correction (tenotomy group), the median TPS, MFCS and HFCS were 4.5, 2.5 and 2.5, respectively. Twenty (57.1%) out of 35 clubfeet with initial TPS of 4.0 and above, and none of the 22 feet with initial TPS of 3.5 and below required six or more casts to achieve correction (P = 0.039). Eleven (50%) out of 22 clubfeet with initial MFCS of 2.5 and above, and none of the 25 clubfeet with initial MFCS of 2.0 and below required up to six casts to achieve correction (P < 0.05). Twenty (37.0%) out of 54 clubfeet with initial HFCS of 2.5 and above, and 2 (7.4%) out of 27 clubfeet with initial HFCS of 2.5 and above required six or more casts to achieve correction (P = 0.072).

 Discussion



The Ponseti method has been widely adopted by orthopaedic surgeons as the initial treatment option for idiopathic clubfoot. The use of the Pirani scoring system to predict the total number of casts required and the need for percutaneous Achilles tenotomy to achieve correction has been evaluated in a number of studies.[25],[26],[27] It is generally believed that the higher the Pirani scores at presentation, the more likely it is that the clubfoot would require percutaneous Achilles tenotomy, as well as increased number of casts to achieve correction.

Clubfeet with initial TPS of 4.5 and above required six casts or more compared to five casts or less required by those with initial TPS of 4.0 and below (P = 0.05). This implies that the more the severity of deformity at presentation, the stiffer the clubfoot, and the higher the number of casts required to achieve correction.

Most (80.3%) of the clubfeet with initial TPS of 3.0 and above required percutaneous Achilles tenotomy compared to only 42.9% of those with initial TPS of 2.5 and below (P = 0.001). This implies that the clubfeet with high Pirani scores at presentation are more likely to require percutaneous Achilles tenotomy to achieve correction. A strong link was established between the initial MFCS and percutaneous Achilles tenotomy (P = 0.032). However, a stronger link was established between the initial HFCS and percutaneous Achilles tenotomy (P = 0.004). This could be explained by the fact that the equinus deformity which is graded using the HFCS is more likely to require percutaneous Achilles tenotomy for its correction with increasing severity. Some of the articles reviewed reported a positive correlation between number of casts/tenotomy and high TPS. The median initial TPS, MFCS and HFCS are higher in the tenotomy group. This implies that the higher the Pirani scores at presentation, the stiffer the foot and the higher the chances that percutaneous Achilles tenotomy will be required to achieve correction. Similarly, the average number of casts required to achieve correction in the tenotomy group was significantly higher, implying that the clubfeet which needed tenotomy to achieve correction had higher Pirani scores at presentation, were stiffer and therefore, required more casts to achieve correction. Higher median MFCS and HFCS at presentation in this group also imply that the need for percutaneous Achilles tenotomy is related to the severity of all the component deformities and not just those of the hindfoot.

For the no tenotomy group, the relationship between the initial HFCS and the number of casts required to achieve correction was statistically significant (P = 0.004). Conversely, the relationship between the initial MFCS and the total number of casts required to achieve correction was not statistically significant (P = 0.078). This clearly suggests that it is the HFCS and not the MFCS that predicts the total number of casts that may be required to correct deformity in this group of patients. For the tenotomy group, the MFCS and not the HFCS showed a strong link with the total number of casts required to achieve correction (P = 0.05). This can be explained by the fact that percutaneous Achilles tenotomy was performed only after correction of the midfoot and forefoot deformities, the total number of casts, therefore, depending on how long it took to correct those deformities.Some of the articles reviewed reported a positive correlation between the number of casts/percutaneous Achilles tenotomy and TPS.[25],[26],[27] However, correlation between the sub-scores (MFCS, HFCS) and the above variables were not stated, making comparison between our observation and their findings unattainable.

Eighty (98.89%) out of the 81 clubfeet studied were successfully corrected. This correction rate is similar to most rates reported in the literature, suggesting that high correction rates are associated with the Ponseti method irrespective of the severity of the clubfoot at presentation.[19],[20],[21],[22],[23]

 Conclusion



This study shows that the Pirani scores at presentation can be used successfully to predict the total number of casts as well as the need for percutaneous Achilles tenotomy to achieve correction. Clubfeet with high Pirani scores at presentation are more likely to require more casts and probably percutaneous Achilles tenotomy to achieve correction.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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