Ponseti Treatment of Rigid Residual Deformity in Congenital Clubfoot After Walking Age

Dragoni, Massimiliano MD; Farsetti, Pasquale MD; Vena, Giuseppe MD; Bellini, Diego MD; Maglione, Pierluigi MD; Ippolito, Ernesto MD

Journal of Bone & Joint Surgery - American Volume:
doi: 10.2106/JBJS.16.00053
Scientific Articles
Abstract

Background: There is no established treatment for rigid residual deformity of congenital clubfoot (CCF) after walking age. Soft-tissue procedures, osseous procedures, and external fixation have been performed with unpredictable results. We applied the Ponseti method to patients with this condition in order to improve the outcomes of treatment.

Methods: We retrospectively reviewed the cases of 44 patients (68 feet) with congenital clubfoot whose mean age (and standard deviation) at treatment was 4.8 ± 1.6 years. All patients had been previously treated in other institutions by various conservative and surgical protocols. Residual deformity was evaluated using the International Clubfoot Study Group Score (ICFSGS), and stiffness was rated by the number of casts needed for deformity correction. Ponseti manipulation and cast application was performed. Equinus was usually treated with percutaneous heel-cord surgery, while the cavus deformity was treated with percutaneous fasciotomy when needed. Tibialis anterior tendon transfer (TATT) was performed in patients over 3 years old. At the time of follow-up, the results were evaluated using the ICFSGS.

Results: Before treatment, 12 feet were graded as fair and 56, as poor. Two to 4 casts were applied, with each cast worn for 4 weeks. Stiffness was moderate (2 casts) in 23 feet, severe (3 casts) in 30 feet, and very severe (4 casts) in 15 feet. Percutaneous heel-cord surgery was performed in 28 feet; open posterior release, in 5 feet; plantar fasciotomy, in 30 feet; and TATT, in 60 feet. The mean length of follow-up was 4.9 ± 1.8 years. Eight feet had an excellent result; 49 feet, a good result; and 11 feet, a fair result. No patient had pain. All of the feet showed significant improvement.

Conclusions: Ponseti treatment with TATT, which was performed in 88% of the feet, was effective, and satisfactory results were achieved in 84% of the feet. At the time of follow-up, no patient showed an abnormal gait, all feet were plantigrade and flexible, but 2 feet (2.9%) had relapsed.

Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Author Information

1Departments of Clinical Science and Translational Medicine (M.D. and G.V.) and Orthopaedics and Traumatology (P.F., D.B., and E.I.), University of Rome “Tor Vergata,” Rome, Italy

2Orthopaedic Unit, Department of Surgery and Transplant Center, Bambino Gesù Children’s Hospital, Fiumicino, Italy

E-mail address for E. Ippolito: ippolito@med.uniroma2.it

Article Outline

The worldwide use of the Ponseti method for the treatment of congenital clubfoot (CCF) has radically improved the result of clubfoot correction in infants, with success rates of 93% to 100%1. However, rigid residual deformity continues to be observed after walking age regardless of the type of treatment that had been originally performed, and its management is challenging2-4.

Currently, no consensus exists on the best treatment. Soft-tissue surgical procedures5-8, osseous surgical procedures9-19, and correction by external fixators20-24 have been mostly adopted, whereas the Ponseti method has been rarely recommended25,26.

We reviewed the result of the Ponseti method27 for treating residual deformity in 44 patients (68 feet) with CCF who were managed at our clinic after walking age at a mean follow-up (and standard deviation) of 4.9 ± 1.8 years.

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Materials and Methods

We enrolled 52 consecutive patients (79 feet with idiopathic CCF) who were treated by us from 2004 to 2012 for rigid residual deformity that was resistant to previous treatment performed in other institutions. The parents of eight patients (11 feet) declined our invitation because they lived too far away. Forty-four patients (68 feet) who came to our clinic for routine follow-up participated in our study.

Fifty-one feet with CCF had been originally classified as having a Pirani score28 of 4 to 6 and a Diméglio classification29 of grade IV, whereas 17 feet were defined as having a “severe deformity” either in their original record or in the discharge note.

We divided our patients into 3 groups on the basis of their original treatment. The first group included 19 children (28 feet) who were treated since birth with 6 to 12 long leg plaster casts each worn for a week followed by percutaneous heel-cord tenotomy (11 feet) or by open heel-cord lengthening (17 feet). A long leg posterior splint was then applied to 15 feet and was worn for 1 year, while shoes with a bar brace were used to manage 13 feet for 6 to 19 months; the parents were told that the Ponseti method had been performed.

The second group included 20 children (30 feet) who were treated with 5 to 8 short leg plaster casts followed first by a posterior long leg splint and afterward by an extensive soft-tissue release performed when the children were 7 to 10 months old. Twelve of those feet had a second posteromedial release associated with osseous procedures at 12 to 28 months of age in the same institution.

The third group included 5 children (10 feet) who were treated with manipulations, active physiotherapy, and splinting, according to the French method, from birth to an average age of 6 months30,31.

For 34 patients, residual deformity was differentiated from recurrence on the basis of the original clinical record in which the involved feet were described as partially corrected after treatment. Furthermore, either radiographs or pedobarographs made at the end of the original treatment showed residual deformity since those children were able to stand and walk. For 10 patients who did not have their clinical records, the discharge note mentioned an “almost corrected deformity.” In addition, their parents stated that the CCF had never been fully corrected, and they provided photographs and videos showing residual deformity.

To uniformly assess the residual CCF deformity before starting our treatment and the result of treatment at the time of follow-up, we adopted the International Clubfoot Study Group Score (ICFSGS) described by Bensahel et al.32. This rating system includes morphologic, radiographic, and functional evaluation of the CCF deformity, with a final score indicating excellent (0 to 5 points), good (6 to 15 points), fair (16 to 30 points), or poor (>30 points) results.

At the beginning of our study, we manipulated the foot with the child awake. Since the majority of our children were restless and uncooperative because they were worried about undergoing the casting procedure, we changed the treatment protocol, in agreement with the parents’ wishes, so that the manipulation was performed under sedation, which was induced and maintained with midazolam administered orally at a dose of 0.05 mg/kg of body weight. Gentle manipulations lasting 5 to 10 minutes were performed according to the Ponseti method27. They were stopped at the point of maximum yield allowed by the stiff fibrous structures that were never overstressed, torn, or damaged in order to avoid inflammatory edema and subsequent scarring.

Each cast was worn for 4 weeks. Percutaneous plantar fasciotomy27 was performed under anesthesia in feet with cavus deformity whenever the plantar fascia was still under tension after the first cast. In feet with equinus deformity, a percutaneous heel-cord tenotomy27, 3-cut percutaneous lengthening33, or open posterior release was performed. After surgery, a long leg plaster cast holding the foot in maximum dorsiflexion was worn for 4 weeks. Children younger than 2.5 years were managed with a Mitchell-Ponseti brace at the end of cast treatment, and those who were over that age had a tibialis anterior tendon transfer (TATT) to the third cuneiform27.

Before treatment and at the time of follow-up, all of the patients were clinically and radiographically evaluated by the 2 senior authors (E.I. and P.F.) using the ICFSGS32.

Clinical measurements were taken in the clinic with a hand goniometer for 3 consecutive times every 20 minutes, and the intraobserver kappa value was 0.805, while the interobserver kappa value was 0.780. Radiographic angles were measured once a week for 3 consecutive weeks using a computer metric program, and the intraobserver kappa value was 0.875, while the interobserver kappa value was 0.827.

The study was approved by the ethics committee of our hospital.

Descriptive statistics consisted of the mean and standard deviation for parameters with Gaussian distribution after confirmation with histograms and the Kolmogorov-Smirnov test. Comparison among continuous variables was performed with 1-way analysis of variance (ANOVA) or 2-way ANOVA and multiple comparisons were performed by the Bonferroni test. Comparison of frequencies among groups was performed with the chi-square test. A p value of <0.05 was considered significant.

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Results

Thirty-three patients were male and 11 were female. Their mean age at the time of treatment was 4.8 ± 1.6 years (range, 1.8 to 8.2 years). Residual deformity was bilateral in 24 patients and unilateral in 20 patients.

Before our treatment, 12 feet with CCF were rated as fair and 56, as poor (Table I). All of the children had a stiff foot deformity. They walked with an abnormal gait and had difficulty with shoe wear, and only 20 were able to run. None of them had pain. Residual adduction was evident in 66 feet; cavus, in 57 feet; varus, in 53 feet; equinus, in 33 feet; and supination, in 10 feet. Dorsal subluxation of the navicular associated with severe cavus was evident in 8 feet that had a posteromedial release.

Following the manipulation, no child had pain after recovering from the sedation. The foot stiffness rating, according to the number of casts required for correction, is shown in Table I. Patients who underwent extensive soft-tissue surgery or were over 6 years old required a mean of 3.4 ± 0.6 casts, while patients treated by conservative methods or who were less than 6 years old had a mean of 2.1 ± 0.4 casts; the difference was significant (p < 0.05). After cast treatment, 6 feet in patients under 4 years old had a percutaneous heel-cord tenotomy, 22 feet had percutaneous lengthening, and 5 feet that had been previously surgically treated for CCF had an open posterior release. Percutaneous plantar fasciotomy was performed in 30 cavus feet, while 60 feet, in which the ossification nucleus of the third cuneiform was present, had TATT (Figs. 1-A and 1-B). Six children (8 feet without the ossification nucleus of the third cuneiform) who were under 3 years old at the end of treatment were managed with a brace for a mean of 16 months.

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The mean length of follow-up was 4.9 ± 1.8 years (range, 2.5 to 10 years). The mean age of the patients at the time of follow-up was 9.8 ± 1.8 years (range, 4.8 to 13.2 years). At the time of follow-up, 8 feet had an excellent result, 49 had a good result, and 11 had a fair result; the improvement was significant (p < 0.05) (Table I, Figs. 1-A through 2-C). All children had plantigrade and flexible feet, could wear normal shoes, had a normal gait, and were able to run. Six of the 8 feet managed with bracing had maintained a good correction and presented no indication for TATT, whereas 2 showed a dynamic relapse and were scheduled for TATT. Dorsal subluxation of the navicular continued to be evident in 6 feet; however, the associated cavus deformity was corrected and the patients were asymptomatic (Figs. 2-A, 2-B, and 2-C). No patient had pain.

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Discussion

Unlike recurrence, in which CCF deformity reappears months or years after a documented correction3,13, a rigid residual deformity has never been corrected by previous treatment6,16,22,34. A recurrence may be superimposed on a residual deformity, but the latter is stiff whereas the former appears initially as a dynamic foot supination27. The amount of time elapsed since treatment, as well as previous imaging and the parents’ judgment, may also help to differentiate the 2 conditions34.

Our patients had been originally treated by unsuccessful conservative and surgical protocols, and over 40% of uncorrected deformities were observed after a faulty application of the Ponseti method. Clinical classification of residual deformities is difficult because some mild deformities are masked by others that are prevalent. We adopted the validated ICFSGS by Bensahel et al.32 that allows a comprehensive evaluation of CCF deformity by including all of its morphologic, radiographic, and functional aspects. We do not believe that the Pirani score used by others26 is ideal to assess residual deformity in children with CCF after 3 years of age when skin creases are barely visible and masked by scars of previous surgery.

In accordance with previous studies2,6,7,10,16, we observed mostly adduction and cavovarus, whereas equinus was less frequent and supination was rare. CCF deformity was severe at birth, as shown by the records of our patients, which partly explains the resistance to treatment.

Various treatments have been proposed for residual CCF deformity: (1) soft-tissue procedures5-8, (2) osseous procedures9-19, (3) a combination of soft-tissue and osseous procedures6,7,16,18, and (4) correction by external fixators20-24. The results of those procedures are difficult to evaluate because preoperative classifications are often missing or not uniform, the length of follow-up is either short or not reported, and postoperative results are assessed either subjectively or by different evaluation scales that are hardly comparable with each other. Foot stiffness and a high recurrence rate reported in longer follow-up studies6,12 negatively affect those treatments. Moreover, extensive surgical releases and osteotomies, especially when repeated, may result in stiff, painful, and shortened feet after the end of growth35.

We applied the Ponseti method to our patients, owing to the good results obtained with this method in patients with CCF who have a recurrence of stiffness36,37, in older infants with untreated CCF38,39, and in patients with neglected CCF40-42. We are aware of only 2 studies published on the application of the Ponseti method to rigid residual CCF deformity and/or recurrence after surgical treatment in children older than 2 years. Garg and Dobbs25 treated 11 children with a mean age of 4.6 years who had a rigid residual deformity following a posteromedial release. The number of casts applied weekly ranged from 1 to 8, and all of the patients had TATT. At the time of follow-up, the initial results were considered excellent. Nogueira et al.26 treated 58 children, at a mean age of 5 years and 2 months, with extensive soft-tissue release, which was associated in a few cases with osseous procedures. Residual deformity was classified by the Pirani score. Casts were changed every week, and the number of plaster casts applied ranged from 1 to 10. At the time of follow-up, only 89% of the feet were plantigrade, but all had a substantial reduction of the Pirani score. However, 20% of them had <30° of subtalar motion, while an unspecified number had 0° of either plantar flexion or dorsiflexion of the foot. Recurrence occurred in 14% of the feet.

We found it necessary to modify the Ponseti method to some extent in our patients with very stiff feet and in those who were older.

Since the majority of our children were worried and uncooperative before entering the plaster cast room, regardless of the presence and reprimands of their parents, it was decided to perform manipulations and cast application with the child under sedation to allow greater stretching of the rigid soft tissues. We increased the manipulation time to 5 to 10 minutes as previously recommended40. However, in no case was manipulation performed forcefully, so as to avoid tearing of the retracted and stiff fibrotic structures that might in turn have caused edema and subsequent scarring. Moreover, no patient had pain after recovery from the sedation. We are aware of the different, cooperative behavior shown by children of other nationalities who have undergone a similar procedure at a similar age but without sedation25,26,36-42. We believe that a different social, cultural, and parental educational background might have played an important role in explaining the different attitude demonstrated by our children.

We decided to maintain the cast for 4 weeks for clinical and basic-science reasons. Increasing the immobilization time in the cast up to 3 weeks was previously recommended for older children treated with the Ponseti method36,40,43. In growing rat ligaments, the load-deformation curve quickly becomes steeper because of the increase of intermolecular collagen cross-links44,45. Moreover, a “creep” phenomenon occurs in both tendons and ligaments, causing gradual yielding of the tissue under constant loading. Therefore, to obtain a permanent elongation, the duration of tissue loading should also be increased according to the increased age-related collagen cross-links46,47. Similar age-related changes also occur in growing osteocartilaginous anlagen in CCF, influencing their biomechanical properties48. Collagen turnover slows down with growth. Therefore, an increasingly longer time is needed for the fibroblasts to remodel the elongated collagen fibers49.

The number of casts we applied was strictly related to the amount of correction obtained. The stiffness of the residual deformity was also rated by the number of casts needed to provide the foot with a flexible correction. Children with CCF who had not had previous operative treatment or those under 6 years old who were treated with minimally invasive surgery had a faster correction (2 casts) in comparison with children with CCF who were more than 6 years old and treated with extensive surgery. The original treatment also partially influenced the final result. Despite their usually good functional result, clubfeet with extensive surgical release showed more radiographic abnormalities than those treated by either the Ponseti or the French method.

Some authors have applied up to 12 weekly casts to correct rigid residual deformity in older children25,26,38,39. We applied a maximum of 4 casts, with 1 applied every 4 weeks. If we consider the traveling involved for the families, the commitment, and the discomfort as well as the cost of the whole procedure, it remains a matter of debate whether 12 casts within 12 weeks are more convenient than 4 casts within 16 weeks.

Although manipulations and cast application were uniformly performed for all of our patients, additional surgery varied depending on the correction obtained at the end of cast immobilization. Percutaneous plantar fasciotomy was performed for cavus correction in 44% of the feet, either percutaneous tenotomy or percutaneous lengthening of the Achilles tendon was performed for equinus correction in 48.5%, and a posterior release was required in 7% because of a previous posteromedial release. In accordance with Garg and Dobbs25, we performed TATT in 88% of the feet as part of the treatment protocol to avoid a recurrence that might have had devastating psychological effects, particularly in children who had already had repeated surgery and/or who might not have easily accepted bracing. In 8 feet, TATT was not performed because the ossification center of the third cuneiform had not yet appeared. Those feet were managed with bracing, but 2 feet (2.9% of the whole series) had recurrence, confirming indirectly that TATT may prevent recurrence, which is particularly a risk in CCF treated for residual deformity and/or recurrence6,12,23,25,26,50. Our overall treatment protocol might not seem to be uniform; however, all of the surgical procedures are part of the Ponseti general management of clubfoot27, except for percutaneous Achilles tendon lengthening and posterior release that were imposed because of the patient age or previous extensive surgery.

At the time of follow-up, we used the same ICFSGS rating system for uniform assessment32: 84% of the feet had achieved excellent or good results, and no foot showed a lack of plantar flexion or was not plantigrade, as has been observed by others26. Deformity correction was also confirmed by the significant improvement of the CCF in our patients after treatment. Radiographic evaluation was particularly useful to assess correction of cavus and adduction that cannot be objectively graded by clinical means.

Dorsolateral subluxation of the navicular was still present in 6 feet, but they were all asymptomatic, as was observed in the study by Thompson et al.50. However, Kuo and Jansen reported additional surgery was needed in 7 (58%) of 12 feet in their study to address this deformity51.

As emphasized by Ponseti27, pain was absent in our patients both before treatment and at the time of follow-up because no foot was fully grown.

Our study has several limitations. It is a retrospective study of a single center, and the number of feet with CCF that were treated is not very large. Moreover, the original clinical records of 10 children were missing as was previous imaging of 16 feet. For all of those patients, we had to rely on the discharge notes, photographs, videos, and parents’ judgment to ascertain the previous clinical history and the evolution of the deformity. A third limitation is the relative shortness of follow-up that does not allow evaluation of the longer-term implications of our treatment. Detection bias is also possible with our outcome evaluation protocol.

In conclusion, we believe that the Ponseti method with some necessary modifications is effective for the treatment of rigid residual CCF deformity in children from 2 to 8 years of age, regardless of the previous treatment, and our results seem to be better than those reported for other surgical procedures. We faced a major problem with older children for whom both walking and mobility were restricted by the application of long leg casts. However, the families enthusiastically agreed to continue the Ponseti treatment as soon as they looked at the improved shape of their child’s foot after removal of the first plaster cast.

Investigation performed at the University of Rome “Tor Vergata,” Rome, Italy

Disclosure: There was no external funding source. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article.

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