➢ The treatment of congenital clubfoot has changed in the past two decades, with Ponseti serial casting being the preferred method in North America.
➢ Although initial correction is achieved in almost 95% of clubfeet after treatment with Ponseti casting, recurrence rates of almost 50% have been reported, and recurrent clubfoot requires additional treatment. Compliance with the use of orthoses after the initial correction can decrease the recurrence rate.
➢ The Ponseti method can result in a favorable long-term outcome in >85% of patients.
➢ Comprehensive soft-tissue release can lead to a plantigrade foot, but such feet are painful and stiff in adulthood.
Congenital clubfoot is one of the most common congenital deformities of the lower extremity. The incidence has been reported to be one to two cases per 1000 live births1. The incidence is higher in the Polynesian population and lower in the Chinese population1,2. Congenital clubfoot is also twice as common in male patients1,2. Treatment of clubfoot has changed in the past two decades in North America, with most providers using serial Ponseti casting and manipulation3-5. Despite full initial correction, recurrence of clubfoot is common and may require later treatment. In the present report, we review the etiology and pathoanatomy of this common abnormality and discuss different treatment methods and their reported long-term outcomes.
The etiology of idiopathic clubfoot is not well understood. Non-idiopathic clubfoot is usually the result of a neurological or syndromic etiology. Between six and twelve weeks of gestational age, the fetal foot assumes a clubfoot position6, which has led physicians to think of clubfoot as an arrest in the development of the foot in the early embryonic stages. This theory cannot explain the dysplastic features seen in tarsal bones in patients with clubfoot as these changes are not seen in normal fetal development7,8.
A genetic etiology is suggested by the evidence of a higher concordance of clubfoot in monozygotic twins than in dizygotic twins, a rate of parent-to-child transmission of as high as 20% in some families, and the effect of ethnicity on prevalence9. There is evidence to suggest that the common disease-common variant hypothesis applies to the genetic etiology of clubfoot, with multiple studies showing associations between idiopathic clubfoot and common gene variants such as Hox homeobox genes10, insulin-like growth factor binding protein 311, and caspase genes12. A polygenic threshold model with sex dimorphism (Carter effect)13 also has been described in association with clubfoot inheritance, with females requiring a higher genetic load to be affected and therefore transmitting the disease to their children at a higher rate2. Another theory that can explain the genetic etiology of clubfoot is the common disease-rare variant hypothesis, in which rare genetic variants have moderate risks with higher penetrance. On the basis of this theory, involvement of the PITX1-TBX4 transcription pathway is seen in 5% of patients with familial isolated clubfoot9.
Besides genetic etiology, early amniocentesis has been shown to increase the rate of clubfoot, suggesting the influence of perinatal factors on the development of this deformity14.
The major clubfoot deformities include hindfoot varus and equinus in addition to forefoot adductus and cavus. These deformities are the result of intraosseous abnormalities (abnormal bone morphology) and interosseous abnormalities (abnormal relationships of bones to each other).
Intraosseous deformity is most pronounced in the talus, with a short talar neck and medial and plantar deviation of the anterior end15. On the inferior surface of the talus, the medial and anterior facets are underdeveloped. The calcaneus is smaller than in normal feet, and the sustentaculum is underdeveloped16.
Interosseous deformity is seen as medial displacement of the navicular and cuboid on the talar head and calcaneus, respectively. Herzenberg et al.17 showed that both the talus and the calcaneus are about 20° more internally rotated relative to the tibiofibular axis in clubfeet as compared with normal feet. In that study, the body of the talus was reported to be externally rotated within the ankle mortise. The presence of internal tibial torsion in clubfoot is controversial, with evidence for18,19 and against20,21 the deformity.
Contractures and fibrosis of the ligaments on the medial side of the foot, including the spring ligament, master knot of Henry, tibionavicular ligament, and plantar fascia, also contribute to the clubfoot abnormality22,23.
Abnormal muscles have been observed during the operative release of clubfoot deformity. Dobbs et al. reported that the flexor digitorum accessorius longus muscle was seen in 6.6% of children who underwent operative release and was more common in children with a positive family history (prevalence, 23%)24. The flexor digitorum accessorius longus has been reported in 1% to 8% of normal adult cadavers25-27. An anomalous soleus muscle also has been described and has been reported to be associated with a high rate of recurrence28.
Study of the blood supply has shown abnormal or absent anterior tibial artery in as many as 90% of clubfeet29,30. Absence of the posterior tibial artery also has been reported30 but is an uncommon finding. This anomalous arterial supply may put the foot at increased risk for vascular complications if one of the dominant arteries is injured during comprehensive soft-tissue release or Achilles tenotomy.
The diagnosis of clubfoot can be made prenatally as early as the second trimester, although studies have shown a false-positive rate of between 0% and 29%31-35. Goltzbecker et al. recently described a sonographic severity scale for clubfoot and showed a decrease in the false-positive rate if only moderate and severe forms of clubfoot were considered to be true abnormalities36.
Diagnosis is usually evident at birth, with the heel in equinus and the foot inverted on the tibia (Fig. 1). True clubfoot cannot be fully passively corrected on examination, unlike a milder form called postural clubfoot. In patients with unilateral involvement, the circumference of the calf on the involved side is smaller than that on the normal side. Clubfoot can be seen in isolation or as a part of other musculoskeletal abnormalities including but not limited to Down syndrome, Larsen syndrome, arthrogryposis, diastrophic dysplasia, spina bifida, Freeman-Sheldon syndrome, and amniotic band syndrome. A complete musculoskeletal examination is required to differentiate among these non-idiopathic forms of clubfoot, which are usually more resistant to nonoperative treatment.
During the examination of clubfoot, the neurological status of the foot should be carefully assessed, typically by means of plantar stimulation of the foot. Lack of dorsiflexion of the toes and a resting position in plantar flexion (the drop toe sign) indicate a neurological form of clubfoot associated with peroneal nerve palsy37,38. Patients with this form typically have a high rate of recurrence following nonoperative treatment; in one series, operative release was required for four (44%) of nine patients37.
Because of the common anomalous vascular anatomy of these feet, the vascular status also should be carefully assessed before any operative procedure is performed in order to avoid potential injury to the dominant arterial supply of the foot.
The amount of initial deformity usually is reported with use of the classification system of either Pirani et al.39,40 or Diméglio et al.41. Both systems have shown very good interobserver reliability after an initial learning period42. With the system of Pirani et al., a 6-point scoring system is used to assess the severity of deformity, with 3 points assigned to the midfoot and 3 points assigned to the hindfoot40,43. With the system of Diméglio et al., a 20-point scoring system is used to assess residual deformity after the application of a gentle corrective maneuver. The severity of the deformity is then graded on a scale of I to IV on the basis of this scoring41,43.
Perry et al. recently reported ultrasonographic evidence of hip dysplasia in nine of 122 children with clubfoot and proposed routine ultrasound screening of the hip in patients with clubfoot44. Paton and Choudry45 did not report any cases of grade-III or IV hip dysplasia in a long-term follow-up study of forty patients with clubfoot. They reported seven cases of grade-II dysplasia, which developed normally during the follow-up period and required no treatment. Other investigators have reported the rate of hip dysplasia in these patients to be <1%46,47. On the basis of the current data, we do not recommend routine sonographic hip screening but recommend a detailed hip examination for patients with clubfoot.
Limb-length discrepancy is also seen in patients with unilateral involvement. Spiegel and Loder48 reported a discrepancy measuring >0.5 cm in twenty-three of forty-seven patients. In that study, the average discrepancy (and standard deviation) was 1.7 ± 1.0 cm, indicating a 2.4% growth inhibition on the involved side, with the majority of the shortening being in the tibia.
Nonoperative treatment is almost always the initial method of treatment for congenital clubfoot, followed by Achilles tenotomy. Complete operative release is reserved for feet that cannot be corrected by nonoperative means or that have rapid recurrence.
Typical Idiopathic Clubfoot
The Ponseti method is the most commonly used nonoperative method for the treatment of clubfoot in North America3. This method is based on gradual correction of the deformity with serial weekly long leg casting. The deformities are corrected in the order of the CAVE acronym (cavus, adductus, varus, and equinus). Cavus is corrected first by elevating the first metatarsal, and adductus deformity is corrected by rotating the forefoot and calcaneus under the fixed talus. This is done by applying upward pressure on the first metatarsal (to prevent forefoot pronation) and downward pressure on the talar head5,49,50. This maneuver around the fixed talar head corrects the hindfoot varus and forefoot adductus simultaneously and prevents crushing of the cuboid.
Equinus is the last deformity to be corrected. Correction of equinus should not be attempted until forefoot adduction is corrected and the forefoot can be abducted easily to 60° relative to the anterior aspect of the ankle. Equinus is the hardest deformity to correct with casting and in most cases is treated with percutaneous Achilles tenotomy5,49,50. Tenotomy can be avoided if 10° of ankle dorsiflexion is achieved with serial casting. Percutaneous Achilles tenotomy is required in 80% to 95% of cases of clubfoot that are treated with the Ponseti method5,49-52. Percutaneous Achilles tenotomy is reported to be safe both as an office procedure and when done with the patient under general anesthesia in the operating room53,54. Injuries to the peroneal artery, lesser saphenous vein, and sural nerve and pseudoaneurysm of the posterior tibial artery have been reported as complications of this procedure55,56. Injury of the peroneal artery potentially can have disastrous complications as this artery may be the only arterial supply to the foot in some cases. The rate of success of serial Ponseti casting and tenotomy has been reported to be around 95% for patients with idiopathic clubfoot5,49-52. Radiographic assessment of the deformity is not done routinely in association this method.
After full correction of the deformity, the patient is managed with foot abduction orthosis full time for three months, followed by part-time wear for two to four years5,57. The foot is placed in 70° of external rotation while in the orthosis. The rate of recurrence of the deformity after initial correction has been reported to be between 37% to 47%5,51. Premature discontinuation of brace wear has been shown to strongly correlate with recurrence58. Parental education showed a correlation with recurrence in one study58, but this association has been questioned in other studies59. Modifications to the original Denis-Browne bar have resulted in better compliance with brace wear60. In one study, part-time brace wear for four years (instead of two years as in initial Ponseti reports) was shown to decrease the rate of recurrence57.
Recurrence of clubfoot deformity after treatment with this method usually happens before the age of four years. Tibialis anterior tendon transfer to the third cuneiform has been shown to prevent recurrence in patients who present with so-called dynamic supination61-64. Dynamic supination implies forefoot supination with ankle dorsiflexion in swing phase and weight-bearing on the lateral side of the foot in some cases. In a case series of 104 feet, Laaveg and Ponseti5 reported that forty-eight feet (46%) required tibialis anterior tendon transfer. Recurrence of other elements of the deformity (cavus, equinus, and hindfoot varus) also can occur and can be treated operatively or with braces according to the rigidity and magnitude of the deformity. Laaveg and Ponseti described four rounds of recurrence (with some feet having four recurrences despite treatment after each recurrence) that were treated with a variety of operative procedures, including plantar fascia release, extensor hallucis longus recession to the neck of the first metatarsal, transfer of the posterior tibialis tendon to the dorsum of the foot, posteromedial release, and triple arthrodesis5.
Masrouha and Morcuende65 studied the recurrence after tibialis anterior tendon transfer and found that 15% of the feet showed a recurrence of at least one element of the deformity after this procedure. In that study, younger age at the time of tibialis anterior tendon transfer correlated with a higher rate of recurrence.
Complex Idiopathic Clubfoot
Complex idiopathic clubfoot is characterized by plantar flexion of all metatarsals (as compared with only the first metatarsal in typical idiopathic clubfoot), rigid equinus, and deep medial creases (Fig. 2). Applying the typical Ponseti casting creates a grotesque deformity with residual cavus66. Ponseti et al.66 reported successful treatment of these feet with a modified method in which the adductus is corrected first, to only 40° of forefoot abduction, followed by correction of the cavus with molding under all metatarsal heads. Feet with complex idiopathic clubfoot may require serial casting after the Achilles tenotomy to correct the residual deformity. After casting, the patient is managed with a specific foot abduction orthosis with three straps that hold each foot in 40° of external rotation66.
French Functional Method
The French functional method involves daily manipulation of the newborn’s feet by a skilled physical therapist, followed by temporary immobilization with elastic or non-elastic adhesive taping67. The manipulations are started in the horizontal plane, and the equinus is addressed after correction of the horizontal plane deformity. Since this method was first used in Europe, it has been modified by the introduction of a continuous passive motion machine to be used sixteen to eighteen hours a day and by the introduction of triceps surae lengthening (fascial recession) to correct residual equinus67. With this method, radiographic assessment of the deformity is done every three to six months67.
Richards et al.51 reported that this method was successful for seventy-two (50.7%) of 142 feet after an average duration of follow-up of thirty-five months. The success rate has increased with the addition of continuous passive motion and triceps surae lengthening to this method67,68. Diméglio et al. evaluated the results for 204 feet after the addition of triceps surae lengthening and reported a need for posterior or posteromedial release in 12.6% of feet with severe involvement (a Diméglio score of 11 to 15) and 70% of feet with very severe involvement (a Diméglio score of 16 to 20)67,68. The modified French method has decreased the rate of posterior and posteromedial release in feet with moderate and severe involvement, but the rate still remains high for feet with very severe involvement.
In our experience, this is a very demanding method with strict requirements and rules and can be successful for the treatment of moderate and severe clubfoot if the physical therapy resources are available. This method has a high failure rate for very severe forms of clubfoot.
Comprehensive Soft-Tissue Release
Comprehensive soft-tissue release is the mainstay of operative treatment of clubfoot. Osteotomies and gradual correction with an external fixator are required in some cases.
Soft-tissue release was the main treatment for congenital clubfoot in the last two decades before the increased popularity of the current nonoperative methods. A recent study showed a decrease in the number of operative releases performed in the United States69. Operative release is still indicated when nonoperative treatment fails to correct the deformity or when the deformity recurs after successful initial treatment. Operative treatment of the residual deformity after initial nonoperative treatment usually requires less soft-tissue release in comparison with that required when procedure is performed as the primary mode of treatment. An operation during the first months of life is associated with a high rate of scarring70, and weight-bearing is helpful for holding the corrected deformity; for these reasons, operative correction is usually performed between nine and twelve months of age for patients who have had a failure of nonoperative treatment71,72.
Different techniques are described for soft-tissue release in the treatment of clubfoot, and description of all of these methods is beyond the scope of this review. The procedure usually is performed with use of a Cincinnati73,74 or a Turco incision72 and involves circumferential release of the subtalar joint and posterior capsule of the ankle joint with lengthening of the Achilles tendon, flexor tendons, and posterior tibialis tendon. Preserving the interosseous ligament (between the calcaneus and the talus) and the deep deltoid ligament can prevent overcorrection50.
Loss of initial correction75,76, triceps surae insufficiency77,78, and overcorrection are well-known complications of soft-tissue release. Treatment of the loss of initial correction or recurrent deformity depends on the severity of the deformity and the age of the patient. Repeat soft-tissue release and lateral-column shortening79,80 may be required in younger patients. Triple arthrodesis is used as a salvage procedure for the treatment of major residual deformity in adolescents.
Plantar flexor weakness after operative release can present as calcaneal gait or can contribute to the development of dorsal bunion deformity81. Transfer of the peroneus brevis, tibialis posterior, and flexor hallucis longus to the calcaneus have been used to treat plantar flexor weakness50 but are unpredictable in terms of their effectiveness for the correction of calcaneal deformity. The best method to treat this complication is to avoid it.
Overcorrection is another complication associated with the operative treatment of clubfoot. This complication is best prevented by preserving the interosseous ligament between the talus and the calcaneus, the deep deltoid ligament, and the plantar fascia if possible50. Correction of this deformity usually requires medial-column shortening and lateral-column lengthening in younger patients or triple arthrodesis in older children.
Correction of clubfoot with use of the Ilizarov technique also has been reported82,83. The Ilizarov technique is used almost exclusively for the treatment of neglected or late-recurring clubfoot because of the prolonged treatment time and the physical and psychological stresses associated with this method. Soft-tissue surgery with or without osseous procedures usually is performed before application of the Ilizarov frame or shortly after initial correction.
Outcomes of Treatment
Laaveg and Ponseti5 reported the results of Ponseti casting in a study of seventy patients (104 clubfeet) with an average duration of follow-up of nineteen years. They used their 100-point functional rating system and reported a satisfactory functional result for ninety-two (88.5%) of the 104 feet.
Cooper and Dietz49 reported the thirty-year results for forty-five patients (seventy-one congenital clubfeet) who were managed with Ponseti casting. Radiographic, pedobarographic, and clinical findings were evaluated in addition to the functional outcome. A modified Laaveg and Ponseti functional rating system was used to assess the outcome and to compare the study group with a group of individuals without a congenital deformity of the foot. Thirty-five (78%) of the forty-five patients who were managed with Ponseti casting reported an excellent or good outcome, compared with eighty-two (85%) of ninety-seven individuals in the control group. In this comprehensive long-term follow-up study, high-demand jobs, higher body mass index (BMI), and low peak pressure under the heel were associated with a poor outcome. Although the clinical and radiographic findings were different between the treated clubfeet and the normal feet, these parameters were not associated with differences in outcome.
El-Hawary et al.84 studied the gait-analysis findings for children who were managed with Ponseti casting at an average age of two years and three months. The authors reported normal ankle sagittal motion in only thirty-seven (47%) of the seventy-nine that were treated with Ponseti casting and reported excessive ankle dorsiflexion in stance in thirty-eight (48%) of these seventy-nine feet. Comparison of these results with the reported gait study findings for clubfeet treated with soft-tissue release85 indicates that normal ankle kinematics are seen more often in feet treated with the Ponseti method than in feet treated with comprehensive soft-tissue release.
French Functional Method
Rampal et al.86 reported the results of the French functional method in a study of 187 feet with an average duration of follow-up of fourteen years. Eighty-five (45.5%) of the 187 feet required comprehensive soft-tissue release to correct the remaining deformity. According to the Ghanem and Seringe score, a very good or good result was reported for 183 (98%) of the 187 feet in the study, including eighty-one (95%) of the eighty-five feet that required soft-tissue release. The difference between the functional grading system used in that study and the Laaveg and Ponseti scoring system makes comparison with the outcomes of the Ponseti method difficult. Functional outcomes for adults managed with this method have yet to be reported.
Chotel et al.87 compared the results of Ponseti treatment with those of French physiotherapy in a study of 219 idiopathic clubfeet with an average duration of follow-up of 5.5 years. The authors reported similar results for Diméglio grade-II feet in both treatment groups and reported better results for feet that had more severe initial deformity (Diméglio grade-III and IV feet) in the Ponseti cohort.
El-Hawary et al.84 evaluated the gait patterns of seventy-five feet that were treated with this method and showed normal ankle sagittal motion in forty-nine feet (65%) and an equinus gait in eleven feet (15%). That study indicates that the frequency of normal ankle kinematics after treatment with this method is similar to that after Ponseti casting and is superior to that after comprehensive soft-tissue release85.
Comprehensive Soft-Tissue Release
Dobbs et al.90 evaluated the long-term results of soft-tissue release in a study of forty-five patients with an average duration of follow-up of thirty-one years. The investigators used the Laaveg and Ponseti functional score5, the Short Form-36 (SF-36) medical evaluation, and clinical and radiographic follow-up evaluations. On the basis of the Laaveg and Ponseti rating, only twelve (27%) of the forty-five patients reported a good or excellent result, with the remaining thirty-three patients (73%) reporting a fair or poor result. The mean physical component summary score of the SF-36 was almost two standard deviations below that for the normal population and was similar to the reported scores for patients with other major medical conditions (chronic heart failure, hemodialysis, etc.). Clinical examination revealed significant limitation in the range of motion of foot and ankle, and a clinical limp was present in nineteen (42%) of the forty-five patients. Weakness of the gastrocnemius-soleus complex, resulting in the inability to walk on the toes, was noted in nineteen (42%) of the forty-five patients. Radiographic analysis showed evidence of moderate to severe osteoarthritis in the talonavicular, calcaneocuboid, and subtalar joints in almost one-half of the patients.
Karol et al.85 evaluated the results of gait analysis in a study of patients with operatively treated clubfoot and reported abnormal ankle motion, with limited dorsiflexion being the predominant pattern. Plantar flexion power was decreased by 23% on the side of surgery, and decreased quadriceps and hamstrings strength was reported in nine and eight of the twenty-two patients, respectively.
A recent long-term study of a single-surgeon series of 120 feet that were treated with extensive medial and lateral release with derotation of talus demonstrated an excellent or good outcome for sixty-nine (58%) of 120 feet after an average duration of follow-up of twenty-one years91. This rate was higher than that reported by Dobbs et al.90.We were not able to find any other reports in the literature to support this favorable long-term outcome in operatively treated clubfeet.
Congenital clubfoot is a common anomaly that involves all of the tissues distal to the knee. With only one prospective study92 (nonrandomized) comparing the Ponseti method with operative treatment, most of the available data in the literature are based on retrospective cohorts. On the basis of these data and our own clinical experience, we believe that the initial treatment should almost always be nonoperative and that good to excellent long-term outcomes can be expected after nonoperative treatment despite a slight amount of residual deformity. Comprehensive release may be associated with good short-term outcomes during teenage years but may result in painful, stiff feet in adulthood.
Source of Funding: No external funds were received for this work.
Investigation performed at Shriners Hospitals for Children, Lexington, Kentucky
Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. One or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. No author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
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