Background: Infants thought to be normal with idiopathic clubfeet when nonoperative treatment begins may later be found to have other complicating diagnoses. The purpose of this study was to determine the incidence of this occurrence, and to compare the clinical outcomes of these "nonidiopathic" patients with idiopathic clubfoot patients.
Methods: Infants below 3 months old with clubfeet who were thought to be normal (idiopathic) at presentation and had ≥2-year follow-up were studied. Treatment consisted of either the Ponseti method or the French physical therapy method. In total, 789 patients with 1174 clubfeet were identified. Those who were idiopathic (group 1) were compared with those later found to be nonidiopathic (group 2). The outcomes at 2 years were assessed as good (plantigrade foot±heelcord tenotomy only), fair (limited procedures), or poor (full-posteromedial release). For those feet rated good at age 2 years, outcomes were again assessed age 5 years and above.
Results: In total, 70 patients (8.9%) of the 789 enrolled patients were eventually found to have another disorder including neurological, syndromic, chromosomal, or spinal abnormalities. The remaining 719 idiopathic patients with 1062 clubfeet (group 1) were compared with these 70 nonidiopathic patients with 112 clubfeet (group 2). At age 2 years, in group 1 81% of the feet were rated good, 11% fair, and 8% poor, whereas in group 2 70% of the feet were rated good, 11% fair, and 19% poor (P=0.0004).With follow-up exceeding age 5 years in those rated good at age 2 years: in group 1, 73% continued to do well, but 22% rated fair, and 5% poor. In group 2, 59% continued to do well, but 31% rated fair, and 10% poor (P=0.046).
Conclusions: For infants with clubfeet who were initially thought to be idiopathic, nearly 9% were later found to have a complicating disorder. Despite this, these patients' clubfeet can be expected to respond favorably to nonoperative treatment. However, they will require more surgical intervention early (by age 2 years) and later (age, 5 years and above) when compared with normal infants with idiopathic clubfeet.
Level of evidence: Level IV-therapeutic, case series.