Neuromuscular Dysfunction in Clubfeet Associated With Constriction Band Syndrome.

INTRODUCTION: Constriction band syndrome (CBS) is a congenital limb anomaly frequently associated with clubfoot. Clubfeet in CBS patients may be associated with peroneal nerve dysfunction in the involved lower extremity; however, the etiology of this neuromuscular dysfunction is not clear. We sought to characterize the distribution of constriction bands on lower extremities with clubfoot and determine if neuromuscular deficit (NMD), defined here as having absent ankle dorsiflexion, was associated with ipsilateral proximal bands. Our secondary aim was to compare the treatment and outcomes of clubfeet with NMD to those without NMD. METHODS: We performed a retrospective review of all patients with CBS and clubfoot presenting to our facility between January 1, 1998 and December 31, 2018. Treatment with the Ponseti method, at least 1 year of follow-up at this facility, and a detailed physical exam describing lower extremity neuromuscular function and the presence and location of constriction bands were required for inclusion in the study cohort. RESULTS: Twenty children with 26 clubfeet were included. Forty-six percent (12/26) of the clubfeet had NMD. Clubfeet with and without NMD had ipsilateral thigh or leg constriction bands at similar rates [42% (5/12) vs. 43% (6/14), P =0.106], and the majority (7/12) of clubfeet with NMD did not have an ipsilateral thigh or leg band. While children with an NMD clubfoot tended toward more casts, relapses, and surgical procedures, these differences did not reach statistical significance. The use of a daytime AFO beyond age four was higher in the NMD clubfeet [58% (7/12) vs. 14% (2/14), P =0.04]. CONCLUSION: Clubfeet with neuromuscular deficits may occur in the absence of proximal ipsilateral constriction bands, suggesting they may be caused by mechanisms other than direct damage from visible constriction bands to underlying nerves. They can also coexist with arthrogrypotic conditions. Clubfeet with an NMD tended toward more casts, relapses, and surgeries than those without NMD, but these differences did not reach statistical significance. These patients often elect long-term use of a daytime AFO.

Clinical Manifestations of Constriction Band Syndrome.

BACKGROUND: Constriction band syndrome (CBS) is a congenital limb anomaly with varying presentation. We sought to characterize the clinical manifestations of CBS by analyzing a large cohort of patients. Our secondary aim was to evaluate potential risk factors for CBS. METHODS: We retrospectively reviewed the records for all patients with CBS who had presented to our tertiary medical center between 1998 and 2018. Examination by a pediatric orthopaedic surgeon and the presence of pathognomonic features were inclusion criteria. Clinical notes, photographs, and radiographs were reviewed to determine the pattern of limb involvement and associated conditions. Demographic data were compared with population averages to assess for possible risk factors. RESULTS: One hundred and twenty-eight children were included. The most prevalent feature was constriction bands (96%), followed by limb or digit amputations (88%) and syndactyly/acrosyndactyly (69%). Children without constriction bands presented with either acrosyndactyly or growth of an osseous spike from a congenital diaphyseal limb or digit amputation. There was a strong predilection for involvement of central digits of the hands and feet, with sparing of the thumb/great toe and small finger/toe. The average number of involved limbs per child was 2.6; 23% of the children had involvement of only 1 limb. Children with at least 1 additional diagnosis had more limbs affected by CBS than those who were otherwise healthy (2 limbs [interquartile range (IQR), 1-3 limbs] versus 3 limbs [IQR, 2-4 limbs]; p = 0.006), suggesting a more severe phenotype. Children with more limbs involved underwent more surgical procedures (p < 0.001). CBS was associated with gestational trauma, prematurity, low birth weight, young and old maternal age, and higher social deprivation. CONCLUSIONS: Children with CBS can be categorized as having either mild or extensive involvement based on the number of involved limbs and associated conditions. Future investigation of prenatal risk factors is necessary to further elucidate the etiology of this heterogenous condition. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.