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.