Perfusion is Not Measurably Decreased in Idiopathic Clubfoot

Vascular aberration has been accepted as a potential etiology of clubfoot, and abnormal vasculature has been observed in as high as 85% of children with severe clubfoot. The perfusion index (PI) corresponds to the ratio of pulsatile to nonpulsatile blood flow at a monitoring site and can be used to quantify perfusion of the extremities. The purpose of this study was to use PI to compare the perfusion of clubfeet to controls in order to further assess the role of abnormal vasculature in clubfoot.

A Masimo Radical 7 Pulse Oximeter (Masimo Corporation, Irvine, California) was used to measure the PI and oxygen saturation (SpO2) of the feet of children 5 years of age and younger with and without clubfoot. The sensor was placed on the great toe. Patients with clubfoot undergoing non-operative treatment and control patients undergoing treatment in a clinic for orthopedic concerns not involving the foot and with no known vascular issues were assessed. The PI and SpO2 for the following three groups were compared: 1. affected feet of patients with bilateral or unilateral clubfoot, 2. unaffected feet of patients with unilateral clubfoot, and 3. control feet.

One hundred and twenty-eight patients were enrolled, 64 with clubfoot (31 bilateral and 33 unilateral) and 64 controls. No significant differences in PI or SpO2 were found between: 64 clubfeet and 64 feet of controls (PI of 2.9 vs. 2.9, p = 0.984; SpO2 of 97.1 vs. 98.1, p = 0.192); unaffected feet of 30 patients with unilateral clubfoot and 64 controls (PI of 3.0 vs.2.9, p = 0.907; SpO2 of 96.9 vs. 98.1, p = 0.224); and affected and unaffected feet of 30 patients with unilateral clubfoot (PI of 3.3 vs.3.0, p = 0.500; SpO2 of 97.4 vs. 96.9, p = 0.527).

No difference was observed in the PI or SpO2 when comparing affected clubfoot limbs with unaffected limbs, suggesting that vascular anomalies cannot fully explain the development of clubfoot.