Objective    To investigate the etiology and provide data for clinical treatment and therapeutic assessment of congenital clubfoot (CCF)

via

neuroelectrophysiology on motor and sensory nerves and ultrastructure of sural nerve.     Methods    Totally 248 patients diagnosed with CCF (338 clubfeet) were studied. Motor nerve conduction ve

locity (MCV)

sensory nerve conduction velocity (SCV) and wave amplitude were detected for any changes. An ultra-structural study of sural nerve ramification was also conducted in 36 patients (36 clubfeet) under electron microscope. The correlation between deformity degree

nerve conduction abnormality and therapeutic outcomes was analyzed.     Results    The motor nerve conduction in 291 clubfeet (86.1%) and the sensory nerve conduction in 252 clubfeet (74.6%) were found with different degrees of abnormalities such as prolonged latency

declined/disappeared wave amplitude

etc

. The ultrastructural observation of sural nerve ramification demonstrated abnormalities in all the 36 cases

showing proliferation of myelin sheath in peripheral myelinated nerve fibers

formation of vacuoles

segmental demyelinating lesions and so on. Part of axial cord was squeezed by the proliferated myelin sheath

which resulted in disappearance of axoplasm. The correlation study showed that as deformity became more severe

the nerve conduction abnormality was more evident

  requiring more complicated treatments

and the therapeutic outcomes were less satisfactory. Statistical analysis by Mantel-Haenszel method showed that: ① the abnormality rate of motor nerve in different types of CCF is signifi-cantly different (χ

2

=32.31

P

<

0.01); ② the abnormality rate of sensory nerve in different types of CCF is also significantly different (χ

2

=134.30

P

<

0.01).    Conclusion    Neuroelectrophysiology provides direct and objective results to indicate peripheral nerve abnormalities

locate the lesions and determine the lesion degree. It reflects objectively that motor nerves and sensory nerves play an important role in the pathogenesis of congenital clubfoot.  The correlation results of this study provides significant guidance for choosing the best treatment option and for assessing middle or long term therapeutic outcomes.