VP1: Clinical Risk of Infrapatellar Neuropathy is Determined by the Anatomical Variation of Infrapatellar Innervation

Abstract

INTRODUCTION: The infrapatellar branch of the saphenous nerve is prone for traumatic, iatrogenic or compression injury, causing infrapatellar neuropathy. Findings of anatomical variation and direct femoral nerve innervation, question the unison textbook course. We aim to identifying the emergence of infrapatellar innervation and its risk for neuropathy. MATERIALS AND METHODS: In 22 fresh-frozen anatomical specimens the course of the infrapatellar branch was examined. Following standardized photo documentation, anatomical risk sites were assessed by computational modelling. RESULTS: Eleven specimens presented with femoral, nine with saphenous and two with combined nerve origin. The subsartorial course was most frequent in saphenous emergence. Anatomical risk sites, such as penetrating, profound distal sartorial muscle relation or crossing course to the medial femoral epicondyle correlated moderately with the emergence type, tested by spearman correlation. CONCLUSION: The clinical risk for infrapatellar neuropathy is determined by emergence of infrapatellar innervation, which is depending on anatomical variation that differ from the textbook course. While the saphenous nerve origin is predestined for subsartorial compression and sartorial muscle penetration, the femoral nerve origin bears reduced anatomical risk for infrapatellar neuropathy. This description may enhance the understanding of infrapatellar neuropathy, potentially improving the diagnostic and therapeutic perspectives of this often misdiagnosed and mistreated condition.