Lateral Epiphyseal Narrowings with Absent Fibula Conform to a Vascular Pattern Deficiency

Abstract

Lateral epiphyseal narrowing with valgus deformities of the knee and ankle are cardinal radiographic features of Congenitally Shortened Limbs (CSL) exhibiting Congenital Fibular Deficiency (CFD). Radiographs of typical CFD limbs reveal valgus deformities and lateral epiphyseal reductions at both the knee and ankle. Arteriography of CSL reveals not only absence of adult vessels, but preservation of primitive vessels. Specifically, the superior and inferior lateral genicular arteries that habitually serve the lateral femoral condyle (LFC) and the lateral aspect of the proximal tibial epiphysis are absent in CSL. Similarly, the usual arteries supplying the distal tibial epiphysis are absent, except for a singular periosteal vessel, which independently serves the anteromedial portion. Active transitioning of the single primitive Axial Artery (AA) to the usual adult pattern of the lower limb accompanies periods of rapid growth and ossification its anlagen. Dysgenesis of the lateral arteries supplying the secondary ossification centers leads to asymmetric growth of the developing epiphyses, caused by relative medial overgrowth. Since vascular dysgenesis manifests at sites of failed embryonic transition of the proximal Femur, fibula and midline Metatarsals (FfM) in CSL, it is herein hypothesized that vascular dysgenesis also underlies the impaired growth of the reduced epiphyses as seen in CSL.