tibio-fibular synostosis (MONDO_0017467) is a rare, non-syndromic limb malformation characterized by fusion of the proximal or distal tibial and fibular metaphysis and/or diaphysis, frequently associated with distal positioning of the proximal tibiofibular joint, leg length discrepancy, bowing of the fibula, and valgus deformity of the knee. Also known as: Tibio-fibular fusion.