<prompt> Pseudahrosis may be seen in all of the following conditions, EXCEPT:FractureIdiopathicNeurofibromatosisOsteomyelitis  <response>: Causes of Pseudahrosis In decreasing order of frequency are: Neurofibromatosis 50 patients of pseudahrosis have NF Nonunion of fracture including pathological fracture Congenital mostly in lower to middle third of tibia with cupping of proximal bone end and pointing of distal bone end Idiopathic Osteogenesis imperfecta Fibrous dysplasia Cleidocranial dysplasia Ankylosing spondylitis in fused bamboo spine Post surgical e.g. triple ahrodesis, spinal fusion etc. as a complication. Ref: Robbins Pathologic basis of Disease 7e, Page 1289; Apleys system of Ohopedics fractures 8e, Page 156,164,544 ; Natarajans ohopedics , Page 27; Murcers Ohopedic surgery 9e, Page 433, 811, 1095, 672,736. 