Pseudahrosis may be seen in all of the following conditions, EXCEPT:

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: Robbin's Pathologic basis of Disease 7/e, Page 1289; Apley's system of Ohopedics & fractures 8/e, Page 156,164,544 ; Natarajan's ohopedics , Page 27; Murcer's Ohopedic surgery 9/e, Page 433, 811, 1095, 672,736.