Congenital Congenital<unk>  is rare, with approximately 350 cases reported in journals, and it typically affects both sides (bilateral) and can be associated with other skeletal problems such as hip and knee abnormalities, finger abnormalities (syndactyly or clinodactyly), or Madelung's deformity. It is sometimes part of known genetic syndromes such as Klinefelter syndrome (48,XXXY variant), Apert, Williams, Cornelia de Lange, or Holt-Oram. It has been reported to run in families typically following an autosomal dominant inheritance pattern which means children of an affected parent have a 50% chance of having the condition. When associated with amegakaryocytic thrombocytopenia this inheritance has been found to be caused by mutations to the HOXA11 gene. Acquired Post-traumatic cases are most likely to develop following surgery for a forearm fracture, this is more common with high-energy injuries where the bones are broken into many pieces (comminuted). It can also develop following soft tissue injury to the forearm where there is haematoma formation.
Radioulnar synostosis
Carpal coalition
Tarsal coalition
Radial dysplasia
Bimalleolar fracture
Calcaneal fracture
Calcaneal spur
Trimalleolar fracture