Congenital Tibia Pseudarthrosis

Congenital Tibiapseudarthrosis is a very rare illness of the shinbone (tibia) which can occur in conjunction with the fibula (the bone behind the shinbone). In 50% of cases, there is a link with Neurofibromatosis (Recklinghausen-Syndrom) recognizable by the formation of cafe au lait spots on the skin. Through the deformation of the affected tubular bone, the formation of a „false joint“occurs (Pseudarthrosis) usually in the middle to lower third of the tibia. Usually the diagnosis is confirmed by x-rays which can show a significant thinning of the bones in the area of the Pseudarthrosis. In most cases, the Pseudarthrosis is very unstable and leads to deformation of the bone in the area of the lower leg, which makes it impossible to put any weight on the leg. Frequently, orthopaedic aids (braces) are needed to support the leg.

Classification of congenital pseudarthrosis of the tibia according to Crawford Boyd Andersen (Hefti 2008)

Classification

Crawford

Type I : Anterior bowing with increased cortical density

Type II : Anterior bowing with a failure of tubulation and narrowed, sclerotic medullary canal

Type III : Anterior bowing with a cystic lesion or pre fracture

Type IV : Anterior bowing with a frank fracture and pseudarthrosis, usually involving the tibia and fibula

Boyd

Type I : Anterior bowing and defect in the tibia at birth, associated with other congenital abnormalities

Type II : Anterior bowing and hour glass constriction of the tibia, spontaneous fracture by 2 years is the most frequent variety and is associated with neurofibromatosis. Recurrence is common

Type III : Pseudarthrosis develops through a congenital cyst

Type IV : Pseudarthrosis develops in a sclerotic segment of bone without narrowing, stress fracture

Type V : Pseudarthrosis of the tibia occurs with a dysplastic fibula, pseudarthrosis of one or both bones (prognosis similar to Type II)

Type VI : Pseudarthrosis occurs in association with an intra-osseous neurofibroma or schwannoma (rare)