Case 34: Recalcitrant Congenital Pseudarthrosis of the Tibia

Abstract

Congenital pseudarthrosis of the tibia (CPT) is a rare condition with an incidence of 1 in 190,000 live births. The pseudarthrosis usually develops in the first 2 years of life although cases have been diagnosed antenatally and in adult life. Although the etiology remains unclear, there is a strong association with neurofibromatosis (NF-1). CPT is variable not only in its clinical presentation and appearance but also in the radiological appearance. Histologically, there is hyperplasia of fibroblasts and dense, almost invasive, fibrous tissue surrounding the site of the pseudarthrosis and between the bone ends if a frank pseudarthrosis has developed. The bone is usually thin and sclerotic, and X-rays or MRI may show abnormal bone at some distance from the focus of the disease. The fibula may be involved, and occasionally a fibula pseudarthrosis is present with a relatively normal tibia. As yet there is no unifying classification based on all these features that offers any therapeutic or prognostic guide to management. CPT is challenging to treat because of the triad of dysplastic poorly vascularized bone; deformity, including shortening; and a propensity for refracture after union is initially obtained. Multiple surgical interventions are common. Maintenance of union is as important as achieving union, and it is also important to consider ankle function. This case has been chosen to illustrate some of the difficulties in managing this condition and the principles that need to be considered.