Congenital pseudarthrosis of the tibia: Biological and biomechanical considerations to achieve union and prevent refracture

Abstract

Congenital pseudarthrosis of the tibia (CPT) is likely to be a primary periosteal disease and secondary bone disease. The primary goal of treatment is to obtain union, correct the diaphyseal deformity, correct any proximal fibular migration and prevent refracture. The pathobiology demonstrates increased osteoclasis by the surrounding fibrous hamartoma and reduced osteogenesis and bone morphogenic protein production by the bone. This leads to a loss of remodelling potential and gradual bowing and atrophy of the bone with eventual fracture of the tibia and or fibula. This recommends the synergistic use of bisphosphonates and bone morphogenic protein. The pathomechanics of CPT implicate the anterolateral bowing, narrow diameter of the atrophic bone ends and proximal fibular migration. These biomechanical factors can be addressed by means of straightening of the deformity, intramedullary support of both bones, stable fixation and reduction of proximal migration of the fibula. A summary of the literature on CPT shows that the mean probability of achieving primary union without refracture, by most treatments is 50% (12% to 80%). Two recent studies have shown a much higher success rate approaching 100%, by creating a cross-union between the tibia and fibula. The cross-union with intramedullary reinforcement of the bone makes refracture unlikely due to the cross-sectional area of union with its two-bar linkage. A new classification to guide such treatment is also proposed. Level of Evidence V – expert opinion

Diagnostic and treatment challenge in adult presentation of congenital pseudoarthrosis of the tibia: A case report

“…The etiology remains unknown. Up to 50% of the cases is associated with neurofibromatosis type I (NF-1) and with lesser extent is associated with fibrous dysplasia [ [5] , [6] , [7] , [8] ].…”

“…According to El-Rosassy-Paley classification, this patient had CPT type 2 with an antero-lateral bowing and a mobile pseudoarthrosis of the bone that have been through multiple failed surgeries. Thus, biologic enhancement of bone healing and managing the remaining bone defect either by bone transport or lengthening procedure are suggested [ 3 , 8 ]. Surgical is mainstay treatment to achieve union, restore alignment, prevent recurrence and limit LLD while preserving articular function.…”

“…Various studies proposed many kinds of fixation devices such as external fixators, intramedullary fixation, and plate and screw. Biological factors can also utilized such as bone graft, periosteal graft, osteo-inductive proteins and bisphosphonates [ 2 , 3 , 7 , 8 ].…”

“…Association of NF to the final outcome is still debatable. Other factors such as age at treatment less than three years, previous failed surgery and years of follow-up also were reported to negatively affect union [ 1 , 8 , [12] , [13] , [14] , [15] , [16] ]. The patient had reached skeletal maturity when treated with Ilizarov method.…”

Outcome of Congenital Pseudoarthrosis Tibia Treated with Illizarov Fixator in Children

“…Congenital pseudoarthrosis tibia (CPT) that may be obvious at birth or incipient, most commonly involves the distal half of tibia and often fibula in the same limb. Incidence is 1 in 250,000 live births [1] . CPT is closely associated with neurofibromatosis that may not be the cause of pseudoarthrosis.…”