Congenital Pseudarthrosis of the Tibia

Abstract

1. There are two distinct types of congenital pseudarthrosis of the tibia. In the first, a cystic defect, with or without fracture, is present and the pathological findings resemble those in fibrous dysplasia. The second shows sclerosis and tapering of the bone ends, probably due to a constricting band of fibrous tissue. In this type, union is more difficult to secure. 2. The etiological factors are still undetermined, but are probably due to a maldevelopment of the mesodermal structure during the fifth week of fetal life, with an associated abnormality occurring in the nerve pathways to the affected leg. 3. Pathological studies of material obtained from within the bone and between the bone ends at the site of pseudarthrosis are notably lacking in the literature. Each specimen excised should be thoroughly studied. 4. Early surgical treatment before the development of marked deformity is advised. In the first type the cyst should be curetted and the defect filled with bone chips; additional bone-grafting may or may not be necessary. In the second type, a wide resection of the constricting band of pathological soft tissue should be done, combined with suitable bone-grafting and adequate internal and external fixation; the latter, achieved by casts followed by suitable braces, should be continued until skeletal maturity or until a tibia of relatively normal size develops. 5. In cases with extreme deformity, amputation may be indicated when one is reasonably sure that a prosthesis will provide a better weight-bearing extremity than the best extremity that could be obtained following successful reconstructive surgery. In making the decision, the surgeon should compare the function of an artificial leg with the best result that can reasonably be expected following reconstructive surgery, not with a normal extremity. 6. Repeated clinical and roentgenographic examinations should be continued until skeletal maturity is reached. If at any time evidence of narrowing of the bone or sclerosis of the medullary cavity appears, prophylactic operative intervention with wide resection of the constricting band of scar tissue should be done. In addition, reinforcing grafts should be placed about the area of previous pseudarthrosis. 7. Multiple operations may be necessary during the growth period. 8. A registry for congenital pseudarthrosis of the tibia is needed in order to enhance our knowledge of its etiology, pathology, treatment, and end results through the age of skeletal maturity.