BACKGROUND

Results of the Charnley-Williams method of intramedullary fixation for treatment of congenital pseudarthrosis of the tibia have varied, in part because of variations in surgical technique. The outcomes of three variations of this procedure were compared to determine which technique was the most likely to result in union.

METHODS

The results in twenty-three consecutive patients with congenital pseudarthrosis of the tibia were reviewed at four to fourteen years following initial surgical treatment with an intramedullary rod. Three types of procedures were performed: type A, which consisted of resection of the tibial pseudarthrosis with shortening, insertion of an intramedullary rod into the tibia, and tibial bone-grafting combined with fibular resection or osteotomy and insertion of an intramedullary rod into the fibula; type B, which was identical to type A except that it did not include fibular fixation; and type C, which consisted of insertion of a tibial rod and bone-grafting but no fibular surgery. The outcome was classified as grade 1 when there was unequivocal union with full weight-bearing function and maintenance of alignment requiring no additional surgical treatment; grade 2 when there was equivocal union with useful function, with the limb protected by a brace, and/or valgus or sagittal bowing for which additional surgery was required or anticipated; and grade 3 when there was persistent nonunion or refracture, requiring full-time external support for pain and/or instability.

RESULTS

Eleven patients (48%) ultimately had a grade-1 outcome; nine, a grade-2 outcome; and three, a grade-3 outcome. The final outcome was not associated with either the initial radiographic appearance of the lesion or the age of the patient at the time of the initial surgery. The results following type-A and B operations were better than those after type-C procedures. Surgery on an intact fibula resulted in a lower prevalence of grade-3 outcomes than was found when an intact fibula was not operated on (p = 0.05). Transfixation of the ankle joint by the intramedullary rod did not decrease the prevalence of grade-3 outcomes.

CONCLUSIONS

There is little justification for a type-C operation, as it either resulted in a persistent nonunion or failed to improve an equivocal outcome in every case. Leaving an intact fibula undisturbed to maintain stability or length also was not successful in this series. In addition, the presence of fibular insufficiency (fracture or a pre-pseudarthrotic lesion) was highly prognostic for subsequent valgus deformity (occurring in ten of twelve cases), whether or not the fibula eventually healed.