Crawford Type IV Congenital Pseudarthrosis of the Tibia: Treatment With Vascularized Fibular Grafting and Outcome at Skeletal Maturity

Abstract

Background: Vascularized fibular grafting (VFG) is currently accepted as one of the best treatments for congenital tibial pseudoarthrosis (CPT). However, with longer follow-up, functional results deteriorate, and some problems become evident.

Methods: Thirty-nine patients with CPT were treated with VFG. Their age at surgery averaged 5.2 years. Twenty-one cases aged 3 years or less at the time of surgery. All cases were Crawford type IV affected by neurofibromatosis-1. Fourteen patients had 1 to 7 previous surgeries with an average of 4.2 procedures. The length of the fibula used averaged 9.9 cm, and the fibula was fixed by intramedullary wires in 26 cases, and transfixion screws in 11 cases.

Results: Follow-up averaged 8.1 years. Seventeen cases (43.6%) reached skeletal maturity before the final follow-up. Primary bone union was achieved in 37 cases (96%) after an average of 3.2 months. Stress fracture occurred in 21 cases (51.3%) and was recurrent in 11 cases. Twenty-one cases (53.8%) developed tibial shaft deformities with an average valgus angle of 13.8 degrees and procurvatum angle of 18.8 degrees. The overall final limb length discrepancy (LLD) averaged 2.2 cm. Ipsilateral ankle valgus deformity occurred in 21 cases (53.8%) and averaged 10 degrees. A total of 17 cases required an average of 2 secondary procedures. The tibial deformity did not appear to remodel with age, but the LLD and the angle of ipsilateral ankle valgus deformity continued to significantly increase until skeletal maturity.

Conclusion: This study reports the largest single center experience of CPT cases treated with VFG. Free VFG is an excellent treatment option for CPT. Best results are achieved when the procedure is performed at or before the age of 3 years, in the absence of previous surgeries, and with the use of intramedullary fixation. The resulting LLD and the degree of ipsilateral ankle valgus increase with age until skeletal maturity, however, tibial deformity does not remodel and should be corrected at any age if it is excessive. Donor side mild ankle valgus may occur despite sound tibiofibular synostosis.

Level of evidence: Level IV.