Effect of distraction osteogenesis in patient with tibial shortening after initial union of congenital pseudarthrosis of the tibia (CPT)

Abstract

Background: This is a Retrospective study which was conducted with the purpose of evaluating the preliminary result of distraction osteogenesis in patients with tibial shortening after initial union of Congenital Pseudarthrosis of the Tibia (CPT). Methods: Identification of all the CPT cases with tibial shortening after initial union managed by proximal tibia lengthening using Ilizarov technique was done. All the patients charts and radiograms were reviewed. Results: 11 CPT cases were included between March 2013 and January 2018 with an average follow up of 41 months (range, 34-51 months). 8.5 years was the mean age at surgery. The average length of discrepancy was 5.6 cm (range, 2.0-8.2 cm). Radiological findings of proximal tibial dysplasia were found in eight cases while three other cases had no radiological findings. The average distraction length gained was 5.3cm (range, 3.5 -8.0 cm) with a mean elongation rate of 21.4% (range, 15-30%). The Healing Index (HI) was 63.1 d/cm (range, 47–77 d/cm). The Findings seen in the eight patients with proximal tibial dysplasia was that out of eight cases, five cases had lateral callus, three had central callus and poor bone regeneration was seen in all of them. In the three patients who had no radiological findings concave shaped callus was identified with an average HI of 52.7 d/cm. None of the patients had refracture, non-union, axis deviation or angulation of the distraction area. Two of the patients were found to have ankle stiffness. There was no evidence of knee contracture in any of the patients. There were five cases with pin tract infection which was managed by regular dressing and oral antibiotics. Conclusions: We concluded that proximal tibial lengthening after initial union of CPT was effective for management of tibial shortening, however poor bone regeneration with various types of callus from normal, greater healing index and prolonged fixator wearing was seen. We recommended that when the limb length discrepancy (LLD) was more than 4 cm in younger children after primary union of CPT, tibia lengthening could be considered.