Date Published: June 4, 2012
Publisher: Informa Healthcare
Author(s): Seung-Ju Kim, Mandar Vikas Agashe, Sang-Heon Song, Hae-Ryong Song.
Complications related to the fibula during distraction osteogenesis could cause malalignment. Most published studies have analyzed only migration of the fibula during lengthening, with few studies examining the effects of fibular complications.
We retrospectively reviewed 120 segments (in 60 patients) between 2002 and 2009. All patients underwent bilateral tibial lengthening of more than 5 cm. The mean follow-up time was 4.9 (2.5–6.9) years.
The average lengthening percentage was 34% (21–65). The ratio of mean fibular length to tibial length was 1.05 (0.91–1.11) preoperatively and 0.83 (0.65–0.95) postoperatively. The mean proximal fibular migration (PFM) was 15 (4–31) mm and mean distal fibular migration (DFM) was 9.7 (0–24) mm. Premature consolidation occurred in 10 segments, nonunion occurred in 12, and angulation of fibula occurred in 8 segments after lengthening. Valgus deformities of the knee occurred in 10 segments.
PFM induced valgus deformity of the knee, and premature consolidation of the fibula was associated with the distal migration of the proximal fibula. These mechanical malalignments could sometimes be serious enough to warrant surgical correction. Thus, during lengthening repeated radiographic examinations of the fibula are necessary to avoid complications.
We retrospectively studied 60 patients (35 men, 120 tibial segments) all of whom underwent bilateral tibial lengthening with Ilizarov ring fixator at our institute between 2002 and 2009. The average age of the patients at the time of surgery was 16 (8–25) years. The etiology was achondroplasia in 32 patients, hypochondroplasia in 15, idiopathic short stature in 10, spondyloepiphyseal dysplasia in 2, and spondylometaphyseal dysplasia in 1 patient. Average follow-up of patients was 4.9 (2.5–6.9) years.
Distal migration of the proximal fibula during tibial lengthening has been reported in association with distraction osteogenesis (Hatzokos et al. 2004). We found that during a large amount of lengthening, the proximal wire which was inserted through the fibular head and crossed the tibia could not hold the fibula due to high resisting force, and often cut out from the fibular head. This resulted in less distraction of the fibula, premature consolidation of the fibula, and distal migration of the proximal fibula. Our study clearly indicates that cut-out of the wire is related to the lengthening percentage of the fibula. PFM was seen in 120 segments and DFM was seen in 96 segments. However, cut-out of the wire occurred in only 10 segments. This is because even though the transfixed wire did not completely cut out from the proximal fibular cortical end, the wire may migrate proximally in the metaphyseal area of the fibular head or it could be bent due to the resisting force.