Background: Inferior subluxation of the proximal part of the fibula
has been reported to occur with distraction osteogenesis of the tibia;
however, the clinical sequelae of this subluxation are unknown. The purpose of
this study was to evaluate inferior subluxation of the proximal part of the
fibula and its possible clinical implications in patients who had undergone
tibial lengthening by distraction osteogenesis with use of a unilateral
Methods: Thirty tibiae in seventeen patients with a variety of
conditions underwent tibial lengthening by distraction osteogenesis with use
of a unilateral external fixator and were followed clinically and
radiographically for a mean of two years and ten months (range, two to four
years). Ten patients were female and seven were male. Their mean age at the
time of the surgery was seventeen years (range, eight to twenty-five years).
The mean tibial lengthening was 8.1 cm (range, 3.5 to 13 cm).
Results: An inferior shift of the fibular head in relation to the
tibia was evident in all cases. The shift, which ranged from 0.4 to 3.3 cm,
was proportionally related to the amount of tibial lengthening. This type of
subluxation is probably attributable to the tension that is exerted by the
intact interosseous membrane during the distraction as well as to the tension
of the regenerated bone of the fibula and the fact that the fibula itself is
not fixed or directly lengthened by the external fixator.
Conclusions: It appears that inferior subluxation of the fibula is a
common phenomenon in patients undergoing tibial lengthening by distraction
osteogenesis with use of a unilateral external fixator. However, no clinical
symptoms or findings related to the inferior subluxation of the fibula were
found in our series.