We wished to examine the effectiveness of tibial lengthening
using a two ring Ilizarov frame in skeletally immature patients.
This is a potentially biomechanically unstable construct which risks
the loss of axial control. We retrospectively reviewed a consecutive series of 24 boys and
26 girls, with a mean age of 8.6 years (4 to 14), who underwent
52 tibial lengthening procedures with a mean follow-up of 4.3 years
(4.0 to 16.9). Tibial alignment was measured before and after treatment
using joint orientation lines from the knee and a calculation of
the oblique plane axis.Aims
Patients and Methods
We reviewed 34 knees in 24 children after a double-elevating osteotomy for late-presenting infantile Blount’s disease. The mean age of patients was 9.1 years (7 to 13.5). All knees were in Langenskiöld stages IV to VI. The operative technique corrected the depression of the medial joint line by an elevating osteotomy, and the remaining tibial varus and internal torsion by an osteotomy just below the apophysis. In the more recent patients (19 knees), a proximal lateral tibial epiphysiodesis was performed at the same time. The mean pre-operative angle of depression of the medial tibial plateau of 49° (40° to 60°) was corrected to a mean of 26° (20° to 30°), which was maintained at follow-up. The femoral deformity was too small to warrant femoral osteotomy in any of our patients. The mean pre-operative mechanical varus of 30.6° (14° to 66°) was corrected to 0° to 5° of mechanical valgus in 29 knees. In five knees, there was an undercorrection of 2° to 5° of mechanical varus. At follow-up a further eight knees, in which lateral epiphysiodesis was delayed beyond five months, developed recurrent tibial varus associated with fusion of the medial proximal tibial physis.
