Guided growth using a tension-band plate in Blount's disease

Our observational study's objective was to determine how effective guided growth with tension-band plates was to correct the deformity in Blount's disease. We reviewed the records of 14 children (18 limbs) with Blount's disease who were treated with tension-band plates as the only surgical intervention at a single institution over eight years. Five children (seven limbs) had infantile Blount's disease with Langenskiöld stage ≤2. Nine children (11 limbs) had late-onset Blount's disease. The mean age at operation was 7.2 years (SD, 3.1, range, 2.9-11.8). The tension-band plate effectively corrected the varus deformity in 78% (14/18) of limbs. Correction to normal mechanical alignment was achieved in 67% (n = 12) of limbs at a mean of 18 months (SD, 7, range, 9-31). Failure to achieve correction of the mechanical axis was due to delayed implant removal and overcorrection in 11% (2/18), mechanical failure due to screw fixation failure in 11% (2/18) and in 6% (1/18) due to a misplaced epiphyseal screw. There was a greater magnitude of correction in the Infantile Blount's disease group (mean, 26°, SD, 9°) when compared to the children with late-onset Blount's disease (13°, SD, 4°) (P = 0.021). The mean correction rate was 1.8°/month in the Infantile Blount's disease group and 0.7°/month in the late-onset Blount's disease group, respectively (P = 0.014). Our findings support the use of tension-band plating in Blount's disease. Further research is required to determine the ideal indications and to investigate the long-term outcome of guided growth in Blount's disease. Level of evidence: Level 4.