A rotational profile should be part of the routine clinical assessment of all Blount’s cases. A CT assessment of anteversion should be considered to quantify this accurately. Overcorrection of the tibial internal version (to correct the added femoral version/torsion) should be considered when doing tibial osteotomies in cases with marked femoral internal version. Some cases of Blount’s disease will require further correction of rotation, after corrective surgery around the knee, that included external rotation of the tibia. Persistent in-toeing may need a de-rotation osteotomy of the femur shaft.
In 1937 Blount described a series of 28 patients with ‘Tibia vara’. Since then, a number of deformities in the tibia and the femur have been described in association with this condition. We analysed 14 children with Blount’s disease who were entered into a cross-sectional study. Their mean age was 10 (2 to 18). They underwent a clinical assessment of the rotational profile of their legs and a CT assessment of the angle of anteversion of their hips (femoral version). We compared our results to previously published controls. A statistically significant increase in femoral anteversion was noted in the affected legs, with on average the femurs in patients with Blount’s disease being 26° more anteverted than those in previously published controls. We believe this to be a previously unrecognised component of Blount’s disease, and that the marked intoeing seen in the disease may be partly caused by internal femoral version, in addition to the well-recognised internal tibial version.
