Abstract
Valgus deformity of the knee in relation to femoral dysplasia and post-traumatic varus deformity in relation to supracondylar fracture often needs to be corrected with varus or valgus distal femoral osteotomy. This procedure must be very precise to avoid compartimental overstress. However, in valgus knee the deformity is very often not only bi-planar but also tri-planar. In fact, the rotational defect of the distal femur can play an important role in determining the clinical symptoms and in altering the pathway of patello-femoral joint.
Therefore, correcting only the valgus deformity does not solve the clinical symptoms related to incorrect rotation of distal femur. The same problem is often encountered in distal femoral deformity in relation to supracondylar fracture. The bad alignment of the healed fracture is very often on the three planes and this fact has always to be taken into account during the pre-operative planning.
The pre-operative planning is fundamental and CT of the knee joint with reference to hip and ankle must be performed to evaluate the degree of rotational deformity that must be corrected. During surgery after the correction of valgus or varus deformity is fundamental to re-check the femur rotation, because the osteotomy automatically changes also the rotation of the distal femur. However, this correction may be insufficient to correct the rotation that can maintain clinical symptoms in the patello-femoral joint. If this is the case, an additional correction in external rotation is usually necessary to achieve an overall correction of distal femoral deformity.
In our opinion, the difficulties and accuracy necessary to correct this type of pathology are often underestimated.
