Rotational defects of the lower limb are frequently encountered and often underestimated. In fact, many symptoms in the lower joint can be related to rotational alteration in the lower leg. These problems are often more visible in the knee joint because they reflect the rotational problems of proximal and distal femur and tibia, respectively. The extensor apparatus, due to the fact that it interacts with both bones, is the more affected joint. Many authors have demonstrated that femoral anteversion increases stress on the patello-femoral joint due to excessive lateralisation of the patella. In the same manner, distal femur internal rotation increases the stress due to altered tracking of the patella during ROM. Valgus knee places stress on the patello-femoral joint, increasing the Q angle and determining a retraction of the lateral structure that causes stress on the lateral patellar face and altered patellar scratch during ROM. External tibial rotation also has been documented to increase the Q angle and patellar tilt, causing excessive stress on the patello-femoral joint. Valgus pronation of the foot, increasing the valgus stress on the knee, can contribute to patello-femoral symptoms, increasing the muscle imbalance at this level. These documented alterations contribute together with other anatomical abnormalities, such as trochlear dysplasia or muscle hypoplasia, in creating the high variability of patello-femoral symptoms that are observed. Rotational deformity of the lower leg therefore represents a frequently encountered pathological condition that must be taken into account when treating patello-femoral symptoms.
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.
