Combined anatomical reconstruction of the MPFL and femoral derotation osteotomy resulted in significant improvement of knee function and good patient satisfaction in young patients with severely increased femoral anteversion. No re-dislocation of the patella occured.

D. Dejour's classification is valid for typing trochlear dysplasia and is particularly useful in separating low-grade from high-grade dysplasia.

Failure to consider additional risk factors, technical intra-operative errors and inappropriate patient selection were identified as reasons for revision surgery after MPFL reconstruction. Identifying the potential causes of failure can help to treat and possibly prevent future complications.

Quantitative measurements of the femoral trochlea have shown to be of limited value for the assessment of trochlear dysplasia. None of the quantitative measurements of the trochlea on transverse images could be assigned to the four-grade descriptive classification of trochlear dysplasia of Dejour. Additionally, measurements could not be reliably performed in high-grade trochlear dysplasia. However, trochlear inclination, trochlear facet asymmetry and depth of trochlear groove may help to distinguish between low-grade and high-grade dysplasia.

Considering the concave curvature of the distal femoral physis, it can be assumed that the femoral insertion of the MPFL is distal to the femoral physis. As a too proximal insertion of the graft can cause unintentional tightening of the MPFL in knee flexion, these results have to be considered when performing reconstruction of the MPFL in children and adolescents with open growth plates.