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.

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.

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

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.

Retrospective study, Level III.

In total, 92.3 % returned to pre-operative sports activities after surgery. A shift away from high impact activities to lower impact activities, a significant decrease of the duration of sports activities and number of sports disciplines was detected. In summary, HTO allows the young, active patient with medial osteoarthritis of the knee to return to work with the same work intensity and to return to sports.

The purpose of this study was to evaluate the early radiological outcome after ultrasound-monitored treatment of developmental dysplasia of the hip (DDH) and to examine whether there was a correlation between the initial severity of DDH, measured by ultrasound, and the severity of residual dysplasia on the radiograph at the first follow-up. At the beginning of ultrasound-monitored treatment, the sonographic findings of 90 children (72 girls, 18 boys, mean age 7.2 weeks) with DDH (29 unilateral, 61 bilateral) were staged according to the Graf classification and assigned to four categories. Treatment was continued until normal ultrasound findings were reached. At the time children started walking (mean age 14.8 months), an anteroposterior radiograph of the pelvis was performed. The acetabular index was measured and classified according to the normal values of the hip joint, as described by Tönnis. The ultrasound findings expressed by the Graf classification were compared with the acetabular index measured at radiographic follow-up. Although normal values in ultrasound were reached before abduction splinting was discontinued, at the time of radiological follow-up, 59 hips (32.8%) showed mild residual dysplasia and another 53 hips (29.4%) showed severe residual dysplasia according to the criteria of Tönnis. Statistically, there was no significant correlation between the Graf classification and the radiological outcome at follow-up. Even after successful ultrasound-monitored treatment, a risk for residual dysplasia remains. Therefore, radiological follow-up of every hip treated once is necessary. We found no correlation between the severity of DDH measured by ultrasound and the subsequent presence of residual dysplasia at radiological follow-up.