Faculty of Health;
University of Witten/Herdecke;
Depart-ment of Orthopedics;
Trauma Surgery and Sports Medicine;
Johanna Etienne Hospital;
Joint Center Hilden and Ruhr-University Bochum;
Center of Trauma and Orthopedic Surgery;
Jena University Hospital;
Trochlea dysplasia; Medial-patellofemoral ligament; Patellofemoral instability; Patella dislocation; Trochleoplasty;