1. Orthopaedic Surgery, Helios ENDO-Klinik, Hamburg, Germany
2. Department of Orthopaedic Surgery, Traumatology and Sports Medicine, Cologne Merheim Medical Center, Witten/Herdecke University, Cologne, Germany
3. Department of Orthopaedic Surgery, Cappagh National Orthopaedic Hospital, Finglas Dublin, Ireland