The treatment of major osseous defects in orthopedic oncology is dominated by surgical techniques which focus on preserving the affected limb. Ablative measures (amputations and rotation plasty) as well as arthrodeses of major joints are avoided as far as possible, if reasonable from an oncologic point of view. Surgeons may choose between different standard procedures: Besides the option of using allogene and autologous graft material, a tumor prosthesis represents a proven solution for the reconstruction of osseous defects. A combined use of allograft and prosthesis is often chosen. During the past few years, modular replacement systems have become more and more popular, since they offer the opportunity to fi ll defects of varying extents with respect to each individual case.

Since 1992, MUTARS® (Modular Universal Tumor And Revision System), has been successfully used for the treatment of major osseous defects of the lower and upper extremities.

Its modular design was developed in co-operation with Prof. Dr. W. Winkelmann ⁽¹⁾ and the further developed with Prof. Dr. G. Gosheger ⁽²⁾ , Department of General Orthopedics and Tumororthopedics at the University Hospital of Münster, Germany. The system shows good functional results and allows an individual solution for major osseous defects, including arthroplasties of the adjacent joints. Until 2009 more than 10,000 MUTARS® prostheses have been implanted successfully. The co-operation with leading European clinics has enhanced continuous further development of the implants and instruments, resulting in the proven instruments available today. This close collaboration enables us to always remain up-to-date and continue further development by using the latest experience in the tumor prosthesis sector by modifying our products according to this latest standard of knowledge. Since March 2003 the new PEEK-OPTIMA® lock is in clinical use and has shown excellent outcome and it is replacing the former PE lock now. Alternatively the system offers M-O-M components which are coupled by the metal-on-metal connecting mechanism which is successfully used in the Proximal Tibial Replacement for more than 15 years. It is recommended to use the M-O-M components in case of extra-articular resection. The non-invasive MUTARS® Xpand Growing Prosthesis could be developed together with a partner company. The

fi rst implantations of the biological Growing Prosthesis MUTARS® BioXpand have shown promising results.

(1)    Prof. Dr. med. W. Winkelmann, ehem. Direktor der Klinik und Poliklinik für Allgemeine Orthopädie, Universitätsklinikum Münster; now: Consultant for Orthpaedic Oncology, Schönklinik Hamburg-Eilbek.

(2)   Univ.-Prof. Dr. med. Georg Gosheger, Direktor Klinik für Allgemeine Orthopädie und Tumororthopädie, Universitätsklinikum Münster.