The GenuX® MK -Modular Knee- system is a further development of the existing GenuX® knee revision implant which is successful in clinical use since 2006. The GenuX® MK has been developed to offer the intraoperative choice between Mobile-Bearing and Fixed-Bearing PE-Inlays. Moreover, the focus is on the new design of the tibial and femoral component with less bone resection and an easy instrumentation. The biomechanically optimized MUTARS® GenuX® MK coupling allows for 130° flexion. The Range of Motion (ROM) of the MUTARS® GenuX® MK coupling is 142°. To simplify the system the same stems are used femorally and tibially in conjunction with offset adapters.

MUTARS® (Modular Universal Tumor And Revision System) has been successefully used since 1992 for the treatment of major osseous defects of the lower and upper extremities.
Its modular design was developed in co-operation with Univ.-Prof. Dr. W. Winkelmann* (em. Director) and Univ.-Prof. Dr. G. Gosheger (Director), Department of General Orthopaedics and Orthopaedic Oncology at the University Hospital of Münster, Germany. The system shows good functional results and allows an individual solution for major osseous defects including arthoplasties of the adjacent joints.

The tibial and femoral components of the GenuX® MK system are fully compatible in tumour treatments with all MUTARS® standard products. With the MK components, the Mobile-Bearing option is possible. MUTARS® MK combines the advantages of the GenuX® MK system and the established MUTARS® system.

In tumour and revision surgery, it is very often preoperatively not clear how much bone in stock and what quality be available after removal of the tumour or the primary implant for implant anchorage. It is highly im- portant to be able to adapt intraoperatively with a highly modular and quality system in all situations. 4 sizes of femoral and tibial components are available. Femorally and tibially the same stems are used in either a cemented or cementless version with four different lengths and nine diameters for anchorage are available. With the offset adapter the stems can be attached in an optimal position to the tibial and femoral compo- nent due to the 360° free adjustable offset. To fill bone defects a variety of spacers of different thicknesses (5-45 mm tibial [5-20 mm unicondylary, 25 – 45 mm bicondylary], femoral 5-10 mm) are available for each size. The patella can be replaced by a cemented PE patella implant.

For the implantation of MUTARS® MK, simple instruments are available. The surgical technique is func- tional, so that the MUTARS® MK system can be implanted after a short learning curve. The surgery is performed with comparatively straight forward instrumentation.