In the proximal femur a modular tumor prosthesis can be used today for reconstruction after resection of primary malignant bone tumors, metastatic lesions, and in revision surgery. The MUTARS® Munster system offers a high modularity and the possibility of combining it with the hip and knee revision system. Technical innovations, like hexagonal press fit bone anchorage, fine adjustment of rotation, silver coating of the surface of the prosthesis, and functional reconstruction with the help of a Trevira tube, guarantee a very good long-term survival of the prostheses and protection against the main complications such as aseptic loosening, deep infection, and instability.