We assessed the clinical results and complications associated with a new endoprosthetic replacement system (Mutars®) used in 250 patients with a malignant bone or soft tissue tumor. The key features of the system are its cementless, hexagonal-shaped stem (titanium alloy), the possibility of torsion adjustments in 5°-increments, and the Trevira® tube for soft tissue attachment. The mean age of the patients was 30.7 years, and the mean followup was 45 months. Prosthetic survival at 5 years was 89.7% for the upper extremity and 68.5% for the lower extremity. Prosthetic survival without any reoperation was 73.4% at 3 years postoperatively and 60.4% at 5 years postoperatively. Prosthetic failure was caused by deep infection in 12% (30 patients) of patients and aseptic loosening in 8% (20 patients) of patients. Stem fracture occurred in only 1.6% (four patients) of patients. Dislocation rates were reduced by using the Trevira® tube. Limb survival was achieved in 82.6% to 93.1% of patients depending on the endoprosthetic replacement site, and functional results ranged between 63% to 83% according to the Tumor Society score. Our results suggest limb salvage with the Mutars® endoprosthesis is successful with good functional results.
Level of Evidence: Therapeutic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.