[Special prosthesis implant with partial femoral replacement. Operation after periprosthetic femoral fracture and ipsilateral long-stem knee prosthesis and fixed-angle osteosynthesis].

The development of modular prostheses is becoming increasingly important in revision surgery due to the rising need of arthroplasty in knee and hip joints. The demand for suitable prostheses is high because of the desire for a higher mobility and a good postoperative functionality, whereby preliminary experience with megaprostheses using modular implant systems in orthopedic oncology have already been obtained. Considering the clinical outcome of our 58-year-old patient (obesity III, BMI 58) and the third revision operation after two periprosthetic fractures, a megaprosthesis was implanted (Mega C-system, co. Link, Hamburg). We aimed both at good clinical functionality and good stability of the knee joint. After the implant, a good functional result was observed at the beginning; however, there were some indices for prosthesis loosening. During the fourth revision we implanted a total femoral replacement. Postoperatively, a good clinical outcome after intensive physiotherapy was observed. Nevertheless, the use of megaprostheses has to be judged cautiously because of a lack of long-term results. In addition, it should not be used as a standard implant in periprosthetic joint surgery because of the risk of aseptic loosening during its course.