Total tibial endoprosthesis including ankle joint and knee joint replacement in a patient with Ewing sarcoma

A 32-year-old man was treated for diaphyseal osteomyelitis of the tibia, proven by an open biopsy. A drilling of the whole tibia through a proximal approach and insertion of gentamycin chains was performed, with no effect on the pain. 8 weeks later, MRI showed pathological changes of the whole tibia and a small soft tissue extension in the mid-diaphyseal area which did not affect the vessels or the nerves. Again, an open biopsy was performed and Ewing sarcoma was diagnosed. After preoperative chemotherapy according to the EURO-Ewing protocol, the patient was referred to our department for knee disarticulation.

Being aware of the contamination of the whole tibia and the anterior proximal skin and soft tissue, we performed a total resection of the tibia including a skin resection of 6 × 5 cm in the proximal tibia area. The flexor digitorum longus muscle, the posterior tibialis muscle and part of the tibialis anterior muscle were left on the tibia to allow a wide margin. The neurovascular bundles, the superficial flexors, the hallucis longus flexor muscle, the extensors and peroneal muscles could be preserved. The bony defect was reconstructed with a modular endoprosthesis (Figure 1) of the MUTARS System (Implantcast, Buxtehude, Germany). The knee joint was reconstructed with a rotating-hinge modular system with a connection to a titanium bone replacement system (MUTARS). The ankle joint was reconstructed with an unconstrained component with a talar surface replacement stabilized with a trans-talar and trans-calcanear stem. An arthrodesis of the talo-calcanear joint was performed. The endoprosthesis was enveloped with a Trevira tube (Gosheger et al. 2001) for attachment of the patellar tendon and attachment of a medial and lateral gastrocnemius flaps, which were transferred to the anterior side of the endoprosthesis for soft tissue coverage (Figure 2). The ventral capsule of the ankle joint was reconstructed with MITEK super anchors in combination with a Trevira Tube. A stable ankle joint could be achieved. A skin defect was covered with a skin-mesh graft on the gastrocnemius flap.