[Treatment of bony defects in femur and tibia : Established and new concepts].

Bone defects in the limbs may result from trauma, debridement during osteitis or pseudarthrosis resection or tumors [1]. Treating bone defects of the femur and tibia poses a substantial challenge in trauma surgery and orthopedics. Interdisciplinary orthoplastic treatment combined with soft tissue reconstruction is often necessary to preserve the extremity and its function. In addition to shortening surgery, various procedures are available for biological reconstruction, including autogenous and allogeneic bone transplantation, the use of osteoconductive bone substitutes, the induced membrane technique also known as the Masquelet technique, distraction osteogenesis and vascularized fibula transfer. Alternatively, megaprostheses can be used as metallic bone substitutes, especially for metaphyseal bone defects of the femur or proximal tibia [1].Bone defects up to 3 cm in size can usually be successfully treated with shortening or primary cancellous bone grafting; however, leg length difference is known to result in functional limitations [2]. The two-stage Masquelet technique can successfully be used to treat not only small and medium-sized defects but also larger defects through modification [2, 3]. Although the Masquelet technique can be used for larger defects, more complex surgical procedures are often employed in such cases. Callus distraction with segment transport is the most common procedure. In addition to external procedures with monorail or ring fixators, internal lengthening procedures with a transporting nail or plate-assisted bone segment transport (PABST) are now available as well [2].