[Internal circular arc osteosynthesis of tibiotalocalcaneal arthrodesis].

Tibiotalocalcaneal arthrodesis has recently become more popular as a form of reconstructive surgery. The precise anatomical orientation and the functional extrinsic musculature of the hindfoot are essential for a satisfactory result. Fixation of the arthrodesis is a mechanical problem. Straight and angulated nails are not anatomically or mechanically ideal. A circular arc nail can fix the tibia, the talus and the calcaneus in anatomical alignment. This is a pure "bone nail", in contrast to the "intramedullary nail," which is driven through an existing opening in long bones. The nail is driven through a circular arc-shaped opening in the bone, which results in optimal form-fit between nail and bone. A corresponding aiming device permits the precise shaping of the bone tunnel, which follows the orientation of the bone trabeculae. The instrumentation was applied in 11 cases, with the following indications: post-traumatic conditions, congenital deformities, chronic polyarthritis and diabetic Charcot arthropathy. The desired alignment of the hindfoot is not affected while the nail is being introduced. The fixation achieves primary stability thus allowing for early functional treatment.