We report our clinical experience with the first 54 cases of long bone fractures treated with the Fixion IM Nail. This innovative nailing system eliminates the need for interlocking screws and reaming of the medullary canal when the nailing of a long bone fracture is needed, offers a minimally invasive procedure for intramedullary nailing, and significantly reduces fluoroscopy exposure. Biomechanically, the nail assumes the hourglass shape of the medullary canal by its abutment to the medullary walls. The formation of a supporting forces entity, that could be defined as “the bone-nail supporting forces system entity,” becomes practically an integral part of the medullary walls at the points of attachment. In order to avoid using interlocking screws and reaming of the medullary canal when the nailing of a long bone fracture is required, the “FIXION IMN” system was proposed. Since March 1999 we have implanted 54 Fixion Intramedullary Nails for traumatic and pathological fractures in 50 patients with a mean age of 52 years (18 to 85). Among these patients, 33 had humeral fractures, 13 had tibial fractures, and 8 had femoral fractures; the pathological fracture cases consisted of 4 humeral cases and 1 femoral case. The Fixion IM Nail system consists essentially of four longitudinal bars connected radially by four thin membranes. The nail is sealed proximally with a unidirectional valve. During insertion, the nail is connected to a driver handle which assists with insertion and serves as a conduit for the saline during the expansion process. Inflation of the nail is by means of a pump that connects to the driver handle. Once in position, the nail is expanded by inflation under controlled pressure with saline. The expansion causes abutment of the longitudinal bars to the inner surface of the canal along the entire length, resulting in fixation of the fracture. The procedure is monitored fluoroscopically and clinically to ensure accurate reduction of the fracture. The surgeries were uneventful. Postoperative complications were not reported in any of the cases. The nail was inserted easily and good fixation was achieved. The patients made a complete recovery with early pain-free mobilisation and full range of motion.