Use of interlocking nails for the management of fractures in growing dogs with osteopenic bones

The study was conducted in 16 cases of femur fractures reported in growing dogs, which were divided in 4 groups of 4 animals each. In groups I (normal bones) and II (osteopenic bones), femoral fracture fixation was carried out with single Steinmann pin by standard retrograde/normograde technique. In animals of groups III (normal bones) and IV(osteopenic bones) fracture immobilization was done by intramedullary interlocking (IMIL) nail. IMIL nailing was done in routine manner, but a nut was tightened at the opposite end of the screw (at far cortex) to avoid possible loosening of the screw. Both techniques were evaluated based on intraoperative observations, and clinical (weight bearing and lameness) and radiographic observations (for status of fracture fixation and healing). IM Steinmann pinning was easier to perform and took less time than IMIL nailing. When compared between normal and osteopenic bones, complications like improper placement of pin and pin migration were more common with osteopenic bones. Further, fracture reduction was also relatively more difficult in cases of osteopenic bones. Fracture healing did not differ markedly between the normal and osteopenic bones, and osteopenic bone fractures healed with relatively large callus. IMIL nailing though required relatively more time for fixation and difficult to fix the screw, it provided more rigid fixation both in normal and osteopenic bones. The weight bearing in animals treated with IMIL nail was better than those treated with Steinmann pin in the immediate postoperative period. Fracture reduction and fixation was also good, and the fixation maintained till the healing occurred in all the animals. The technique of using nut to lock the screw helped to prevent loosening of the screw and thus displacement of nail, suggesting that the modified technique of IMIL nailing could provide stable fixation of fractures in osteopenic bones.