The Role of Osteoporosis and Fracture Comminution in the Outcome of Anatomically Reduced and Adequately Fixed Intertrochanteric Femoral Fractures

To assess the role of osteoporosis and fracture comminution in the migration of the tip of the sliding screw within the femoral head, as well as the fracture collapse in anatomically reduced and adequately fixed intertrochanteric fractures, 151 patients, whose intertrochanteric fractures had been treated surgically with anatomic reduction and a centrally placed Dynamic Hip Screw (Protek Synthes, Switzerland), were reviewed with an average follow-up of 6 months after the fracture had healed (mean 9 months after fracture fixation). Osteoporosis was determined using the Singh scale, whereas fracture comminution was classified using the Tronzo criteria. Vertical and horizontal screw migration as well as fracture collapse (screw retrolisthesis) were measured in immediate anterioposterior postoperative roentgenograms and in roentgenograms at the end of the treatment. Failure in osteosynthesis occurred in 2.65% of the cases. Osteoporosis is strongly related to vertical (P = 0.00001), and horizontal (P = 0.0125) migration of the tip of the screw within the femoral head and less so to fracture collapse. On the other hand, fracture comminution is strongly related to fracture collapse (P = 0.0124) but not to the migration of the screw within the femoral head. The successful outcome of treating patients with intertrochanteric fractures depends on both adequate biology (no severe osteoporosis) and adequate mechanics (proper implant and surgical technique). Anatomic reduction and central placement of the sliding screw must be performed as a routine. Modifications to decrease the loading of the fractured hip (medial displacement and valgus osteotomy) should only be considered in exceptional cases in the presence of significant osteoporosis, thus avoiding the expected severe vertical and horizontal migration of the tip of the screw as well as fracture collapse.