Osteonecrosis of femoral head after cement augmented TFNA nailing for an intertrochanteric fracture: A case report.

Failure of fixation devices (cut through) in proximal femoral fractures continues to be a concern in severe osteoporosis. Bone cement augmentation using TFNA (Trochanteric Femoral Nail-Advanced™; DePuy Synthes) increases the bone implant interphase and thereby the biomechanical stability, offering better resistance to avoid cut through. Cement augmentation does not improve implant positioning or reduction but only provides mechanical advantage to the osteoporotic bone and was reported as a safer technique in literature. Most commonly reported complication following cement augmented TFN-A insertion is cement leakage through the fracture. While ONFH (Osteonecrosis of Femoral Head) following Intertrochanteric fractures is not an uncommon complication, its incidence in AO 31A3.3 fracture pattern is very rare. An in vitro study demonstrated that there was a transient increase in intraosseous pressure with injection of 6 ml of bone cement, yet posing a very low risk of developing ONFH. Despite appropriate primary fixation for an AO 31 A3.3 fracture using a TFN-A, we observed ONFH following fracture healing. This subsequently progressed to cephalic screw cut-through and the development of an acetabular bone defect, necessitating total hip arthroplasty with acetabular augments. Among patients treated with cement augmented TFN-A, any new complaint of hip pain after fracture healing should prompt strong suspicion for ONFH and warrant thorough evaluation. Undue delay will progress ONFH and cause structural damage to acetabulum due to the exposed helical blade.