Modes of failure of proximal femoral nail (PFN) in unstable trochanteric fractures

Trochanteric fractures are one of the commonest fractures in aging population.1 The prevalence of these fractures has increased substantially over the last few decades as a result of the larger longevity of the population.2 About 35 to 40% of such fractures are unstable one.3,4 Surgical stabilization of these fractures is preferred method of treatment for restoring pre-fracture mobility.5,6 Several fixation devices have been developed to overcome the difficulties encountered in the management of the unstable trochanteric fractures. Of late, most of these fractures were treated by lateral devices. As lateral devices were associated with high rates of complications7,9 intramedullary fixation devices have become gradually more prevalent.10–12 The proximal femoral nail (PFN) is an intramedullary system, intended to improve the management of unstable trochanteric fractures. Intramedullary implants are preferred in treatment of unstable trochanteric fractures, especially in the absence of medial buttress.13,14 In 1997 the AO designed an innovative intramedullary implant, the proximal femoral nail (PFN)6 for management of such fractures. Hence, PFN in unstable fracture patterns is progressively becoming standard method of fixation in view of its superior biomechanics and prevention of varus collapse in comparison to extramedullary devices.15 However, the evolution of the procedure may include complications associated with the migration of the interlocking head screws (Z-effect and reverse Z-effect), varus collapse, screw cutout, peri-implant fracture, nonunion, delayed union, shortening and infection. The objective of the paper is to describe the technical hitches, errors and modes of failure of PFN in unstable trochanteric fractures with their literature-based explanations and the recommendations to avoid such complications.