Avascular necrosis of the femoral head following trochanteric fractures in adults: A systematic review

Avascular necrosis of the femoral head (ANFH) following trochanteric fractures (TFx) is infrequent. The causal relationship between ANFH and TFx remains controversial. Although several major risk factors for ANFH have been proposed, most of them remain under discussion. In this study we undertook a systematic review of the literature to investigate the incidence of AVN, risk factors and outcomes following Tfx fixation.A comprehensive review of the literature was undertaken using the PRISMA guidelines with no language restriction. Case reports of ANFH and series of TFx with or without cases of ANFH published between inception of journals to December 2013 were eligible for inclusion. Relevant information was divided in two sections. Part I: included the analysis of detailed case reports of ANFH, either published isolated or included in series of TFx, with the objective of establishing potential risk factors, clinical and radiological presentation, time to development, treatment and outcome of this complication. Part II: analyzed series of TFx, which included cases of ANFH with or without details of aetiology, treatment modalities and outcomes, with the objective of assessing the incidence of ANFH in TFx.Overall 80 articles with 192 cases of ANFH after TFx met the inclusion criteria. The most probable developmental pathway appears to be a disruption of the extra osseous arterial blood supply to the femoral head. Suggested risk factors included high-energy trauma with fracture comminution and displacement, and an atypical course of the fracture line, more proximal, at the base of the neck. Most cases were diagnosed within the first two years after fracture. The clinical and radiological features appear to be similar to those of idiopathic avascular necrosis of the femoral head. The incidence of AVFH with a minimum of 1-year follow-up was calculated 0.95%, and with a minimum 2-year follow-up it was 1.37%. Total hip replacement was the mainstay of treatment.The incidence of AVFH after Tfx fixation is small 1.37% within the first 2 years of injury. Risk factors for the development of this complication are related to the severity of trauma, fragment geometry and fracture displacement. Optimum surgery of these fractures cannot guarantee prevention of ANFH.