Non prosthetic peri-implant femur fracture classification system and treatment algorithm: a systematic review

Abstract

Non-prosthetic peri-implant femoral fractures (NP-PIFFs) are an increasingly recognised complication of fracture fixation, particularly in elderly and osteoporotic patients. These fractures occur in femora containing retained fixation hardware and present unique biomechanical and surgical challenges. Despite their growing prevalence, current literature lacks consensus on classification systems and optimal management. This systematic review aimed to summarise existing classification systems, treatment strategies, and reported outcomes in NP-PIFFs. This review was conducted in accordance with PRISMA guidelines and registered with PROSPERO (CRD420251102564). Searches of Medline and Google Scholar were performed using the keywords peri-implant fracture, femur, classification, and treatment algorithm. Studies were included if they reported on NP-PIFF classification, management, and at least one outcome measure (union rate, one-year mortality, or complications). Study quality was assessed using the National Heart, Lung, and Blood Institute (NHLBI) tool, and data were synthesised narratively due to heterogeneity. Nineteen studies published between 2016 and 2025 met inclusion criteria, encompassing 984 patients (mean age 82 years). Seven distinct classification systems were identified, with Videla-Cés et al and Chan (NPPIF) being most commonly used. Reported treatment strategies consistently emphasised constructs spanning the entire femur, minimisation of stress risers, and preservation of stable implants to reduce operative trauma. Union rates were high (95-100%), but one-year mortality ranged from 2.7% to 36%, largely reflecting patient frailty. Complications included mechanical failure, loss of fixation, varus collapse, and medical issues such as pneumonia, delirium, and thromboembolic events. NP-PIFFs are complex injuries that remain inconsistently classified and managed across studies. Although union rates are favourable when biological fixation principles are respected, patient outcomes are significantly influenced by age, comorbidity, and systemic complications. Future research should focus on standardising classification systems, validating treatment algorithms, and developing multidisciplinary strategies to optimise both surgical and medical care.