The prevalence, associated factors and complications of Peri-implant femur fracture following retrograde intramedullary nailing at Muhimbili Orthopaedic Institute

Abstract

ABSTRACT Introduction: Peri-implant femur fracture is a likely increasing entity in orthopaedic traumatology. However, the prevalence, associated factors and anticipated complications for peri-implant femoral fractures following retrograde intramedullary nail at Muhimbili Orthopaedic Institute are not evident. The main goal of this study was to determine the prevalence, associated factors and complications among patients who developed peri-implant femur fracture following retrograde intramedullary nailing at MOI - January, 2008 to December, 2022. Method: The study design was a retrospective descriptive cross-sectional study and employed the use of secondary data from the SIGN database. The MUHAS Institutional Ethical Review Board committee (IRB) was consulted for approval and ethical clearance. Patients were identified from the SIGN database (those with femur fractures, those receiving antegrade IM nailing and those receiving retrograde IM nailing). Medical records and radiological reports of patients receiving retrograde IM nailing were reviewed and appropriate data were collected using structured questionnaire. Independent variables included demography, nail size, nail tip location and complications of PIFF whilst dependent variable was peri-implant femur fracture. Data was analysed as prevalence, percentages, mean and Chi-square test. Results: Out of 3076 patients treated with retrograde IMN, 29 (0.94%) experienced PIFF. Notably, 69% of these patients were aged 18-39 years, and 79% were male. The predominant nail sizes were 9mm and 10mm, each constituting 34.5% of the cases with the 360mm nail length being the most frequent (31%). 69% of PIFF cases had their nail tip positioned below the lesser trochanter, with mean a distance of 28.4mm, though this was not statistically significant (p=0.232). Remarkably, no complications were reported following PIFF treatment. Conclusion: The study concludes that the incidence of PIFF following retrograde IMN at MOI is relatively low. The findings highlight the need for a surgical plan tailored to each patient’s unique characteristics as well as prioritizing meticulous pre-operative planning and intra-operative techniques which can in the long run reduce the risk of PIFF. Nonetheless, further study to investigate whether these factors are independent risk factors is highly recommended.