PERIPROSTHETIC SUBTROCHANTERIC FEMORAL FRACTURE FOLLOWING OSTEOSYNTHESIS OF FEMORAL NECK FRACTURE USING BIPLANE DOUBLE-SUPPORTED SCREW FIXATION

Background. Global population aging has led to a significant increase in femoral neck fractures (FNF) among elderly patients. Despite the widespread use of cannulated screws, complication rates reach 46%, prompting the search for alternative techniques such as Biplanar Double-Supported Fixation (BDSF). Objective. To present a rare complication of BDSF – periprosthetic subtrochanteric fracture – and analyze its etiological factors. Materials and Methods . We describe a clinical case of a 64-year-old female with Garden type II FNF complicated by a periprosthetic fracture 1.5 months after BDSF. Data from a cohort of 31 patients who underwent BDSF between September 2021 and December 2024 at City Clinical Hospital No. 31 were analyzed. Results . Periprosthetic subtrochanteric fracture occurred in 3.2% of cases (n=1). Revision osteosynthesis with an intramedullary nail resulted in a successful outcome. Conclusion . This case highlights the necessity of strict adherence to the biomechanical principles of BDSF (Biplane Double-Supported Fixation) and the development of a guiding device for distal screw insertion, which would minimize the risk of repeat peri-implant femoral fractures.