Risk Factors for Tibial Periprosthetic Fractures After Total Knee Arthroplasty: The Influence of Fixation and Implant Design

Abstract Tibial periprosthetic fractures (PPF) after total knee arthroplasty are multifactorial, arising from a dynamic interplay between implant mechanics, fixation strategy, surgical technique, and patient bone quality. Cemented fixation, while providing immediate stability, intensifies proximal stress shielding and periprosthetic bone loss, whereas cementless fixation favors physiologic load transfer but risks early micromotion and compromised osseointegration. Stemmed implants generate distal stress concentration at the stem tip, identifying predictable fracture initiation sites. Implant geometry, particularly keel versus peg design, baseplate size, and polyethylene thickness, modulates intraoperative and early postoperative fracture risk. Metal-backed components exacerbate proximal strain reduction, while all-polyethylene designs maintain local bone density but increase interface motion. Patient factors such as low bone mineral density, preoperative valgus alignment, advanced age, and being a woman synergistically amplify mechanical vulnerabilities. Surgical technique errors, including aggressive keel preparation and oversizing, can precipitate fractures even in structurally sound bone. Recognizing these biomechanical and patient-specific interactions provides a framework to optimize implant selection, fixation methods, and operative strategies, potentially reducing tibial PPF incidence.