The relationship between stress shielding, bone density changes and implant migration, failure and fracture after total knee arthroplasty: A systematic review

Purpose: Total knee arthroplasty (TKA) represent a well‐established treatment for advanced osteoarthritis. Despite advancements in implant design and materials, the impact of stress shielding on bone mineral density (BMD) and its relationship with implant migration, loosening, and fracture remains insufficiently explored. This study aims to evaluate the association between stress shielding, BMD changes, and implant outcomes after TKA. Methods: A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta‐Analysis (PRISMA) guidelines. Four major databases (MEDLINE (PubMed), Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science (WOS), EMBASE) were thoroughly reviewed. Results: A total of 491 studies were initially identified, of which nine met the inclusion criteria and were included in the final review. Eight were randomised controlled trials, and one was a prospective observational study. All studies were conducted in clinical settings, comprising a total of 467 patients. BMD variations due to stress shielding were most pronounced during the first 6–12 months postoperatively. However, except for one isolated case, no direct correlation was identified between BMD changes caused by stress shielding and implant migration, loosening or fracture. Conclusions: This systematic review highlights that variations in bone mineral density due to stress shielding are not directly correlated with implant failure, migration or loosening in TKA. Stress shielding remains a critical phenomenon, particularly in the early postoperative phases, emphasising the importance of optimised materials, fixation methods and implant designs to reduce bone loss and improve long‐term stability. Due toits recognised occurrence in clinical practice, further in vivo studies would contribute to a better understanding of the stress shielding.