On the Horizon from the Ors (Orthopedic Surgery‪)‬

Functional Micromechanics: Moving Beyond Migration in the evaluation of Implant Fixation. Aseptic loosening is the most common indication for revision surgery in total hip arthroplasty (THA) and total knee arthroplasty (TKA). (1) Radiostereometric analysis (RSA), considered the benchmark for in vivo evaluation of implant fixation, provides a sensitive method for detecting implant migration. (2) Available evidence from patients who have undergone TKA suggests that excessive early migration ( 0.2 mm within the second postoperative year) is a strong indicator of components that will eventually become clinically loose. (3) RSA migration data reflect permanent motions that have occurred between the implant and the surrounding bone; these data do not provide detailed information about real-time micromotion that may be occurring at the interface of a loaded implant.