Tibial component fixation in porous-and hydroxyapatite-coated total knee arthroplasty: A radiostereometric evaluation of migration and inducible displacement after 5 years

A total of 51 knees (45 patients) with osteoarthrosis were stratified in a randomized study to receive a hydroxyapatite-coated Freeman-Samuelson (FS HA) or a porous-coated Miller-Galante II (MG II) uncemented total knee arthroplasty. Repeated clinical, radiographic, and radiostereometric analysis (RSA) evaluations of the tibial components were done for 5 years. The clinical outcome was equal at the 5-year follow-up (mean Hospital for Special Surgery score, 93). Standard radiographs displayed more zones around the tibial stem in the MG II group. RSA revealed that the FS HA components migrated less (smaller maximum total point motion and maximum subsidence) after 5 years and showed less inducible displacements at the 1-year follow-up. The stability of the implants obtained is equal to or better than cemented implants after 5 years.