425 - Micromotion at the tibial plateau in total knee arthroplasty

Freely available online open Access BJR vol. 5, No. 4, apRil 2016 122 Article focus „ an investigation of tibial component sta- bility as it relates to femoral and tibial component malalignment in total knee arthroplasty (TKa). „ Establishment of a methodology to assess movement at the bone-implant interface using three-dimensional digital image correlation. Key messages „ Rotating platform tibial components gen- erate reduced implant micromotion by lessening tibiofemoral torque transfer. Strengths and limitations „ The study is the first to implement non- contact digital image correlation meth- odologies to quantify three-dimensional micromotion between the tibial tray and neighbouring bone in a TKa model. „ This study is limited in that it uses com- posite tibial specimens in a simplified loading scenario in order to assess differ- ence in stability of fixed and rotating plat- form component designs. Introduction Cemented total knee arthroplasty (TKa) has been a highly successful elective procedure, Micromotion at the tibial plateau in primary and revision total knee arthroplasty: fixed versus rotating platform designs Objectives Initial stability of tibial trays is crucial for long-term success of total knee arthroplasty (TKA) in both primary and revision settings. Rotating platform (Rp) designs reduce torque transfer at the tibiofemoral interface. We asked if this reduced torque transfer in Rp designs resulted in subsequently reduced micromotion at the cemented fixation interface between the pros- thesis component and the adjacent bone. Methods composite tibias were implanted with fixed and Rp primary and revision tibial trays and biomechanically tested under up to 2.5 kn of axial compression and 10° of external femoral component rotation. Relative micromotion between the implanted tibial tray and the neigh- bouring bone was quantified using high-precision digital image correlation techniques. Results Rotational malalignment between femoral and tibial components generated 40% less overall tibial tray micromotion in Rp designs than in standard fixed bearing tibial trays. Rp trays reduced micromotion by up to 172 µm in axial compression and 84 µm in rotational malalignment models. Conclusions Reduced torque transfer at the tibiofemoral interface in Rp tibial trays reduces relative com- ponent micromotion and may aid long-term stability in cases of revision TKA or poor bone quality. cite this article: Bone Joint Res 2016;5:122–129. Keywords: micromotion; total knee arthroplasty; rotating platform; biomechanics; initial stability 54.200 BJR0010.1302/2046-3758.54.2000481 research-article2016 „ ARthROplASty doi:10.1302/2046-3758.54.2000481 Bone Joint Res 2016;5:122–129. Received: 24 June 2015; Accepted: 29 February 2016 S. R. Small, R. D. Rogge, R. A. Malinzak, E. M. Reyes, p. l. Cook, K. A. Farley, M. A. Ritter JRSI Foundation, Inc., Indiana, United States „„ S. R. Small, MS, Engineering Director „„ R. a. Malinzak, MD, orthopaedic Surgeon „„ M. a. Ritter, MD, Executive Director JRSi Foundation, inc., 1199 Hadley Road, Mooresville, iN 46158, USa. „„ R. D. Rogge, phD, professor of Biology and Biomedical Engineering „„ E. M. Reyes, phD, assistant professor of Mathematics „„ p. l. Cook, MS, Undergraduate student „„ K. a. Farley, BS, Undergraduate student Rose-Hulman institute of Technology, 5500 Wabash avenue, Terre Haute, iN 47803, USa. Correspondence should be sent to Mr S. R. Small; email: smallsr@ rose-hulman.edu MAY 2019 | The Surgical Technologist | 203