Micromotion at the tibial plateau in primary and revision total knee arthroplasty: fixed versus rotating platform designs.
OBJECTIVE
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 prosthesis 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 neighbouring 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 component micromotion and may aid long-term stability in cases of revision TKA or poor bone quality.Cite this article: Mr S. R. Small. Micromotion at the tibial plateau in primary and revision total knee arthroplasty: fixed versus rotating platform designs. Bone Joint Res 2016;5:122-129. DOI: 10.1302/2046-3758.54.2000481.
JRSI Foundation, Inc., 1199 Hadley Road, Mooresville, IN 46158, USA smallsr@rose-hulman.edu.
S R
SR
Small
JRSI Foundation, Inc., 1199 Hadley Road, Mooresville, IN 46158, USA.
R D
RD
Rogge
JRSI Foundation, Inc., 1199 Hadley Road, Mooresville, IN 46158, USA.
R A
RA
Malinzak
Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803, USA.
E M
EM
Reyes
Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803, USA.
P L
PL
Cook
Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803, USA.
K A
KA
Farley
Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803, USA.
M A
MA
Ritter
biomechanics; initial stability; micromotion; rotating platform; total knee arthroplasty