Upsizing the femoral component increases patellofemoral contact force in total knee replacement.


In posterior stabilised total knee replacement (TKR) a larger femoral component is sometimes selected to manage the increased flexion gap caused by resection of the posterior cruciate ligament. However, concerns remain regarding the adverse effect of the increased anteroposterior dimensions of the femoral component on the patellofemoral (PF) joint. Meanwhile, the gender-specific femoral component has a narrower and thinner anterior flange and is expected to reduce the PF contact force. PF contact forces were measured at 90°, 120°, 130° and 140° of flexion using the NexGen Legacy Posterior Stabilized (LPS)-Flex Fixed Bearing Knee system using Standard, Upsized and Gender femoral components during TKR. Increasing the size of the femoral component significantly increased mean PF forces at 120°, 130° and 140° of flexion (p = 0.005, p < 0.001 and p < 0.001, respectively). No difference was found in contact force between the Gender and the Standard components. Among the patients who had overhang of the Standard component, mean contact forces with the Gender component were slightly lower than those of the Standard component, but no statistical difference was found at 90°, 120°, 130° or 140° of flexion (p = 0.689, 0.615, 0.253 and 0.248, respectively). Upsized femoral components would increase PF forces in deep knee flexion. Gender-specific implants would not reduce PF forces.

DOI: 10.1302/0301-620X.94B1.27514
Citations per Year

229 Citations

Semantic Scholar estimates that this publication has 229 citations based on the available data.

See our FAQ for additional information.

Cite this paper

@article{Kawahara2012UpsizingTF, title={Upsizing the femoral component increases patellofemoral contact force in total knee replacement.}, author={Shinya Kawahara and Sachiko Matsuda and Shingo Fukagawa and Hiroaki Mitsuyasu and Hirotomo Nakahara and Hidehiko Higaki and Takeshi Shimoto and Yukihide Iwamoto}, journal={The Journal of bone and joint surgery. British volume}, year={2012}, volume={94 1}, pages={56-61} }