scholarly journals Alignment of the femoral component in a mobile-bearing unicompartmental knee arthroplasty: A study in 10 cadaver femora

The Knee ◽  
2007 ◽  
Vol 14 (4) ◽  
pp. 280-283 ◽  
Author(s):  
N.P. Kort ◽  
J.J.A.M. van Raay ◽  
B.J.W. Thomassen
Keyword(s):  
Femoral Component ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Mobile Bearing ◽  
Unicompartmental Knee

scholarly journals Meniscal Bearing Dislocation of Unicompartmental Knee Arthroplasty with Faint Symptom

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Tadashi Fujii ◽  
Yoshio Matsui ◽  
Marehoshi Noboru ◽  
Yusuke Inagaki ◽  
Yoshinori Kadoya ◽  
...  
Keyword(s):  
Femoral Component ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Tibial Component ◽  
Mobile Bearing ◽  
Lateral Wall ◽  
Lateral Part ◽  
Medial Condyle ◽  
Medial Side ◽  
Unicompartmental Knee

We experienced two cases of atypical lateral dislocations of meniscal bearing in UKA (unicompartmental knee arthroplasty) without manifest symptoms. The dislocated bearing, which jumped onto the wall of tibial components, was found on radiographs in periodic medical examination although they could walk. Two thicker size bearing exchanges were promptly performed before metallosis and loosening of components. Continual examination is important to mobile bearing type of UKA because slight or less symptoms may disclose such unique dislocation. One case showed malrotation of the femoral component on 3D image. Anteroposterior view hardly disclosed the malrotation of the femoral component. Epicondylar view is an indispensable view of importance, and it can demonstrate the rotation of the femoral component. The the femoral distal end is wedge shaped and is wider posteriorly. If the femoral component is set according to the shape of medial condyle, the femoral component shifts to medial site compared with tibial component in flexion. It can account for such rare dislocation as follows. If excessive force applies on most medial side of the bearing during flexion, the lateral part of the bearing pops and the force squeezes it laterally simultaneously. Finally, the bearing jumps onto the lateral wall of the tibial component.

scholarly journals Reduction in tibiofemoral conformity in lateral unicompartmental knee arthroplasty is more representative of normal knee kinematics

2019 ◽  
Vol 8 (12) ◽  
pp. 593-600 ◽  
Author(s):  
Yong-Gon Koh ◽  
Jin-Ah Lee ◽  
Hwa-Yong Lee ◽  
Hyo-Jeong Kim ◽  
Hyun-Seok Chung ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Femoral Component ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Tibial Plateau ◽  
Knee Kinematics ◽  
Lateral Tibial Plateau ◽  
Unicompartmental Knee ◽  
Tibial Insert ◽  
Femoral Rollback

Aims Commonly performed unicompartmental knee arthroplasty (UKA) is not designed for the lateral compartment. Additionally, the anatomical medial and lateral tibial plateaus have asymmetrical geometries, with a slightly dished medial plateau and a convex lateral plateau. Therefore, this study aims to investigate the native knee kinematics with respect to the tibial insert design corresponding to the lateral femoral component. Methods Subject-specific finite element models were developed with tibiofemoral (TF) and patellofemoral joints for one female and four male subjects. Three different TF conformity designs were applied. Flat, convex, and conforming tibial insert designs were applied to the identical femoral component. A deep knee bend was considered as the loading condition, and the kinematic preservation in the native knee was investigated. Results The convex design, the femoral rollback, and internal rotation were similar to those of the native knee. However, the conforming design showed a significantly decreased femoral rollback and internal rotation compared with that of the native knee (p < 0.05). The flat design showed a significant difference in the femoral rollback; however, there was no difference in the tibial internal rotation compared with that of the native knee. Conclusion The geometry of the surface of the lateral tibial plateau determined the ability to restore the rotational kinematics of the native knee. Surgeons and implant designers should consider the geometry of the anatomical lateral tibial plateau as an important factor in the restoration of native knee kinematics after lateral UKA. Cite this article: Bone Joint Res 2019;8:593–600.

scholarly journals Fracture of the Femoral Component Caused by Insufficient Crimping after Modern Unicompartmental Knee Arthroplasty

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Yoichi Ishibashi ◽  
Tasuku Mashiba ◽  
Masaki Mori ◽  
Tetsuji Yamamoto
Keyword(s):  
Femoral Component ◽  
Knee Arthroplasty ◽  
Revision Surgery ◽  
Unicompartmental Knee Arthroplasty ◽  
Radiolucent Line ◽  
Cement Mantle ◽  
Metallic Component ◽  
Postoperative Course ◽  
Unicompartmental Knee ◽  
First Case

Fracture of a femoral component after modern unicompartmental knee arthroplasty is very rare. Although this is not the first case on this subject, no study has reported insufficient crimping as the cause of femoral component loosening that led to breakage of a metallic component. A 69-year-old man underwent medial unicompartmental knee arthroplasty for right medial knee osteoarthritis. His early postoperative course was good; however, the 1-year postoperative radiograph showed an apparent radiolucent line around the femoral component, and he occasionally had right knee pain. However, he had been followed up conservatively because he had been doing well even while doing heavy agricultural work. At 8 years after surgery, because breakage of the femoral component was found, revision surgery was performed using bicruciate-retaining total knee arthroplasty. The removed fractured femoral component revealed a thick cement mantle detached from the bone surface. The postoperative course of the patient after the revision surgery was excellent. We suggest that the causes of femoral component breakage include early implant loosening caused by uneven cement crimping of the femoral component to the bone and excessive loading stress as a result of heavy labour.

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