scholarly journals Intentionally Increased Flexion Angle of the Femoral Component in Mobile Bearing Unicompartmental Knee Arthroplasty

2018 ◽  
Vol 30 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Kye-Youl Cho ◽  
Kang-Il Kim ◽  
Sang-Jun Song ◽  
Kyu-Jin Kim
Keyword(s):  
Femoral Component ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Mobile Bearing ◽  
Flexion Angle ◽  
Unicompartmental Knee

scholarly journals Effects of contact stress on patellarfemoral joint and quadriceps force in fixed and mobile-bearing medial unicompartmental knee arthroplasty

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Hyuck Min Kwon ◽  
Jin-Ah Lee ◽  
Yong-Gon Koh ◽  
Kwan Kyu Park ◽  
Kyoung-Tak Kang
Keyword(s):  
Knee Joint ◽  
Contact Stress ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Patellofemoral Joint ◽  
Mobile Bearing ◽  
Flexion Angle ◽  
High Flexion ◽  
Unicompartmental Knee ◽  
Quadriceps Force

Abstract Background Unicompartmental knee arthroplasty (UKA) is an effective treatment for end-stage, symptomatic unicompartmental osteoarthritis of the knee joint. However, patellofemoral joint degeneration is a contraindication to medial UKA. Therefore, the objective of this study was to evaluate the biomechanical effect of medial UKA using fixed-bearing (FB) and mobile-bearing (MB) design prostheses on the patellofemoral joint. Methods A three-dimensional finite-element model of a normal knee joint was developed using medical image data. We performed statistical analysis for each model. The differences in contact stress on the patellofemoral joint and the quadriceps force between the FB and MB designs were evaluated under a deep-knee-bend condition. Results At an early flexion angle, the results of contact stress showed no significant difference between the FB and MB medial UKA models compared with the intact model. However, at high flexion angles, we observed a significant increase in contact stress with the FB models compared with the intact model. On the contrary, in the case of the MB models, we found no statistically significant increment compared with the intact model. A larger quadriceps force was needed to produce an identical flexion angle for both the FB and MB UKA designs than for the intact model. At high flexion angles, a significant increase quadriceps force whit the FB model compared with the intact model. Conclusions Our results indicate that with medial UKA, the contact stress increased and greater quadriceps force was applied to the patellofemoral joint. However, performing UKA on a patellofemoral joint with osteoarthritis should not be difficult, unless anterior knee pain is present, because the increase in contact stress is negligible.

Sagittal flexion angle of the femoral component in unicompartmental knee arthroplasty: is it same for both medial and lateral UKAs?

2010 ◽  
Vol 18 (7) ◽  
pp. 928-933 ◽  
Author(s):  
Elcil Kaya Bicer ◽  
Elvire Servien ◽  
Sebastien Lustig ◽  
Guillaume Demey ◽  
Tarik Ait Si Selmi ◽  
...  
Keyword(s):  
Femoral Component ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Flexion Angle ◽  
Unicompartmental Knee

scholarly journals Effects of contact stress on patellarfemoral joint and quadriceps force in fixed and mobile-bearing medial unicompartmental knee arthroplasty

2020 ◽  
Author(s):  
Hyuck Min Kwon ◽  
Jin-Ah Lee ◽  
Yong-Gon Koh ◽  
Kwan Kyu Park ◽  
Kyoung-Tak Kang
Keyword(s):  
Knee Joint ◽  
Contact Stress ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Mobile Bearing ◽  
Element Model ◽  
Flexion Angle ◽  
Unicompartmental Knee ◽  
Significant Difference ◽  
Quadriceps Force

Abstract Background Unicompartmental knee arthroplasty (UKA) is an effective treatment for end-stage, symptomatic unicompartmental osteoarthritis (OA) of the knee joint. However, patellofemoral (PF) joint degeneration is a contraindication to medial UKA. Therefore, the objective of this study is to evaluate the biomechanical effect on the PF joint in medial UKA using fixed-bearing (FB) and mobile-bearing (MB) design prostheses. Methods A three-dimensional finite-element model of a normal knee joint was developed using medical image data. We performed statistical analysis for each model. The differences in the contact stress on the PF joint and the quadriceps force between the FB and MB designs were evaluated under a deep-knee-bend condition. Results At an early flexion angle, the results of the contact stress were showed that there was no significant difference between the FB and MB medial UKA models compared with the intact model. However, at a large flexion angle, we observed a significant increase in the contact stress of FB models. On the contrary, in the case of the MB models, there was no statistically significant increment compared to the intact model. Our results indicate that with medial UKA, the contact stress increased, and a greater quadriceps force was applied to the PF joint. However, there should be no difficulty in performing UKA on a PF joint with OA, unless there is anterior knee pain. This is because the increase in the contact stress is negligible. Conclusions Our results showed that there was no significant difference in contact stress on the PF joint between medial UKA and intact knee joints. In particular, such a mechanism was easily found in mobile-bearing medial UKA. Therefore, this study biomechanically showed that degenerative changes in the PF joint should not be considered an absolute contraindication for treatment with medial UKA.

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.

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