A 180° Spin of the Femoral Component in Unicompartmental Knee Arthroplasty

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

Case Reports in Orthopedics ◽

10.1155/2019/5938598 ◽

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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Central Implantation of the Femoral Component Relative to the Tibial Insert Improves Clinical Outcomes in Fixed-Bearing Unicompartmental Knee Arthroplasty

The Journal of Arthroplasty ◽

10.1016/j.arth.2020.05.071 ◽

2020 ◽

Vol 35 (11) ◽

pp. 3108-3116 ◽

Cited By ~ 1

Author(s):

Tomoyuki Kamenaga ◽

Koji Takayama ◽

Kazunari Ishida ◽

Shinya Hayashi ◽

Ryosuke Kuroda ◽

...

Keyword(s):

Clinical Outcomes ◽

Femoral Component ◽

Knee Arthroplasty ◽

Unicompartmental Knee Arthroplasty ◽

Fixed Bearing ◽

Unicompartmental Knee ◽

Tibial Insert

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Does new instrument for Oxford unicompartmental knee arthroplasty improve short-term clinical outcome and component alignment? A meta-analysis

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-020-01926-w ◽

2020 ◽

Vol 15 (1) ◽

Author(s):

Xiao Wei Sun ◽

Fei Fan Lu ◽

Kun Zou ◽

Mao Hong ◽

Qi Dong Zhang ◽

...

Keyword(s):

Femoral Component ◽

Knee Arthroplasty ◽

Unicompartmental Knee Arthroplasty ◽

Revision Rate ◽

Meta Analysis ◽

Phase Iii ◽

Cochrane Library ◽

Radiological Assessment ◽

Short Term ◽

Unicompartmental Knee

Abstract Background The Microplasty (MP) instrumentation designed for the Phase III Oxford mobile-bearing unicompartmental knee arthroplasty (UKA) system is considered a better option to achieve more accurate component positioning and alignment. In the present study, we focused on short-term clinical and radiological outcomes to determine whether the MP instrumentation can reduce the short-term revision rate and occurrence of outliers of metallic components. Methods The literature in PubMed, Embase, the Cochrane Library, and Web of Science was searched up to May 2020. Studies were scrutinized by two independent authors, and the revision rate, complication spectrum, and radiological assessment with outlier rates were specifically analyzed. RevMan 5.3 was used for the statistical analysis. Results Seven studies were included in the meta-analysis. Four studies reported both clinical and radiological outcomes, two reported only radiological outcomes, and one reported only clinical outcomes. The pooled analysis showed that the revision rate in the MP instrumentation group was 0.866 per 100 component years, while that in the control group was 1.124 (odds ratio, 0.77; p < 0.05). The subgroup analysis of the bearing dislocation rate showed a significantly greater reduction in the Korean population than in the populations of other countries (p < 0.05). The radiological assessment showed that the alignment of the femoral component was significantly improved (p < 0.05), while that of the tibial component was not (p > 0.05). Conclusion The newly developed MP instrumentation for Oxford UKA significantly reduced the revision rate of this treatment. The positioning of the femoral component was also proven to be better by radiological assessments.

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Medial femoral head border is a reliable and reproducible reference for axis determination for femoral component of unicompartmental knee arthroplasty

Knee Surgery Sports Traumatology Arthroscopy ◽

10.1007/s00167-012-2227-8 ◽

2012 ◽

Vol 21 (11) ◽

pp. 2442-2446 ◽

Cited By ~ 1

Author(s):

T. Hiranaka ◽

H. Pandit ◽

H. S. Gill ◽

Y. Hida ◽

H. Uemoto ◽

...

Keyword(s):

Femoral Head ◽

Femoral Component ◽

Knee Arthroplasty ◽

Unicompartmental Knee Arthroplasty ◽

Unicompartmental Knee

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Femoral component rotation angle after unicompartmental knee arthroplasty using the anatomical tibial component cutting technique with computer-assisted surgery by CT-scan

10.29007/3cm2 ◽

2019 ◽

Author(s):

Kittikun Thienthong ◽

Pornpavit Sriphirom ◽

Anuchit Vejjaijiva ◽

Soros Suwansawaiphol

Keyword(s):

Ct Scan ◽

Internal Rotation ◽

Femoral Component ◽

Knee Arthroplasty ◽

Unicompartmental Knee Arthroplasty ◽

Rotation Angle ◽

Computer Assisted ◽

Femoral Component Rotation ◽

Unicompartmental Knee ◽

Component Rotation

Complication following UKA in medial compartment OA knee often related to rotatory malposition of the femoral component The purpose of this study was to study outcome following Femoral component rotation angle after unicompartmental knee arthroplasty using the anatomical tibial component cutting technique with computer-assisted surgery by CT-scan measurement in Rajavithi hospitalRetrospective descriptive study of 16 patients performed medialUKA in Rajavithi Hospital Bangkok Thailand.Single orthopedic surgeon and using computer-assisted with anatomical tibia cutting technique(tibial resection in 3-degree varus).The femoral component rotation was assessed in an axial cut CT scan. measure angle between Epicondylar axis and Posterior condylar axisThe authors analyzed 16 knees with mean age about 56 years, male 2 Female 14 and the mean BMI was 24 kg/m 2 (average body weight 63 kg)Mean of Femoral component rotation angle in this study is 2.94-degree internal rotation(internal rotation compare with Epicondylar axis). A range of femoral component internal rotation was 0-6 degree .mean varus-valgus angle was 1.81-degree varus and mean flexion-extension angle was 5.56-degree flexionFemoral component rotation angle in unicompartmental knee arthroplasty(UKA) in medial compartment osteoarthritis knee with using of the computer-assisted with anatomical tibia cutting technique have a favorable result (Mean = 2.94-degree internal rotation 1.81-degree varus and 5.56-degree flexion).

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Robot-Assisted Unicompartmental Knee Arthroplasty: Increasing Surgical Accuracy? A Cadaveric Study

The Journal of Knee Surgery ◽

10.1055/s-0039-1698771 ◽

2019 ◽

Cited By ~ 4

Author(s):

Magaly Iñiguez ◽

Roberto Negrín ◽

Jaime Duboy ◽

Nicolás O. Reyes ◽

Rodrigo Díaz

Keyword(s):

Femoral Component ◽

Knee Arthroplasty ◽

Unicompartmental Knee Arthroplasty ◽

Functional Results ◽

Tibial Slope ◽

Clinical Results ◽

Robot Assisted ◽

Post Surgery ◽

Unicompartmental Knee ◽

Significant Difference

AbstractUnicompartmental knee arthroplasty (UKA) represents 10% of knee arthroplasties. Advantages are better functional results, quicker recovery, shorter hospitalization time, and lower blood loss, among others. However, revision rates are larger than total knee arthroplasty. Among the most important factors that explain this are the implant position and alignment, and the correct surgical indication. Greater accuracy in the implant placement may improve clinical results and increase the rate of implant survival. The objective of this study is to evaluate the precision of the Navio robot-assisted system in the position and alignment of medial UKA compared with the conventional technique. This is an experimental pilot study. Twenty-six cadaveric models were randomized into 2 groups: Robot-Assisted surgery (R) and Conventional Surgery (C). Radiological study was performed pre- and post-surgery, evaluating the medial distal femoral angle (MDFA), medial proximal tibial angle (MPTA), tibial slope, tibiofemoral angle (TFA), sagittal femoral angle (SFA), and size of the femoral and tibial components. The main result measurement was the change in postoperative angulation. The results of this study are MDFA median of 1.07° (0.19–4.5) for group R and 0.12° (0.03–10.4) with a significant difference in variances; a Welch t-test of p = 0.013; and an MPTA of 1.28° (0.05–5.87) for R and 1.3°(0.08–14.1) for C with significantly different variances (p = 0.0064). Size of the femoral component has a difference of p < 0.05 between groups. No differences for dispersion of TFA nor for the size of the tibial component were observed. In conclusion, using robot-assisted UKA allows for greater accuracy in the positioning of the implants and in the prediction of the size of the femoral component.

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