The clinical epicondylar axis is not the functional flexion axis of the human knee

Background Preoperative templating of total knee arthroplasty (TKA) can nowadays be performed three-dimensionally with software solutions using computed tomography (CT) datasets. Currently there is no consensus concerning the axial orientation of TKA components in three-dimensional (3D) planning. Purpose To assess intra-/inter-observer reliability of detection of different bony landmarks in planning axial component alignment using axial CT images and 3D reconstructions. Material and Methods Intra- and inter-observer reliability of determination of four predefined axial femoral and tibial axes was calculated using data from CT scans. Axes determination was performed on the axial slices and on the 3D reconstruction using preoperative planning software. In summary, 61 datasets were analyzed by one medical student (intra-observer reliability) and 15 datasets were analyzed by four different observers independently (inter-observer reliability). Results For the femur, clinical epicondylar axis and posterior condylar axis showed the best reliability with an inter-observer variability of 0.7° and 0.5°, respectively. For the tibia, posterior condylar axis provided best reliability (inter-observer variability: 1.7°). Overall variability was greater for tibial than for femoral axes. Reliability of axis determination was more accurate using axial CT slices rather than 3D reconstructions. Conclusion The femoral clinical epicondylar axis is highly reliable. Landmarks for the tibia are not as easily identifiable as for the femur. The tibial posterior condylar axis presents the axis with highest reliability. Based on these results, clinical epicondylar axis for orientation of the femoral TKA component and posterior condylar axis for the tibial implant, both defined on axial slices can be recommended.

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Load-Bearing in the Ovine Medial Tibial Condyle: Effect of Meniscectomy

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.1055/s-0038-1633027 ◽

1993 ◽

Vol 06 (02) ◽

pp. 100-104 ◽

Cited By ~ 8

Author(s):

D. M. Pickles ◽

C. R. Bellenger

Keyword(s):

Knee Joint ◽

Contact Area ◽

Mammalian Species ◽

Total Removal ◽

Load Bearing ◽

Human Knee ◽

Biochemical Effects ◽

Pressure Sensitive ◽

Medial Meniscectomy ◽

Tibial Condyle

SummaryTotal removal of a knee joint meniscus is followed by osteoarthritis in many mammalian species. Altered load-bearing has been observed in the human knee following meniscectomy but less is known about biochemical effects of meniscectomy in other species. Using pressure sensitive paper in sheep knee (stifle) joints it was found that, for comparable loads, the load-bearing area on the medial tibial condyle was significantly reduced following medial meniscectomy. Also, for loads of between 50 N and 500 N applied to the whole joint, the slope of the regression of contact area against load was much smaller. Following medial meniscectomy, the ability to increase contact area as load increased was markedly reduced.The load bearing area on the medial tibial condyle was reduced following meniscectomy.

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Experimentally Applied Mechanical Load to the Human Knee Systematically Affects the Morphology of Articular Cartilage

10.1055/s-0038-1639516 ◽

2018 ◽

Author(s):

Grischa Bratke ◽

Steffen Willwacher ◽

David Maintz ◽

Gert-Peter Brüggemann

Keyword(s):

Articular Cartilage ◽

Mechanical Load ◽

Human Knee

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Design of a Human Knee Reeducation Mechanism

Acta Universitatis Sapientiae Electrical and Mechanical Engineering ◽

10.2478/auseme-2019-0004 ◽

2019 ◽

Vol 11 (1) ◽

pp. 42-53

Author(s):

Allaoua Brahmia ◽

Ridha Kelaiaia

Keyword(s):

Lower Limb ◽

Mechanical Design ◽

Kinematic Chain ◽

Lower Limbs ◽

Kinematic Structure ◽

Robotic Device ◽

Human Knee ◽

Kinematic Study ◽

Rehabilitation Exercise ◽

New Machine

Abstract To establish an exercise in open muscular chain rehabilitation (OMC), it is necessary to choose the type of kinematic chain of the mechanical / biomechanical system that constitutes the lower limbs in interaction with the robotic device. Indeed, it’s accepted in biomechanics that a rehabilitation exercise in OMC of the lower limb is performed with a fixed hip and a free foot. Based on these findings, a kinematic structure of a new machine, named Reeduc-Knee, is proposed, and a mechanical design is carried out. The contribution of this work is not limited to the mechanical design of the Reeduc-Knee system. Indeed, to define the minimum parameterizing defining the configuration of the device relative to an absolute reference, a geometric and kinematic study is presented.

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