Abstract: Tracked mobile x-ray imaging equipment is used to produce single or stereo long calibrated views of the anatomy of a patient on the operating table. The system estimates the position and orientation of the anatomical planes, virtually places measurement grids over these reference planes, and transforms any radiographic views taking by the x-ray imaging system onto these calibrated planes. The system may apply information about the depth of the anatomy to remove parallax artifacts. This system enables displaying and evaluation of the entire radiographic length of the anatomical planes using a mobile x-ray equipment. It also provides a platform for overlaying the real time x-ray images taken during operation with radiographic images of the patient or schematic of the surgical plan developed before the surgery for quick evaluation of a surgical plan.

Abstract: Tracked mobile x-ray imaging equipment is used to produce single or stereo long calibrated views of the anatomy of a patient on the operating table. The system estimates the position and orientation of the anatomical planes, virtually places measurement grids over these reference planes, and transforms any radiographic views taking by the x-ray imaging system onto these calibrated planes. The system may apply information about the depth of the anatomy to remove parallax artifacts. This system enables displaying and evaluation of the entire radiographic length of the anatomical planes using a mobile x-ray equipment. It also provides a platform for overlaying the real time x-ray images taken during operation with radiographic images of the patient or schematic of the surgical plan developed before the surgery for quick evaluation of a surgical plan.

Abstract: A knee prosthesis comprising a femur component defining a ball-like femoral condyle and a tibia component defining a cavity on its medial side corresponding to the ball-like condyle. The knee prosthesis enables pivoting of the tibia component about the medial side of the femur component as a function of the flexion angle ? as long as there is joint compression applied to the knee prosthesis as exemplified by muscle forces, weight, and ligament tensions, to enforce contact between the tibia component and the femur component. The geometries of the spherical load bearing surfaces of the medial tibia condyle and medial femur condyle provide the kinematic degrees of freedom and the geometric constraints required for proper guiding of the rolling and sliding surfaces of the femoral component and tibial component during articulation of the present knee prosthesis.

Abstract: An imaging system such as a medical C-arm x-ray fluoroscopy machine includes a tracking system that tracks a position of an x-ray source and an x-ray detector using sensors which monitor positions of joints which allow relative motions of segments in a support for the x-ray source and detector. Sensor readings are used in a kinematic chain. One or more segments that behave in a non-rigid manner are replaced by a virtual rigid link in the kinematic chain that takes into account deformations of the segments (e.g. under the influence of gravity). Calibration methods permit calibration of the system using images of phantoms.

Abstract: An imaging system such as a medical C-arm x-ray fluoroscopy machine includes a tracking system that tracks a position of an x-ray source and an x-ray detector using sensors which monitor positions of joints which allow relative motions of segments in a support for the x-ray source and detector. Sensor readings are used in a kinematic chain. One or more segments that behave in a non-rigid manner are replaced by a virtual rigid link in the kinematic chain that takes into account deformations of the segments (e.g. under the influence of gravity). Calibration methods permit calibration of the system using images of phantoms.

Abstract: An imaging system such as a medical C-arm x-ray fluoroscopy machine includes a tracking system that tracks a position of an x-ray source and an x-ray detector using sensors which monitor positions of joints which allow relative motions of segments in a support for the x-ray source and detector. Sensor readings are used in a kinematic chain. One or more segments that behave in a non-rigid manner are replaced by a virtual rigid link in the kinematic chain that takes into account deformations of the segments (e.g. under the influence of gravity). Calibration methods permit calibration of the system using images of phantoms.

Abstract: An imaging system such as a medical C-arm x-ray fluoroscopy machine includes a tracking system that tracks a position of an x-ray source and an x-ray detector using sensors which monitor positions of joints which allow relative motions of segments in a support for the x-ray source and detector. Sensor readings are used in a kinematic chain. One or more segments that behave in a non-rigid manner are replaced by a virtual rigid link in the kinematic chain that takes into account deformations of the segments (e.g. under the influence of gravity). Calibration methods permit calibration of the system using images of phantoms.

Abstract: A knee prosthesis for a knee joint with a medial ball-like femoral condyle and with a width “w” is characterized on the lateral compartment by:—a trace-line “Lt1” of contact points “Pt1” for the tibia component (2) as a predetermined curve (15) on a spherical surface “Sc1”, which has its centre at the centre Mb of the medial ball 1 and which has a radius in the range “Rc1”=0.65 w+/?0.25 w—a trace-line “Lt2” of common contact points “Pt2” at given flexion angles ? for a similar spherical surface “Sc2” attached to the femoral component with radius “Rc2”=Rc1, whereby at a given flexion angle ? there exists a plane “E1” through the centre Mb and the common contact point Pt1/Pt2, which contains the same guiding curves “Bi”, “Be” on the tibial and on the femoral components, “Bi” towards medial and “Be” towards lateral, both of which stay in a geometrically fixed relation to the common contact point Pt1/Pt2, and—guiding curves “Bi” and “Be”, which generate an enforced gilding and rolling movement in both directions.

Abstract: A knee prosthesis for a knee joint with a medial ball-like femoral condyle and with a width “w” is characterized on the lateral compartment by:—a trace-line “Lt1” of contact points “Pt1” for the tibia component (2) as a predetermined curve (15) on a spherical surface “Sc1”, which has its centre at the centre Mb of the medial ball 1 and which has a radius in the range “Rc1”=0.65w+/?0.25w—a trace-line “Lt2” of common contact points “Pt2” at given flexion angles ? for a similar spherical surface “Sc2” attached to the femoral component with radius “Rc2”=Rc1, whereby at a given flexion angle ? there exists a plane “E1” through the centre Mb and the common contact point Pt1/Pt2, which contains the same guiding curves “Bi”, “Be” on the tibial and on the femoral components, “Bi” towards medial and “Be” towards lateral, both of which stay in a geometrically fixed relation to the common contact point Pt1/Pt2, and—guiding curves “Bi” and “Be”, which generate an enforced gliding and rolling movement in both directions.