Abstract: A computer-assisted surgery system for guiding alterations to a bone, comprises a trackable member secured to the bone. The trackable member has a first inertial sensor unit producing orientation-based data. A positioning block is secured to the bone, and is adjustable once the positioning block is secured to the bone to be used to guide tools in altering the bone. The positioning block has a second inertial sensor unit producing orientation-based data. A processing system providing an orientation reference associating the bone to the trackable member comprises a signal interpreter for determining an orientation of the trackable member and of the positioning block. A parameter calculator calculates alteration parameters related to an actual orientation of the positioning block with respect to the bone.

Abstract: A computer-assisted surgery system for obtaining a distance between at least two fixed points relative to a bone comprises a first accelerometer unit located at a first fixed location on the bone, and producing first acceleration data during a movement of the bone. A second accelerometer unit is located at a second fixed location on the bone, and simultaneously producing second acceleration data during the movement. A gyroscope unit is fixed to the bone and simultaneously producing angular rates of change of said movement. A processor unit obtains the acceleration data and the angular rates of change for calculating the distance between the first fixed position and the second fixed position on the bone using a distance value of a distance vector between the accelerometer units. An interface outputs the distance between the first fixed position and the second fixed position relative to the bone. A method for calculating a distance between at least two points on a bone is provided.

Abstract: A computer-assisted surgery system for obtaining a distance between at least two fixed points relative to a bone comprises a first accelerometer unit located at a first fixed location on the bone, and producing first acceleration data during a movement of the bone. A second accelerometer unit is located at a second fixed location on the bone, and simultaneously producing second acceleration data during the movement. A gyroscope unit is fixed to the bone and simultaneously producing angular rates of change of said movement. A processor unit obtains the acceleration data and the angular rates of change for calculating the distance between the first fixed position and the second fixed position on the bone using a distance value of a distance vector between the accelerometer units. An interface outputs the distance between the first fixed position and the second fixed position relative to the bone. A method for calculating a distance between at least two points on a bone is provided.

Abstract: A computer-assisted surgery system for guiding alterations to a bone, comprises a trackable member secured to the bone. The trackable member has a first inertial sensor unit producing orientation-based data. A positioning block is secured to the bone, and is adjustable once the positioning block is secured to the bone to be used to guide tools in altering the bone. The positioning block has a second inertial sensor unit producing orientation-based data. A processing system providing an orientation reference associating the bone to the trackable member comprises a signal interpreter for determining an orientation of the trackable member and of the positioning block. A parameter calculator calculates alteration parameters related to an actual orientation of the positioning block with respect to the bone.

Abstract: A system for tracking a femoral frame of reference in computer-assisted surgery comprises a sensor unit. The sensor unit is adapted to be secured to the femur. The sensor unit comprises accelerometer and gyroscope sensors that produce orientation data. A processing unit receives gyroscope and accelerometer data. The processing unit comprises a gyroscope-data calculator to provide calculated acceleration data resulting from movements of the femur, an accelerometer-data calculator to calculate measured acceleration data resulting from movements of the femur, and an acceleration comparator to relate an orientation of the sensor unit to the femur to define a femoral frame of reference. The femoral frame of reference is defined from the comparison between the calculated and the measured acceleration data. A sensor orientation interface provides orientation data for the femur from a tracking of the femoral frame of reference. A method for tracking a femoral frame of reference is also provided.

Abstract: A computer-assisted surgery system for guiding alterations to a bone, comprises a trackable member secured to the bone. The trackable member has a first inertial sensor unit producing orientation-based data. A positioning block is secured to the bone, and is adjustable once the positioning block is secured to the bone to be used to guide tools in altering the bone. The positioning block has a second inertial sensor unit producing orientation-based data. A processing system providing an orientation reference associating the bone to the trackable member comprises a signal interpreter for determining an orientation of the trackable member and of the positioning block. A parameter calculator calculates alteration parameters related to an actual orientation of the positioning block with respect to the bone.

Abstract: A computer-assisted surgery system for obtaining a distance between at least two fixed points relative to a bone comprises a first accelerometer unit located at a first fixed location on the bone, and producing first acceleration data during a movement of the bone. A second accelerometer unit is located at a second fixed location on the bone, and simultaneously producing second acceleration data during the movement. A gyroscope unit is fixed to the bone and simultaneously producing angular rates of change of said movement. A processor unit obtains the acceleration data and the angular rates of change for calculating the distance between the first fixed position and the second fixed position on the bone using a distance value of a distance vector between the accelerometer units. An interface outputs the distance between the first fixed position and the second fixed position relative to the bone. A method for calculating a distance between at least two points on a bone is provided.

Abstract: A computer-assisted surgery system for obtaining a distance between at least two fixed points relative to a bone comprises a first accelerometer unit located at a first fixed location on the bone, and producing first acceleration data during a movement of the bone. A second accelerometer unit is located at a second fixed location on the bone, and simultaneously producing second acceleration data during the movement. A gyroscope unit is fixed to the bone and simultaneously producing angular rates of change of said movement. A processor unit obtains the acceleration data and the angular rates of change for calculating the distance between the first fixed position and the second fixed position on the bone using a distance value of a distance vector between the accelerometer units. An interface outputs the distance between the first fixed position and the second fixed position relative to the bone. A method for calculating a distance between at least two points on a bone is provided.

Abstract: A computer-assisted surgery system for guiding alterations to a bone, comprises a trackable member secured to the bone. The trackable member has a first inertial sensor unit producing orientation-based data. A positioning block is secured to the bone, and is adjustable once the positioning block is secured to the bone to be used to guide tools in altering the bone. The positioning block has a second inertial sensor unit producing orientation-based data. A processing system providing an orientation reference associating the bone to the trackable member comprises a signal interpreter for determining an orientation of the trackable member and of the positioning block. A parameter calculator calculates alteration parameters related to an actual orientation of the positioning block with respect to the bone.

Abstract: A computer-assisted surgery system for guiding alterations to a bone, comprises a trackable member secured to the bone. The trackable member has a first inertial sensor unit producing orientation-based data. A positioning block is secured to the bone, and is adjustable once the positioning block is secured to the bone to be used to guide tools in altering the bone. The positioning block has a second inertial sensor unit producing orientation-based data. A processing system providing an orientation reference associating the bone to the trackable member comprises a signal interpreter for determining an orientation of the trackable member and of the positioning block. A parameter calculator calculates alteration parameters related to an actual orientation of the positioning block with respect to the bone.

Abstract: A method tracks a tool with respect to a bone in computer-assisted surgery. A reference tracker with a MEMS unit is secured to the bone. The tracker outputs data relating to its orientation. A tool provided with a MEMS unit and secured to the bone is preset with an initial orientation. The tool outputs tracking data related to orientation of the tool once initialized. A trackable frame of reference relating the bone to the orientation of the tracker is created. The MEMS unit of the tool is initialized. A relation between the initial orientation of the tool and the orientation of the tracker at initialization of the MEMS unit of the tool is recorded. Orientational data of the tool relative to the frame of reference of the bone calculated using the relation is displayed. A computer-assisted surgery system for tracking a tool with respect to a bone after an initialization of a MEMS unit is also described.

Abstract: A method tracks a tool with respect to a bone in computer-assisted surgery. A reference tracker with a MEMS unit is secured to the bone. The tracker outputs data relating to its orientation. A tool provided with a MEMS unit and secured to the bone is preset with an initial orientation. The tool outputs tracking data related to orientation of the tool once initialized. A trackable frame of reference relating the bone to the orientation of the tracker is created. The MEMS unit of the tool is initialized. A relation between the initial orientation of the tool and the orientation of the tracker at initialization of the MEMS unit of the tool is recorded. Orientational data of the tool relative to the frame of reference of the bone calculated using the relation is displayed. A computer-assisted surgery system for tracking a tool with respect to a bone after an initialization of a MEMS unit is also described.

Abstract: A method for determining a mechanical axis of a tibia using a tibial digitizer is disclosed. The method includes: determining an upper reference point on a tibial plateau corresponding to an entry point of the mechanical axis; fastening an upper mounting end of the tibial digitizer to the tibial plateau at the upper reference point; and fastening a lower mounting end of the tibial digitizer to medial and lateral malleoli of the ankle, by inwardly displacing opposed caliper arms of a self-centering malleoli engaging mechanism toward each other in a common plane until the caliper arms abut the malleoli. A lower reference point located at a midpoint between the medial and lateral malleoli is then determined by identifying a corresponding midpoint between the caliper arms when they are clamped onto the medial and lateral malleoli.

Abstract: A system for tracking a femoral frame of reference in computer-assisted surgery comprises a sensor unit. The sensor unit is adapted to be secured to the femur. The sensor unit comprises accelerometer and gyroscope sensors that produce orientation data. A processing unit receives gyroscope and accelerometer data. The processing unit comprises a gyroscope-data calculator to provide calculated acceleration data resulting from movements of the femur, an accelerometer-data calculator to calculate measured acceleration data resulting from movements of the femur, and an acceleration comparator to relate an orientation of the sensor unit to the femur to define a femoral frame of reference. The femoral frame of reference is defined from the comparison between the calculated and the measured acceleration data. A sensor orientation interface provides orientation data for the femur from a tracking of the femoral frame of reference. A method for tracking a femoral frame of reference is also provided.

Abstract: A computer-assisted surgery system for obtaining a distance between at least two fixed points relative to a bone comprises a first accelerometer unit located at a first fixed location on the bone, and producing first acceleration data during a movement of the bone. A second accelerometer unit is located at a second fixed location on the bone, and simultaneously producing second acceleration data during the movement. A gyroscope unit is fixed to the bone and simultaneously producing angular rates of change of said movement. A processor unit obtains the acceleration data and the angular rates of change for calculating the distance between the first fixed position and the second fixed position on the bone using a distance value of a distance vector between the accelerometer units. An interface outputs the distance between the first fixed position and the second fixed position relative to the bone. A method for calculating a distance between at least two points on a bone is provided.

Abstract: A system for tracking a femoral frame of reference in computer-assisted surgery comprises a sensor unit. The sensor unit is adapted to be secured to the femur. The sensor unit comprises accelerometer and gyroscope sensors that produce orientation data. A processing unit receives gyroscope and accelerometer data. The processing unit comprises a gyroscope-data calculator to provide calculated acceleration data resulting from movements of the femur, an accelerometer-data calculator to calculate measured acceleration data resulting from movements of the femur, and an acceleration comparator to relate an orientation of the sensor unit to the femur to define a femoral frame of reference. The femoral frame of reference is defined from the comparison between the calculated and the measured acceleration data. A sensor orientation interface provides orientation data for the femur from a tracking of the femoral frame of reference. A method for tracking a femoral frame of reference is also provided.

Abstract: A system tracks an object in computer-assisted surgery. The system comprises a sensor unit secured to the femur. Gyroscopes on the sensor unit produce readings related to orientation data about three axes of rotation. A tracking unit receives the gyroscope readings. An axis calibrator on the tracking unit comprises a calculator for adding at least part of the gyroscope readings for specific movements of the object about a desired axis. An axis normalizer on the tracking unit determines an orientation of the desired axis with respect to the sensor unit from the added gyroscope readings. A tracking processor tracks the desired axis from the gyroscope readings. An interface displays orientation data for the object from a tracking of the desired axis. A method for tracking an object with a gyroscope sensor unit is also provided.

Abstract: A computer-assisted surgery system for guiding alterations to a bone, comprises a trackable member secured to the bone. The trackable member has a first inertial sensor unit producing orientation-based data. A positioning block is secured to the bone, and is adjustable once the positioning block is secured to the bone to be used to guide tools in altering the bone. The positioning block has a second inertial sensor unit producing orientation-based data. A processing system providing an orientation reference associating the bone to the trackable member comprises a signal interpreter for determining an orientation of the trackable member and of the positioning block. A parameter calculator calculates alteration parameters related to an actual orientation of the positioning block with respect to the bone.

Abstract: A method for determining a mechanical axis of a tibia using a tibial digitizer is disclosed. The method includes: determining an upper reference point on a tibial plateau corresponding to an entry point of the mechanical axis; fastening an upper mounting end of the tibial digitizer to the tibial plateau at the upper reference point; and fastening a lower mounting end of the tibial digitizer to medial and lateral malleoli of the ankle, by inwardly displacing opposed caliper arms of a self-centering malleoli engaging mechanism toward each other in a common plane until the caliper arms abut the malleoli. A lower reference point located at a midpoint between the medial and lateral malleoli is then determined by identifying a corresponding midpoint between the caliper arms when they are clamped onto the medial and lateral malleoli.

Abstract: A computer-assisted surgery system for guiding alterations to a bone, comprises a trackable member secured to the bone. The trackable member has a first inertial sensor unit producing orientation-based data. A positioning block is secured to the bone, and is adjustable once the positioning block is secured to the bone to be used to guide tools in altering the bone. The positioning block has a second inertial sensor unit producing orientation-based data. A processing system providing an orientation reference associating the bone to the trackable member comprises a signal interpreter for determining an orientation of the trackable member and of the positioning block. A parameter calculator calculates alteration parameters related to an actual orientation of the positioning block with respect to the bone.