Abstract: A single-layer valve is provided. The valve comprises a microfluidic pathway at least partially defined by a flexible membrane which is configured to deform when subjected to an actuation torque, and a discontinuity bounded by a first surface. The length of the discontinuity is constant across the full width of the first surface. The valve is configured such that the actuation torque on the membrane is larger in a first direction than a second direction substantially opposite to the first direction.

Abstract: A fluidic system is provided. The system comprises: a rigid housing (12), a plurality of flexible reagent containers (14) contained within the housing (12); wherein each reagent container (14) has a connection port (16) through which a reagent can flow, in use, on the application of pressure. The system further comprises a single pressure source (18) configured to apply pressure to the interior of the rigid housing (12); a microfluidic device configured to analyse one or more fluids provided from the plurality of reagent containers; and a plurality of channels (20) configured to transfer fluid from the plurality of reagent containers (14) to the microfluidic device. The ratio of resistances provided by a combination of the connection ports and the plurality of channels dictates the ratio of flow rates of the reagents. The claimed system allows for an accurate control of the various reagent flow rates while minimizing fluctuations in the relative flow rates.

Abstract: A single-layer valve is provided. The valve comprises a microfluidic pathway at least partially defined by a flexible membrane which is configured to deform when subjected to an actuation torque, and a discontinuity bounded by a first surface. The length of the discontinuity is constant across the full width of the first surface. The valve is configured such that the actuation torque on the membrane is larger in a first direction than a second direction substantially opposite to the first direction.

Abstract: A fluidic system is provided. The system comprises: a rigid housing (12), a plurality of flexible reagent containers (14) contained within the housing (12); wherein each reagent container (14) has a connection port (16) through which a reagent can flow, in use, on the application of pressure. The system further comprises a single pressure source (18) configured to apply pressure to the interior of the rigid housing (12); a microfluidic device configured to analyse one or more fluids provided from the plurality of reagent containers; and a plurality of channels (20) configured to transfer fluid from the plurality of reagent containers (14) to the microfluidic device. The ratio of resistances provided by a combination of the connection ports and the plurality of channels dictates the ratio of flow rates of the reagents. The claimed system allows for an accurate control of the various reagent flow rates while minimizing fluctuations in the relative flow rates.

Abstract: A femoral sizing instrument for use in a knee joint replacement procedure has a housing which includes formations by which it can be located relative to the femoral posterior condyles. A cortex arm has a tip for engaging the anterior cortex of the femur and a sulcus arm has a tip for engaging the sulcus. Each of the cortex and sulcus arms can be adjusted relative to the housing to adjust the distance between its tip and the posterior condyles measured generally parallel to the anterior posterior axis. The instrument includes at least one scale for indicating the positions of the tips of the cortex and sulcus arms relative to the posterior condyles.

Abstract: A cutting guide instrument for use in a cutting step in an orthopedic surgical procedure comprises a reference component comprising a first element which can be attached or otherwise aligned relative to the bone in a predetermined arrangement and a locator arm. The invention further comprises a cutting block comprising a reference surface which can be engaged by a cutting tool to define the location and orientation of the tool during the cutting step. The cutting block further comprises at least one fixation bore for receiving a fixation pin to fix the cutting block to the bone. The locator arm can be fitted against the reference surface so that the reference component and cutting block are arranged in a predetermined manner.

Abstract: Patient specific surgical instruments, and in particular cutting guides, and methods of use and manufacture are described. The surgical instrument can be used in an orthopaedic arthroplasty procedure to be carried out on a joint of a patient and can allowing soft tissue balancing for the joint. The instrument comprises a body having an attachment area configured using data specific to a bone of the joint of the patient so as to attach to the bone in a unique position. The instrument includes at least a first cutting guide and an adjustment mechanism operable to change the position of the cutting guide relative to the bone.

Abstract: A femoral sizing instrument for use in a knee joint replacement procedure has a housing which includes formations by which it can be located relative to the femoral posterior condyles. A cortex arm has a tip for engaging the anterior cortex of the femur and a sulcus arm has a tip for engaging the sulcus. Each of the cortex and sulcus arms can be adjusted relative to the housing to adjust the distance between its tip and the posterior condyles measured generally parallel to the anterior posterior axis. The instrument includes at least one scale for indicating the positions of the tips of the cortex and sulcus arms relative to the posterior condyles.

Abstract: A femoral sizing instrument for use in a knee joint replacement procedure has a housing which includes formations (4) by which it can be located relative to the femoral posterior condyles. A cortex arm (14) has a tip (16) for engaging the anterior cortex of the femur and a sulcus arm (20) has a tip (24) for engaging the sulcus. Each of the cortex and sulcus arms can be adjusted relative to the housing to adjust the distance between its tip and the posterior condyles measured generally parallel to the anterior posterior axis. The instrument includes at least one scale (13,23,27,25) for indicating the positions of the tips of the cortex and sulcus arms relative to the posterior condyles.

Abstract: An instrument for use in determining an anterior-posterior dimension of a femur during a minimally invasive surgical procedure includes a body having a base and a member extending upwardly from the base, said member providing a first part of a sliding mechanism. A stylus includes a stylus support providing a second part of a sliding mechanism which can engage with the member to allow relative sliding movement between the stylus and base, and a stylus member mounted on the stylus support. An implant size indicator interacts with the sliding mechanism to be moved relative to a scale by the member to indicate a size of an implant corresponding to the relative positions of the body and stylus.

Abstract: An orthopaedic surgical instrument system that includes an orthopaedic surgical instrument adapted to be positioned on a proximal end of a patient's tibia, and a tibial bearing trial assembly configured to be coupled to the orthopaedic surgical instrument. The tibial bearing trial assembly includes a plurality of tibial bearing surface trial components and at least one shim.

Abstract: A femoral sizing instrument for use in a knee joint replacement procedure has a housing which includes formations (4) by which it can be located relative to the femoral posterior condyles. A cortex arm (14) has a tip (16) for engaging the anterior cortex of the femur and a sulcus arm (20) has a tip (24) for engaging the sulcus. Each of the cortex and sulcus arms can be adjusted relative to the housing to adjust the distance between its tip and the posterior condyles measured generally parallel to the anterior posterior axis. The instrument includes at least one scale (13,23,27,25) for indicating the positions of the tips of the cortex and sulcus arms relative to the posterior condyles.

Abstract: Patient specific surgical instruments, and in particular cutting guides, and methods of use and manufacture are described. The surgical instrument can be used in an orthopaedic arthroplasty procedure to be carried out on a joint of a patient and can allowing soft tissue balancing for the joint. The instrument comprises a body having an attachment area configured using data specific to a bone of the joint of the patient so as to attach to the bone in a unique position. The instrument includes at least a first cutting guide and an adjustment mechanism operable to change the position of the cutting guide relative to the bone.

Abstract: A cutting guide instrument for use in a cutting step in an orthopedic surgical procedure comprises a reference component comprising a first element which can be attached or otherwise aligned relative to the bone in a predetermined arrangement and a locator arm. The invention further comprises a cutting block comprising a reference surface which can be engaged by a cutting tool to define the location and orientation of the tool during the cutting step. The cutting block further comprises at least one fixation bore for receiving a fixation pin to fix the cutting block to the bone. The locator arm can be fitted against the reference surface so that the reference component and cutting block are arranged in a predetermined manner.

Abstract: An instrument for use in determining an anterior-posterior dimension of a femur during a minimally invasive surgical procedure includes a body having a base and a member extending upwardly from the base, said member providing a first part of a sliding mechanism. A stylus includes a stylus support providing a second part of a sliding mechanism which can engage with the member to allow relative sliding movement between the stylus and base, and a stylus member mounted on the stylus support. An implant size indicator interacts with the sliding mechanism to be moved relative to a scale by the member to indicate a size of an implant corresponding to the relative positions of the body and stylus.

Abstract: A cutting tool for preparing a cavity in a bone for receiving a component of an orthopaedic joint prosthesis. The shape of the tool is based on a shell having a rotationally symmetrical outer surface. The tool has at least one portion cut out from it, the cut out portion extending from the peripheral edge of the shell toward the pole of the shell, such that the tool has no more than one plane of symmetry passing through the axis of rotation. The external surface of the shell presents at least two outwardly directed cutting teeth, arranged such that the net translational force on the tool in the plane which is perpendicular to the axis of rotation, resulting from the accumulated resistance of the teeth when rotated against a rotationally symmetrical cavity in which the tool is a snug fit, is approximately balanced.