Patent ID: 12232966

DETAILED DESCRIPTION OF THE INVENTION

Design Method

The present invention is directed to a system, comprising a method, apparatus and computer programs, for designing a guide tool12comprising a positioning mark500, and/or medical implant comprising a positioning mark500, and/or associated tools comprising positioning marks and wherein said guide tool12insert tool502and implant10all comprises a positioning mark500marking out the same direction or axis in relation to the joint during use when replacing damaged cartilage in a joint. The associated set of tools is devised for the placement of an implant that replaces damaged cartilage in a joint and is adapted to the specific implant as well as a specific joint for which the implant is intended. The surgical kit provided by the present invention has the effect that successful implant insertion is less dependent on surgical circumstances and the skills of the surgeon compared to previously known implants. Due to the design and the function of using the positioning marking in guide tool and/or implant and/or inert tools gives improved implantation precision and a precise desired placement of the implant in the joint every time. The precision of the surgery is “built in” into the design of the tools.

FIG.1shows an example of a surgical kit designed according to a method of one embodiment of the present invention. This particular exemplifying embodiment of a surgical kit according to the invention is especially adapted for cartilage replacement at the femur of a knee joint. The invention may however be applied for cartilage replacement in an articulating surface in any other joint in the body, e.g. elbow, ankle, finger, hip, toe and shoulder. The guide tool12according to the invention may be equipped with a guide-channel13and a positioning body11and may be used together with an implant10, and a drill guide8, a cutting tool6, which in this exemplifying embodiment is a punch, a drill-bit8, preferably equipped with a depth gauge1and/or a reamer-bit4, preferably equipped with a depth gauge3, and/or a hammer tool35and/or a reamer guide28, and/or implant dummy36. The details of examples of insert tools502which may be used inside the guide tool12are further described and exemplified below.

FIG.1schematically illustrates the design process according to an embodiment of the inventive concept for designing a guide tool and/or insert tools502and/or implant10.

The design system comprises the basic blocks of:

I. Determining physical parameters for a cartilage damage in a joint and then using this information in order to;

II. Generate design parameters of a medical implant10.

III. Generate design parameters of a guide tool12for use during implantation of said implant.

The physical parameters as well as the design parameters are represented as digital data that is processed or generated by specifically designed computer program code portions executed in a data processing system. The system may be fully automated or may comprise portions of computer supported manual steps of for example selections. The design parameters resulting from the process are stored in a format suitable for use as input in an automated manufacturing process.

IV. Determine a positioning mark placement which placement helps the surgeon to determine the orientation of the placement of the guide tool in a joint and wherein the positioning mark500for example may be chosen to be placed in a position on the guide tool which indicate an orientation selected from a position or direction on the patient which is known for the surgeon and based on the anatomy of a patient selected, for example selected from anterior or posterior, right lateral or left lateral, dorsal or ventral, proximal or distal orientation or axis direction.

and wherein blocks II-IV above can be performed in any order.

In one embodiment according to the invention the design system is a system to design a guide tool12to be used to guide inserts tools and/or an implant or other cartilage repair objects comprises the basic blocks of:

I. Determining physical parameters for a cartilage damage in a joint and then using this information in order to;

II. Generate design parameters of a medical implant10.

III. Generate design parameters of a guide tool12for use during implantation of said implant. The physical parameters as well as the design parameters are represented as digital data that is processed or generated by specifically designed computer program code portions executed in a data processing system. The system may be fully automated or may comprise portions of computer supported manual steps of for example selections. The design parameters resulting from the process are stored in a format suitable for use as input in an automated manufacturing process.

IV. Determine placement for placement of a positioning mark500on the guide tool wherein the positioning mark500is designed to be aligned with the center503of said guide channel54in a determined joint axis501direction and thereby indicating a placement direction of the guide tool12in relation to the selected joint axis501during use of the guide tool12. The direction is also indicated by placement of the positioning mark500of the guide tool12on a side of the guide channel which faces the chosen direction in relation to the joint.

The placement of the positioning mark on a guide tool, may be on top of the guide channel54or on top of the positioning body11on the side of the guide channel or at any place visible for the surgeon using the guide tool.

and wherein blocks II-IV above can be performed in any order.

In one embodiment according to the invention, the insert tools502and or the implant10is also designed to comprise a position mark500, and the position of the position mark is designed to be on a surface which is visible for the surgeon during surgery and use of the insert tools502and or implant10. Example of such surfaces are on the top of the insert tools, on a surface facing the surgeon during use of the insert tools, for example on a surface opposite to the surface facing the cartilage damage. The positioning marking500of an implant10may for example be on the articulating surface15of the implant, preferably not placed in the center but parted from the center of the implant or on a surface which is visible for the surgeon, or for example on a top surface of an insert tool pointing in the opposite direction compared to the cartilage contact surface50of the positioning body11.

According to certain aspects, the technology disclosed provides a design method that allows for producing an implant which is easy to fit to an individual damage and an individual patient. The design build-up method comprises choosing size, at least two circular shapes, implant thickness, implant surface shape, articular surface etc. for each implant. This build-up makes the proposed solution and implant unique and easy to individualize, but still suitable for large scale industrial manufacturing. The design process further comprises designing the implant to have at least one positioning mark on the surface of one of the circular shapes, where the positioning mark is adapted to be used for pointing out a direction for placement of the implant in a recess. The circular shapes building up the implant makes the implant easy to place by drilling and/or reaming, thereby providing for a fit of each implant in every patient.

According to certain aspects of the technology disclosed, the positioning or location of the at least one positioning mark on the surface of the implant may be determined based on one or more of images taken of the damaged cartilage surface of a joint. A technical effect of introducing at least one positioning mark on the implant is that the contour curvature of an articulating surface15of the implant body, which is built up from the at least two circular shapes, may be to enable or facilitate orientating and positioning of the implant (e.g. by the surgeon or a robot) so that the implant is aligned to the cartilage surface surrounding the recess in a correct way. Furthermore, by introducing at least one positioning mark on the implant, the contour curvature of an articulating surface15of the implant body may be (rotationally) oriented/positioned in a recess to correspond to a simulated healthy cartilage reconstructed from one or more of the images taken of the damaged cartilage surface of the joint.

Embodiments herein relate to design methods for design of an implant having at least one positioning mark where the design of the implant is based on a 3D virtual model of an implant. The design method may then comprises identifying a damage area, presenting a virtual 3D view of the identified damage area and creating a 3D virtual implant comprising virtually placing in the 3D view a shape. The area of the shape then covers or partly covers the identified damage area, producing an implant based on the created 3D virtual implant. The shape comprises at least two substantially circular shapes, where the surface of at least one of the at least two substantially circular shape is designed to be provided with at least one positioning mark. Each circular shape may partly overlap at least one other circular shape, and the area of the circular shapes may cover or partly cover the identified damage area.

The method for designing the implant by building up the implant from at least two circular shapes may further comprise placing at least two points, each from where an axis will origin from on the bone surface of the joint in or nearby the damage area or on a simulated bone surface which is a virtually created surface covering the damage area. In embodiments, each circular shape may comprise a respective axis, and the overlap of the circular shapes may depend on the selection of diameter for the respective circular shape in combination with the selection of distance between an axis of one circular shape and another axis of another circular shape.

In certain embodiments, the selections of diameter for respective circular shape and distance between axes may be combined with the selection of a desired coverage for the implant of the damage area. In some embodiments, the identifying of a damage area in a patient may be performed by taking CT, CBCT, MRI images or the like of a joint of a patient and using the images to create a 3D view of the bone and/or cartilage area using for example a software program useful for virtual 3D animation. In embodiments, the design step of using CT, CBCT, MRI images of a joint to create the 3D view may include determining the position or location on the surface of the implant for at least one positioning mark. The position for the at least one positioning mark on the surface may then be determined from the CT, CBCT, MRI images of the joint of a patient, thereby being designed for providing for a correct rotational positioning/orientation of the implant in a recess made in the joint.

In certain embodiments, the positioning mark provided on the surface of at least one of the plurality of circular shapes of the implant is adapted to be used for alignment of the positioning mark of the implant to a certain anatomic dependent direction associated with the joint in which the implant is to be inserted. The introduction of a positioning mark on the surface of one circular shape may be particularly beneficial when a plurality of placement options for inserting the implant in a recess exist, e.g. when the implant to be inserted is built-up with a plurality of substantially circular shapes having essentially the same diameter.

By using the design method according to different embodiments herein, a surgeon, or a robot, is provided with a precise way to correctly place and rotationally position an implant in a recess made in the joint. According to embodiments of the design methods and system of the technology disclosed, implant shapes may be built individually depending on cartilage damage and location of damage in the joint. This provides for a selection from different sizes of circular shapes, or substantially circular shapes, which are partly overlapping each other and which may or may not be individually selected for one patient, allowing for the surgeon to choose an implant which fits the size and shape of the specific bone and or cartilage damage or defect, and further gives the surgeon an easy to use design method and tool set for making the excisions needed.

In a certain embodiment, at least one positioning mark provided on an implant which is designed to be built-up from and comprise one substantially circular shape or a plurality of overlapping substantially circular shapes may provide guidance to a surgeon, or a robot having a vision system. The vision system may then be adapted and configured for detecting the at least one of the positioning mark on the surface of the implant in relation to a mark made on side of a recess, where the mark made on side of the recess may be made in a pre-determined anatomic dependent direction or in a direction/position determined from the process for designing the implant. The direction/position of the positioning mark may then be determined from at least one image taken of the damaged joint. Following detection by the vision system of the at least one of the positioning mark on the implant and the mark made on side of the recess, the implant may be correctly inserted/oriented in the recess by directing the positioning mark, e.g. provided on the surface of one of the implant's circular shapes, in at least one of the direction of a mark previously made on side of the recess (which position may be determined in the design process) and in a pre-determined anatomic dependent direction. Here, by correctly inserted/oriented, it is meant that the contour curvature of an articulating surface15of the implant, which may be designed based on a 3D virtual implant created using one or more CT, CBCT, MRI images or the like of a joint of a patient, corresponds to a simulated healthy cartilage reconstructed from one or more of the images taken of the damaged cartilage surface of the joint and that the contour curvature of the articulating surface15of the implant may further be aligned to the cartilage surface surrounding the recess.

In a certain embodiment of a surgical method using the technology disclosed, no mark is made on side of the recess but the detection of the positioning mark on the surface of at least one of the circular shapes, which may be detected by e.g. a vision system associated with a robot or in computer-assisted surgery, is used for pointing the positioning mark in a pre-determined anatomic dependent direction so that the implant is correctly placed in the recess. This may provide the same effect as mentioned above in that the implant, which is designed based on a 3D virtual implant created using one or more CT, CBCT, MRI images or the like of a joint of a patient, may be correctly inserted/oriented in the recess in that the contour curvature for the articulating surface15of the implant corresponds to a simulated healthy cartilage reconstructed from one or more of the images taken of the damaged cartilage surface of the joint and in that the contour curvature for the articulating surface15of the implant may further be aligned to the cartilage surface surrounding the recess.

In certain embodiments, a guide tool may further be used in the surgical method of inserting an implant in the recess and the positioning mark provided on the implant may then be pointing out a direction for placement of the implant in a recess in relation to a joint axis with the guide tool, or an anatomic dependent direction, and may point out the same direction as a positioning mark on the guide tool used for placing the implant.

In embodiments, the contour curvature for an articulating surface15of the implant body of the implant is built-up with at least two substantially circular shapes and is dependent on a determined surface curvature of the cartilage and/or the subchondral bone. At least one of the articulating surface15and the cartilage contacting surface19of at least one of the circular shapes is then provided with a positioning mark which is parted from the center of the implant to thereby be designed to be pointing out a pre-determined anatomic dependent direction and/or which is designed to be pointing in the direction of a mark made on side of the recess, where the mark made on the recess is indicating the direction in which the implant is to be placed. The articulating surface of the implant may then have a curvature that corresponds to a simulated healthy cartilage reconstructed from an image taken e.g. with MRI or CT-scanning of the damaged cartilage surface of the joint.

In certain embodiments, the positioning mark is placed on either the articulating surface15or the cartilage contacting surface19of one of the plurality of circular shapes of the implant and is adapted to be used for alignment of the positioning mark of the implant, i.e. aligning the implant, to a mark made on side of the recess, where the mark made on the recess is indicating the direction in which the positioning mark on the surface of one of the plurality of circular shapes is to be directed to rotationally position the implant correctly in the recess.

According to certain aspects, the technology disclosed describes a design method for designing of an individually customized implant, where a second virtual model making step comprises making a 3D model of a virtual implant including a step of virtually placing in the 3D view at least two circular shapes, where each of the at least two circular shapes is partly overlapping at least one other circular shape.

According to other aspects, the technology disclosed describes a design method for design of an individually customized implant provided with a positioning mark and comprising at least two substantially circular shapes, where each circular shape comprises an axis and where an overlap of the circular shapes depends on selection of diameter of the substantially circular shapes in combination of selection of closeness of an axis of one circular shape in relation to another axis of another circular shape in combination with selection of desired coverage for the implant of the bone and/or cartilage damage.

In an automated process, a computer program, for example a radiography software program, could be adapted to scan the images for predetermined characteristics of an area and or spread, curvature and or a location of bone and/or cartilage damage in the image data. The automatically marked 2D images may then be combined into a 3D view which may be called the damage representation CAD animation model. The size of the area which is of interest to map or to create a 3D view of is usually not depending of the size of the cartilage damage and the type of joint or bone part which is to be repaired, usually the surgeon does not know where in the joint the damage is located before taking images of the patients joint, therefore typically, images of the whole bone and or cartilage area of the joint are used to create a virtual 3D view. A virtual 3D view is a joint representation CAD animation model which may be selected to show the bone and or cartilage area, the bone and or cartilage damage, placement of virtual implants etc.

In certain embodiments, a first damage identification step of the design method according to embodiments herein comprises identifying a bone and/or cartilage area in a patient by taking images of the injury or damage in the joint of a patient and then use these images of the individual patient's bone and/or cartilage area to create a joint representation CAD animation model. In embodiments, the technology disclosed relates to a method for designing an implant comprising designing the implant so that the contour curvature of an articulating surface15of the implant is designed to correspond to a simulated healthy articulating surface of a damaged articulating surface of a joint. The method for designing the implant may then comprise placing, in a virtual 3D view, at least two substantially circular shapes such that each of the circular shapes is partly overlapping at least one other circular shape in that the combined area of the circular shapes is designed to cover, or partly cover, a damaged area. The method for designing the implant by creating a virtual 3D view may further include determining a position for an implant positioning mark and/or the actual design of the positioning mark in the same design process steps that include placing the at least two substantially circular shapes in the virtual 3D view.

Hence, the method for designing the implant may further include designing the implant by providing at least one positioning mark on at least one of the at least two substantially circular shapes in the virtual 3D view such that the at least one positioning mark is designed to be used for determining the rotational orientation in which the implant is to be placed in a recess made in a damaged articulating surface of a joint. In embodiments, the design method may further includes providing the at least one of the at least one positioning mark on the articulating surface15, i.e. the top articulating surface15, of one of the at least two substantially circular shapes and/or providing the at least one positioning mark on the cartilage contacting surface19, i.e. the side edge surface, of one of the at least two substantially circular shapes of the implant. The positioning mark on the articulating surface15is then parted from the center of the implant to be adapted for rotationally positioning the implant. In embodiments, the positioning mark on the articulating surface15may preferably be placed on the surface peripheral of the articulating surface15.

The design method may further include designing the contour curvature of the implant so that the articulating surface15of the implant and the at least one positioning mark correspond to a simulated healthy articulating surface reconstructed from a 3D model based on one or more images taken with MRI or CT-scanning of a damaged articular surface of a joint. In certain embodiment, the design method may then include designing the implant by providing the at least one positioning mark on only one of the at least two substantially circular shapes in the virtual 3D view for the implant so that the at least one positioning mark is designed to be pointing in an anatomic dependent direction or a mark to be made on side of a recess in which the implant is to be inserted, thereby providing for a correct rotational orientation of the implant when inserted in the recess made in a damaged articulating surface of the joint.

In other embodiments, the design method may include designing the at least one positioning mark of the implant so that the direction of the positioning mark on the contour curvature of the articulating surface15of one circular shape of the plurality of circular shapes of the implant is determining the rotational placement orientation of the implant in a recess in that the placement direction of the at least one positioning mark is also to be indicated by a mark made on the side of a recess made in the articulating surface of a joint. The positioning mark on the articulating surface15of one circular shape of the plurality of circular shapes is then parted from the center of the implant to be adapted for rotationally positioning the implant. In embodiments, the positioning mark on the articulating surface15of one circular shape of the plurality of circular shapes may preferably be placed on the surface peripheral of the articulating surface15.

In embodiments, the technology disclosed relates to a method for inserting an implant in a joint comprising providing an implant having at least one positioning mark, wherein the at least one positioning mark is positionally adapted on the surface of the implant to be visible for detection by a vision system. The method for inserting an implant may then further include detecting, by the vision system, the at least one positioning mark in relation to at least one of at least one mark made on the side of a recess in the articulating surface of the joint and at least one pre-determined anatomic dependent direction. The insertion of the implant in the recess may be performed by directing the at least one implant positioning mark in a direction dependent on the direction of at least one of at least one mark made on the side of a recess made in the articulating surface of the joint and at least one pre-determined anatomic dependent direction. The insertion may then be aided by the detecting by the vision system.

In embodiments, the inserting of the implant in the recess may be performed by directing the at least one implant positioning mark in the direction of at least one of at least one mark made on the side of the recess on the articulating surface. In embodiments, the method for inserting an implant in a joint may then include detecting, by a vision system, both the mark made on the side of the recess and at least one implant positioning mark on the articulating surface15, i.e. the top articulating surface15, of one substantially circular shape among at least two partly overlapping substantially circular shapes of the implant. The positioning mark on the articulating surface15of one circular shape of the plurality of circular shapes is then parted from the center of the implant to be adapted for rotationally positioning the implant. In embodiments, the positioning mark on the articulating surface15of one circular shape of the plurality of circular shapes may preferably be placed on the surface peripheral of the articulating surface15. In other embodiments, the method for inserting an implant in a joint may include detecting, by a vision system, both the mark made on the side of the recess and at least one implant positioning mark on the cartilage contacting surface19, i.e. the side edge surface19, of the implant.

Robotic surgery, computer-assisted surgery, and robotically-assisted surgery are terms for technological developments that use robotic systems to aid in surgical procedures. Robotically-assisted surgery was developed to overcome the limitations of pre-existing minimally-invasive surgical procedures and to enhance the capabilities of surgeons performing open surgery.

In the case of robotically-assisted minimally-invasive surgery, instead of directly moving the instruments, the surgeon may use one of two methods to control the instruments, either a direct telemanipulator or through computer control. A telemanipulator is a remote manipulator that allows the surgeon to perform the normal movements associated with the surgery whilst the robotic arms carry out those movements using end effectors and manipulators to perform the actual surgery on the patient. In computer-controlled systems, the surgeon uses a computer to control the robotic arms and its end-effectors, though these systems can also still use telemanipulators for their input. One advantage of using the computerised method is that the surgeon does not have to be present, but can be anywhere in the world, leading to the possibility for remote surgery. In the case of enhanced open surgery, autonomous instruments may replace traditional steel tools, performing certain actions with much smoother, feedback-controlled motions than could be achieved by a human hand. The main object of such smart instruments is to reduce or eliminate the tissue trauma traditionally associated with open surgery without requiring more than a few minutes' training on the part of surgeons. This approach seeks to improve open surgeries that have so far not benefited from minimally-invasive techniques.

In embodiments of the technology disclosed, a computer-assisted surgical system may be used for inserting the implant in a recess. Different types of computer-assisted surgical systems can be used for pre-operative planning, surgical navigation and to assist in performing surgical procedures.

Robotically-assisted surgical (RAS) devices are one type of computer-assisted surgical system. Sometimes referred to as robotic surgery, RAS devices enable the surgeon to use computer and software technology to control and move surgical instruments through one or more tiny incisions in the patient's body (minimally invasive) for a variety of surgical procedures. The benefits of a RAS device may include its ability to facilitate minimally invasive surgery and assist with complex tasks in confined areas of the body. The device is not actually a robot because it cannot perform surgery without direct human control.

RAS devices generally have several components, which may include at least one of the following components:1) a console, where the surgeon sits during surgery. The console is the control center of the device and allows the surgeon to view the surgical field, e.g. through a 3D endoscope, and control movement of the surgical instruments;2) a bedside cart that may include at least one mechanical arm, at least one camera and surgical instruments that the surgeon may or may not control during surgical procedures; and3) a separate cart that may contain supporting hardware and software components, such as an electrosurgical unit (ESU), suction/irrigation pumps, and light source for the camera.

Most surgeons use multiple surgical instruments and accessories with the RAS device, such as scalpels, forceps, graspers, dissectors, cautery, scissors, retractors and suction irrigators.

In these days, there are a lot of medical devices in operation room. In addition, several surgical master-slave robots have been commercialized, and are becoming common.

In embodiments of the technology disclosed, a surgical robot comprising control software may be used for inserting the implant in a recess. By introducing surgical robots, it is possible to perform more precise insertion of the implant in the recess. In certain embodiments, the surgeon may uses one of two methods to control the instruments, either a direct telemanipulator or through computer control, and to insert the implant in the recess.

Typically, the control software has hardware dependencies based on actuators, sensors and various kinds of internal devices.

The method for inserting an implant in a recess according to the present invention may include inserting the implant in the recess by use of at least one mechanical arm, e.g. a robot arm, such that the software-controlled movement of the at least one mechanical arm is aided by the detecting of at least one implant positioning mark in relation to at least one of at least one mark made on side of the recess and at least one pre-determined anatomic dependent direction. The method for inserting an implant may then further include detecting, by a vision system, the at least one positioning mark in relation to at least one of at least one mark made on the side of a recess made in the articulating surface of the joint and at least one pre-determined anatomic dependent direction. The insertion of the implant in the recess may be performed by directing the at least one implant positioning mark in a direction dependent on the direction of at least one of at least one mark made on the side of a recess made in the articulating surface of the joint and at least one pre-determined anatomic dependent direction. The insertion is then aided by the detecting by the vision system.

In embodiments, the inserting of the implant in the recess may be performed by directing the at least one implant positioning mark in the direction of at least one of at least one mark made on the side of the recess on the articulating surface. The method for inserting an implant in a joint may then include detecting, by a vision system, an implant positioning mark on the articulating surface15, i.e. the top surface15, of one substantially circular shape among at least two partly overlapping substantially circular shapes of the implant. In other embodiments, the method for inserting an implant in a joint may include detecting, by a vision system, an implant positioning mark on the cartilage contacting surface19, i.e. the side edge surface19, of the implant. The positioning mark on the articulating surface15of at least one circular shape of the plurality of circular shapes is then parted from the center of the implant to be adapted for rotationally positioning the implant. In embodiments, the positioning mark on the articulating surface15of at least one circular shape of the plurality of circular shapes may preferably be placed on the surface peripheral of the articulating surface15.

In certain embodiments, the inserting of the implant in the recess is performed by use of at least one mechanical arm, e.g. a robot arm, such that the inserting of the implant by the at least one mechanical arm is aided by the detecting by the vision/sensor system in that at least one sensor and/or camera is producing at least one of sensor data, still images and video images indicating the relative positioning of at least one of the at least one implant positioning mark in relation to at least one of at least one mark made on side of the recess and at least one pre-determined anatomic dependent direction.

In yet another embodiment, the method for inserting an implant further includes providing a guide tool comprising a positioning feature/mark and making, by one of a surgeon and a mechanical arm such as a robot arm, a mark on the side of a recess made in an articulating surface of the joint in the direction of the positioning mark of the guide tool, thereby determining the future placement orientation of the implant.

In embodiments, the technology disclosed relates to a surgical method and a storage unit for storing the implant prior to inserting the implant in a human joint comprising providing an implant having at least one positioning mark, where the at least one positioning mark may be positioned or located on the surface of the implant to be visible for detection. The method for inserting the implant may further involve a storage unit, e.g. a box, for storing an implant prior to inserting the implant in a recess of a human joint where the storage unit comprises at least one reference feature such as a positioning mark. The storage unit may comprise a mechanical recess structure and/or holding means adapted for fixing or holding the implant in a rotationally fixed position in the storage unit and the at least one reference feature of the storage, e.g. a corner/edge of the storage unit or a positioning mark on the surface of the storage unit, is adapted and/or designed to be used to determine the rotational orientation of the implant when placed in the storage unit.

The method for inserting the implant may further include detecting the at least one positioning mark in relation to the at least one reference feature and placing the implant in the storage unit by directing the at least one implant positioning mark on the surface of the implant in a specific, e.g. pre-determined, rotational direction in relation to the at least one reference feature of the storage unit. The method for inserting the implant in a human joint may further include removing the implant from the storage unit in that the implant is rotationally oriented in accordance with the specific rotational direction of the at least one implant positioning mark in relation to the at least one reference feature of the storage unit. This provides the effect that the implant is removed from the storage unit and inserted in a recess made in a human joint in a correct or more accurate rotational placement orientation. The correct, or more accurate, rotational placement orientation may then be determined by how the implant is rotationally positioned in the storage unit in relation to the at least one reference feature of the storage unit.

In embodiments, the detection of the at least one implant positioning mark in relation to the at least one reference feature when placing the implant in the storage unit is performed by a vision and/or sensor system comprising at least one camera and/or sensor. The vision and/or sensor system may thereby be used for facilitating the correct placement of the implant in the storage unit.

In embodiments, at least one of the steps of gripping the implant in the storage unit, removing the implant from the storage unit and the inserting the implant in the human joint (in a correct placement orientation) may be performed by the use of at least one mechanical arm, e.g. a robot arm. The step of inserting the implant in the correct placement orientation in the recess of the joint may then be determined by how the implant is rotationally positioned/oriented in the storage unit in that the software-controlled movement of the mechanical arm from the storage unit to the recess is pre-programmed based on the rotational positioning/orientation of the implant in the storage unit.

In embodiments, the technology disclosed relates to a storage unit for storing an implant prior to inserting the implant in a human such as a human joint. The storage unit may then be provided with at least one reference feature, such as a positioning mark, which is adapted to be used for providing a correct or more accurate rotational orientation of the implant when placing the implant in the storage unit.

The implant may then be placed in the storage unit by directing at least one implant positioning mark on the surface of the implant in a specific, e.g. pre-determined, rotational direction in relation to at least one reference feature of the storage unit. In certain embodiments, the implant is placed in the storage unit by directing at least one implant positioning mark in the direction of a reference feature, e.g. a corner, edge or holding means of the storage unit, e.g. a box, or a positioning mark provided on the surface of the storage unit.

The storage unit may further be adapted to allow for gripping of the implant in the storage unit so that the implant is rotationally oriented in accordance with a specific rotational direction of the at least one implant positioning mark in relation to the at least one reference feature or holding means of the storage unit. The design and location of the at least one implant positioning mark on the surface of the implant may then be dependent on the design and location of the at least one reference feature of the storage unit.

In embodiments, the storage unit may be configured so that at least one of the steps of gripping the implant in the storage unit, removing the implant from the storage unit and inserting the implant in the human joint may be performed by use of at least one mechanical arm, e.g. a robot arm. The software-controlled movement of the mechanical arm from the storage unit to the recess may then be pre-programmed based on the rotational positioning/orientation of the implant in the storage unit and the rotational placement orientation of the implant in a recess of a human joint may then be determined by how the implant is rotationally positioned in the storage unit in relation to the at least one reference feature of the storage unit.

In another embodiment, the present invention relates to an individually design of surgical kit and/or a guide tool12comprising position marks and to a design method for design of such a kit.

In one embodiment, the placement of the position mark is determined by first determine the size, spread and placement of the cartilage contact surface in a computer model and then use this model of a cartilage contact surface and determine a direction, based on the virtual placement of the model cartilage contact surface on the simulated joint (or on an image of an individual 3D image of a joint surface). And after deciding the direction, place a virtual position mark on that place, which may be a place pointing in any direction in comparison to the placement of the guide tool in the joint, for example pointing in an anterior direction etc. The position mark is designed to be placed on a surface of the positioning body of the guide tool12which is a surface pointing in an opposite direction compared to the cartilage contact surface of the positioning body. The said placement of the positioning mark500is also determined in relation to the design of the guide channel54and its placement on the cartilage contact surface50of the guide tool12.

This placement of said position mark on the guide tool12may then be used by the surgeon in order to place the individually designed guide tool in the right placement during surgery by knowing in which direction the positioning mark500is designed to point.

For example, if a guide tool12is designed to point in an anterior direction during knee surgery, and the guide tool12then has a positioning mark500, placed for example on a side or on top of the guide channel or on a top surface52of the positioning body12. Then the surgeon knows that the positioning mark500should point in an anterior direction if he placed the guide tool in a correct direction, see for an example inFIG.2for a placement of an implant comprising a positioning mark500in an anterior direction in relation to the knee joint.

A further effect of the invention is that the size of the cartilage contact surface can be designed to be smaller in area spread because the surgeon now know due to the positioning mark if the guide is placed in the correct position from start and does not need a large cartilage contact surface of the guide tool to “feel” when the guide is placed correctly.

In other embodiment, the design of the insert tools are also designed to comprise a position marking and the position marking of the insert tools is designed to coincide with the positioning mark of the guide tool12when the insert tools are placed within the guide tool in their first positions or their starting position. This alignment gives instruction to the surgeon about rotational start direction when using the insert tools502.

This is exemplified inFIG.6wherein a height adjustment device is used as an insert tool502and inFIG.6, the insert tool is placed in a starting position where both the positioning mark500of the insert tool is aligned with the positioning mark500of the guide tool12.

See for exampleFIG.2for further examples of the invention where the implanted implant has a position mark pointing in an anterior direction compared to the joint and limb. The positioning mark500on the guide tool12used during placement of this implant also pointed in the same direction, se for example inFIG.5.

FIG.4-10shows use of the guide tool of the invention together with different insert tools,FIG.4ashows the guide tool without insert tools.FIG.4bshows use of a drill guide8inside the guide channel54of the guide tool12.

FIG.5shows the guide tool12together with a height adjustment device16inside the guide channel. A height adjustment device16according to the invention comprises a male part47and a female receiving part48which when used together allows for stepwise adjustment of drill depth.

In one embodiment the present invention comprises a design method for design of a surgical kit where one part is related to the design of a guide tool according to the present invention described herein and one part is directed to the design of insert tools502comprising positioning marks500which is aligned with the positioning marks of the designed guide tool when inserted in the guide tool12in a start position which indicating the correct rotational start position of the insert tools to the surgeon during use of the guide tool and insert tools during surgery.

FIG.11shows a medical implant comprising a positioning mark according to the invention and wherein the direction of the positioning mark of the implant also is indicated on the cartilage surface due to previous guidance using the guide tool according to the invention during surgery.

The present invention concerns a guide tool12which is designed to comprising a cartilage contact surface52which is individually designed to correlate to a surface and curvature in the joint. Due to this the guide tool12according to the invention may be correctly placed in the joint in one predetermined direction. The direction is determined during the design of the guide tool12.

This predetermined direction may now be easier to visually see for the surgeon when he receives a guide tool according to the invention, designed to have a predetermined positioning mark, indicating a predetermined position instructing the surgeon about how he should place the guide tool12on the cartilage surface in the joint.

I. Determining Physical Parameters for a Cartilage Damage in a Joint.

An image or a plurality of images representing a three dimensional image of a bone member of the joint in a patient's limb may be obtained by a selected one of a per se known imaging technology for non-invasive imaging of joints, such as magnetic resonance imaging (MRI), computerized tomography (CT) imaging or a combination of both, or other suitable techniques such as delayed Gadolinium-enhanced MRI of cartilage (dGEMRIC) techniques. The image of the joint should comprise a representation of cartilage in the joint as well as the underlying subchondral bone in the area of the cartilage damage. Image data making up a three dimensional image representation of the joint is stored in a digital format in a manner that enables to keep track of the dimensions of the real joint that the image depicts.

The image data is analyzed in a data processing system to identify and determine physical parameters for the cartilage damage. The physical parameters to determine comprise the presence, the location and the size and shape of the cartilage damage, as well as curvature of the surface contour of the cartilage or the subchondral bone in an area of the cartilage damage.

In one embodiment of the inventive concept the design system operates to determine physical parameters on images of the patient's individual joint and the current cartilage damage, and thereby produces an individually designed guide tool12. In another embodiment the design system operates on a collection of images of joints constituting a statistical basis for determining physical parameters for producing a guide tool12adapted for a selected location and a selected size of cartilage damage in a joint of a selected size.

The following steps, not limiting the design method according to the invention are in one exemplifying embodiment comprised in determining the physical parameters of cartilage damage:a. Obtaining image data representing a three dimensional image of a bone member of the joint. By way of example, a sample of a set of several images which together represents a three dimensional image of a joint.b. Identifying in the image data cartilage damage in an articulating surface of the bone member. In an automated process a computer program may be adapted to scan the image data for predetermined characteristics of a spot of cartilage damage in the image data. In a process with a manual part in this step an operator would visually scan a displayed image of the joint and identify a spot that has the visual characteristics of cartilage damage.c. Determining based on the image data the location of the cartilage damage.A set of data that represents a position of the cartilage damage in the joint is selected automatically or manually. The position data is for example stored as a set of defined coordinates in the image data.d. Determining based on the image data the size and shape of the cartilage damage.Selected measurements for size and shape of the cartilage are calculated in the image date, for example by determining a boundary line for the healthy cartilage surrounding the cartilage damage. A circular cross-section shape is preferably selected such that it covers the cartilage damage with a perimeter at a predetermined safe distance from the fringes of the damaged cartilage. The size and shape data is for example stored as a set of perimeter and thickness data with a predetermined resolution.e. Determining based on the image data the surface contour curvature of the cartilage and/or the subchondral bone in the joint in a predetermined area comprising and surrounding the site of cartilage damage.The curvature of the surface contour is determined for example by per se known surface matching methods in image processing. The determined curvature information can be represented as an equation or as a set of image data. The determined curvature preferably comprises two subsets of curvature information. Firstly, one subset comprises the curvature of the contour portion that comprises the cartilage damage within the cross-section shape defining the selected boundary line for the area covering the cartilage damage. Secondly, the second subset comprises the curvature of a contour portion that surrounds the site of cartilage damage, preferably comprising mutually opposing sloping parts.
II. Generating Design Parameters for a Medical Implant (10).

Based on the physical parameters for the cartilage damage, design parameters for an implant are generated by processing the physical parameters in a design stage95according to a predetermined scheme for the shape of an implant in the specific surgical application.

The shape and size of the implant are calculated or selected dependent on the size and shape of the cartilage damage, and dependent on the curvature of the contour of the cartilage and/or of the subchondral bone in the area substantially coinciding with the cartilage damage, optionally a positioning mark is added to the articulating surface of said implant which indicate rotational positioning to the surgeon. The positioning mark500of the implant10may for example point out a direction in relation to the joint axis501or other anatomic dependent direction and may point out same direction as the positioning mark on the guide tool12used for placing said implant.

The following steps are in one non limiting exemplified embodiment of the design method of the invention comprised in generating design parameters for a medical implant10:f. Generating the contour curvature for an articulating surface of an implant body27dependent on said determined surface curvature of the cartilage and/or the subchondral bone.The contour curvature for the articulating surface of the implant body is generated to correspond to the curvature that covers the cartilage damage.g. Generating a cross-section for the implant body dependent on and substantially corresponding to said determined size and shape of the damaged cartilage.The cross-section for the implant body is generated to correspond to the cross-section shape determined for the cartilage damage.h. Generating an edge height14for the implant body that substantially corresponds to the thickness of healthy cartilage plus a selected height of a bone contacting part of the implant for countersinking the implant into a recess to be made in the bone to fit and receive the implant.A first part of the edge height14for the implant body27is generated to correspond to the determined height of the healthy cartilage, and a second part corresponds to a countersink height selected automatically according to a predetermined scheme or selected manually by an operator.i. Optionally generating a length and a cross-section profile for an extending post23extending from a bone contacting surface of the implant dependent on predetermined rules related to the size and shape of the cartilage damage.The size and shape of the extending post is selected automatically according to a predetermined scheme or is selected manually by an operator.The image based tool may also be configured for using predetermined shapes that are adapted to the determined physical parameters to automatically or manually fit to the cartilage damage and thereby generate the design parameters.

Generating design parameters for a guide tool12for implanting the implant.

The design parameters for the guide are generated dependent on the physical parameters for the cartilage damage and/or dependent on the design parameters for the medical implant.

The following steps are in one exemplified embodiment of the invention comprised in generating design parameters for a medical implant:j. Generating the contact points for a cartilage contact surface50of a positioning body11dependent on said determined surface contour curvature of the cartilage and/or the subchondral bone in the joint in a predetermined area comprising and surrounding the site of cartilage damage, such that said cartilage contact surface50of the positioning body corresponds to and fits to said surface contour of the cartilage or the subchondral bone in the joint.k. Generating the cross-section profile for a guide channel54in a guide body13extending from the positioning body, said guide channel54passing through said positioning body11and said guide body13,the cross-section profile for the guide channel being generated dependent on and substantially corresponding to said determined size and shape of the damaged cartilage, andsuch that the guide channel54is designed to have a cross-sectional profile that corresponds to the cross-section of the plate shaped implant body27,and such that the guide channel54is designed to have a muzzle29on the cartilage contact surface50of the positioning body at a position corresponding to the site of the diseased cartilage.

In further exemplifying embodiments inserts tools intended to be used inside the guide channel54may comprise positioning marks pointing in same direction as positioning mark on the guide tool12;

Comprising of generating the cross-section profile for an insert tool to have a cross-sectional profile that corresponds to the cross-sectional profile of the guide channel54with a tolerance enabling the insert tool8to slide within the guide channel54further comprising a positioning mark pointing in same direction as the positioning mark on the guide tool12.

Further Exemplified Embodiments of Design of Insert Tools;

Embodiments of the invention further comprise optional combinations of the following:

Generating design parameters for a drill bit2dependent on the design parameters for the extending post and such that a cross-sectional area for a drill bit is slightly smaller than the cross-sectional area for the extending post23. Wherein the drill bit2is designed to comprise positioning marks pointing in same direction as the positioning mark present on the guide tool12.

Generating design parameters for a cartilage cutting tool6,105with a cross-sectional profile that is designed to correspond to the cross-sectional profile of the guide channel54with a tolerance enabling the cartilage cutting tool6, to slide within the guide channel54. Wherein the cutting tool is designed to comprise positioning marks pointing in same direction as the positioning mark present on the guide tool12indication in which rotational direction the cartilage cutting tool6should enter the guide channel54of the guide tool12.

Generating design parameters for the implant comprises generating design parameters for an implant body27of the implant10being substantially flat, having a thickness14of approximately 0.5-5 mm.

Generating design parameters for the positioning body comprises generating design parameters for the cartilage contact surface of the positioning body having three contacting points40,42,44, spread out around the guide body13, for contacting parts of the joint in order to provide stable positioning of the guide tool12in the joint. Optionally designing the placement of the positioning mark on top said positioning body, so that the surgeon easily may see the mark during usage of the guide tool and wherein the positioning mark may point out a direction for placement of the guide tool in the joint in relation to the joint axis501or other anatomic dependent direction and may point out same direction as the positioning mark on the guide tool12used for placing said implant.

Generating design parameters for the guide channel54to have a height31of 3-10 cm.

Generating design parameters for the guide channel comprises generating design parameters for an orifice leading through the guide body13at the foot of said guide body.

Generating design parameters for a hammer tool35with a cross-sectional profile that is designed to correspond to the cross-sectional profile of the guide channel54with a tolerance enabling the hammer tool35to slide within the guide channel54.

Details of the Surgical Kit

The Implant Structure

FIG.3a-3bshows a medical implant10of a surgical kit according to an embodiment of the inventive concept. The plate shaped implant body27has an articulating surface (first surface)15configured to face the articulating part of the joint and a bone contact surface (second surface)21configured to face bone structure in the joint, the plate shaped implant body27has a cross-section that substantially corresponds to the area of the damaged cartilage and the articulating surface15has a curvature that substantially corresponds to the curvature of a healthy articulating surface at the site of diseased cartilage. The extending post23extends from the bone contact surface21. Since the implant10of the inventive concept is custom made for a specific patient,FIG.3a-bis an exemplifying schematic picture displaying one embodiments of the implant10. Between the articulating surface15and the bone contact surface21there is a cartilage contacting surface19.

The implant is specially designed, depending on the knees appearance and the shape of the damage and in order to resemble the body's own parts, having a surface which preferably corresponds to a three dimensional (3D) image of a simulated healthy cartilage surface. The implant will be tailor-made to fit each patient's damaged part of the joint.

Implant Body

The implant body27is substantially plate shaped, meaning that the shortest distance (represented by24inFIG.3) crossing the surface15of the implant body27is substantially larger, e.g. at least 1.5 times larger than the thickness14of the implant body27. By substantially plate shaped is meant that the implant body27may be substantially flat or may have some curvature, preferably a 3D curvature of the articulating surface15. The articulating surface15may for example have a curvature that corresponds to a simulated healthy cartilage reconstructed from an image taken e.g. with MRI or CT-scanning of the damaged cartilage surface of the joint. Once the implant10is placed in the joint there will be a surface with no parts of the implant pointing up from or down below the surrounding cartilage—the implant is incorporated to give a smooth surface.

The area and the shape of the implant surface15are individual depending on the size of cartilage damage and location of the cartilage damage. The area and shape of the implant can be decided by the surgeon himself or be chosen from predetermined shapes. For instance the cross-section of the implant body27may have a circular or roughly circular, oval, triangular, square or irregular shape, preferably a shape without sharp edges (seeFIG.8a-band implant10). The implant head or implant body27can vary in size and shape and are adjusted to the size and shape of the damaged cartilage tissue and to the needs of particular treatment situations. The size of the implant10may also vary. The area of the articulating surface15of the implant varies in different realizations of the inventive concept between 0.5 cm2and 20 cm2, between 0.5 cm2and 15 cm2, between 0.5 cm2and 10 cm2, between 1 cm2and 5 cm2or preferably between about 0.5 cm2and 5 cm2.

In general, small implants are preferred since they have a smaller impact on the joint at the site of incision and are also more easily implanted using arthroscopy or smaller open surgical procedures. The primary factor for determining the size of the implant is however the nature of the lesion to be repaired.

The Extending Post

The implant replaces an area of damaged cartilage in an articulating surface of a joint. Before the implant is placed in the desired position, the damaged cartilage is removed and also a part of the bone beneath, i.e. a recess fitting the implant is made in the bone. Furthermore, a hole can be drilled in the bone to fit the implant structure. The extending post of the implant or the rod-part23of the implant10, is used for securing the implant10in the drilled hole of the bone. The length22of the extending post23, extending from the implant head27, is adjusted to a length needed to secure the implant10in the bone. The extending post23is intended to give a primary fixation of the implant10, it provides mechanical attachment of the implant10to the bone in immediate connection with the surgical operation.

The position of the extending post23on the bone contact surface21can be anywhere on the bone contact surface21or the extending post23may have a central position.

The extending post23has a physical structure in the form of for example a cylinder or other shapes such as one or more of a small screw, peg, keel, barb or the like.

In one embodiment, the extending post23has a positioning part25, where the positioning part25is located distal to the plate shaped implant body27. The longitudinal symmetry axes of the first part of the extending post23and the positioning part25coincide. The diameter of the positioning part25is smaller than the diameter of the first part of the extending post23.

The Guide-Tool

FIG.13a-bshows exemplifying embodiments of a guide-tool12. Other examples of guide tools according to the invention is The guide tool12comprises a positioning body11and a guide body13, with a guide channel54through said guide body13and positioning body11. The positioning body has a cartilage contact surface50that has a shape and contour that is designed to correspond to and to fit the contour of the cartilage or the subchondral bone in the joint in a predetermined area surrounding the site of diseased cartilage. The guide tool12also has a top surface52facing the opposite direction compared to the cartilage contacting surface50. The guide body13extends from said top surface52of the guide tool12.

The guide channel54has an inner cross-sectional profile that is designed to correspond to the cross-section of the plate shaped implant body10. In other words, the plate shaped implant body10fits the guide channel54, with a slight tolerance to allow a sliding movement of the implant in the guide channel54. The positioning body11has a mouth or muzzle29which is the guide channel's54opening on the cartilage contact surface50. The mouth29is in a position on the cartilage contact surface50, corresponding to the site of the diseased cartilage in a joint. The height31of the guide channel54must be sufficiently long to give support to the tools used inside the guide body13. The height31is preferably higher than the thickness of the surrounding tissue. In this way, the opening of the guide channel54is easy to access for the surgeon. The height31of the guide channel54is between 1 and 10 cm, preferably 3-10 cm, and always sufficiently high to ensure stabilization of the tools that are to be inserted into the guide channel54.

The guide tool12is easy to place due to the precise fit of the positioning body11on the cartilage surface. The guide tool12is designed to be inserted in as lesion which is as small as possible to be able to repair the specific cartilage damage. The height31of the guide channel54is sufficiently high to be easily accessible for the surgeon during surgery. In one embodiment, the top of the guide channel54is designed to project above the tissue surrounding the surgery cut when the guide tool is placed on the cartilage in a joint during surgery.

The size and shape of cartilage contact surface50of the guide tool12is determined depending on the size and shape of the damaged cartilage and thus on the cross section of the implant body10and the guide channel54, and also depending on the position of the cartilage area in a joint. The size, shape or spread of the surface50is a consideration between the following aspects; minimize surgery lesion, maximize stability for guide tool12, anatomic limitations on the site of the injury. Not all cartilage surfaces in a joint can be used for placement of the guide tool. A large spread of the cartilage contact surface50is to prefer to get good stability of the guide tool, however, a large surface area of the surface50may also lead to a large surgical intervention which is undesired. Thus the size of the cartilage contact surface50and of the positioning body13is determined by a balance between the desire to achieve good positioning stability and small surgical operations. Also, the cartilage contact surface50need not have a continuous, regular shape, but may have an irregular shape, as long as it gives adequate support and stable positioning of the guide tool12. The cartilage contact surface may also consist of three separated points.

When designing the guide tool, the cartilage contact surface50can be designed to cover three points (40,42,44for an example, seeFIG.13b) distributed over the cartilage surface of the joint where the implant is to be inserted. The points are chosen to give maximum support and positional stability for the positioning body11and thus these points, either decided and identified by the surgeon or automatically identified by design software, serve the ground when designing the surface50of the guide tool12. The cartilage contact surface50can also be formed such that it uses the curvature in the cartilage surface in a joint for stability. For example, in a knee joint, the condyles are separated from each other by a shallow depression, the posterior intercondyloid fossa, this curvature together with the medial epicondyle surface can be used to give the cartilage contact surface50a stabile attachment to the cartilage surface in a knee joint. The cartilage contact surface does not need to be a continuous, regular surface but preferably has the three points exemplified by40,42and44for stability. Optionally the cartilage contacting surface50can be further stabilized by attachment with nails, rivets or similar attachment means to the bone surrounding the cartilage in a joint (seeFIG.4b). This additional attachment with rivets48or the like gives additional support and stability and also gives the possibility to keep the cartilage contact surface as small as possible. The position of the rivets may be predetermined and marked out on the surface50by premade drill holes33.

The guide-tool12aids with exact precision removal of a volume of cartilage and subchondral bone and the guide tool12also guides the placement of the implant10in for example a knee. Placement of an exemplified embodiment of the guide-tool12on the cartilage surface on a knee can be seen inFIG.13a.

The guide body13comprises an orifice, seeFIG.11, at the foot of the guide body that leads from the guide channel into the open outside the guide body. The orifice145is designed to enable output of waste such as cartilage tissue and bone chips from boring or reaming in the preparation of the recess for the implant in the joint. The orifice is preferably also designed to enable visual inspection into the implant site during surgical operation.

The guide tool according to the present invention is further designed to comprise a positioning mark500, comprised in the structure of the positioning body or guide body or guide channel construction of the guide tool and wherein the positioning mark is aligned with the center503of the guide channel54in a chosen joint axis501direction.

The guide tool12may be placed in the joint using pins506and clamps507for stabilization and fastening see for example inFIG.7.

The Insert Tool502

The insert tool502is in different embodiments of the invention for example selected from; the cartilage cutting tool, the punch, the cartilage cut drill, the reamer guide, the drill guide or the hammer tool, implant dummy, cartilage cutter. The insert tool is used inside the guide channel54of the guide tool12and fits in the guide channel54, with a slight tolerance to allow a sliding movement of the insert tool in the guide channel54. The cross-sectional profile, and thus the circumferential shape of the insert tool, corresponds to the chosen cross-section of the implant surface15in size and shape

The Cartilage Cutting Tool

The cartilage cutting tool is a tool which is used to cut the cartilage in the joint around the area of damaged cartilage to prepare for the insertion of the implant. The cartilage cutting tool may for example be a punch6or a cartilage cut drill105. It is used inside the guide channel54of the guide tool12and fits in the guide channel54, with a slight tolerance to allow a sliding movement of the cartilage cutting tool in the guide channel54. The cartilage cutting tool preferably cuts the cartilage so that the cut edges of the cartilage are sharp and smooth. These sharp and smooth edges are of great importance when the implant is placed into the prepared recess in the cartilage and bone. In one embodiment the cartilage cutting tool, in addition to cutting the cartilage, may also cut/carve/drill the underlying bone. A hole in the cartilage which is cut (punched or drilled) with the cartilage cutting tool according to the inventive concept ends up with a precise fit of the implant into the prepared cartilage since the cartilage cutting tool allows for an exact, precise cut. The recess in the cartilage and/or bone, made by the cartilage cutting tool always correspond to the chosen cross-section of the implant surface15in size and shape

In one exemplifying embodiment of the inventive concept the cartilage cutting tool is a punch6. The punch6is a solid body with a hollow shape or recess5in one end. The recess5has sharp edges60. The punch6is used to punch out and remove the damaged cartilage from the joint. The punch is to be placed inside the guide channel54of the guide tool12, with the recess pointing down onto the cartilage. A hammer is then used to hammer the punch recess5through the cartilage. In this way the damaged cartilage is removed by punching. The depth59of the recess5on the punch6may be adjusted to the individual person's cartilage thickness. It is of great importance that the punch has sharp cutting edges60.

The punch6fits the inside of the guide channel54, with a slight tolerance to allow a sliding movement of the punch in the guide channel54. The fit ensures the correct, desired placement of the punch on the cartilage surface and thus the precise removal of the damaged cartilage area.

The punch preferably gives sharp precise edges of the remaining cartilage in the joint surrounding the removed cartilage piece, which is of importance when placing the implant10in the joint. The contour of the cutting edge60, i.e. the contour of the surface of the cutting edge60that is to face and cut the cartilage, is in one embodiment designed to match the contour of the patient's cartilage and/or bone at the site of the joint where the punch is to cut. This further ensures that the cartilage will be properly and efficiently cut, giving sharp precise edges of the remaining cartilage as well as minimized damage to the underlying bone.

The length56of the punch6is in one embodiment longer than the height31of the guide channel54. The length56of the punch6is preferably between 4 and 12 cm.

The cross-sectional profile, and thus the circumferential shape of the cutting edge60, of the punch6corresponds to the chosen cross-section of the implant surface15in size and shape The cross-sectional profile of the punch varies in different realizations of the inventive concept between 0.5 cm2and 20 cm2, between 0.5 cm2and 15 cm2, between 0.5 cm2and 10 cm2or preferably between about 1 cm2and 5 cm2.

In one exemplifying embodiment of the inventive concept the cartilage cutting tool is a cartilage cut drill. The cartilage cut drill is used to cut the cartilage in the joint around the area of damaged cartilage to prepare for the insertion of the implant with a cut-drill technique.

The cartilage cut drill105is a drill, with a drill body111and with sharp cutting edges108and a center marker106. The cartilage cut drill105has a cross-sectional profile that is designed to correspond to the inner cross-sectional profile of the guide channel54with a tolerance enabling cartilage cut drill body111to slide within the guide channel54. Also, the cross-sectional profile is designed to correspond to the cross-section of the implant.

The Reamer Guide

In one embodiment of the inventive concept the surgical kit comprises a reamer guide that is placed in the guide channel54before reaming the recess in the bone. The reamer guide placed in the guide channel54protects the cartilage surrounding the implant site while the reamer bit4is used inside the guide channel54of the guide tool12.

The reamer guide28, is a channel shaped structure with thin walls designed to fit the inside of the guide channel54, with a slight tolerance to allow a sliding movement of the reamer guide28in the guide channel54. In other words, the cross-sectional profile of the reamer guide28fits the cross sectional profile of the guide channel54such that the reamer guide28may be used as a lining, lining the insides of the guide channel54(seeFIG.8). The walls of the reamer guide28have a thickness of less than 1 mm. The reamer guide28preferably has a height66that is at least the height achieved by adding the inner height31of the guide channel54with the height59of the recess5of the punch6.

The Height Adjustment Device or Insert Tool

A height adjustment device16according to the invention comprises a male part47and a female receiving part48which when used together allows for stepwise adjustment of drill depth.

The male part is in the outermost position in a zero-mode and may from there be adjusted inwards allowing the surgeon stepwise the for example make stepwise deeper drill holes. When the height adjustment device16is in starting mode or outermost zero-mode the positioning marking of the guide tool12and the positioning marking of the height adjustment device are aligned, se for exampleFIG.6.

Thus, by being able to adjust the length31of the guide channel the surgeon is also able to adjust the depth of drilling and cutting into the bone. The length31of the guide channel may be varied since the guide body13and the height adjustment device16parts are able to move in relation to one another. Further, the male part47and the female receiving part48of the height adjustment device may be arranged such that the length31of the guide channel may be varied at certain stepwise intervals115, e.g. at 200 μm or at 100-300 μm intervals or steps, or any other desired interval, see for exampleFIG.16. For example, the height might be adjusted between for example 0.2-3 mm, in one or several steps. This may for instance be achieved by arranging the male part47inside the female receiving part48of the height adjustment device16such that the male part47insert tool to have a cross-sectional profile that corresponds to the cross-sectional profile of the female part guide channel120with a tolerance enabling the insert tool to slide within the guide female part guide channel120. For example, the construction may be arranged such that the guide body13and height adjustment device16may be turned in relation to one another at preset steps, by lifting the male part sot that the protruding ridges may slip out of one groove and enter another groove. When the male part47is fitted in the female part their position are locked in relation to each other or prone to hook each other at those intervals. The female part comprises grooves or ledges17at different heights relative to the positioning body of the guide tool. The male part47comprises a guide channel54inside the male part47, the guide channel54may be cylinder shaped and protruding ridges105on the outer surface of the male part47. When the male part47is placed inside the female receiving part48the protruding ridges105of the male part47are placed or located inside one of the grooves17on the female receiving part48. The position of the grooves17and the position of the ridges105in relation to the positioning body or the cartilage contact surface50adjust or regulate the length31of the guide body13. The height adjustment device16may be used by the surgeon to adjust the depth of drilling, e.g. by increasing the drill depth in steps at the preset intervals. The height adjustment device16may advantageously be used together with an implant dummy36, as described below, to make sure that the drill depth in the bone matches the height14of the implant body27. This ensures that the articulating surface15of the implant10will be in line with the surrounding cartilage at the site of implantation once implanted.

The Drill-Guide,

In one embodiment of the inventive concept the surgical kit comprises a drill guide8that is used to direct a drill for drilling a hole in the bone at the site of cartilage damage, for fastening of the extending post23of the implant10in the bone tissue. The drill guide8comprises a drill guide body and a guide channel7passing through the drill guide body. The guide channel7is designed to receive and guide the drill during the surgical procedure. The drill guide8is designed to fit the inside of the guide channel54, with a slight tolerance to allow a sliding movement of the drill guide8in the guide channel54, seeFIG.8a-b. In other words, the cross-sectional profile of the drill guide body matches the cross-sectional profile of the guide channel54The fit ensures the correct, desired placement of the drill guide8on the cartilage surface and thus ensures the precise direction and placement of the drill hole in the bone.

The guide channel7is designed to be positioned in the drill guide body such that the position corresponds to the desired position of the drill hole in the bone. The positioning of the guide channel7in the drill guide8is coordinated with the positioning of the extending post23on the bone contacting surface21of the implant to ensure correct positioning of the implant in the bone.

The length62of the drill guide8and thus the drill channel7is longer than the height31of the guide channel54. The length is preferably 4-12 cm.

The cartilage contacting surface64of the drill guide8corresponds to the chosen implant surface15in size and shape. The surface64varies in different realizations of the inventive concept between 0.5 cm2and 20 cm2, between 0.5 cm2and 15 cm2, between 0.5 cm2and 10 cm2or preferably between about 1 cm2and 5 cm2. In one embodiment the cartilage contacting surface64of the drill guide8is designed to match the contour of the patient's cartilage and/or bone at the site of the joint where the implant is to be inserted.

SeeFIG.9cfor a demonstration of how the drill-guide8fits inside the guide-channel54of the guide-tool12.

Drill-Bit

The surgical kit of the present inventive concept may also comprise a drill-bit2, seeFIG.12. The drill-bit2may have an adjustable depth gauge1. The depth gauge1on the drill-bit2is supported by the top30of the guide channel54and by using this support the depth of the drill hole can be controlled. The drill-bit2fits inside the drill channel7in the drill-guide8to give a drill-hole in the bone with an exact position and depth and where the depth is depending on the placement of the depth gauge1on the drill-bit2, and also depending on the height of the guide-channel31.

Reamer-Bit

The surgical kit of the present inventive concept may also comprise a reamer-bit. The reamer-bit4may have a depth gauge3. The reamer bit4is used together with the guide-tool12and possibly the reamer guide28. The reamer-bit4is used inside the guide channel54, removing bone tissue, aided by the guide channel54and possibly the reamer guide28. The depth gauge3on the reamer-bit4is supported by the top30of the guide channel54and by using this support the depth of the reamed bone recess can be controlled. The depth of the reamed recess in the bone is depending on the placement of the depth gauge3on the reamer-bit4, and also depending on the height31of the guide-channel54. The depth of the reamed surface is determined depending on the injury and on the desired implants size.

Hammer Tool

The optional hammer tool35(seeFIG.12) consists of a solid body and is designed to fit the inside of the guide channel54, with a slight tolerance to allow a sliding movement of the hammer tool35in the guide channel54, seeFIG.8. The hammer tool35is used inside the guide channel54to hammer the implant in place. The height of the hammer tool68is the same height62as of the drill guide8. Once the hammer tool is hammered in the same level as the top of the guide channel, the hammering and thus the placement of the implant is finished.

Implant Dummy and Dummy Reference

The implant dummy36and dummy reference37, seeFIG.12, are used to make sure that the cut, carved or drilled recess in the bone that is to receive the implant body27, is deep enough to fit the implant. This is very important, since the articulating surface15of the implant10must not project over the surface of the surrounding cartilage tissue. If it would it could cause a lot of damage to the surrounding cartilage and to the cartilage on the opposite side of the joint. Preferably the articulating surface15should form a continuous surface with the surrounding cartilage, neither projecting above nor being sunken below the surface of the surrounding cartilage. The checking of the recess depth is difficult or impossible to do with the implant10itself, since the implant10, e.g. with its extending post23, is designed to be fixed in the bone once inserted, and thus is difficult or impossible to remove. The implant dummy, on the other hand, is designed for easy removal from the recess once the recess depth has been checked.

The implant dummy36, seeFIG.12, has an implant element41that is designed to match the implant body27. The lower surface41aof the implant element41is a replica of the bone contact surface21of the implant that is to be implanted. That is, if the implant10and bone contact surface21is custom made for the specific patient, the implant element41and its lower surface41awill also be custom made and the lower surface41abe a replica of the bone contact surface. The cross-sectional profile of the implant element41corresponds to the cross-sectional surface of the implant body, or is slightly smaller in order to ensure easy removal of the implant dummy from the recess.

The implant dummy36also has a top surface. The distance between the lower surface of the implant element41and the top surface corresponds to the distance that you get when adding the thickness14of the implant body27(corresponding to the depth of the recess in the bone plus the thickness of the corresponding cartilage). The dummy reference37, seeFIG.12, is arranged to fit to, and possibly releasable attach to, the guide hole53of the guide base12, see.

To ensure that the implant dummy36is placed in a correct orientation in the recess of the bone, i.e. in an orientation that corresponds to the orientation that the implant10is to be inserted in, the top surface43and/or the implant element41may be provided with positioning mark500. A corresponding positioning mark500is provided also on the implant dummy36and on the guide base12.

A Medical Implant Comprising at Least Two Substantially Circular Shapes

FIGS.14aand14bshow a medical implant1410according to the invention which comprises two substantially circular shapes1411where one of the circular shapes is provided with a positioning mark1420on its articulating surface15.

The positioning mark1420on the articulating surface15, i.e. the top surface15facing the articulating part of the joint, of one of the circular shapes of the medical implant illustrated inFIGS.14aand14bis designed to be used for determining the orientation in which the implant is to be placed in a recess made in a damaged articulating surface of a joint.

The positioning mark1420on the articulating surface15, i.e. the top surface15facing the articulating part of the joint, of one of the circular shapes of the implant illustrated inFIGS.14aand14bmay be designed so that the direction of the positioning mark1420is determining the placement orientation of the implant in a recess in that the placement orientation of the positioning mark is also to be indicated by a mark made on the side of a recess made in the articulating surface of a joint in which the implant is to be inserted, thereby providing for a correct or more accurate orientation of the implant when inserted in the recess made in a damaged articulating surface of a joint.

The positioning mark1420on the articulating surface15, i.e. the top surface15facing the articulating part of the joint, of one of the circular shapes of the implant1420illustrated inFIGS.14aand14bmay be designed so that the direction of the positioning mark is designed to be pointing in an anatomic dependent direction in relation to a recess made in the articulating surface of a joint in which the implant is to be inserted, thereby providing for a correct or more accurate orientation of the implant when inserted in the recess made in a damaged articulating surface of a joint.

FIGS.15aand15bshows a medical implant1510according to the invention which comprises two substantially circular shapes1511, e.g. designed from using a virtual model comprising two substantially circular shapes, where one of the circular shapes is provided with a positioning mark1520on its the cartilage contacting surface19, i.e. its side edge surface19.

The positioning mark1520on the cartilage contacting surface19, i.e. the side edge surface19, of one of the circular shapes of the medical implant illustrated inFIGS.15aand15bis designed to be used for determining the orientation in which the implant1520is to be placed in a recess made in a damaged articulating surface of a joint.

The positioning mark1520on the cartilage contacting surface19, i.e. the side edge surface19, of one of the circular shapes of the implant illustrated inFIGS.15aand15bmay be designed so that the direction of the positioning mark1520is determining the placement orientation of the implant in a recess in that the placement orientation of the positioning mark is also to be indicated by a mark made on the side of a recess made in the articulating surface of a joint in which the implant is to be inserted, thereby providing for a correct or more accurate orientation of the implant when inserted in the recess made in a damaged articulating surface of a joint.

The positioning mark1520on the cartilage contacting surface19, i.e. the side edge surface19, of one of the circular shapes of the implant illustrated inFIGS.15aand15bmay be designed so that the direction of the positioning mark is designed to be pointing in an anatomic dependent direction in relation to a recess made in the articulating surface of a joint in which the implant is to be inserted, thereby providing for a correct or more accurate orientation of the implant when inserted in the recess made in a damaged articulating surface of a joint.

Storage Units for Storing a Medical Implant Prior to Inserting the Implant in a Human Joint

FIG.16shows a storage unit1610adapted for storing a substantially circular shaped medical implant1612prior to inserting the medical implant in a recess made in a joint. The storage unit1610illustrated inFIG.16comprises a plurality of reference features in the form of a positioning mark1620, an edge1621and a corner1622.

The storage unit1610illustrated inFIG.16further comprises both a mechanical recess structure1630and holding means1640adapted for holding and positioning the implant1612in a rotationally fixed position in the storage unit1610.

The plurality of reference features1620,1621,1622of the storage unit1610illustrated inFIG.16are adapted to be used for rotationally positioning the substantially circular shaped implant1612in the storage unit1610in that a positioning mark1614on the substantially circular shaped implant to be stored in the storage unit1610is used for rotationally positioning the implant1612in relation to the plurality of reference features1620,1621,1622. The implant1612is then placed in the storage unit1610by directing the implant positioning mark1614on the surface of the implant in a specific, e.g. pre-determined, rotational direction in relation to at least one of the plurality of reference features of the storage unit.

FIG.17shows a storage unit1710adapted for storing a medical implant comprising two circular shapes1713prior to inserting the medical implant1712in a recess made in a joint. The storage unit1710illustrated inFIG.17comprises a plurality of reference features in the form of a positioning mark1720, an edge1721and a corner1722.

The storage unit1710illustrated inFIG.17further comprises a mechanical recess structure1730adapted for holding and positioning the implant in a rotationally fixed position in the storage unit.

The plurality of reference features1720,1721,1722of the storage unit1710illustrated inFIG.17are adapted to be used for rotationally positioning an implant1712comprising the two circular shapes1713in the storage unit1710in that a positioning mark1714on one of the circular shapes1713is used for rotationally positioning the implant1712in relation to the plurality of reference features. The implant is then placed in the storage unit1710by directing the implant positioning mark1714on the surface of the implant in relation to at least one of the plurality of reference features of the storage unit, e.g. the implant positioning mark1714may be directed in the direction of the positioning mark1720on the upper surface of the storage unit1710.