Joint implant, preoperative planning method and arthroplasty method

Abstract

A joint implant (2) to be mounted to hard tissue of a patient comprises a body portion (21). The joint implant (2) has a body portion (21) having a tissue face (211) configured to contact a preparation surface of hard tissue of a patient when the joint implant (2) is mounted to the hard tissue of the patient. The tissue face (211) of the body portion (21) comprises an anchoring structure (212) configured to anchor the joint implant (2) on hard tissue of a patient. The body portion (21) is formed to cooperate with a preparation surface of hard tissue such that the joint implant (2) is held in a predetermined target position when mounted to the hard tissue.

Description

Technical Field

[0001] The present invention relates to providing an at least partially artificial joint and, more particularly, to a joint implant, an arthroplasty method and a process for preoperatively planning an arthroplasty procedure. Background Art

[0002] In order to treat various joint diseases and joint dysfunctions, it is known to provide artificial joints or joint parts. Typically, joint implants are installed or placed surgically, wherein the implant is typically integrated or attached to the natural bone adjacent to the joint.

[0003] For example, the surgical treatment options for knee osteoarthritis (OA) today are total knee arthroplasty (TKA) or partial knee arthroplasty (PKA), the latter mostly being unilateral knee arthroplasty (UKA). In this regard, arthritis is an umbrella term describing several conditions that cause inflammation of the joints. In some cases, inflammation can also affect adjacent skin, muscles, and organs. The most common type is OA, compared to rheumatoid arthritis, etc.

[0004] OA is usually caused by normal wear and tear of the joints and cartilage. Cartilage is the smooth tissue that covers the ends of bones and helps joints move. Over time, the cartilage may degenerate and may even disappear completely. This causes bone-to-bone contact in the joint, causing pain, stiffness, and sometimes swelling. OA can affect any joint in the body. It is most likely to affect the joints of the hips, knees, shoulders, hands, ankles, and neck. The risk of developing OA increases with age.

[0005] Treatment options for arthritis or other types of arthritis may include: medications, such as over-the-counter (OTC) acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs); physical therapy, in which a therapist teaches the patient exercises to help strengthen and stabilize the joints and restore or maintain range of motion; occupational therapy, in which a therapist helps develop strategies for adjusting work environment or habits to help manage the overall condition; orthotics, such as braces, splints, or insoles that help reduce stress and pressure on damaged joints; joint surgery, such as arthroscopic surgery, arthroplasty, or joint fusion, to clean, replace, or fuse damaged joints.

[0006] Often, less invasive treatments are attempted before surgery, as revision options for implants are very limited. If all treatments fail, the final state may be severe pain or stiffness, which may result in the inability to walk. Typically, surgical joint treatment is divided into three stages:

[0007] Early treatment with lavage or debridement, both arthroscopic procedures, aims to remove growth, excess and disturbed cartilage / tissue. Therefore, these are palliative measures and do not address or treat the underlying cause of the inflammation.

[0008] Reduction osteotomy, primarily high tibial osteotomy (HTO), is a surgical procedure to correct misalignment and realign the axis to prevent overloading of the joint surface and its associated consequences.

[0009] Joint replacements are most commonly used for total hip (THA), shoulder (TSA) or knee (TKA) arthroplasties or partial arthroplasties, such as unilateral knee arthroplasty (UKA). UKA implants can be used for both ankles in TKA, which has not yet been established as a standard procedure. In addition, implants for more distal, smaller joints are emerging in niche markets.

[0010] Currently, implant design and associated surgery limit revision options, especially considering that the goal of any treatment is usually to preserve natural structures such as bone and restore healthy autologous tissue. To achieve this goal, it has been found that a combination of bone or tissue grafts and thin-walled implant designs may be advantageous. However, this solution requires technology to accurately remove the exact amount of damaged or impaired structure as needed.

[0011] Although precise bone removal is now possible, known procedures for combined tissue grafts and thin-walled implants are often cumbersome and prone to error, especially at the expense of microstructural precision. The prior art uses mechanical cutting tools, such as saw blades or milling cutters.

[0012] Furthermore, it can be challenging to precisely maintain a thin-walled implant in its target position and orientation with today's possible anchoring options, which are more or less limited to linear or circular geometries, such as planes and cylinders or pyramids and cones, respectively.

[0013] The design of optimized thin-wall implants is often limited by the minimum required wall thickness due to the edges resulting from the intersection of planar cutting planes produced by the saw blade.

[0014] Therefore, there is a need for systems and components that allow for improved procedures for replacing a natural joint or portion thereof, while preserving as much of the natural hard tissue, such as bone or cartilage, as possible. Summary of the invention

[0015] According to the invention, this need is solved by a joint implant as defined by the features of independent claim 1, a kit as defined by the features of independent claim 15, a preoperative planning method as defined by the features of independent claim 16, an arthroplasty method as defined by the features of independent claim 23 and a treatment method as defined by the features of independent claim 35. Preferred embodiments are subject matter of the dependent claims.

[0016] In one aspect, the present invention is a joint implant to be installed on the patient's hard tissue. The joint implant comprises a main body, and this main body has a tissue surface, and this tissue surface is configured to contact the preparation surface of the patient's hard tissue when the joint implant is installed to the patient's hard tissue. The tissue surface of the main body comprises an anchoring structure, and this anchoring structure is configured to anchor the joint implant on the patient's hard tissue. The main body is formed to cooperate with the preparation surface of the hard tissue so that the joint implant remains on a predetermined target position when being installed to the hard tissue.

[0017] The term "hard tissue" as used in the context of the present invention may refer to tissue that is mineralized and / or has a firm intercellular matrix. Hard tissue may in particular be bone tissue, cartilage tissue and / or ligament tissue.

[0018] A joint implant may be an orthopedic implant, which is used to replace a portion or part of a joint of a human or animal patient. Once implanted, it may be referred to as a partial or total artificial joint. The joint may be any joint of a human or animal, such as a shoulder joint or glenohumeral joint, an elbow or elbow joint, a hip joint or a finger joint. In a particularly advantageous embodiment, the joint implant is an artificial part of a knee joint, i.e. a total knee arthroplasty (TKA) or a unilateral knee arthroplasty (UKA).

[0019] The anchoring structures may be of any geometrical or structural design allowing integration into corresponding structures of the prepared surface of the hard tissue, such as pins or strips of any shape and depth profile.

[0020] Joint implant according to the present invention allows to be effectively held on hard tissue. More specifically, by forming the main body portion to be suitable for the preparation surface, it can be connected to the hard tissue like a clip, such as a cap or a helmet. Therefore, the anchoring structure can allow to increase the surface of contact bone tissue for osseointegration or healing into the hard tissue. In addition, it allows to accurately determine the position of the joint implant on the hard tissue, particularly its preparation surface, i.e. positioning and orientation.

[0021] The joint implant may be a thin-walled joint replacement implant with minimal wall thickness. It may be produced specifically for the patient based on preoperative planning data, or it may be a one of a kind off-the-shelf implant, for example provided in the dimensions of a finely crafted item.

[0022] Preferably, the main body is formed to slide with the preparation surface of the hard tissue, that is, it can achieve accurate sliding on the preparation surface of the hard tissue. The sliding fit may particularly involve friction, elastic force and / or clamping force. This sliding fit allows the joint implant to be effectively and conveniently installed on the hard tissue.

[0023] Preferably, the anchoring structure of the tissue surface of the main body portion comprises at least one anti-pivot projection having a non-rotationally symmetrical cross section. By means of such an asymmetric anti-pivot projection, the implant can be effectively and accurately oriented and positioned relative to the hard tissue.

[0024] In a particularly advantageous embodiment, at least one anti-pivot projection of the anchoring structure of the tissue surface of the main body part comprises a plurality of wavy protuberances.This wavy portion allows stabilizing implants in multiple directions.Therefore, compared with, for example, a linear protuberance that blocks relative one-dimensional translational motion or a curved protuberance that blocks relative one-dimensional rotational motion, the wavy protuberance allows blocking multidimensional rotational and translational motions by a kind of geometric structure.Therefore, the particularly effective cooperation of the preparation surface of joint implant and hard tissue is possible.In addition, this protuberance allows joint implant to be easily installed on the hard tissue, while the joint implant is accurately positioned on the hard tissue.

[0025] In another embodiment, at least one anti-pivot projection of the anchoring structure of the tissue surface of the main body portion comprises a column with an angular or spline polygonal or star-shaped cross section. Such a column allows the joint implant to be securely connected to hard tissue to prevent the joint implant from accidentally rotating relative to the hard tissue.

[0026] Preferably, the anchoring structure of the tissue surface of the main body part comprises at least one form-fitting projection, and this projection is configured to be matched with the form-fitting cavity shape of the preparation surface of hard tissue.This form-fitting projection allows to provide the relatively firm and safe connection of joint implant and hard tissue.Particularly, joint implant can be clamped in or stuck on hard tissue or its preparation surface or wherein.Particularly, the form-fitting projection that interacts with the form-fitting cavity allows to stop the movement of joint implant relative to hard tissue in a predetermined direction, for example particularly away from the direction of hard tissue.For example, the joint implant with this form-fitting projection can be installed on the hard tissue in a button-like manner.

[0027] By means of the form-fitting projections, a particularly beneficial, effective and stable mounting of the joint implant to the hard tissue can be achieved. In this way, precise and effective healing or growth of the implant in the hard tissue can be achieved at a well-defined position.

[0028] Therefore, at least one form-fitting projection preferably has a cross section that increases in the direction of the preparation surface intended to point to the hard tissue. Such a projection with an increased cross section allows a relatively easy-to-manufacture mating structure to be provided. The form-fitting projection can be a straight or wavy rod-shaped portion extending from the tissue surface, wherein the cross-sectional size increases. For example, the cross section of such a rod-shaped portion can be a trapezoid or a similar shape. In addition, the form-fitting projection can be an inverted pyramid or a truncated cone, and the plane of the pyramid can be flat, concave or convex, and the envelope surface of the cone can be circular or elliptical.

[0029] Preferably, the joint implant is configured to snap fit with the preparation surface of the hard tissue. Therefore, the snap fit can be combined with a sliding fit and a form fit. This snap fit structure allows the joint implant to be conveniently and stably installed on the hard tissue and realizes the proper retention of the joint implant to the hard tissue.

[0030] Preferably, the body portion is made of a biocompatible metal or metal alloy, which may be modified or enhanced with additional materials or substances to facilitate or promote integration of hard tissue or bone. Such body portions are quite strong and reliable. Furthermore, such materials may be biocompatible, making them suitable for implantation.

[0031] Preferably, joint implant comprises shell part, wherein main body part has exposed face, this exposed face is exposed towards the hard tissue of a part of joint rather than joint implant to be installed, and wherein shell part is fixed to main body part so that the exposed face of main body part is covered by shell part.The exposed face can be more or less relative with tissue face.Shell part allows to provide different properties or features at hard tissue and exposed face place.

[0032] Therefore, the shell part is preferably made of a cross-linked plastic, and more preferably, the cross-linked plastic is polyethylene that is finally provided with an antioxidant such as vitamin C. Such a plastic shell part allows a relatively soft but still strong design to be provided. For example, the shell can be arranged to contact and receive another joint implant.

[0033] In a preferred embodiment, the joint implant is configured to be installed to the knee end of tibia. In another preferred embodiment, the tissue surface is formed around the knee end of femur. This joint implant allows to provide an artificial knee or a part thereof. This is equally applicable to other joints, for example, respectively for the femur and pelvis of hip or for the humerus and glenoid of shoulder.

[0034] On the other hand, the present invention is a joint implant kit.The joint implant kit comprises the first joint implant as described above and the second joint implant with the shell part as described above.The first joint implant comprises the first main body with tissue surface, and this tissue surface is configured to contact the preparation surface of the first hard tissue of patient's joint when the first joint implant is installed to the first hard tissue of patient's joint.The second joint implant comprises the second main body with tissue surface, and this tissue surface is configured to contact the preparation surface of the second hard tissue of patient's joint when the second joint implant is installed to the second hard tissue of patient's joint.When the first joint implant is installed to the first hard tissue of patient's joint and the second joint implant is installed to the second hard tissue of patient's joint, the second main body of the second joint implant has the exposed face exposed towards the first joint implant.The second joint implant has the shell part fixed to the second main body so that the exposed face of the second main body is covered by the shell part.

[0035] The joint implant kit according to the present invention allows the effects and benefits of the above-described joint implant and its preferred embodiments to be realized in applications where parts of a natural joint are replaced.

[0036] On the other hand, the present invention is a preoperative planning method comprising the following steps: (i) obtaining tissue surface data representing the geometry of the tissue surface of the main part of the joint implant as described above; (ii) obtaining image data of the initial state of the patient's joint hard tissue; (iii) defining the target position of the joint implant on the hard tissue image generated by the image data; and (iv) using the image and the defined target position to calculate a cutting geometry to prepare a surface of the hard tissue, wherein the cutting geometry is suitable for producing a prepared surface of the hard tissue corresponding to the tissue surface of the main part of the joint implant.

[0037] The image obtained can be, in particular, a medical image, which can depict the initial state through a cross-sectional view of the joint tissue.

[0038] The general contour of the prepared surface can be adapted to the general contour of the tissue surface of the joint implant. It can also be provided with a structure that matches the anchoring structure of the tissue surface of the main body part.

[0039] The preoperative planning method can be implemented by a computer and can be implemented by a computer program executed on a computer system.

[0040] The preoperative planning method allows to accurately plan the surgical procedure necessary for applying the joint implant to the patient. In particular, it allows to plan an accurate surgical procedure on hard tissue in order to accurately mount the joint implant to the hard tissue. Furthermore, it allows to provide the hard tissue with a suitable structure suitable for accurately receiving the anchoring structure.

[0041] Preferably, the cutting geometry is adapted to remove a volume of hard tissue of the joint until a target hard tissue of the joint covered by the volume of hard tissue is reached. By precisely removing a large amount of hard tissue and retaining as much other hard tissue as possible, it can be achieved that relatively less hard tissue must be removed, so that relatively more native hard tissue can be retained or maintained. However, by removing the volume of hard tissue, a more suitable or better provided tissue of the hard tissue can be accessed, which allows for more effective and better healing.

[0042] In one embodiment, the target hard tissue is a calcified layer of hard tissue located between the cortical hard tissue and the subchondral bone tissue. This method allows replacement of natural cartilage tissue.

[0043] In another embodiment, the target hard tissue is cancellous bone tissue. Anchoring in such cancellous bone tissue allows particularly effective healing, in particular when laser ablation is applied, which allows the natural structure of the cancellous bone tissue to be maintained or only minimally damaged.

[0044] Preferably, image data of the initial state of the hard tissue are obtained before surgery by computer tomography (CT) or magnetic resonance imaging (MRI). CT allows accurate three-dimensional information about the hard tissue, including its lesions and defects. Thus, accurate planning of the surgical operation can be achieved like this.

[0045] Preferably, the preoperative planning method comprises a step of forming the joint implant based on the image data of the initial state and advantageously based on the defined target position.Such a forming step allows designing and providing a patient-specific implant (PSI).

[0046] Alternatively, the preoperative planning method preferably comprises the step of selecting a joint implant from a plurality of ready-for-use joint implants based on the image data of the initial state. This selection allows providing an implant suitable for the patient's needs.

[0047] In another aspect, the present invention is a method of arthroplasty, comprising the following steps: (a) obtaining a channel for hard tissue close to a patient's joint; (b) preparing the surface of the joint hard tissue by providing a laser beam to the hard tissue, thereby ablating a certain volume of hard tissue until reaching a target hard tissue covered by the certain volume of hard tissue, and providing a laser beam to the target hard tissue to produce a structure in the target hard tissue that matches the anchoring structure of the tissue surface of the main part of the joint implant as described above; and (c) assembling the main part of the joint implant to the prepared surface of the hard tissue so that the joint implant is maintained at a predetermined target position on the hard tissue.

[0048] The use of lasers to remove the volume of hard tissue allows the preparation surface to be produced efficiently and precisely. Moreover, such laser cutting can be performed in a fully automated manner. Furthermore, laser ablation does not or only to a small extent affect the hard tissue in the vicinity of the incision, so that the structure of the remaining hard tissue can remain more or less intact, i.e. have its natural structure.

[0049] More specifically, robot-assisted cold laser ablation can be used for such joint surgery. This allows specific three-dimensional geometries to be excavated, thereby creating space for, for example, bone grafts or tissue transplants, or to shape or deform surfaces in order to create connection geometries for joint implants in a complex manner.

[0050] Based on the features and benefits of laser ablation thin-wall implant design, it is feasible to reduce the mechanical load in a lightweight structure with reinforcing ribs and structures for ensuring translational and rotational forces. The three-dimensional free-form surface of the implant can be mapped one-to-one into the target hard tissue, producing a highly accurate implant bed for a good sliding fit or form fit of the implant with the hard tissue.

[0051] The unique combination of robot-assisted cold laser ablation and specially adapted thin-walled implant design offers a new treatment option with maximum hard tissue sparing and the potential for bone / tissue regeneration, supported, for example, by transplantation or other pharmacological or biomedical therapies.

[0052] In a preferred embodiment, the target hard tissue is a calcified layer of hard tissue located between the cortical hard tissue and the cancellous hard tissue. By ablating the hard tissue to a minimum extent until the calcified layer, effective replacement of cartilage is possible. In particular, the natural hard tissue structure can be maintained to a large extent.

[0053] In another preferred embodiment, the target hard tissue is cancellous bone tissue. By anchoring the implant into the cancellous bone tissue, effective healing can be achieved.

[0054] Preferably, the arthroplasty method comprises the steps of analyzing the hard tissue to be ablated by the laser beam; generating tissue data related to the analyzed hard tissue; and using the generated tissue data when providing the laser beam to the hard tissue to ablate a certain volume of cortical hard tissue to determine when the target hard tissue is reached. By including the tissue data in the provision of the laser beam, it can be achieved that the type and structure of the ablated tissue can actually be taken into account. In particular, the laser beam can be adjusted according to the tissue actually ablated. In addition, once the target hard tissue is reached, the provision of the laser beam at the same point can be effectively stopped. In this way, the removal of a relatively small volume of hard tissue can be achieved.

[0055] Therefore, analyzing the hard tissue and generating tissue data is preferably performed in real time. As such, removal of the target hard tissue can be very effectively prevented. Advantageously, the analysis and tissue data generation are performed inter pulse, so that the sufficiency of ablation is determined pulse by pulse.

[0056] Furthermore, by analyzing hard tissue, diseased, degenerated or dead tissue can be identified and removed. For example, such analysis allows the detection of inflamed or cancerous tissue that can be removed. Like this, effective treatment of joints is possible.

[0057] The hard tissue is preferably analyzed by laser induced breakdown spectroscopy (LIBS). LIBS allows a rapid, accurate and reliable analysis of ablated tissue. Thus, LIBS can determine the elements contained in the plasma plume generated when ablating hard tissue. Alternatively, it can analyze the tissue by advantageously delivering a separate analytical laser beam to the hard tissue between pulses.

[0058] Preferably, the arthroplasty method comprises the following steps: obtaining an image of the initial state of the hard tissue; defining a target position of the joint implant on the image of the hard tissue; and using the image and the defined target position to calculate a cutting geometry so as to provide a laser beam to the hard tissue to ablate a certain volume of hard tissue. The image can in particular be a digital image, such as a digital image obtained by CT. Advantageously, defining the target position on the image is performed digitally, such as by a computer or the like. In this way, the physician can efficiently handle case assessment and planning.

[0059] The image of the initial state of the hard tissue can be obtained in any suitable manner. However, as mentioned above, it is preferably obtained by CT. This imaging allows the generation of a three-dimensional accurate representation of the hard tissue or boundary surface. In addition, it allows the image to be provided digitally, which can substantially simplify further processing.

[0060] Additionally or alternatively, the arthroplasty method includes obtaining another image of the current state of the hard tissue and controlling the step of providing the laser beam to the target hard tissue based on the other image. Such control of the laser beam allows the latest situation and state of the hard tissue to be accurately reflected in real time or instantaneously.

[0061] Therefore, the additional image of the current state of the hard tissue is preferably obtained by optical coherence tomography or by means of a reference indicator / pointer for navigation. Like this, the additional image can be effectively obtained in the operating room, ie, during surgery.

[0062] This image or another image can be a medical image. It can also depict one or more cross sections of joint tissue. In addition, before or when calculating the cutting geometry, the image can be further processed, for example in a multimodal image model.

[0063] Preferably, the arthroplasty method comprises a step of forming the joint implant based on the image of the initial state and advantageously based on the defined target position. This forming step allows designing and providing the PSI.

[0064] Thus, a joint implant, a focal defect implant or a graft can be formed intraoperatively so that it can be adapted to the current state of the hard tissue. In particular, in embodiments where hard tissue is ablated based on real-time analysis of the hard tissue and generation of tissue data, a particularly effective provision of PSI can be achieved, advantageously with the aid of LIBS or real-time OCT. For example, in the case of detection and ablation of focal defects by LIBS, and in the case where the final state of the hard tissue cannot be foreseen with appropriate effort, this patient-specific joint implant formed at run time allows the realization of a precisely fitting joint implant and ultimately prevents any corrective measures, such as transplantation at the hard tissue.

[0065] The process of forming a joint implant, a focal defect implant, or a graft such as a PSI may involve additive manufacturing, such as 3D printing.

[0066] Alternatively, the arthroplasty method preferably comprises the step of selecting a joint implant from a plurality of ready-made joint implants based on the image of the initial state. This selection allows providing an implant suitable for the patient's needs.

[0067] In yet another aspect, the present invention is a method for treating a patient's joint, comprising the steps of obtaining an image of the joint; defining unwanted joint hard tissue on the image of the joint; obtaining access to the joint; and removing unwanted hard tissue by providing a laser beam and thereby ablating the unwanted hard tissue of the joint. The image of the joint can be, for example, an image of an initial state of the joint obtained before surgery and / or a current or actual image of the joint obtained during surgery. The technology for acquiring the image can include navigation by CT, OCT, or a reference pointer.

[0068] Unwanted tissue can be diseased tissue, degenerate tissue, dead tissue, inflamed tissue and / or cancerous tissue in particular. Some of these unwanted tissues may relate to focus defects. Therefore, the removal of this unwanted tissue allows the treatment of focus defects. This focus defect is normally the source of joint diseases such as arthrosis or osteoarthritis. Therefore, by removing unwanted tissue, joints can be effectively treated and healed. In addition, removing this focus defect is vital for acceptance and healing of the joint implant being implanted into bone.

[0069] The effects and benefits of the present invention and its preferred embodiments can be achieved through the processing methods according to the present invention and its preferred embodiments described below.

[0070] Unwanted hard tissue can be removed using a robot-assisted cold laser ablation device.

[0071] If necessary, a channel close to the joint can be obtained, such as a target implant bed close to the joint, by passing through or reaching the cartilage, through or reaching the calcified layer, through or reaching the subchondral bone and beyond into the cancellous bone from the joint space. In particular, the subchondral bone tissue can be approached like this, and inflamed or otherwise damaged tissue can be removed. Alternatively, if necessary, the cancellous bone can be passed from the middle section of the long bone from bottom to top, and finally through the subchondral bone to the calcified layer and further into the cartilage, thereby entering the subchondral bone tissue. The cutting strategy and sequence can consist of a series of pulses in the following order: aiming beam / visualization (optional); ablative laser; LIBS detection / analysis of the response; and depth measurement by OCT or sound detection and response analysis for depth / progress control. Coaxial video recording and illumination of the surgical site and laser focus can be performed in parallel and continuously. Under the full control of visual imaging, channels and unwanted hard tissues can be ablated layer by layer through surface slices. As described below, LIBS can analyze the type of tissue and provide feedback when good or unwanted tissue has been ablated, thus supporting the decision to continue or stop ablation. Depth measurement by OCT or acoustic detection may be another technique to support the decision to continue or stop ablation based on preoperative planning and predetermined depth profiles.

[0072] Tissue ablated according to the invention may include cartilage, calcified layers, subchondral bone and cancellous or cortical bone. Cartilage is generally relatively soft, less dense, and has a high fluid content: this allows for a fast laser cutting process and a smooth and uniformly flat surface, out of focus, distributing the energy over a larger surface. Layers of cells can be clearly visibly removed, which may include a color change from pure white to pale yellow with depth as the calcium content increases.

[0073] The calcified layer is usually thin, dense and hard. It can be easily ablated by any energy setting. It is a clearly visible yellowish layer through which the reddish subchondral bone shines. Identification of the calcified layer can be supported by LIBS to detect the calcium content and stop at a pre-determined threshold before reaching this layer. The depth can be controlled relative to the pre-operative planning.

[0074] Subchondral hard tissue is usually cancellous bone, i.e. well perfused but without blood extravasation (which could compromise ablation or laser detection). It allows for clear visualization of cavity ablation and detection of cells of different colors. Ablation can be supported by LIBS detection of various cell types and stopping in the absence of a predetermined (damaged) cell type. Depth control can further support the delineation of pre-planned segmentation volumes.

[0075] Preferably, defining the unwanted hard tissue comprises the steps of: determining the alignment of the joint anatomy to balance the joint; and calculating a cutting geometry using the image and the determined joint alignment. Thus, removing the unwanted hard tissue comprises ablating the hard tissue of the joint according to the cutting geometry. As such, the joint can be balanced relative to the tension of the ligaments and / or the loading of the cartilage.

[0076] Preferably, determining unwanted hard tissue in the joint comprises: analyzing hard tissue ablated by the laser beam; and generating tissue data associated with the analyzed hard tissue, wherein the generated tissue data is used in providing laser beam ablation of the hard tissue.

[0077] Therefore, analyzing hard tissue and generating tissue data is preferably performed in real time.

[0078] Hard tissue is preferably analyzed by LIBS. LIBS allows accurate and rapid identification of unwanted tissue.

[0079] Preferably, defining unwanted joint hard tissue on the image of the joint includes identifying degenerative, diseased or dead hard tissue. The degenerative, diseased or dead hard tissue may be a focal defect of cartilage or defective subchondral hard tissue. In particular, by involving LIBS, the identified degenerative, diseased or dead hard tissue may be effectively and accurately removed.

[0080] Preferably, images of the joint are obtained by CT, MRI, OCT, etc.

[0081] Preferably, the treatment method includes the step of transplanting hard tissue at the section where the unwanted hard tissue is ablated. Such transplantation allows the hard tissue to be flattened or treated after the unwanted tissue is removed. This can allow the remaining hard tissue to maintain its stability or regenerate, which may be particularly important when implanting.

[0082] Preferably, the treatment method comprises the step of fitting the main body part of the joint implant as described above onto the prepared surface of the hard tissue so as to hold the joint implant at a predetermined target position on the hard tissue.

[0083] Therefore, the processing method preferably includes a step of forming a joint implant based on the image of the initial state, or a step of selecting a joint implant from a plurality of spare joint implants based on the image of the initial state. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] The present invention is described in more detail below by means of exemplary embodiments and with reference to the accompanying drawings, in which:

[0085] Figure 1A perspective view of a femoral knee implant according to a first embodiment of a joint implant according to the present invention is shown as a first embodiment of a joint implant kit according to the present invention;

[0086] Figure 2 shows a perspective view of a femoral knee end prepared according to an embodiment of the arthroplasty method according to the present invention;

[0087] Figure 3 Shown as a basis Figure 1 A perspective view of a first tibial knee implant according to a second embodiment of a joint implant of the present invention of a joint implant kit;

[0088] Figure 4 Shown as a basis Figure 1 A perspective view of a second tibial knee implant according to a third embodiment of a joint implant of the joint implant kit of the present invention; and

[0089] Figure 5 A perspective view of a tibial knee end prepared according to the arthroplasty method according to the present invention is shown. DETAILED DESCRIPTION

[0090] In the following description, certain terms are used for convenience, but not for limiting the present invention. The terms "right", "left", "up", "down", "below" and "above" refer to the directions in the figure. The terms include the terms explicitly mentioned and their derivatives and terms with similar meanings. In addition, spatial relative terms, such as "below", "below", "lower", "upper", "above", "near side", "distal side", etc., can be used to describe the relationship between an element or feature and another element or feature, as shown in the figure. In addition to the positions and orientations shown in the figures, these spatial relative terms are intended to cover different positions and orientations of the device in use or operation. For example, if the device in the figure is turned over, the elements described as "below" or "below" other elements or features will be "above" or "above" other elements or features. Therefore, the exemplary term "below" can include the position and orientation of the top and bottom. The device can be oriented in other ways (rotated 90 degrees or other orientations), and the spatial relative descriptors used here are interpreted accordingly. Similarly, the description of the movement along and around various axes includes various special device positions and orientations.

[0091] In order to avoid repetitions in the drawings and descriptions of various aspects and illustrative embodiments, it should be understood that many features are common to many aspects and embodiments. The omission of an aspect from the description or drawings does not mean that the aspect is missing in the embodiments containing the aspect. On the contrary, the aspect may have been omitted for clarity and to avoid lengthy descriptions. In this case, the following applies to the remainder of this specification: If, in order to clarify the drawings, the drawings contain reference numerals that are not explained in the directly related parts of the specification, reference is made to the preceding or following description. In addition, for clarity, if in one figure, not all features of a component are provided with reference numerals, reference is made to other figures showing the same component. The same numbers in two or more figures represent the same or similar elements.

[0092] Figure 1 A femoral knee implant 2 as a first embodiment of a joint implant according to the present invention is shown. The femoral knee implant 2 forms a part of a joint implant kit 1 according to the present invention. It has a main body portion 21 of a generally arched metal so as to be suitable for press-fitting onto the femur 4 of the patient. The main body portion 21 has a tissue surface 211 and an exposed surface 215 relative to the tissue surface 211, and the tissue surface 211 is configured to contact the prepared surface 41 of the femur 4 of the patient. The tissue surface 211 includes an anchoring structure 212, which is configured to anchor the femoral knee implant 2 onto the femur 4 of the patient.

[0093] The anchoring structure 212 of the tissue surface 211 includes a plurality of anti-pivot protrusions with a non-rotationally symmetrical cross section. In particular, the anti-pivot protrusions include a plurality of wavy protrusions 213 and a column 214 with a star-shaped cross section.

[0094] exist Figure 2 , the knee end of a patient's femur 4 is shown, wherein the knee end is provided with a prepared surface 41 to receive the tissue surface 211 of the femoral knee implant 2.

[0095] Before any intervention, the application of joint implant kit is planned in the embodiment of the preoperative planning method according to the present invention. The preoperative planning method comprises the steps of OCT scanning the femoral end of femur 4 and generating the tissue surface image data of the geometry of the tissue surface 211 representing the femoral knee implant 2. The doctor defines the target position of the femoral knee implant 2 on the femoral image generated by the image data. This step is performed on a computer system. The computer system uses the image and the defined target position to calculate the cutting geometry to prepare the surface of the femur 4. The cutting geometry is suitable for producing the preparation surface 41 of the femur 4 corresponding to the tissue surface 211 of the femoral knee implant 2.

[0096] Then, the surface of the femur 4 is processed by an embodiment of the arthroplasty method according to the present invention. In this method, the knee end of the patient's femur can be approached. Based on the image generated in the preoperative planning method and the defined target position, the cutting geometry is calculated and the laser beam is provided according to the calculated cutting geometry. Therefore, the surface of the femur 4 of the knee is prepared by providing a laser beam to the femur 4 and ablating a certain volume of cortical hard tissue until the cancellous bone tissue of the femur 4 covered by the cortical hard tissue is reached.

[0097] In order to control the ablation of cartilage and / or bone tissue as accurately as possible to the cancellous bone tissue, the ablated tissue is analyzed. Therefore, an analytical laser beam is provided between pulses, so that the elements in the plasma plume are analyzed in real time by laser induced breakdown spectroscopy (LIBS). LIBS generates tissue data related to the analyzed tissue. And when a laser beam is provided to the surface to ablate the certain volume of hard tissue, the generated tissue data is used to determine when the cancellous bone tissue is reached. If the generated tissue data shows that the ablated hard tissue is degenerated, diseased or dead, the ablation is continued until healthy cancellous bone tissue is identified.

[0098] Once healthy cancellous bone tissue is reached, a laser beam is provided to create a structure 411 in the cancellous bone tissue that matches the anchoring structure 212 of the tissue surface 211 of the main body portion 21. The structure 411 includes a wavy depression 412 corresponding to the wavy protrusion 213 of the femoral knee implant 21 and a star-shaped groove corresponding to the column 214 of the femoral knee implant 2.

[0099] After preparation, the main body 21 of the femoral knee implant 2 is assembled to the prepared surface 41 of the femur 4 so that the femoral knee implant 2 is maintained at a defined target position on the femur 4. To achieve this, the main body 21 of the femoral knee implant 2 is curved to match the prepared surface 41 of the femur 4.

[0100] Figure 3 A first tibial knee implant 31 of a second embodiment of a joint implant according to the present invention is shown as a tibial knee implant set 3 of a joint implant set 1. Figure 4In the figure, the second tibia knee implant 32 of the third embodiment of the joint implant according to the present invention as the tibia knee implant kit 3 of the joint implant kit 1 is shown.The first and second tibia knee implants 31,32 have a metal body part 311,321, and its size is designed to be positioned on the knee end of tibia 5.Main body part 311,321 has a tissue surface 312,322 equipped with anchoring structures 315,325, and anchoring structures 315,325 have a plurality of parallel wavy protuberances 313,323 as anti-pivot projections.In addition, tibia knee implant 31,32 has a shell 314,324 covering the exposed face 316 relative to the tissue surface 311,321.

[0101] Figure 5 The knee end of the tibia 5 is shown, which has two preparation surfaces 51, which are provided by the preoperative planning method and the arthroplasty method, as described above in conjunction with the femoral knee implant. Therefore, the preparation surface 51 forms a structure 511 that matches the anchoring structure of the corresponding tibial implant 31, 32. In particular, the preparation surface 51 has a cavity equipped with a wavy depression 512 corresponding to the wavy protuberances 313, 323 of the tibial knee implant 31, 32. Figure 5 , the first tibial knee implant 31 is assembled into the right prepared surface of the tibia 5 so that the exposed surface 315 of the main body portion 311 faces the cavity of the knee.

[0102] This description and drawings showing aspects and embodiments of the present invention should not be considered as limiting the claims defining the protected invention. In other words, although the present invention has been described and described in detail in the drawings and the foregoing description, such description and illustration are considered to be illustrative or exemplary rather than restrictive. Various mechanical, compositional, structural, electrical and operational changes may be made without departing from the spirit and scope of the present specification and claims. In some cases, in order not to obscure the present invention, well-known circuits, structures and techniques are not shown in detail. Therefore, it should be understood that changes and modifications can be made by those of ordinary skill within the scope and spirit of the appended claims. In particular, the present invention covers other embodiments having any combination of features from the different embodiments described above and below.

[0103] The present disclosure also covers all further features shown individually in the figures, although they may not be described in the preceding or following description. Furthermore, individual alternatives of the embodiments described in the figures and the description and individual alternatives of their features may be abandoned from the subject matter of the present invention or the disclosed subject matter. The present disclosure includes subject matter consisting of the features defined in the claims or in the exemplary embodiments, as well as subject matter comprising said features.

[0104] Furthermore, in the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single unit or step may implement the functions of several features listed in the claims. The fact that certain measures are cited in mutually different dependent claims does not mean that the combination of these measures cannot be used advantageously. The terms "substantially", "approximately", "approximately", etc. related to an attribute or value particularly also precisely define the attribute or value, respectively. In the context of a given numerical value or range, the term "approximately" refers to a numerical value or range within 20%, within 10%, within 5%, or within 2% of a given numerical value or range, for example. Components described as coupled or connected may be directly electrically or mechanically coupled, or they may be indirectly coupled via one or more intermediate components. Any figure mark in the claims should not be interpreted as limiting the scope.

Claims

1. A device to be mounted on a patient's hard tissue (4; 5) Joint implants (2; 31 ； 32), the joint implant comprises: The main body part (21; 311; 321) has a tissue surface (211; 312; 322), the tissue surface being configured to contact a prepared surface (41; 51) of a patient's hard tissue (4; 5) when the joint implant (2; 31; 32) is mounted on the patient's hard tissue (4; 5); wherein the tissue surface (211; 312; 322) of the main body portion (21; 311; 321) comprises an anchoring structure (212; 315; 325) configured to anchor the joint implant (2; 31; 32) to the hard tissue (4; 5) of the patient, and The main body part (21; 311; 321) is formed to cooperate with the prepared surface (41; 51) of the hard tissue (4; 5), so that the joint implant (2; 31; 32) is maintained in a predetermined target position when being installed in the hard tissue (4; 5).

2. The joint implant (2; 31; 32) according to claim 1, wherein: The main body portion (21; 311; 321) is formed to slideably fit with a prepared surface (41; 51) of hard tissue (4; 5).

3. The joint implant (2; 31; 32) according to claim 1 or 2, wherein: The anchoring structure (212; 315; 325) of the tissue surface (211; 312; 322) of the main body portion (21; 311; 321) includes at least one anti-pivot protrusion (213, 214; 313; 323) having a non-rotationally symmetric cross-section.

4. The joint implant (2; 31; 32) according to claim 3, wherein: The at least one anti-pivot protrusion (213, 214; 313; 323) of the anchoring structure (212; 315; 325) of the tissue surface (211; 312; 322) of the main body portion (21; 311; 321) includes a plurality of wavy protrusions (213; 313; 323).

5. The joint implant (2; 31; 32) according to claim 3 or 4, wherein: The at least one anti-pivot protrusion (213, 214; 313; 323) of the anchoring structure (212; 315; 325) of the tissue surface (211; 312; 322) of the main body portion (21; 311; 321) comprises a cylinder (214) having an angular, spline polygonal or star-shaped cross-section.

6. A joint implant (2; 31; 32) according to any one of the preceding claims, wherein: The anchoring structure (212; 315; 325) of the tissue surface (211; 312; 322) of the main body portion (21; 311; 321) comprises at least one shape-fitting protrusion, and the at least one shape-fitting protrusion is configured to fit in shape with a shape-fitting cavity of the prepared surface (41; 51) of the hard tissue (4; 5).

7. The joint implant (2; 31; 32) according to claim 6, wherein: The cross section of the at least one form-fitting projection increases in the direction of the prepared surface (41; 51) intended to be directed toward the hard tissue (4; 5).

8. A joint implant (2; 31; 32) according to any one of the preceding claims, configured to snap-fit ​​with the prepared surface (41; 51) of the hard tissue (4; 5).

9. A joint implant (2; 31; 32) according to any one of the preceding claims, wherein: The main body portion (21; 311; 321) is made of a biocompatible metal or metal alloy, which is optionally modified or enhanced with a bone integration promoter.

10. A joint implant (2; 31; 32) according to any one of the preceding claims, comprising a shell part (314; 324), wherein the main body part (21; 311; 321) has an exposed surface (215; 316), which is exposed toward a portion of the joint other than the hard tissue (4; 5) on which the joint implant (2; 31; 32) is to be installed, wherein the shell part (314; 324) is fixed to the main body part (21; 311; 321) so that the exposed surface (215; 316) of the main body part (21; 311; 321) is covered by the shell part (314; 324).

11. The joint implant (2; 31; 32) according to claim 10, wherein: The housing part (314; 324) is made of plastic.

12. The joint implant (2; 31; 32) according to claim 11, wherein: The plastic is cross-linked polyethylene, optionally provided with an antioxidant such as vitamin C.

13. A joint implant (2; 31; 32) according to any one of claims 10 to 12, configured to be mounted to the knee end of a tibia (5).

14. The joint implant (2; 31; 32) according to any one of claims 1 to 9, wherein: The tissue surface (211; 312; 322) is formed to surround the knee end of the femur (4).

15. A joint implant kit (1) comprising a first joint implant (2; 31; 32) according to any one of the preceding claims and a second joint implant (2; 31; 32) according to any one of claims 10 to 13, wherein: The first joint implant (2; 31; 32) comprises a first main body portion (21; 311; 321) having a tissue surface (211; 312; 322), wherein the tissue surface of the first main body portion is configured to be attached to a first hard tissue (4; 5) is contacted with a prepared surface (41; 51) of a first hard tissue (4; 5) of a joint of a patient, The second joint implant (2; 31; 32) comprises a second body portion (21; 311; 321) having a tissue surface (211; 312; 322), the tissue surface of the second body portion being configured to contact a prepared surface (41; 51) of a second hard tissue (4; 5) of a joint of the patient when the second joint implant (2; 31; 32) is mounted to a second hard tissue (4; 5) of a joint of the patient, wherein the second main body portion (21; 311; 321) of the second joint implant (2; 31; 32) has an exposed surface (215; 316), the exposed surface of the second main body portion being exposed toward the first joint implant (2; 31; 32) when the first joint implant (2; 31; 32) is mounted to the first hard tissue (4; 5) of the patient's joint and the second joint implant (2; 31; 32) is mounted to the second hard tissue (4; 5) of the patient's joint, and The second joint implant (2; 31; 32) has a shell part (314; 324), and the shell part of the second joint implant is fixed to the second main body part (21; 311; 321) so that the exposed surface (215; 316) of the second main body part (21; 311; 321) is covered by the shell part (314; 324).

16. A preoperative planning method comprising the following steps: Obtaining data of a tissue surface (211; 312; 322), wherein the data of the tissue surface represents the geometric shape of the tissue surface (211; 312; 322) of the main part (21; 311; 321) of the joint implant (2; 31; 32) according to any one of claims 1 to 14; Obtaining image data of an initial state of a hard tissue (4; 5) of a joint of a patient; In the hard tissue generated by image data (4; 5) on the image defining the target position of the joint implant (2; 31; 32); as well as Using the image data and the defined target position, a cutting geometry is calculated to prepare the surface of the hard tissue, wherein the cutting geometry is suitable for producing the hard tissue (4; 5), the prepared surface (41; 51) corresponding to the tissue surface (211; 312; 322) of the main part (21; 311; 321) of the joint implant (2; 31; 32).

17. The preoperative planning method according to claim 16, wherein: The cutting geometry is adapted to remove a volume of hard tissue of the joint until reaching a target tissue of the hard tissue (4, 5) covered by the volume of hard tissue.

18. The preoperative planning method according to claim 16 or 17, wherein: The target tissue is a calcified layer of tissue located between cartilage tissue and cancellous bone tissue.

19. The preoperative planning method according to claim 16 or 17, wherein: The target hard tissue is cartilage tissue or cancellous bone tissue.

20. The preoperative planning method according to any one of claims 16 to 19, wherein: Image data of the initial state of the hard tissue (4; 5) of the joint are obtained by optical coherence tomography.

21. A preoperative planning method according to any one of claims 16 to 20, comprising forming the joint implant (2; 31; 32) based on the image data of the initial state.

22. The preoperative planning method according to any one of claims 16 to 20, comprising selecting a joint implant (2; 31; 32) from a plurality of spare joint implants based on the image data of the initial state.

23. A method of arthroplasty, comprising: Obtain hard tissue close to the patient's joint (4; 5) channel; The surface of the hard tissue (4; 5) of the joint is prepared in the following manner: by providing a laser beam to the hard tissue (4; 5) and thereby ablating a certain volume of hard tissue until a target hard tissue covered by the certain volume of hard tissue is reached, and by providing the laser beam to the target hard tissue and thereby generating in the target hard tissue a structure that matches the tissue surface (211; 312; 322) of the main part (21; 311; 321) of the joint implant (2; 31; 32) according to any one of claims 1 to 14; and The main body (21; 311; 321) of the joint implant (2; 31; 32) is assembled to the prepared surface (41; 51) of the hard tissue (4; 5) so that the joint implant (2; 31; 32) is maintained at a predetermined target position on the hard tissue (4; 5).

24. The arthroplasty method of claim 23, wherein: The target hard tissue is a calcified layer of tissue located between the cortical hard tissue and the subchondral bone tissue.

25. The arthroplasty method of claim 23, wherein: The target hard tissue is cancellous bone tissue.

26. A method of arthroplasty according to any one of claims 23 to 25, comprising: analyzing hard tissue ablated by the laser beam; generating tissue data associated with the hard tissue being analyzed; and when to hard tissue (4; 5) Using the generated tissue data when providing a laser beam to ablate the volume of cortical hard tissue to determine when the target hard tissue is reached.

27. The arthroplasty method of claim 26, wherein: Analyzing hard tissue and generating tissue data is performed in real time.

28. The arthroplasty method according to claim 26 or 27, wherein: The hard tissue is analyzed by means of laser induced breakdown spectroscopy.

29. A method of arthroplasty according to any one of claims 23 to 28, comprising: Obtaining an image of the initial state of hard tissue; Defining joint implants on hard tissue images (2; 31 ； 32) target location; and using the image and the defined target position to calculate a cutting geometry in order to provide the laser beam to the hard tissue (4; 5) to ablate the certain volume of hard tissue.

30. The arthroplasty method of claim 29, wherein: The image of the initial state of the hard tissue (4, 5) is obtained by computer tomography.

31. A method of arthroplasty according to any one of claims 23 to 30, comprising: obtaining additional images of the current state of the hard tissue; and aligning the target hard tissue according to the additional image (4; 5) The provision of the laser beam is controlled.

32. The arthroplasty method of claim 31, wherein: The further image of the current state of the hard tissue (4, 5) is obtained by optical coherence tomography or by means of a navigated fiducial marker.

33. A method of arthroplasty according to any one of claims 23 to 32, wherein: It comprises forming the joint implant (2; 31; 32) based on the image of the initial state.

34. Arthroplasty method according to any one of claims 23 to 32, comprising selecting the joint implant (2; 31; 32) from a plurality of ready-made joint implants based on the image of the initial state.

35. A method for treating a joint of a patient, comprising: obtaining an image of the joint; defining unwanted hard tissue of the joint on the image of the joint; gaining access to the joint; as well as The unwanted hard tissue of the joint is removed by providing a laser beam and thereby ablating the unwanted hard tissue.

36. The process according to claim 35, wherein: Defining the unwanted hard tissue includes: determining an alignment of the anatomical structure of the joint to balance the joint; and calculating a cutting geometry using the image and the determined alignment of the joint, wherein removing the unwanted hard tissue includes ablating the hard tissue according to the cutting geometry.

37. The process according to claim 35 or 36, wherein: Defining the unwanted hard tissue of the joint includes analyzing the hard tissue ablated by the laser beam; and generating tissue data related to the analyzed hard tissue, wherein the generated tissue data is used in providing the laser beam to ablate the hard tissue.

38. The process according to claim 37, wherein: Analyzing hard tissue and generating tissue data is performed in real time.

39. The method according to claim 37 or 38, wherein: The hard tissue is analyzed by means of laser induced breakdown spectroscopy.

40. The method according to any one of claims 35 to 39, wherein: Defining unwanted hard tissue of the joint on the image of the joint includes identifying degenerated, diseased, or dead hard tissue.

41. A method according to any one of claims 35 to 40, wherein: An image of the initial state of the joint is obtained by computed tomography, optical coherence tomography or a navigational reference marker.

42. A method of treatment according to any one of claims 35 to 41, comprising transplanting the unwanted hard tissue at the section where the hard tissue is ablated.

43. The processing method according to any one of claims 35 to 41 comprises mounting the main part (21; 311; 321) of the joint implant (2; 31; 32) according to any one of claims 1 to 14 onto the prepared surface (41; 51) of the hard tissue (4; 5) so that the joint implant (2; 31; 32) is maintained at a predetermined target position on the hard tissue (4; 5).

44. The processing method according to claim 43, comprises forming the joint implant (2; 31; 32) based on the image of the initial state.

45. The processing method according to claim 43, comprises selecting the joint implant (2; 31; 32) from a plurality of spare joint implants based on the image of the initial state.

Images