Surgical instrument

Abstract

To provide a surgical instrument for use in a knee joint replacement operation.SOLUTION: The surgical instrument comprises: a cutting block which has a block rear face configured to abut on a distal end face of a resected femur, and has a guide slot extending from the block rear face to a distally opposite block front face and configured to receive and guide a saw blade; a reference foot that is mountable or mounted on the cutting block in a region of a rear block lower face of the cutting block, the reference foot having a foot upper face that is anteriorly oriented and configured to abut on posterior condyles of the femur; and a probe that is mountable or mounted on the cutting block in a region of a block upper face lying anteriorly opposite the block lower face, the probe comprising a probe tip which, in a mounted state of the probe, protrudes proximally beyond the block rear face and is configured to abut on an anterior face of the femur.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to surgical instruments for use in knee replacement surgery.

Background Art

[0002] The use of orthopedic prostheses as artificial replacements for damaged or worn natural bone structures is a common medical practice. In particular, hip and knee replacement surgeries are routine in orthopedics today.

[0003] In knee replacement surgery, or total knee arthroplasty (TKA), the diseased or damaged and worn or affected joint surfaces of the femur and / or tibia are replaced by a knee prosthesis. Such a knee prosthesis typically comprises a femoral component implanted at the distal end of the femur and a tibial component implanted at the proximal end of the tibia. To ensure proper functioning of the artificial joint, the aforementioned components must be placed as accurately as possible in a defined position and orientation with respect to the patient's anatomical structure and body axis. Otherwise, unsatisfactory results for the patient must be expected. There are various surgical approaches regarding the positioning of the components.

[0004] In the approach known as mechanical alignment, which has been mainly used so far, the position and orientation of the artificial joint axis of the knee prosthesis have been provided to be mechanically ideal without considering any orthopedic deformities of the patient. The longitudinal axis of the tibia has often been used here as a reference axis for orientation and positioning. Clinical studies have shown that the mechanical alignment approach can lead to the artificial knee joint feeling unnatural in its function.

[0005] A further approach is known as kinematic alignment. In this technique, the femoral and tibial components are positioned taking into account any orthopedic deformities in the patient. Its aim is to restore the patient's natural joint orientation, which, in some cases, is affected by the deformity. Clinical studies have shown that the kinematic alignment approach is often associated with improved patient satisfaction, particularly with the function of the total knee joint being perceived as more natural by the patient.

[0006] In addition to precise positioning, it is crucial that the femoral and tibial components are selected and implanted in sizes appropriate to the patient's anatomical structure. The size of the femoral components largely depends on the size of the femur, which is determined during the procedure using measuring instruments provided for this purpose. Such measuring instruments are also called femoral sizers or femoral sizing systems.

[0007] It is customary to determine the size after the distal femur has been resected. A known measuring instrument is placed on the resected end face of the distal femur and oriented relative to an anatomical reference plane or anatomical landmark. After the size has been determined, the distal femur is further prepared for the application of femoral components. This requires further resection, which usually includes anterior resection, posterior resection, and so-called chamfer resection. These resections are performed using a cutting block or cutting fixture fixed to the distal end face of the femur. Because femoral sizes vary, various cutting blocks with varying anterior-posterior and / or medial-lateral dimensions are usually available. In each case, the required dimensions are selected according to the femoral size previously determined by the operating surgeon. Determining the femoral size individually, then selecting an appropriate cutting block, and then applying the cutting block to the femur can be costly in terms of time and equipment, and can be a source of potential errors. [Overview of the project] [Problems that the invention aims to solve]

[0008] To further improve patient satisfaction, there is a fundamental need for surgical instruments that are as accurate, easy to use, and cost-effective as possible for performing kinematic alignment. This invention deals with such surgical instruments and corresponding instrument systems. [Means for solving the problem]

[0009] The object of the present invention is to provide a surgical instrument for use in knee joint replacement surgery, which overcomes or mitigates the drawbacks of the prior art and enables savings, particularly with respect to time and / or instruments.

[0010] This objective is achieved by providing a surgical instrument having the features of claim 1.

[0011] The surgical instrument according to the present invention comprises: a cutting block having a proximal posterior surface of the block configured to abut against the distal end face of the excised femur, and at least one guide slot extending distally from the posterior surface of the block to the opposite anterior surface of the block, elongated in the medial-lateral direction, and configured to receive and guide a saw blade; a reference foot having an anteriorly oriented foot surface, which is attachable to or attached to the cutting block in the region of the posterior lower surface of the cutting block, and in the attached state, the foot surface protrudes proximally beyond the posterior surface of the block and is configured to abut against the posterior condyle of the femur; and a probe having a probe tip that protrudes proximally beyond the posterior surface of the block and is configured to abut against the anterior surface of the femur, in the attached state. The solution according to the present invention eliminates the need for individual size measurements and / or size checks, and eliminates the need for individual measuring instruments that are normally required for this purpose. In this way, it is possible to save time, reduce equipment expenditures, and therefore reduce associated costs. The surgical instrument according to the present invention enables, on the one hand, the necessary size measurement and / or size checking of the femur. A reference foot and probe exist, particularly for this purpose, and are attached to or can be attached to the cutting block. On the other hand, the surgical instrument according to the present invention enables guiding of the cutting portion necessary for further resection of the femur. For this purpose, a cutting block exists, having the aforementioned at least one guide slot for receiving and guiding the saw blade. In one embodiment, the reference foot and probe are each detachably attached to the cutting block. In a further embodiment, the reference foot and probe are each permanently connected to the cutting block. The cutting block may also be called a sawing block or cutting jig. In a preferred embodiment, the cutting block has a plurality of guide slots, preferably an anterior guide slot, a posterior guide slot, and two chamfer guide slots, and may also be called a four-in-one cutting block.The posterior surface of the block is useful for distal reference. During the use of surgical instruments, the posterior surface of the block contacts the distal end face of the resected femur. The superior surface of the foot is useful for posterior reference. During the use of surgical instruments, the superior surface of the foot contacts the posterior condyle of the femur. The probe, more precisely its tip, is useful for anterior reference. During the use of surgical instruments, the tip of the probe contacts the aforementioned anterior surface of the femur. The probe may also be a stylus. In one embodiment, the tip of the probe is movable relative to the cutting block, preferably linearly movable in the proximal-distal direction, and / or rotatable around an anterior-posterior pivot axis. In further embodiments, the tip of the probe is not movable relative to the cutting block.

[0012] The designations of position, orientation, and / or direction used herein relate to the patient's body, particularly the patient's femur, and to this extent, they should be understood according to their usual anatomical meaning. Thus, “anterior” indicates extending forward, or towards the front; “posterior” indicates extending backward, or towards the back; “medial” indicates extending medially, or towards the medial side; “lateral” indicates extending laterally, or towards the lateral side; “proximal” indicates toward the center of the body; and “distal” indicates away from the center of the body. Furthermore, “proximal-distal direction” indicates preferably parallel along the proximal-distal axis; “anterior-posterior direction” indicates preferably parallel along the anterior-posterior axis; and “medial-lateral direction” indicates preferably parallel along the medial-lateral axis. The aforementioned axes are orthogonal to each other and can of course be understood in relation to the X, Y, and Z axes, which are not related to the patient's anatomical structure. For example, the proximal-distal axis can alternatively be the X axis. The medial-lateral axis can be the Y axis. The anterior-posterior axis can be defined as the Z-axis. For better explanation and simplification of terminology, the aforementioned anatomical position, orientation, and / or direction names are primarily used below. Furthermore, with respect to proximal observation directions, names such as "posterior" are used, for example, for components such as cutting blocks or parts of surgical instruments. In contrast, names such as "anterior" are used with respect to distal observation directions.

[0013] In one embodiment of the present invention, the cutting block has a first fixed recess positioned at the rear, and the base foot has a complementary fixed element, and the first fixed recess and the fixed element are removablely connectable to each other or connected to each other by shape fit and / or force fit engagement. In different embodiments, the first fixed recess and the fixed element form different types of coupling connections. In one embodiment, there is a removable plug connection. In other embodiments, there are latch connections, clamp connections and / or snap-fit ​​connections, etc. Furthermore, screw connections are conceivable. The removable connection between the cutting block and the base foot means that after a size check has been performed, the base foot can be removed from the cutting block. The cutting block can then be used to perform the appropriate cut.

[0014] In a further embodiment of the present invention, the first fixing recess is a linear and elongated receiving slot extending from the rear surface of the block to the front surface of the block, and the fixing element is a flat plug element configured to be inserted into the receiving slot by shape fit and / or force fit engagement. To fix the reference foot, the plug element is inserted into the receiving slot proximal to the front surface of the block. The plug element has a shape that complements the receiving slot, and vice versa. In the inserted state, the plug element is held in the receiving slot by shape fit and / or force fit engagement. This allows for simple yet secure fixing of the reference foot.

[0015] In a further embodiment of the present invention, the plug element has at least one separation gap that is substantially U-shaped in the longitudinal direction to form an elastically resiliently movable spring tongue, and in the mounting state of the reference foot, the spring tongue is biased against the inner wall of the receiving slot. In this way, friction is increased between the reference foot, more precisely the spring tongue and the receiving slot, more precisely the inner wall of the receiving slot. This improves the fixation of the reference foot. Due to the substantially U-shaped longitudinal extension of the separation gap, the spring tongue is tongue-shaped and / or has a tongue shape. The separation gap extends in the longitudinal direction and thus extends completely from the front-facing upper surface of the plug element to the rear-facing lower surface of the plug element. In one embodiment, the spring tongue presses against the inner wall of the receiving slot from the upper surface (forward) of the plug element, and in a further embodiment, from the lower surface (rearward) of the plug element.

[0016] In a further embodiment of the present invention, the receiving slot has two separate slot portions separated from each other in the inward and outward directions by a web, and the plug element has two separate plug portions separated from each other in the inward and outward directions by a gap. In the fixed state of the reference foot, the web enters the gap, further improving the fixation, particularly in the inward and outward directions. In this embodiment of the present invention, it is also possible to refer to the first slot portion and the second slot portion, and therefore the first plug portion and the second plug portion.

[0017] In a further embodiment of the present invention, the receiving slot is configured to receive and guide the saw blade when the reference foot is not attached, forming a rear guide slot for the cutting block. This is a particularly preferred embodiment of the present invention. In this embodiment, the receiving slot has a number of particularly advantageous functions. On the one hand, the receiving slot serves to receive a plug element for the purpose of removably securing the reference foot to the cutting block. On the other hand, the receiving slot functions as a guide slot for the saw blade. In this way, a particularly simple and compact structure of the cutting block can be achieved.

[0018] In a further embodiment of the present invention, the first fixing recess is a receiving pocket recessed proximal to the front surface of the block, and the fixing element is configured to form a latching and / or clamping connection with the receiving pocket. Thus, the fixing element is a latching element in one embodiment and a clamping element in another embodiment.

[0019] In a further embodiment of the present invention, the reference foot forms a flat, extended portion, which is spaced posteriorly from the fixed element, and whose upper surface forms the upper surface of the foot. When the reference foot is fixed, the extended portion is positioned below the lower surface of the block, i.e., spaced posteriorly from the lower surface of the block. For this purpose, the elongation portion is spaced posteriorly from the fixed element. The upper surface of the elongation portion faces anteriorly and is configured to abut against the posterior condyle of the femur. The elongation portion projects proximally beyond the posterior surface of the block. In one embodiment, the elongation portion has two separate elongations separated from each other in the medial and lateral directions by a web. In this embodiment, the first and second elongations, or alternatively, the medial and lateral elongations, may also be referred to. The medial elongation portion is provided to refer to the medial posterior condyle. Thus, the lateral elongation portion is provided to refer to the lateral posterior condyle.

[0020] In a further embodiment of the present invention, the reference foot has a distally positioned grip portion, and the fixing element and / or extension portion project proximally from the grip portion, the grip portion having a first grip surface facing outward, a second grip surface facing inward, and a proximal resting surface. The grip portion allows for ergonomic manual manipulation of the reference foot by the operating surgeon. For this purpose, the grip portion is positioned distally on the reference foot. Thus, in the fixed state of the reference foot, the grip portion is positioned to be easily accessible from the front of the block. The grip portion can be grasped between the fingers of one hand and for this purpose has two grip surfaces. The outward-facing first grip surface is positioned outward and can therefore be an outer grip surface. The inward-facing second grip surface is positioned inward and can therefore be an inner grip surface. The proximal resting surface is particularly advantageous in embodiments in which the fixing element of the reference foot is designed as a plate-shaped plug element. In this case, the proximal-facing stop surface limits the depth to which the plug element is inserted into the receiving slot.

[0021] In a further embodiment of the present invention, the cutting block has a second anteriorly positioned fixing recess, and the probe has a complementary fixing element, and the second fixing recess and the fixing element of the probe are removablely connectable to or connected to each other by shape-fit and / or force-fit engagement. In this way, after sizing and / or sizing checks are performed, the probe can be easily removed from the cutting block. The cutting block can then be used to perform further resection of the distal femur. In different embodiments, the second fixing recess and the fixing element of the probe form different bonding connections, such as plug connections, latch connections, clamp connections, and / or snap-fit ​​connections. Furthermore, screw connections are conceivable.

[0022] In further embodiments of the present invention, the second fixation recess is designed as a component of a general-purpose fixation system and is configured to connect to further instrument components, preferably surgical navigation devices. Thus, the further instrument components similarly have complementary fixation elements. The general-purpose fixation system allows for a selection of various instrument components that are fixed to and removable from the cutting block. In particular, a probe and, alternatively, at least one further instrument component, in particular the aforementioned navigation device, can be detachably fixed to the cutting block.

[0023] In a further embodiment of the present invention, the second fixation recess has a latch recess that is recessed rearward in the upper surface of the block, is elongated in the inward and outward directions, and opens at the inner or outer end, and the fixation element of the probe has a complementary latch portion that interacts with the latch recess of the cutting block to form a removable snap-fit ​​connection. The latch recess is elongated in the inward and outward directions, and in one embodiment opens toward the outer surface of the inner block, and in a further embodiment opens toward the outer surface of the outer block. Thus, the complementary latch portion can be pushed into the latch recess in the outward or inward direction and can be connected to the latch recess to form a snap-fit ​​connection. The latch recess is further recessed in the upper surface of the block and opens toward the forward direction by that amount. In this way, the snap-fit ​​connection is particularly easy for the surgeon to see. Thus, it is easy to identify whether the snap-fit ​​connection is formed as required.

[0024] In further embodiments of the present invention, the second fixing recess has a plug recess extending inward and outward within the outer surface of the cutting block, and the fixing element of the probe has a complementary plug portion that interacts with the plug recess to form a removable plug connection. Preferably, the plug recess has a cylindrical, preferably circular, cross-sectional shape. The same applies to the cross-sectional shape of the complementary plug portion of the probe, with necessary modifications. The plug portion may also be a pin, a bolt, and / or a peg. Thus, the plug recess may also be a bore, a pin recess, a peg recess, and / or a bolt recess. In one embodiment, the plug recess begins on the outer surface of the cutting block and extends inward into the interior of the cutting block. In another embodiment, in contrast, the plug recess begins on the outer surface of the cutting block and extends outward into the interior of the cutting block. This embodiment of the present invention is particularly advantageous in combination with embodiments in which the second fixing recess additionally has a latch recess. In this case, the plug recess contributes to improved fixing. The plug recess is preferably located on the cutting block at a position rearward from the latch recess.

[0025] In further embodiments of the present invention, there are multiple different compensating elements having different anterior-posterior thicknesses, each of which is attachable to, or preferably insertable, the upper surface of the foot and configured to compensate for different degrees of wear of the posterior condyle. The different compensating elements help to correct the orientation of the cutting block with respect to the longitudinal axis of the femur. In other words, the rotation of the cutting block about the proximal-distal axis can be adjusted by the different compensating elements. The kinematic alignment approach generally provides a so-called 0° orientation. To ensure 0° orientation, any wear of the posterior condyle must be compensated for. Wear can, of course, vary considerably. Therefore, there are multiple compensating elements of various dimensions, and more precisely, various thicknesses. The greater the degree of wear, the thicker the compensating element required. Each of the different compensating elements is attachable to the upper surface of the foot and configured to make direct contact with the posterior condyle. Preferably, the multiple different compensating elements include a lateral compensating element for contacting the lateral posterior condyle and a medial compensating element for contacting the medial posterior condyle.

[0026] The present invention further relates to a surgical instrument system for use in knee replacement surgery, having at least one surgical instrument as described above, wherein the reference foot and the probe are each removably attached to a cutting block, and the system has further different cutting blocks that are different from each other with respect to at least one dimension, particularly the anteroposterior and / or mediolateral dimensions, and the reference foot and the probe are each attachable to each of the further different cutting blocks. During use of the surgical instrument system, an appropriate cutting block is selected, for example, based on a preoperative examination, an X-ray image, etc. After preselecting the cutting block from a plurality of different cutting blocks, the reference foot and the probe can be attached to the cutting block. Here, in a first example, the reference foot and the probe serve to check the preselection of the size of the cutting block. For this purpose, the upper surface of the foot is placed on the posterior condyle of the femur in the manner described above. The rear surface of the block is placed on the distal end face of the resected femur. The actual check is performed by the tip of the probe. Thus, it is possible to presume that the correctly sized cutting block has been preselected when the tip of the probe simultaneously contacts the front surface of the femur in the region where the front protection of the femoral component to which the implant will be located later is located, with the upper surface of the foot and the rear surface of the block positioned.

[0027] In a further embodiment of the present invention, the reference foot and the probe are each permanently attached to the cutting block. In this embodiment, the corresponding connections between the reference foot and the cutting block and between the probe and the cutting block are not removable, at least during the surgery. For example, in each case, there can be a non-removable coupling connection.

[0028] The present invention further relates to a surgical instrument system for use in knee replacement surgery having a plurality of different surgical instruments according to the foregoing embodiments, wherein the plurality of different surgical instruments have at least one dimension of each cutting block, particularly the dimensions in the anteroposterior direction and / or the mediolateral direction, different from each other. In this surgical instrument system, each of the plurality of different surgical instruments has a respective cutting block, a reference foot, and a probe. The reference feet and probes of the different surgical instruments are respectively permanently and / or irreversibly attached onto their respective cutting blocks.

[0029] Further advantages and features of the present invention will be obtained from the claims and from the following description of the preferred exemplary embodiments of the present invention, which is described with reference to the drawings.

Brief Description of the Drawings

[0030] [Figure 1] FIG. 1 shows a schematic perspective view of an embodiment of a surgical instrument according to the present invention, having a cutting block, a reference foot, and a probe. [Figure 2] FIG. 2 shows a further schematic perspective view of the surgical instrument according to FIG. 1. [Figure 3] FIGS. 1 and 2 show the surgical instrument according to FIGS. 1 and 2 in a schematic plan view. [Figure 4] FIGS. 1 and 2 show the surgical instrument according to FIGS. 1 and 2 in a schematic side view. [Figure 5] FIGS. 1 and 4 show a schematic perspective view of an example of the intraoperative situation where the surgical instrument according to FIGS. 1 and 4 is placed on the distal femur. [Figure 6] FIG. 5 shows a further schematic perspective view of the intraoperative situation according to FIG. 5. [Figure 7] FIGS. 1 to 6 show another schematic perspective view of the cutting block of the surgical instrument according to FIGS. 1 to 6, seen in the direction of the front of the block. [Figure 8] FIGS. 1 to 6 show another schematic perspective view of the cutting block of the surgical instrument according to FIGS. 1 to 6, seen in the direction of the back of the block. [Figure 9] FIGS. 1 to 6 show a schematic perspective view of the reference foot of the surgical instrument according to FIGS. 1 to 6. [Figure 10] Figure 9 shows a schematic lateral view of the reference foot. [Figure 11] Figures 1 to 6 show schematic perspective views of surgical instrument probes. [Figure 12] Figure 11 shows a schematic longitudinal cross-sectional view of the probe along the cross-section BB shown in Figure 13. [Figure 13] Figures 11 and 12 show schematic plan views of the probe. [Figure 14] A schematic perspective view of a further embodiment of the surgical instrument according to the present invention is shown. [Figure 15] Figure 14 shows a schematic perspective view of a surgical instrument cutting block, viewed from the front of the block. [Figure 16] Figure 14 shows a schematic perspective view of the reference foot of a surgical instrument. [Figure 17] A simplified schematic block diagram of an embodiment of the surgical instrument system according to the present invention is shown. [Figure 18] Further embodiments of the surgical instrument system according to the present invention are shown in the manner corresponding to Figure 17. [Modes for carrying out the invention]

[0031] According to Figures 1 to 6, a surgical instrument 1 for use in knee joint replacement surgery is provided, and the surgical instrument 1 comprises a cutting block 100, a reference foot 200, and a probe 300.

[0032] The cutting block 100 has a proximal oriented posterior block surface 101, a distally opposite posterior block surface 102, an anterior block upper surface 103, a posterior block lower surface 104, an lateral block outer surface 105, and an medial block outer surface 106. The posterior block surface 101 is configured to abut against the distal end face S of the resected femur F (see Figures 5 and 6). The normal direction of the posterior block surface 101 is oriented parallel to the proximal-distal axis shown in Figures 1 and 2 and points in the proximal direction. The cutting block 100 further has at least one guide slot 107. In this example, multiple guide slots, i.e., at least one guide slot 107, are provided, which may also be designated as an anterior guide slot 107, a posterior guide slot 108, and chamfer guide slots 109, 110. Guide slots 107, 108, 109, and 110 each extend from the front surface 102 of the block to the rear surface 101 of the block. Furthermore, guide slots 107, 108, 109, and 110 are each elongated in the inward and outward directions, i.e., parallel to the inward and outward axes shown in Figures 1 and 2. Guide slots 107, 108, 109, and 110 are each configured to receive and guide a saw blade (not shown).

[0033] The reference foot 200 is attached to the amputation block in the region of the posterior block lower surface 104 and has a foot upper surface 201 oriented forward. Thus, the surface normal (not shown) of the foot upper surface 201 is parallel to the anterior-posterior axis shown in Figures 1 and 2 and points forward. The foot upper surface 201 protrudes proximally beyond the posterior block surface 101 and is configured to abut against the posterior condyles KL, KM of the femur F (see Figures 5 and 6). In this embodiment, the reference foot 200 is detachably connected to the amputation block 100, as will be described in detail later.

[0034] The probe 300 is attached to the cutting block 100 in the region of the block's upper surface 103 and has a probe tip 301. The probe tip 301 is configured to proximal project beyond the block's rear surface 101 and to contact the anterior surface A of the femur F (see Figures 5 and 6). In this embodiment, the probe 300 is detachably connected to the cutting block 100, as will be described in detail later.

[0035] Surgical instrument 1 serves multiple purposes. On the one hand, surgical instrument 1 can be used for measuring and / or checking the size of the distally resected femur F. On the other hand, the surgical instrument serves to guide the aforementioned saw blade during femoral resection.

[0036] For size measurement and / or size checking, the posterior surface 101 of the block contacts the end face S. Simultaneously, the upper surface 201 of the foot contacts the posterior condyles KL and KM. In this way, the surgical instrument is oriented with respect to the anterior-posterior axis and the proximal-distal axis of the femur F. Actual size measurement and / or size checking is performed by the probe 300 based on whether the tip 301 of the probe contacts the anterior surface A of the femur F when the surgical instrument 1 is in a predetermined orientation in contact with the end face S and the posterior condyles KL and KM.

[0037] After size measurement and / or size checking is performed, the cutting block 100 is fixed to the femur by appropriate pins, screws, etc., in a manner known to those skilled in the art. These can be introduced into fixing openings 111 provided in the cutting block for this purpose (see Figures 7 and 8). After the cutting block 100 is fixed to the femur, further resection of the femur F is performed. For this purpose, the saw blade is guided through guide slots 107, 108, 109, 110 in a manner known to those skilled in the art, thereby resecting the femur. In the embodiment illustrated herein, both the reference foot 200 and the probe 300 are removed from the cutting block 100 before the resection is performed.

[0038] In the illustrated embodiment, the cutting block 100 and the base foot 200 are connected to each other by a removable force-fit and / or shape-fit joint connection. For this purpose, the cutting block 100 has a rearward-positioned first fixing recess 112 (see Figures 7 and 8). The base foot 200 has a fixing element 202 that complements the first fixing recess 112 (see Figures 9 and 10).

[0039] The first fixed recess 112 is located in the area of ​​the lower surface 104 of the block. In the illustrated embodiment, the first fixed recess 112 is a receiving slot 113 that extends from the rear surface 101 of the block to the front surface 102 of the block, and is straight and elongated in the inward and outward directions. In the illustrated embodiment, the receiving slot 113 has two separate slot portions 1131, 1132, which can also be called the inner slot portion 1132 and the outer slot portion 1131. The two slot portions 1131, 1132 are separated from each other in the inward and outward directions by the web 114. The outer slot portion 1131 opens outward at the end opposite to the web 114. The inner slot portion 1132 opens inward at the end opposite to the web 114.

[0040] In the illustrated embodiment, the receiving slot 113 has a number of particularly advantageous functions. On the one hand, the receiving slot serves to receive a complementary fixing element 202 in shape-fit and / or force-fit engagement. On the other hand, the receiving slot 113 functions as a rear guide slot 108 when the reference foot 200 is not fixed to the cutting block 100. In other words, the rear guide slot 108 functions simultaneously as a receiving slot 113.

[0041] The complementary fixing element 202 (see Figures 9 and 10) is designed to fit into the receiving slot 113 and, in this example, is a flat plug element 203 configured to be inserted into the receiving slot 113 by shape fit and / or force fit engagement. In this example, the plug element 203 is flat with respect to the inward-outward direction and the proximal-distal axis. In its broadest sense, corresponding to the two-part receiving slot 113, the plug element 203 has two separate plug portions 2031, 2032. These can also be called the inner plug portion 2032 and the outer plug portion 2031. The two plug portions 2031, 2032 are separated from each other in the inward-outward direction by a gap 204. Here, the inward-outward spread of the gap 204 is greater than the corresponding spread of the web 114.

[0042] To secure the reference foot portion 200 to the cutting block 100, the plug element 203 is inserted proximal to the receiving slot 113. At this time, the outer plug portion 2031 is inserted into the outer slot portion 1131, and the inner plug portion 2032 is inserted into the inner slot portion 1132.

[0043] In the illustrated embodiment, the plug element 203 has at least one separation gap 2033 that is substantially U-shaped in the longitudinal direction, extending in the front-rear direction and forming an elastic and movable spring tongue portion 2034. When the plug element 203 is inserted, the spring tongue portion 2034 is subjected to a spring force load and abuts against the inner wall (not shown in detail) of the receiving slot 113. The spring tongue portion 2034 presses the aforementioned inner wall forward or backward. This increases friction and thus improves, and in particular secures, the fixation of the reference foot portion 200. In the illustrated embodiment, the separation gap 2033 and the spring tongue portion 2034 are located in the outer plug portion 2031 and may also be referred to as the outer separation gap 2033 and the outer spring tongue portion 2034. In this example, the inner plug portion 2032 has a corresponding design having an (inner) separation gap 2035 and an (inner) spring tongue portion 2036.

[0044] In the illustrated embodiment, the foot upper surface 201 is formed on a flat, plate-shaped extension 205. In other words, the upper surface (not described in detail) of the extension 205 forms the foot upper surface 201. The extension 205 is flat with respect to the medial-outward axis and the proximal-distal axis, and at least partially projects proximally beyond the rear surface 101 of the block. In this example, the extension 205 is oriented parallel to the plane with respect to the fixed element 203. The extension 205 is spaced rearward from the fixed element 203. In the fixed state of the reference foot 200, the extension 205 engages below the bottom surface 104 of the block (see Figure 4 in particular).

[0045] The extension portion 205 has an outer extension portion 2051 and an inner extension portion 2052. The two extension portions 2051 and 2052 are separated from each other in the inward and outward directions by a gap 206. The outer extension portion 2051 is positioned to contact the outer posterior condyle KL. Therefore, the inner extension portion 2052 is positioned to contact the inner posterior condyle KM.

[0046] To compensate for any wear of the posterior condyle KL, KM, the surgical instrument 1 in the illustrated embodiment also has a plurality of compensating elements. Only one of the plurality of compensating elements, compensating element 400, is shown in this drawing. The various compensating elements differ in thickness in the anterior-posterior direction, and each is configured to be mountable on the foot surface 201. In this example, the compensating element 400 is mounted on the lateral extension 2051. For this purpose, various joint connections between the compensating element 400 (the plurality of different compensating elements) and the foot surface 201 are conceivable in various embodiments. In this example, the compensating element 400 is inserted into the lateral extension 2051 in a manner not shown in detail. By mounting the compensating element 400 on the lateral extension 2051, any wear of the lateral posterior condyle KL can be compensated, because, despite the aforementioned wear, it can be ensured that the surgical instrument 1 is oriented to rotate around the proximal-distal axis so as to satisfy the requirements and concepts of kinematic alignment.

[0047] To show that the surgical instrument 1 has multiple different compensating elements, the compensating element 400 in Figure 9 is indicated by further reference numerals 400', 400'', and 400'''' in parentheses. These reference numerals relate to the first compensating element 400', the second compensating element 400'', and the third compensating element 400'''', which are not shown separately in the drawing. The front-to-back thickness of the first compensating element 400' is smaller than the front-to-back thickness of the second compensating element 400'' and the third compensating element 400''''. The front-to-back thickness of the second compensating element 400'' is larger than the front-to-back thickness of the first compensating element 400' and smaller than the front-to-back thickness of the third compensating element 400''''. The front-to-back thickness of the third compensating element 400'''' is larger than the front-to-back thickness of the first compensating element 400' and the second compensating element 400''''.

[0048] In the illustrated embodiment, the reference foot 200 further has a grip portion 207. The grip portion 207 is positioned distally on the reference foot 200 and has an outer grip surface 2071, an inner grip surface 2072, and a stopping surface 2073. The grip portion 207 is useful for simplified manual operation of the reference foot 200. A fixing element 202 protrudes proximally from the grip portion 207. An extension portion 205 protrudes proximally from the grip portion 207. The outer grip surface 2071 is substantially oriented outward, with the corresponding surface normal being substantially parallel to the medial-outward axis and pointing outward. The same applies to the inner grip surface 2072, with modifications where necessary. To fix and release the reference foot, the grip portion 207 is grasped between the fingers of one hand, for example, with the thumb placed on the outer grip surface 2071 and the index finger on the inner grip surface 2072. The stop surface 2073 faces proximal and primarily serves to limit the depth to which the plug element 203 is inserted into the receiving slot 113. In the inserted state, the stop surface 2073 contacts the front surface 102 of the block.

[0049] To removably connect the probe 300 to the cutting block 100, the cutting block has a second fixing recess 115 positioned at the front. The probe 300 has a fixing element 302 that complements the second fixing recess 115. The second fixing recess 115 and the fixing element 302 of the probe 300 are connectable or connected to each other by shape fit and / or force fit engagement.

[0050] In particular, as shown in Figures 7 and 8, the second fixed recess, here 115, has a latch recess 116 and a plug recess 117.

[0051] The latch recess 116 sinks into the upper surface 103 of the block in the rearward direction, starting from the outer surface 106 of the inner block and extending inward and outward within the cutting block 100. Here, the latch recess 116 opens forward (upward). Therefore, the latch recess 116 is a pocket-shaped design in the broadest sense.

[0052] The plug recess 117 begins on the outer surface 106 of the inner block and is introduced outward into the cutting block 100. In this example, the plug recess 117 has a circular cylindrical cross-section and may be called a bore. In embodiments not shown, both the latch recess 116 and the plug recess 117 are positioned outward on the cutting block 100. The cutting block may also have a second fixing recess both inward and outward. The plug recess 117 is spaced rearward from the latch recess 116.

[0053] The complementary fixing element 302 of the probe 300 has a latch portion 304 and a plug portion 305 (see Figure 11).

[0054] The latch portion 304 is designed to complement the latch recess 116 and, in this example, has two elastic spring rims 3041. The elastic spring rims 3041 are positioned opposite each other with respect to the proximal-distal axis and are elastically movable along the coaxial direction. Between the two spring rims 3041 with respect to the proximal-distal axis, the latch portion 304 has a guide pin 3042.

[0055] The plug portion 305 is designed to complement the plug recess 117 and therefore, in this example, has a peg shape, a pin shape, and / or a bolt shape. The plug portion 305 is straight and elongated in the inward and outward directions.

[0056] In the fixed position of the probe 300, the plug portion 305 is oriented coaxially with the plug recess 117 and is inserted axially into the plug recess. This causes the latch portion 304 to latch into the latch recess 116. The two spring rims 3041 latch into the inner contour (not shown in detail) of the latch recess 116 by shape-fit engagement. This design of the second fixed recess 115 and the complementary fixed element 302 improves torque support, particularly around the inward-outward axis. In this way, undesirable relative movement of the probe tip portion 301 with respect to the cutting block 100 is prevented.

[0057] In the illustrated embodiment, the second fixing recess 115 is an integral part of a general-purpose fixing system and is configured to connect to further instrument components not shown in detail in the drawings. In this way, instead of the probe 300, further instrument components having similarly complementary fixing elements may be selected to be removably connected to the cutting block 100. The instrument components in question are, in particular, surgical navigation devices.

[0058] In the illustrated embodiment, the probe tip 301 is movable relative to the cutting block 100. For this purpose, the probe 300, in this example, includes a bearing block 306 and a probe element 307 movably mounted thereon.

[0059] The probe element 307 is elongated between a first end 3071 and a second end 3072, with the probe tip 301 formed at the second end 3072. The probe element 307 is longitudinally guided relative to the bearing block 306 and is linearly movable on it. Furthermore, the probe element 307 is rotatable relative to the bearing block 306 about a pivot axis. The pivot axis (not shown in detail) is oriented parallel to the longitudinal axis. The bearing block 306 has a complementary fixing element 302 and therefore has both a latch portion 304 and a plug portion 305.

[0060] Figure 14 shows a further embodiment of surgical instrument 1a according to the present invention. The function and structure of surgical instrument 1a are substantially identical to those of surgical instrument 1 shown in Figures 1 to 6. To avoid repetition, only the main differences between surgical instrument 1a and surgical instrument 1 are described below. Functionally identical structural parts and / or parts of surgical instrument 1a are not described individually. Instead, the disclosure of surgical instrument 1 is explicitly referenced.

[0061] Surgical instrument 1a differs primarily in the way the reference foot 200a is fixed to the amputation block 100a. In contrast, the fixation of the probe 300 to the amputation block 100a is identical to that of the probe 300 of surgical instrument 1.

[0062] The cutting block 100a has a first fixing recess 112a. In this example, the first fixing recess 112a is a receiving pocket 113a that is recessed proximally within the front surface 102a of the block. The receiving pocket 113a is spaced forward from the rear guide slot 108a of the cutting block 100a and is located approximately in the center between the outer surfaces 105a and 106a of the block.

[0063] The reference foot portion 200a (Figure 16) has a fixing element 202a that complements the receiving pocket 113a. The fixing element 202a is configured to establish a latching and / or clamping connection with the receiving pocket 113a. In the illustrated embodiment, the fixing element 202a has a wedge-shaped design and extends between the distal end 2021a and the proximal end 2022a. The fixing element 202a flattens while maintaining its wedge shape in the direction of the proximal anterior end 2022a.

[0064] For a removable connection to the cutting block 100a, the fixing element 202a is inserted into the receiving pocket 113a with its proximal end 2022a facing forward. In this way, the latch connection and / or clamp connection described above are obtained.

[0065] In other respects, the reference foot 200a has a structure substantially corresponding to the reference foot 200 of surgical instrument 1 shown in Figures 1 to 13. Here again, there are an outer extension 2051a and an inner extension 2052a. Here, the inner extension 2052a is provided with a spring tongue 2036a that presses against the lower surface 104a of the block with a spring force load in order to frictionally support the fixation of the reference leg. A compensation element 400 is inserted into the outer extension 2051a to compensate for condylar wear, although this is of course not essential.

[0066] Figure 17 shows an embodiment of the surgical instrument system 10 according to the present invention. The surgical instrument system 10 has the surgical instrument 1 shown in Figures 1 to 6, and further comprises additional cutting blocks 100', 100''. The cutting blocks 100, 100', 100'' will also be referred to below as the first cutting block 100, the second cutting block 100', and the third cutting block 100''. The cutting blocks 100, 100', 100'' differ in dimensions and are provided for use with femurs of different sizes. Apart from the difference in dimensions, the second cutting block 100' and the third cutting block 100'' have the same function and design as the first cutting block 100.

[0067] The reference foot 200 and the probe 300 can be attached to the cutting blocks 100, 100', and 100'', respectively. This is done by the aforementioned fixing recesses and fixing elements.

[0068] Figure 18 shows a further embodiment of the surgical instrument system 10b according to the present invention. The surgical instrument system 10b also has a surgical instrument 1b comprising a cutting block 100b, a reference foot 200b, and a probe 300b. With respect to its function and design, the surgical instrument 1b is substantially identical to the surgical instrument 1 shown in Figures 1 to 6. The first difference is the way in which the reference foot 200b and the probe 300b are fixed to the cutting block 100b. Instead of removable fixation, the reference foot 200b and the probe 300b in the surgical instrument 1b are permanently attached to the cutting block 100b, respectively. Permanently means that the reference foot 200b and the probe 300b are not configured to be positioned on the cutting block 100b and removed. Instead, permanent joint connections (not shown or described in detail) exist between the reference foot 200b and the cutting block 100b on the one hand, and between the probe 300b and the cutting block 100b on the other hand.

[0069] The surgical instrument system 10b also has further surgical instruments 1b', 1b''. The surgical instruments 1b, 1b', 1b'' are hereafter referred to as the first surgical instrument 1b, the second surgical instrument 1b', and the third surgical instrument 1b''. The surgical instruments 1b, 1b', 1b'' differ in their dimensions and are provided for use with femurs of different sizes. Here, the surgical instruments 1b, 1b', 1b'' differ at least in terms of the medial-lateral dimensions of their respective cutting blocks 100b, 100b', 100b''. Furthermore, each probe 300b, 300b', 300b'' may have different dimensions, particularly along the proximal-distal axis. The same may be true for the reference foot 200b, 200b', 200b''.

Claims

1. A surgical instrument (1, 1a, 1b) for use in knee replacement surgery, comprising: A cutting block (100, 100a, 100b) a proximally facing block rear surface (101, 101a) configured to abut the distal end surface (S) of the resected femur (F); at least one guide slot (107, 108, 110; 107a, 108a, 109a, 110a) extending distally from the rear face (101, 101a) of the block to a front face (102, 102a) of the block opposite thereto, elongated inward and outward, and configured to receive and guide a saw blade; The cutting block (100, 100a, 100b) having a reference foot (200, 200a, 200b) attachable or attached to the cutting block (100, 100a, 100b) in the region of the rear block lower surface (104, 104a) of the cutting block (100, 100a, 100b), the reference foot (200, 200a, 200b) having a foot upper surface (201, 201a) facing forward, wherein in the attached state of the reference foot (200, 200a, 200b), the foot upper surface (201, 201a) protrudes proximally beyond the block rear surface (101, 101a) and is configured to abut against the posterior condyles (KL, KM) of the femur (F); a probe (300, 300b) attachable or attachable to the cutting block (100, 100a, 100b) in the region of the block upper surface (103, 103a) located anteriorly opposite the posterior block lower surface (104, 104a), the probe (300, 300b) having a probe tip (301) configured to protrude proximally beyond the block posterior surface (101, 101a) and to abut against the anterior surface (A) of the femur (F) in the attached state of the probe (300, 300b); The surgical instrument (1, 1a, 1b),

2. The cutting block (100, 100a) has a first fixing recess (112, 112a) disposed rearward, the reference feet (200, 200a) have complementary fixing elements (202, 202a); 2. The surgical instrument (1, 1a) according to claim 1, characterized in that the first locking recess (112, 112a) and the locking element (202, 202a) are removably connectable to each other or connected to each other in a form-fit and / or force-fit engagement.

3. The first fixing recess (112) is a receiving slot (113) that is elongated and linear in the inward and outward direction and extends from the rear surface (101) of the block to the front surface (102) of the block; 3. The surgical instrument (1) according to claim 2, characterized in that the fixation element (202) is a flat-shaped plug element (203) configured to be inserted into the receiving slot (113) in a form-fit and / or force-fit engagement.

4. the plug element (203) has at least one separating gap (2033, 2035) that is substantially U-shaped in the longitudinal direction so as to form elastically resiliently movable spring tongues (2034, 2036) extending in the front-to-rear direction, 4. The surgical instrument (1) according to claim 3, characterized in that in the mounted state of the reference foot (200), the spring tongues (2034, 2036) are biased against the inner wall of the receiving slot (113).

5. The receiving slot (113) has two separate slot portions (1131, 1132) separated from each other in the inward and outward direction by a web (114); 4. The surgical instrument (1) according to claim 3, characterized in that the plug element (203) has two separate plug portions (2031, 2032) separated from each other in the inward-outward direction by a gap (204).

6. 4. The surgical instrument (1) according to claim 3, wherein the receiving slot (113) is configured to receive and guide the saw blade in an unattached state of the reference foot (200) and forms a rear guide slot (108) of the cutting block (100).

7. the first locking recess (112a) is a receiving pocket (113a) recessed proximally into the block front face; The surgical instrument (1a) according to claim 2, characterized in that the fixation element (202a) is configured to form a latching and / or clamping connection with the receiving pocket (113a).

8. 3. The surgical instrument (1, 1a, 1b) according to claim 2, characterized in that the reference foot (200, 200a, 200b) forms a plate-shaped extension (205, 205a) that is spaced apart, in particular rearwardly, from the fixing element (202, 202a) and whose upper surface forms the foot upper surface (201, 201a).

9. the reference foot (200, 200a) has a distally disposed gripping portion (207, 207a), and the fixation element (202, 202a) and / or the extension portion (205, 205a) protrude proximally from the gripping portion (207, 207a); 9. The surgical instrument (1, 1a) according to claim 8, characterized in that the gripping portion (207, 207a) has an outwardly facing first gripping surface (2071, 2071a), an inwardly facing second gripping surface (2072, 2072a), and a proximally facing stop surface (2073, 2073a).

10. The cutting block (100, 100a) has a second fixing recess (115, 115a) disposed in the front, The probe (300) has a complementary fixation element (302), 2. The surgical instrument (1, 1a) according to claim 1, characterized in that the second fixation recess (115, 115a) and the fixation element (302) of the probe (300) are removably connectable to or connected to each other in a form-fit and / or force-fit engagement.

11. 11. The surgical instrument (1, 1a) according to claim 10, characterized in that the second fixation recess (115, 115a) is designed as part of a universal fixation system and is adapted for connection to a further instrument component, preferably a surgical navigation device.

12. the second locking recess (115, 115a) is recessed rearwardly into the block upper surface (103, 103a), elongated in the inward-outward direction, and has a latch recess (116, 116a) open at its inner or outer end; 11. The surgical instrument (1, 1a) according to claim 10, characterized in that the fixation element (302) of the probe (300) has a complementary latch portion (304) that interacts with the latch recess of the cutting block (100, 100a) to form a removable snap-fit ​​connection.

13. the second fixing recess (115, 115a) has a plug recess (117, 117a) extending inwardly and outwardly in the block outer surface (105, 106; 105a, 106a) of the cutting block (100, 100a); 11. The surgical instrument (1, 1a) according to claim 10, characterized in that the fixing element (302) of the probe (300) has a complementary plug portion (305) that interacts with the plug recess (117, 117a) to form a detachable plug connection.

14. 2. The surgical instrument (1, 1a, 1b) according to claim 1, characterized in that there are a plurality of different compensation elements (400, 400', 400'', 400''') with different anterior-posterior thicknesses, each of said different compensation elements (400, 400', 400'', 400''') being attachable or preferably insertable to said upper foot surface (201, 201a) and configured to compensate for different degrees of wear of the posterior condyles (KL, KM).

15. A surgical instrument system (10) for use in knee replacement surgery, comprising at least one surgical instrument (1, 1a) according to claim 1, the reference foot (200, 200a) and the probe (300) are removably attached to the cutting block (100, 101a), respectively; the system (10) comprises further different cutting blocks (100', 100'') which differ from each other in at least one dimension, in particular in the anterior-posterior and / or medial-lateral dimension, The surgical tool system (10) wherein the reference foot (200, 200a) and the probe (300) are each attachable to each of the further different cutting blocks (100', 100'').

16. 2. The surgical instrument (1b) of claim 1, wherein the reference foot (200b) and the probe (300b) are each permanently attached to the cutting block (100b).

17. 17. A surgical instrument system (10b) for use in knee replacement surgery, comprising a plurality of different surgical instruments (1b, 1b', 1b'') according to claim 16, A surgical tool system (10b) in which the plurality of different surgical tools (1b, 1b', 1b'') differ from each other in at least one dimension of the respective cutting blocks (100b, 100b', 100b''), in particular the anterior-posterior and / or medial-lateral dimension.

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