Description

CLAMP FOR REGISTRATION OF BONE POSITION AND SURGICAL ROBOT BY USING THE SAME

Technical Field

[1] The present invention relates to a clamp for artificial joint surgery and a surgical instrument operated by a robot using the same, and more particularly, to a clamp used in hip joint surface replacement and a surgical instrument operated by a robot. Background Art

[2] In recent times, the number of patients with joint injuries due to disease and accidents has been increasing. While joint injuries may heal naturally, when the joint injuries do not or when the joint injuries cause serious pain, artificial joint replacement must be performed.

[3] Various artificial joint surgeries and artificial joint products have been used.

Basically, artificial joint surgery is a surgical process of finely cutting both sides of injured bone and cartilage and fixing an artificial product to the cut parts to function as the joint.

[4] Currently, about half of all artificial joint replacements are artificial hip joint replacements, most of the other half is knee joint replacement, and the remainder is shoulder or finger joint replacement.

[5] Artificial hip joint replacement will be described in brief below with reference to

FIGS. 1 and 2.

[6] A semi-spherical acetabular cup 2200 formed of metal or plastic is installed at an acetabulum 1210 of a pelvis 1200, and a femoral head 1110 is removed from a side surface of a femur 1100. Then, an artificial joint 2100 having a length of about 15cm to about 25cm is inserted into the side surface of the femur 1100, and a head 2110 of the artificial joint 2100 is inserted into a socket 2210 of the acetabular cup 2200, so that the parts are enabled to operate as a single joint.

[7] In particular, in recent times, artificial hip joint surgery called artificial hip joint surface replacement and related products have been presented and clinically used. Products such as Birmingham Hip Resurfacing (Smith & Nephew, UK) and Durom (Zimmer, USA) have been used, and while the products are currently used in no more than 10% of all artificial hip joint replacements, their utilization frequency is increasing.

[8] Artificial hip joint surface replacement will be described in brief below with reference to FIG. 3.

[9] After exposing the affected part of a patient to the exterior, the pelvis 1200 and the

femur 1100 are separated from each other, a space for inserting an acetabular cup 2200 is formed in the acetabulum 1210 of the pelvis 1200 using a surgical instrument, and then the acetabular cup 2200 is adhered to the acetabulum 1210 of the pelvis 1200 using cement.

[10] In addition, after exposing the femoral head 1110 to the exterior to be resurfaced, the femoral head 1110 is cut to correspond to an inner groove of a joint cap 2300 using a surgical instrument, and then an insertion shaft 2320 of the joint cap 2300 is inserted into a through-hole 1111 of the femoral head 1110 to be installed therein.

[11] Next, the joint cap 2300 is inserted into a socket 2210 of the acetabular cup 2200, and then the cut is stitched up to complete the surgical operation.

[12] The artificial hip joint surface replacement is basically similar to a general artificial hip joint surgery, but different in that the surface of the femoral head 1110 of the injured femur 1130 is covered with the joint cap 2300 formed of an empty metal ball, instead of inserting a metal rod into the femur 1130. The artificial hip joint surface replacement has advantages in that less of the femoral head is removed and a general artificial hip joint surgery is still possible if a problem occurs after the replacement.

[13] Artificial hip joint surface replacement through a manual operation will be described in detail below with reference to FIGS. 4 to 8.

[14] First, the joint cap 2300 is inserted into the femoral head 1110 exposed to the exterior, or a tool such as a drill, etc. is used to form the through-hole 1111 corresponding to a center axis for resurfacing the femoral head 1110.

[15] Next, as shown in FIG. 4(a), a center shaft 3110 of a femoral head cutter 3100 is inserted into the through-hole 1111 formed in the femoral head 1110, and as shown in FIG. 4(b), the femoral head cutter 3100 is rotated to process a peripheral surface 1112 of the femoral head 1110 using a cutter part 3120.

[16] When the peripheral surface 1112 of the femoral head 1110 is completely processed, as shown in FIG. 5, a femoral head guard 3200 grips the peripheral surface 1112 to prevent movement of the femur 1100, and a first upper surface cutter 3300 is used to primarily process an upper surface of the femoral head 1110 exposed to an upper surface of the femoral head guard 3200.

[17] When the upper surface of the femoral head 1110 is primarily cut, as shown in FIG.

6, a center shaft 3410 of a second upper surface cutter 3400 is inserted into the through-hole 1111 formed in the femoral head 1110, and the second upper surface cutter 3400 is rotated to process the upper surface of the femoral head 1110 to a desired femoral head upper surface 1114 using a cutter part 3420.

[18] Since a load may be concentrated on an edge formed by the peripheral surface 1112 of the femoral head 1110 and the femoral head upper surface 1114, as shown in FIG. 7, the edge is chamfered to form a slope 1113 using a slope cutter 3500.

[19] Even when the slope cutter 3500 is used, a center shaft 3510 of the slope cutter 3500 is inserted into the through-hole 1111 of the femoral head 1110 acting as a center axis of the surgical operation, and the slope cutter 3500 is rotated to form the slope 1113 at the femoral head 1110 using a cutter part 3520.

[20] When the surface of the femoral head 1110 is completely processed, as shown in

FIG. 8, an insertion shaft 2320 of the joint cap 2300 is inserted into the through-hole 1111 of the femoral head 1110 using a chisel 3600 and a hammer 3700.

[21] According to clinical experience and biomechanical analysis, it is preferable that the femoral head is processed to form the above-mentioned shape through the artificial hip joint surface replacement as described above. In addition, when the installation direction is undesirable or the installation depth is too deep or too shallow, the femoral head is likely to be broken during normal activities after the surgical operation.

[22] Therefore, in a real surgical operation, a surgeon must process the femoral head through various manual processes.

[23] In addition, since the through-hole of the femoral head must be precisely processed to obtain good results, the surgeon must check the position and direction of the through-hole at each manual process. Though the operation time differs depending on the surgeon's experience, a relatively long time, at least 10 to 15 minutes, is required to process the femoral head.

[24] Further, when the surface of the femoral head is processed through the manual processes, cutting accuracy is decreased. As a result, a load is likely to be concentrated on a specific point after an operation. In particular, while the through-hole of the femoral head is an important part used as a central axis of surgical cutters throughout the entire surgical operation, when the through-hole is formed in an undesirable direction by the manual operation of the surgeon, the load may be more seriously concentrated.

[25] For this reason, in order for the surgeon to readily check the cutting positions of the through-hole and the surface of the femoral head, an electronic biomechanical positioning auxiliary device referred to as a surgical navigation system has already been commercially used, for example, Orthopilot (Aesculap, USA), BrainLab (Germany), and so on. U.S. Patent Nos. 6470207, 6430434 and 6205411 disclose technologies related to the above-mentioned instruments.

[26] When the navigation system is used, an appropriate operating position can be checked in real time. However, for this purpose, the position of the bone must be measured at least one time during the surgical operation. In addition, since the processing is performed manually, the processed shape may still remain inaccurate. As is already known, even though operation accuracy is increased by using the navigation system in comparison with the manual operation, it is still not perfect.

[27] In addition, an artificial joint surgery robot is also commercially used to process the bone after measuring the position of the bone to be operated. U.S. Patent Nos. 5806518 and 6033415 disclose technologies related to such instruments.

[28] Even when the robot is used, similar to the navigation system, the position of the bone must be measured before processing the bone during the operation. However, since the operation robot can process the bone more precisely than manual processing using the navigation system, the bone must be measured with much higher precision. For example, a specific system (ROBODOC surgical robot system) must measure the position of the bone with a precision of 0.3mm. However, in order to measure the bone position with such high precision, a substantial amount of time (about 10 to about 20 minutes) is needed. In addition, the surgeon may endure stress concerning measurement error.

[29] A process of measuring a biomechanical position of the bone and calculating a preferable operating position using the navigation system or the surgical robot is referred to as registration. Various registration methods will be described in brief below.

[30] FIG. 9 is a schematic view for explaining a registration method. Referring to FIG.

9(a), coordinate systems for an operation using a robot generally include a reference coordinate system {F}, a robot coordinate system {R} with respect to a path programmed into the robot, and a bone coordinate system {B} with respect to the actual femur of a patient undergoing operation.

[31] The robot coordinate system {R} is transformed into a relative coordinate system with respect to the reference coordinate system {F}, and the bone coordinate system {B } is transformed into a relative coordinate system with respect to the reference coordinate system {F}, so that the robot coordinate system {R} and the bone coordinate system {B} are primarily transformed with respect to the same reference coordinate system {F}. Then, a transformation matrix T between the transformed robot coordinate system {R} and the transformed bone coordinate system {B} is obtained and applied to the robot coordinate system {R} so that a processing path of the robot can be applied to the actual position of the bone.

[32] Here, a registration method for obtaining the transformation matrix T may be a pin- based registration method, an image-based registration method, or the like.

[33] The pin-based registration method includes photographing a CT image in a state in which a plurality of pins inserted into the femur of a patient are fixed to the inside of a thigh, and setting a processing path of the robot on the basis of the CT image.

[34] At this time, the reference coordinate system on the processing path of the robot is set by the plurality of pins in the CT image.

[35] When design of the cutting path is completed, the pins fixed to the affected part of

the patient are aligned with the pins in the CT image as a reference of the processing path to perform the registration during the actual surgical operation.

[36] However, since the pin-based registration needs the plurality of pins to be inserted into the affected part of the patient before the operation, the patient must endure pain and inconvenience in a state in which the pins are inserted into the affected part until the operation.

[37] The image-based registration includes obtaining a CT image of the femur of a patient, and setting a processing path on the basis of the CT image. A three-dimensional image obtained from the CT image is aligned with a two-dimensional x-ray image of the femur of the patient during the actual operation to perform the registration.

[38] However, the image-based registration may cause numerous errors during segmentation of the femur 1100 from other parts such as the pelvis 1200, ligaments, and so on, for obtaining three-dimensional modeling of the femur from the CT image. In addition, an edge detection process from a two-dimensional X-ray image obtained during the surgical operation also causes numerous errors.

[39] Further, due to the problems of the aforementioned methods, an apparatus for total artificial joint replacement using a commercialized robot uses technology that performs registration for aligning a specific point of the CT image obtained before the operation with a specific point measured by a digitizer.

[40] However, during the operation, in order for a surgeon to measure a plurality of specific points of the femur using probes of the digitizer, tips of the probes must be pressed against the surface of the femur with a certain pressure. When the pressure is small, errors of measurement points occur due to the skin or flesh around the femur, and when the pressure is too large, a depression may be made in the surface of the femur.

[41] In addition, the surgeon must measure a large number of measurement points to reduce errors during the operation. Further, it is difficult for the surgeon to precisely align the measurement pins with the measurement points guided by a monitor installed at the operation equipment.

[42] Furthermore, since there is a need for measurement points in a wide region of the femur, a wide region of the femur must be exposed to the exterior during the operation, and thus an otherwise unnecessarily large incision must be made in the patient's thigh. Disclosure of Invention Technical Problem

[43] An feature of the present invention is to remove inconvenience brought about by complex procedures using a large number of surgical cutters in artificial joint surface

replacement. [44] Another feature of the present invention is to prevent surgical errors caused by a manual operation and load concentration on a specific point after a surgical operation using a robot in artificial joint surface replacement. [45] Still another feature of the present invention is to provide a method capable of performing artificial joint surface replacement using a robot without complex procedures.

Technical Solution [46] The foregoing and/or other objects of the present invention may be achieved by providing a clamp for joint surface replacement using a robot, including: a grip part for gripping a predetermined region of a bone; and a body connected to the grip part and having at least three measurement points at one surface thereof. [47] In addition, the body may include a first body and a second body, wherein the second body is coupled to the first body and moves relative to the first body. [48] Further, the first body may include the at least three measurement points.

[49] Furthermore, the second body may include the at least one measurement point.

[50] In addition, the measurement point may be a recess.

[51] Another object of the present invention may be achieved by providing a clamp for joint surface replacement using a robot including: a first body having at least three measurement points at one surface thereof; a second body coupled to the first body and moving relative to the first body; and a grip controller connected to the first body or the second body and moving the first and second bodies relative to each other to grip the femur. [52] In addition, the second body may include at least one measurement point at one surface thereof.

[53] Further, the measurement point may be a recess.

[54] Furthermore, a tip of the first body may include a first hook-shaped grip part bent in a first direction, a tip of the second body may include a second hook-shaped grip part bent in a direction opposite to the first direction, and the first and second grip parts may cooperate to grip the femur. [55] In addition, the first grip part and the second grip part may grip a femoral neck of the femur.

[56] Further, the second body may slide relative to the first body.

[57] Still another object of the present invention may be achieved by providing operating equipment including: a clamp including a grip part for gripping a predetermined region of a bone, and a body having at least three measurement points at one surface thereof; a coordinate measurement apparatus for measuring the measurement points to

recognize a first coordinate system corresponding to the position and direction of the clamp; and a robot for cutting the bone along a pre-programmed processing path on the basis of the first coordinate system.

[58] In addition, the bone may be a femur, and the part cut by the robot may be a femoral head of the femur.

[59] Further, the equipment may further include a jig for fixing the clamp to a support base.

[60] Furthermore, the robot may further include a cutter for cutting the bone and a load sensor for measuring the load transmitted from the cutter.

[61] In addition, a controller for controlling the robot may recognize a second coordinate system corresponding to the position and direction of the bone on the basis of a signal received from the load sensor when a tip of the cutter is in contact with a predetermined region of the bone.

[62] Further, the controller may correct the processing path of the robot using the second coordinate system.

Advantageous Effects

[63] According to the present invention, artificial joint surface replacement using a robot is not complicated compared to a manual operation and enables the bone to be processed with high precision. [64] In addition, in accordance with the present invention, it is possible to reduce an operation time. [65] Further, in accordance with the present invention, it is possible to prevent processing errors caused by a manual operation. [66] Furthermore, it is possible to minimize load concentration on a specific point after an operation. [67] While several exemplary embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes may be made to these embodiments without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.

Brief Description of Drawings [68] The above and other objects, aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings, in which:

[69] FIG. 1 is an anatomical perspective view of a hip joint of a human body;

[70] FIG. 2 is a perspective view of a hip joint and an artificial joint during total artificial hip joint replacement;

[71] FIG. 3 is a perspective view of a hip joint and an artificial joint during artificial hip joint surface replacement; [72] FIGS. 4 to 8 are perspective views showing conventional procedures of artificial hip joint surface replacement;

[73] FIG. 9 is a conceptual view for explaining a registration process;

[74] FIG. 10 is a perspective view of a clamp for artificial joint surgery in accordance with an exemplary embodiment of the present invention; [75] FIG. 11 is a perspective view of operating equipment for artificial joint surgery in accordance with an exemplary embodiment of the present invention; and [76] FIGS. 12 and 13 are flowcharts showing artificial joint surgery in accordance with various exemplary embodiments of the present invention. [77] <Description of Major Reference Numerals>

[78] 1100: Femur 1110: Femoral head

[79] 1120: Femoral neck 1130: Femoral shaft

[80] 1200: Pelvis 1210: Acetabulum

[81] 2200: Acetabular cup 2210: Acetabular groove

[82] 2300: Joint cap 2310: Outer periphery of cap

[83] 2320: Insertion shaft 4000: Clamp

[84] 4100: First body 4110: First measurement point

[85] 4120, 4220: Grip part 4130: Sliding guide

[86] 4140: Grip control guide 4200: Second body

[87] 4210: Second measurement point 4300: Grip controller

[88] 5000: Coordinate measurement apparatus 5100: Measurement pin

[89] 6000: Robot 6100: Cutter

[90] 7000: Jig 7100: Grip

Mode for the Invention [91] The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. [92] FIG. 10 is a perspective view of a clamp for artificial joint surgery in accordance with an exemplary embodiment of the present invention. The clip generally includes grip parts 4120 and 4220 for gripping a bone to be operated on, and bodies 4100 and

4200 including measurement points for registration. [93] The bodies 4100 and 4200 are divided into a first body 4100 and a second body

4200. The second body 4200 is coupled to the first body 4100 to move, preferably, slide, relative to the first body 4100. [94] Here, a grip controller 4300 is coupled to the second body 4200 to control the diameter or thickness gripped by the grip parts 4120 and 4220 through sliding

movement of the second body 4200 relative to the first body 4100.

[95] In an exemplary structure of the bodies 4100 and 4200 and the grip controller 4300, the first body 4100 includes a first hook-shaped grip part 4120 extending from a tip thereof, a sliding guide 4130 extending from an intermediate part of the first body 4100 to be coupled to the second body 4200 and guiding sliding movement of the second body 4200, and a grip control guide 4140 having a female screw shape and extending from a rear end of the first body 4100 to guide movement of the grip controller 4300.

[96] In addition, the second body 4200 includes a second hook-shaped grip part 4220 extending from a tip thereof to correspond to the first grip part 4120 extending from the first body, and a rear end connected to the grip controller 4300.

[97] Here, the grip controller 4300 is provided with a male screw-shaped body having a pitch corresponding to the female screw part of the grip control guide 4140 of the first body 4100, and includes a handle formed at a rear end thereof and rotated by a user.

[98] Therefore, the grip controller 4300 coupled to the bodies 4100 and 4200 is rotated so that the second body 4200 slides relative to the first body 4100, and thus the first grip part 4120 and the second grip part 4220 grip the bone to prevent movement thereof.

[99] Further, one surface of the first body 4100 includes at least three measurement points for measuring a coordinate system of the first body. The measurement points may be recesses formed in a surface of the first body corresponding to a central axis of a grip region defined by the grip parts 4120 and 4220 for gripping the bone.

[100] Measurement of the measurement points 4110 and 4210 can be performed using a predetermined coordinate measurement apparatus 5000. The apparatus may be an articulated digitizer having sharp tips corresponding to the measurement points 4110 and 4210 having a recess shape.

[101] Since the first body is formed of a rigid body and has at least three measurement points, it is possible to measure a coordinate value of a predetermined reference coordinate system to recognize the position and direction of the first body.

[102] Here, the reference coordinate system of the first body 4100 corresponds to a coordinate system of the coordinate measurement apparatus 5000.

[103] Therefore, the coordinates of the bone gripped by the first grip part 4120 formed at the tip of the first body can be predicted. In addition, when the region of the bone gripped by the grip parts 4120 and 4220 is a femoral neck 1120, it is possible to substantially recognize the position and direction of a femoral head 1110, even though everybody's is a slightly different shape and size.

[104] In order to more precisely recognize the position and direction of the bone, at least one measurement point may be formed in one surface of the second body 4200 to recognize the position of the second grip part 4220 formed at the tip of the second

body 4200, and thus the size and direction of the femoral neck 1120 can be precisely recognized.

[105] Here, in the position and direction of the bone with respect to the coordinate system of a clamp 4000, by calculating a transformation matrix of the clamp coordinate system with respect to the coordinate system of the coordinate measurement apparatus 5000, the position and direction of the bone with respect to the coordinate system of the coordinate measurement apparatus 5000 can be obtained.

[106] FIG. 11 is a perspective view of operating equipment for artificial joint surgery in accordance with an exemplary embodiment of the present invention.

[107] After gripping the femoral neck 1120 of a femur 1100 to be operated using the clamp 4000 shown in FIG. 10, a predetermined region of the clamp 400, preferably, a predetermined region of the first body 4100 is gripped using a jig 7000.

[108] Here, the jig 7000 may have an articulated structure to conveniently process the femoral head 1120 of the femur 1100 using a cutter 6100 of a robot or to readily grip the femur 1100 of a patient.

[109] The jig 7000 and the clamp 4000 may be integrally formed with each other. That is, a grip 7100 of the jig 7000 may be formed as the clamp 4000.

[110] The equipment includes an articulated digitizer as the coordinate measurement apparatus 5000 for measuring measurement points formed on one surface of the clamp 4000 gripping the fixed femur 1100, and a user may measure the measurement points of the clamp 4000 by moving the digitizer.

[I l l] At this time, while the measurement points of the clamp 4000 may be measured using the tip of the cutter 6100 of the robot 6000, since it is inconvenient for the user to manually move the robot 6000, it is preferable that the measurement points of the clamp are measured using the digitizer.

[112] The position and direction of the femoral head 1110 of the femur 1100 gripped by the clamp 4000 can be obtained on the basis of the position of the clamp 4000 measured by the digitizer. Therefore, the robot 6000 cuts the femoral head 1110 along the programmed processing path using the cutter 6100.

[113] At this time, since the coordinate systems of the jig 7000, the digitizer and the robot 6000 are fixed to the base of an operating table, the transformation matrix for the coordinate systems is already recognized. Therefore, the registration of the position and direction of the femur 1100 with respect to the robot coordinate system can be performed through matrix multiplication between the measurement values of the femur 1100, the clamp coordinate system and the clamp.

[114] That is, the processing path of the cutter 6100 of the robot 6000 designed on the basis of the coordinate system of the robot 6000 is registered with the coordinate system of the femur 1100 so that the cutter 6100 of the robot 6000 can process a desired region

of the femur 1100.

[115] Here, measurement and registration of only the measurement points 4110 and 4210 of the clamp 4000 can be performed in a non-serious range, even though people have different shapes and sizes of the femoral neck 1120 and the femoral head 1110.

[116] However, in order to more precisely perform the registration, after registration of the clamp coordinate system in which the measurement points 4110 and 4210 of the clamp 4000 are measured, approximate position and direction of the femoral head 1110 may be recognized, and a predetermined region of the femoral head 1110 may be measured through a tip of the cutter 6100 of the robot 6000.

[117] For this purpose, the cutter 6100 of the robot 6000 may include a load cell for detecting a load. The load cell can determine as a position of the predetermined point of the femoral head 1110 where a repulsion force is measured by contact between the cutter 6100 of the robot 6000 and the surface of the femoral head 1110.

[118] The position and direction of the femoral head 1110 modeled in a circular shape are calculated on the basis of the coordinates measured after three to five points on the surface of the femoral head 1110 are primarily measured. In order to more precisely measure the position and direction of the femoral head 1110, another point of the femoral head 1110 is repeatedly measured on the basis of the primarily measured and calculated values to increase precision of the position and direction of the femoral head 1110.

[119] The processing path programmed into the robot 6000 is registered on the basis of an actual position of the femoral head 1110 measured by the cutter 6100 of the robot 6000, and then the surface of the femoral head 1110 is processed.

[120] Here, the robot 6000 must have a joint of at least three degrees of freedom, preferably, five degrees of freedom. In the present exemplary embodiment of the present invention, the robot 6000 has a joint of six degrees of freedom.

[121] When the surface of the femoral head 1110 is completely processed, a joint cap is covered on the femoral head and inserted into the acetabulum in the same manner as in a manual operation.

[122] As a result, since the surgeon can grip the femur 1100 to be operated on using the clamp 4000 and measure the measurement points marked on the clamp 4000 using the coordinate measurement apparatus 5000, it is possible to simplify the surgical operation procedure in comparison with the manual operation. In addition, registration in accordance with the present invention can be more readily performed by a simple apparatus than conventional registration for total joint replacement using a robot.

[123] FIGS. 12 and 13 are flowcharts showing joint surface replacement in accordance with various exemplary embodiments of the present invention.

[124] FIG. 12 shows a method including photographing an affected part of a patient before

operating using CT and setting a processing path of a robot on the basis of the image (Sl 100), and gripping the femur 1100 of the patient using the clamp 4000 after the femur 1100 is exposed to the exterior and measuring measurement points 4110 and 4210 formed at one surface of the clamp 4000 using the coordinate measurement apparatus 5000 (S 1200).

[125] Next, registration for aligning a coordinate value of the femur 1100 with the robot coordinate system, which is a reference of the processing path of the robot, using a coordinate value of the clamp 4000 measured by the coordinate measurement apparatus 5000 is performed (S 1300).

[126] After the registration is completed, the robot 6000 processes the surface of the femoral head 1110 according to the coordinate value transformed through the registration (S 1400). When the processing is completed, a joint cap is inserted onto the processed femoral head 1110 (S 1500). Subsequent steps are the same as in a manual operation.

[127] In FIG. 13, the method further includes measuring the surface of the femoral head 1110 to more precisely register the position and direction of the femoral head 1110 between measuring the measurement points of the clamp (S 1200) and registration for aligning the coordinate system (S 1300).

[128] The surface of the femoral head 1110 may be measured using the cutter 6100 of the robot 6000 along the measurement path pre-programmed into the robot 6000.

[129] The robot 6000 calculates a coordinate value of the clamp obtained by measuring the measurement points 4110 and 4210 of the clamp 4000 and a coordinate value of the femoral head 1110 predicted therefrom, moves the cutter 6100 to near the predicted coordinate value of the femoral head 1110 and slowly moves it forward to make the cutter 6100 contact the surface of the femoral head 1110, and then recognizes position coordinates of the surface of the femoral head 1110 using a load measured by a load measurement apparatus included in a predetermined region of the cutter 6100.

[130] After measuring three to five points on the surface of the femoral head 1110, the position and direction of the surface of the femoral head 1110 are corrected, and then three to five points on the surface of the femoral head 1110 are repeatedly measured on the basis of the corrected coordinate value of the femoral head 1110.

[131] Measurement of the measurement points may be performed at least two times, preferably, three times, to recognize position coordinates of the surface of the femoral head 1110.

[132] Therefore, the surface of the femoral head 1110 is more precisely processed using the robot 6000 through the registration (S 1300) for aligning the position coordinates of the surface of the femoral head 1110 with the processing path coordinate system of the robot 6000.

[133] While exemplary embodiments of the present invention applied to the femur as a region for hip joint surgery have been described, the present invention may be used for a knee joint or a shoulder joint as well.

[134] In addition, while exemplary embodiments of the present invention applied to surface replacement of the femoral head have been described, the clamp and registration method in accordance with the present invention may be adapted to readily perform registration for any surgical operation using a conventional robot.

[135] That is, a mechanism for fixing a bone near the affected part using an anatomical shape of the bone may be installed around the affected part during an operation, and the position of the mechanism may be measured to recognize the position of the affected part, or automatic registration may be performed using the robot on the basis of the position of the affected part indirectly estimated through the mechanism.

[136] Further, exemplary embodiments of the present invention employing the digitizer as the coordinate measurement apparatus have been described, a method using a non- contact sensor may be used.

[137] That is, the measurement points 4110 and 4210 of the clamp 4000 may be formed using an infrared reflective marker, and the coordinate measurement apparatus may include an infrared transmitter and an infrared receiver. In addition, the measurement points 4110 and 4210 of the clamp 4000 may be formed using an emission marker emitted at a predetermined frequency, and the coordinate measurement apparatus may be constituted by a recognition apparatus for recognizing a corresponding frequency.

[138] While the invention has been shown and described with reference to m certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.