Method and system for cutting knee joint using robot

Abstract

A method and a system for cutting the knee joint using a robot. A cantilevered cutter is introduced into the knee joint from inside and outside of upper and lower bones of the knee joint to realize a tunnel cutting technique in which cutting is conducted such that tunnels are defined in bone and remnant bone is cleared. The cutter includes a shaft in which a substantial axial portion is fitted into a sleeve and a remaining axial portion serves as a cantilever extending out of the sleeve, and a head which is formed at a distal end of the shaft. A length of the cantilever and a diameter of the head are determined to have minimum sizes as long as the head can be introduced into bone in such a way as to define a tunnel and can be moved in the bone while cutting the bone.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to surgery using a robot, and more particularly, to a method and a system for cutting the knee joint using a robot, wherein a surface, on which an artificial joint is to be coupled to the knee joint, can be formed with maximum safety and high precision in implementing total knee replacement arthroplasty while minimizing the incision of the skin by the robot without causing damage to the tissue around the patella.[0003]2. Description of the Related Art[0004]These days, as old age population increases, arthritis and osteoporotic hip fracture tend to increase.[0005]In this regard, by directly implementing knee replacement arthroplasty rather than using an indirect therapy such as parmacotherapy, physical therapy and intra-articular injection therapy, which is mainly used in the past, early mobilization is enabled without pain. Also, with the development of joint mechanics, the lifetime of an a...

AI Technical Summary

Benefits of technology

[0024]Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a method for cutting the knee joint using a robot wherein, in place of the conventional total knee replacement arthroplasty using a robot in which a cutter is moved only in the leftward and rightward directions from the anterior side of the knee joint when milling the bone using the robot, minimal invasive replacement surgery is combined with the total knee replacement arthroplasty using a robot to realize a surgical method based on a tunnel cutting technique in which a cutter is introduced not only from the anterior side of the knee joint but also outside or inside from the posterior center of the knee joint while defining an angle and cuts the bone, so that the minimal incision of the skin is required and the damage to the important tissue such as the skin, the flesh, the muscle and the bone, which is likely to be caused during the surgery, can be minimized and the surgery can be performed in a quick and efficient manner to obtain agreeable clinical results after the completion of the surgery and provide satisfaction to a patient, and a system for cutting the knee joint using a robot wherein, in order to realize the cutting method, the cutter is optimized to have a minimal diameter for permitting the cutting of bone tissue and a maximum length in consideration of the breakage, quivering, etc. of the cutter due to cutting resistance induced when cutting the bone.

[0025]In order to achieve the above object, according to one aspect of the present invention, there is provided a method for cutting the knee joint using a robot, wherein, when cutting the knee joint to implement total knee replacement arthroplasty, a cantilevered cutter having a small diameter is used and is introduced into the knee joint from inside and outside of upper and lower bones of the knee joint to realize a tunnel cutting technique in which cutting is conducted such that tunnels are defined in a bone and remnant bone is cleared, and wherein, when the upper bone of the knee joint is cut by moving the cutter toward the inside, the cutter is moved while being kept parallel to the Whiteside's line, and when the upper bone of the knee joint is cut by moving the cutter toward the outside, the cutter is moved while being slanted to a prescribed angle with respect to the Whiteside's line so as to avoid impingement between the cutter and surrounding tissue such as the patella and the ligament structure.

[0026]Here, preferably, while forming a tunnel by cutting the upper bone of the knee joint, the remnant bone serves as a natural safety shield which prevents the cutter from projecting out of the bone and damaging surrounding soft tissue.

[0028]Preferably, when cutting the distal surface of the lower bone of the knee joint, the formation of the plane is effected by moving the cutter inward in a zigzag pattern, and in order to prevent surrounding soft tissue from being damaged, cutting is conducted such that a safety rim is left on the edge of the plane.

[0030]Here, it is preferred that the cutter have chatter blockers for preventing chattering during cutting and a prescribed helix angle to ensure easy discharge of chips and be made of a material having a hardness in the range of HRC80˜120.

Problems solved by technology

In arthroplasty which is currently and directly conducted by a surgeon, since bone milling is not precise, it is difficult to precisely insert an artificial joint.

Also, due to the imprecise insertion of the artificial joint, various complications may arise, and because the lifetime of the artificial joint is not so long, inconvenience is caused in that it is necessary to conduct surgery again some time in the future.

However, in the case that master surgeon directly conduct surgery, since it is difficult to handle precisely the surgery instruments and mill precisely the bone, an excessive amount of the bone is likely to be damaged during the milling of the bone or surrounding tissue is likely to be damaged.

However, although the conventional method and the system contribute to some extent to the improvement in the precision of the surgery, they suffer from defects as described below.

Also, due to the rotation of the head 110 having the large size, it is difficult to properly protect the important tissue such as the periosteum attached to the bone, and serious damage to the bone can be caused.

Moreover, because a substantial amount of foreign substance such as bone particles are produced during milling, a surgery condition is deteriorated, and as the bone particles are introduced into the surrounding tissue, an inflammation may be caused after conducting the surgery, which can lead to a sequela of the surgery.

Further, since the conventional method and system adopt the top down milling scheme in which the bone is gradually milled out level by level, a lengthy period of milling time is required and a surgery time is extended as well.

In addition, while the conventional level to level milling method has a characteristic in terms of precision, the patient and the master surgeon who has performed the surgery cannot be satisfied only with the precision.

Nevertheless, since the surgery is performed in a narrow space, the tissue is excessively retracted and therefore is likely to be damaged.

Also, due to the incision of the skin to the lesser degree, the field of view becomes narrow, and it is difficult to insert precisely the implant.

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