Abstract:
A cartilage fragment removal device and method permits the removal of articular cartilage fragments, without undue risk of harm to the healthy cartilage surface. The device consists of a brush attachment located at the end of a shaft, which shaft is in turn coupled to a drive mechanism. The drive mechanism imparts a desired brushing motion to the brush attachment, the bristles of which are brought into contact with the articular cartilage fragment during an arthroscopic procedure so as to cause the fragment&#39;s removal. The removed fragment is then suctioned from the joint cavity, preferably using a suction tube that is integral to the cartilage fragment removal device.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to articular cartilage repair generally and, more particularly, to a device and method for removing loose articular cartilage fragments during an arthroscopic procedure with a reduced risk of damage to healthy cartilage. 
     2. Description of the Prior Art 
     Diarthroses in the human body, freely movable joints, are distinguished by, among other things, the presence of articular cartilage on the surfaces of the articulating bones. The articular cartilage does not bind the bones together; instead, it acts to reduce friction when the bones move and helps to absorb shock. There are a number of different types of diarthroses, including gliding, hinge, pivot, condyloid, saddle, and ball and socket. The two major diarthroses are the knee and the shoulder joints. 
     With specific regard to the knee joint, the surfaces where the femur, tibia and patella touch are all covered with articular cartilage. As a result of excess stress on the joint, trauma, muscle weakness, or perhaps other factors, a fragment (or fragments) of articular cartilage may partially dislodge from the articular cartilage surface—so that it extends into the joint cavity but is still partially attached to the cartilage surface. Such loose cartilage fragments can be sources of clicking, catching, or popping in the joint—and/or can cause pain, swelling or other mechanical irritation. While the knee joint is provided as an example, it should be understood that the problem of articular cartilage occurs in the shoulder and other diarthroses in the body as well. 
     Loose cartilage fragments can be removed during an arthroscopic surgical procedure. One prior art device for the removal of loose fragments is an arthroscopic surgery blade made by Smith &amp; Nephew, Inc. The Smith &amp; Nephew blade is a rotary vacuum shaver, having an external stationary tube having a sidefacing opening at its distal end, and an internal rotating blade. When the opening is brought in contact with the loose cartilage fragments, the rotating blade shears the fragment, which may then be suctioned through the instrument and out of the joint cavity. 
     One significant drawback to the Smith &amp; Nephew device, however, is that during operation the blade can nick or cut healthy articular cartilage or can inadvertently remove healthy cartilage with the fragment—undermining the healthy cartilage surface. 
     A need therefore existed for a device and method for removing articular cartilage fragments from a joint, with a reduced risk of undermining the healthy cartilage surface. The articular cartilage brush and method of the present invention provides these and other related advantages. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide an improved device and method for removing articular cartilage fragments from any body joint with a reduced risk of undermining the healthy cartilage surface. 
     It is a further object of this invention to provide an improved device and method for removing articular cartilage fragments from the knee joint with a reduced risk of undermining the healthy cartilage surface. 
     BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In accordance with one embodiment of the present invention, an improved cartilage fragment removal device is disclosed. The device comprises, in combination: a shaft having a proximal end and a distal end and dimensioned to be inserted into an incision of the size made for insertion of surgical instruments during arthroscopic surgery; a brush attachment having a plurality of bristles thereon coupled to the distal end of the shaft; and drive means coupled to a proximate end of the shaft for driving the brush attachment. 
     In accordance with a further embodiment of the present invention, a method for removing articular cartilage fragments comprising the steps of: providing a cartilage fragment removal device comprising: a shaft having a proximal end and a distal end and dimensioned to be inserted into an incision of the size made for insertion of surgical instruments during arthroscopic surgery; a brush attachment having a plurality of bristles thereon coupled to the distal end of the shaft; and drive means coupled to a proximate end of the shaft for driving the brush attachment; making an incision in a portion of a body for permitting access to an area having an articular cartilage fragment to be removed; inserting into the incision the brush attachment; driving the brush attachment; bringing the brush attachment in a driving condition into contact with the articular cartilage fragment to be removed until the articular cartilage fragment is detached; and removing the detached articular cartilage fragment from the body. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an embodiment of the cartilage fragment removal device of the present invention. 
     FIG. 2 is a perspective view of another embodiment of the cartilage fragment removal device of the present invention. 
     FIG. 3 is a front view of a cartilage fragment removal device of the present invention being used on an articular cartilage surface in the knee joint. 
     FIG. 4 is a side, cross-sectional view of another embodiment of the cartilage fragment removal device of the present invention. 
     FIG. 5 is a perspective view of a prior art cartilage fragment removal device. 
     FIG. 6 is a cross-sectional view of the prior art cartilage fragment removal device of FIG. 5, taken along line  6 — 6 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring first to FIGS. 5 and 6, the prior art Smith &amp; Nephew cartilage removal device (hereinafter“Smith &amp; Nephew device  100 ”) is shown. The Smith &amp; Nephew device  100  has an external stationary tube  110  with a side-facing opening  120  at its distal end, and an internal rotating blade  130  at the end of a cannula  140 . When the opening  120  is brought in contact with loose cartilage fragments, the rotating blade  130  shears the fragment, which may then be suctioned through the cannula  140  and out of the joint cavity. In use, the rotating blade  130  can inadvertently nick or cut the healthy cartilage surface proximate the area where the fragment is attached. 
     Referring to FIGS. 1 and 2, reference numbers  10   a  and  10   b  refer to two embodiments of the cartilage fragment removal device (referred to generically as the cartilage fragment removal device  10 ) of the present invention. The cartilage fragment removal device  10   a  generally comprises a shaft  12   a  (referred to generically as a shaft  12 ), coupled at first end to a driver  14   a  (referred to generically as a driver  14 ) and at a second end to a brush attachment  16   a  (referred to generically as a brush attachment  16 ). The brush attachment  16   a  has a plurality of bristles  18   a  (referred to generically as bristles  18 ) thereon. The cartilage fragment removal device  10   b  generally comprises a shaft  12   b , coupled at first end to a driver  14   b  and at a second end to a brush attachment  16   b . The brush attachment  16   b  has a plurality of bristles  18   b  thereon. 
     Referring specifically to FIG. 1, the brush attachment  16   a  has bristles  18   a  positioned thereon in a circular arrangement. The bristles  18  may be comprised of any desired material having sufficient strength to detach articular cartilage fragments upon activation of the cartilage fragment removal device  10 , yet not so abrasive as to damage healthy articular cartilage when the bristles  18 , in motion, are brought into contact with such cartilage. Exemplary materials can include nylon, plastic, and the like. The bristles  18  must also be rooted to the brush attachment  16  with sufficient strength so as not to become detached during operation, and potentially left in the joint cavity. 
     The brush attachment  16  and shaft  12  should be dimensioned to be insertable into an incision of the type and size typically made for the insertion of surgical instruments used during arthroscopic surgery, including arthroscopes, cannulas, prior art cartilage fragment removal devices, repair devices, etc. Preferably, the diameter of the brush attachment  16   a  would be in the range of from about 3.5 millimeters to about 5.5 millimeters, with different sizes available depending on the joint in which the device is to be used, the size of the fragment to be removed, and other considerations. 
     The driver  14  may be an electric motor or other drive mechanism, coupled to the brush attachment  16  through the shaft  12  in such manner so as to impart to the brush attachment  16  the desired brushing motion. (Optionally, the driver  14  could simply be a manual drive force supplied by the surgeon or other attending health care professional who imparts the desired brushing motion in a manner like that in which a person using a manual toothbrush can apply any desired brushing motion, as necessary.) As shown in FIG. 1, the brush attachment  16   a  is moved in a circular motion by the driver  14   a.    
     Referring now to FIG. 2, another embodiment of the cartilage fragment removal device  10  of the present invention is shown. The cartilage fragment removal device  10   b  has a brush attachment  16   b  with bristles  18   b  positioned thereon in a foursided, preferably rectangular arrangement. In this embodiment, and unlike the embodiment of FIG. 1, the bristles are at a ninety degree angle relative to the shaft  12   b . It may also be preferable, for some uses, to provide a cartilage fragment device  10  having a brush attachment  16  at an angle orientation other than what is shown in FIGS. 1 or  2 , e.g., at a forty-five degree angle relative to the shaft  12 . Optionally, the shaft  12  (or at least a portion thereof proximate the brush attachment  16 ) or the brush attachment  16  itself may be made of flexible material so as to permit adjustment of the orientation of the brush attachment  16  during use. 
     While four-sided and circular arrangements of bristles  18  are shown, it would be possible to provide other arrangements of the bristles  18 , including for example oval, triangular, and other configurations, without departing from the spirit or scope of the present invention. 
     The driver  14   b , which in this embodiment is on the same axis as the shaft  12   b  but which could alternatively be arrayed at an angle thereto as in FIG. 1, may be an electric motor or other drive mechanism, coupled to the brush attachment  16   b  through the shaft  12   b  in such manner so as to impart to the brush attachment  16   b  the desired brushing motion. As shown in FIG. 2, the brush attachment  16   b /driver  14   a  may be coupled so as to impart a side to side or back and forth oscillating motion, as desired. 
     Referring now to FIG. 4, another embodiment of the cartilage fragment removal device  10  of the present invention is shown. In this embodiment, a shaft  220  has a suction tube  230  therethrough, which suction tube  230  has an opening in a brush attachment  240  at a distal end of the shaft  220 . When a cartilage fragment is removed using the brush attachment  240 , the removed fragment may then be suctioned out of the joint cavity through the suction tube  230 . The use of a suction tube  230  as an integral part of the cartilage fragment removal device  10  is possible with any disclosed embodiments of the device including the cartilage fragment removal device  10   a  and  10   b . As an alternative to the positioning of a suction tube  230  within the shaft  220 , the suction tube  230  could be separate from the cartilage fragment removal device and could be separately inserted into the joint cavity through a second incision. 
     Referring now to FIG. 3, a front view of a cartilage fragment removal device  10  of the present invention is shown being used on an articular cartilage surface in the knee joint. While the knee joint is herein illustrated, it should be understood that the cartilage fragment removal device of the present invention may be used in any body joint having an articular cartilage surface wherein a cartilage fragment is present and requires removal. 
     As shown in FIG. 3, the joint surfaces of the femur  30  and tibia  32  are each covered with an articular cartilage surface  34 . The cartilage fragment removal device  10  is inserted through an incision  36  proximate the joint cavity, so as to enable the positioning of the brush attachment portion  16  proximate the articular cartilage fragment to be removed. The positioning of the brush attachment portion  16  is guided by the surgeon using an arthroscope (not shown)—until the bristles  18  on the brush attachment  16  are in contact with the articular cartilage fragment. Either before or after contact has been made, the driver  14  is activated, imparting the desired brushing motion to the brush attachment  16 —either circular, oscillating from side to side, oscillating back and forth, some combination of these motions or some other desired brushing motion. The bristles  18 , in motion, remain in contact with the articular cartilage fragment until that fragment has been detached from the healthy, surrounding articular cartilage surface. The fragment is then suctioned from the joint cavity, using either a separate suction tube (not shown) inserted into the joint cavity through a second incision, or through the suction tube  230  (see FIG.  4 ). 
     Because the bristles  18  when in motion will not damage healthy articular cartilage, the cartilage fragment removal device  10  may also be used to conduct a general cleaning of the articular cartilage surface, so as to ensure that all fragments have been removed—including ones that may not visible with the arthroscope. Indeed, such a cleaning can be made part of a standard arthroscopic procedure. 
     It should be noted that the brush attachment  16  and the shaft  12  are preferably disposable, with the driver  14  dimensioned to release the shaft  12  after a single use and accept a replacement shaft  12  for the next use. 
     While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.