The present invention relates to repair of articular cartilage in joints and, more particularly, to a technique and instruments for preparing subchondral tissue and bone, and implanting an articular cartilage repair unit therein.
Articular cartilage is a type of hyaline cartilage that lines the surfaces of the opposing bones in a diarthrodial joint (e.g., knee, hip, shoulder, etc.). Its primary function is to permit smooth, near frictionless movement during articulation between bones of the joint by providing a low-friction interface between the contacting cartilage surfaces of the joint. Articular cartilage is also load bearing, and serves to transmit and distribute compressive joint loads to the underlying subchondral bone (i.e. bone beneath the cartilage or subchondral tissue).
Articular cartilage is typically damaged in one of two ways, acute trauma inflicted through physical activity (such as twisting motion of the leg, sharp lateral motion of the knee, or repetitive impact), or degenerative conditions (such as arthritis or other systemic conditions). In addition, as a person ages, articular cartilage loses mechanical strength, rendering the cartilage even more susceptible to trauma, such that even common motions (e.g. squatting, stair climbing, etc.) can cause articular cartilage tears. Because articular cartilage tissue is aneural (little or no nerves) and avascular (little or no blood vessels), the spontaneous healing of damaged articular cartilage is limited. As a result, focal (localized) defects can tend to lead toward progressive degeneration of the joint surface(s) until total joint replacement is eventually necessary.
Surgical methods are available for treatment of damaged articular cartilage tissue with their aim being to partially or completely repair the chondral defect and decrease the risk of the development of osteoarthritic changes within the joint. These surgical methods can be loosely classified into three categories: 1) debridement and stabilization of loose or worn articular cartilage, 2) stimulation of a repair process from the subchondral bone, and 3) repair or replacement of the damaged articular surface.
With respect to debridement and stabilization of loose or worn cartilage, the basic strategy is to stabilize the defect by removal of any partially attached flap(s) of cartilage or badly worn areas that may be present. This method typically involves procedures such as arthroscopic debridement of the loose cartilage and removal of any detached cartilage tissue bodies that may be floating with the joint space, which could also be a potential source of inflammation. Arthroscopic debridement is considered when medical management has failed to satisfactorily alleviate symptoms. In addition, it is generally agreed that while this method is able to produce short-term alleviation of pain, the long-term effect is frequently eventual deterioration of the joint surface(s).
With respect to stimulation of a repair process from the subchondral bone, the basic strategy is to enhance the intrinsic capacity of the cartilage (and the subchondral bone) to heal itself. This is done by stimulating healing by recruiting cells from the underlying bone marrow in the subchondral bone. This method typically involves penetrating the subchondral bone by drilling, microfracture, or abrasion. It is generally agreed that with the techniques that are available today for executing this method, the results are similar to debridement and stabilization in that short-term pain may be alleviated through the growth of fibrous tissue. However, over the long-term, the effect typically is the eventual deterioration of the joint surface(s).
With respect to repair or replacement of the damaged articular surface, the basic strategy is to regenerate a new joint surface by transplanting chondrocytes, chondrogenic cells or tissue that has the potential to grow new cartilage. This method typically involves techniques such as osteochondral autographing (mosaicplasty), in which “plugs” of cartilage tissue and subchondral bone are harvested from a patient and implanted into the damaged cartilage area, or autologous chondrocytes transplantation, in which cartilage cells are harvested from a patient, cultured, and then implanted into the damaged cartilage area.
While the most preferred treatment method is restoration and repair of the damaged cartilage, the most common method today is debridement and stabilization, followed by stimulation of a repair process from the subchondral bone. Additionally, and as indicated above, while the first two categories of methods may be effective in the short-term relief of pain and discomfort to the patient, the long-term effect is typically an eventual deterioration of the cartilage surface, leading to the need for a total joint replacement.
With respect to repair of damaged articular cartilage, various devices have been developed in order to facilitate such repair. DePuy Orthopedics of Warsaw, Indiana (and assignee of the present invention) has developed such a device termed an Articular Cartilage Repair Unit (ACRU) whose function is based on the second category explained above, i.e. stimulation of a repair process from the subchondral bone. The ACRU utilizes a resorbable mesh material that acts as a scaffold or matrix for cell infiltration and proliferation.
The ACRU and other implants requires that the material be removed from the existing defect to expose the subchondral bone, allowing the scaffold or matrix and autologous cells access to stimulate the healing of the tissue. Such implants are preferably implanted arthroscopically. Particularly, the general surgical technique for implantation of the implant requires that the articular cartilage surrounding the damaged cartilage be prepared. Thereafter, the subchondral bone beneath the damage cartilage is prepared, and a pilot hole prepared into the subchondral bone.
Although various techniques and instruments have been developed that have attempted to address the need for articular cartilage repair, such techniques and instruments have not been optimal. For instance, either they are not arthroscopic in nature (see e.g. U.S. Pat. No. 6,171,340) or have a relatively difficult surgical procedure associated with such implantation (see e.g. WO96/24304).
In view of the above, it is an object of the present invention to provide a device for implanting an articular cartilage repair device into subchondral bone.
In view of the above, it is an object of the present invention to provide a device for arthroscopically implanting an articular cartilage repair device into subchondral bone.
In view of the above, it is an object of the present invention to provide a device for preparing an articular cartilage site for implantation of an articular cartilage repair device into subchondral bone.
In view of the above, it is an object of the present invention to provide a device for arthroscopically preparing an articular cartilage site for arthroscopic implantation of an articular cartilage repair device into subchondral bone.
In view of the above, it is an object of the present invention to provide a combination articular cartilage cutter and instrument guide for preparation of an articular cartilage site and/or the implantation of an articular cartilage repair device in subchondral bone.
In view of the above, it is an object of the present invention to provide a combination articular cartilage reamer and implantation borer for implantation of an articular cartilage repair device into subchondral bone.
In view of the above, it is an object of the present invention to provide a set of surgical instruments for the preparation of an articular cartilage site for implantation of an articular cartilage repair device into subchondral bone.
In view of the above, it is an object of the present invention to provide a set of surgical instruments for the arthroscopic preparation of an articular cartilage site for arthroscopic implantation of an articular cartilage repair device into subchondral bone. These and other objects of the present invention will become readily apparent to one skilled in the art.
The present invention is, in one form, an instrument set and surgical procedure (technique or method) for implanting an articular cartilage repair unit (ACRU) or device at an articular cartilage joint site.
A technique for the arthroscopic delivery and fixation of an articular cartilage repair unit (ACRU) fixation device or implant is provided. The technique includes the use of a cannula tube that functions as both a cartilage cutter and a guide to pass instruments into the body arthroscopically. One such instrument is an end-cutting reamer that both prepares the subchondral bone by re-surfacing it down to a specified depth and also simultaneously drills a pilot hole in the subchondral bone to accept the ACRU fixation device. A delivery device is utilized to hold and deliver the ACRU fixation device to the delivery site.
According to one aspect of the principles of the present invention, there is provided a cannula. The cannula includes a tubular body that defines a proximal and a distal end, a bore disposed in the tubular body and extending from the proximal end to the distal end, and a blade disposed at a tip of the distal end of the tubular body and configured to incise about an articular cartilage area. According to another aspect of the present invention, there is provided a surgical instrument guide and articular cartilage cutter. The surgical instrument guide and articular cartilage cutter includes a tubular body having a longitudinal instrument bore extending from a proximal end of the tubular body to a distal end of the tubular body, a surgical instrument stop defined at the proximal end of the tubular body and configured to provide an abutment for limiting a length of travel of a surgical instrument, and an articular cartilage cutting blade defined at the distal end of the tubular body and configured to incise about an articular cartilage area.
According to another aspect of the principles of the present invention, there is provided a surgical cutting tool. The surgical tool includes a shaft defining a proximal end and a distal end, an attachment head disposed at the proximal end of the shaft and configured to be received in a rotation device, and a reamer disposed at the distal end of the shaft and configured to ream about an incised articular cartilage area and to simultaneously prepare a bore in subchondral bone underneath the incised articular cartilage area.
According to another aspect of the principles of the present invention, there is provided a surgical drill for preparing an area of damaged articular cartilage on subchondral bone of a joint. The surgical drill includes a drill shaft having a proximal end and a distal end, an attachment tip on the proximal end of the drill shaft and configured to be received in a rotation device, and a site preparation tip on the distal end of the drill shaft and configured to ream an incised area of the damage damaged articular cartilage and to simultaneously prepare a bore in the subchondral bone underneath the reamed area of the damaged articular cartilage.
According to another aspect of the principles of the present invention, there is provided an implant delivery device. The implant delivery device includes a handle defining a proximal end and a distal end, a shaft extending from the distal end of the handle and having an application end with a retention slot configured to releasably receive an articular cartilage repair assembly comprising an articular cartilage repair unit releasably retained on an articular cartilage implant retainer, and a retaining sleeve disposed on the insert and operative in a first mode to allow the articular cartilage implant retainer to be received in the retention slot, and in a second mode that prevents egress of the articular cartilage implant retainer from the retention slot.
According to another aspect of the principles of the present invention, there is provided an implant delivery device. The implant delivery device includes a tubular sleeve having a longitudinal bore and defining a proximal end and a distal end, and an insert extendable from and retractable into the longitudinal bore of the tubular sleeve, the insert having an application end with a retention slot configured to releasably receive an articular cartilage repair assembly comprising an articular cartilage repair unit releasably retained on an articular cartilage implant retainer.
According to another aspect of the principles of the present invention, there is provided a set of surgical tools for preparing a damaged articular cartilage site on subchondral bone of a joint and implanting an articular cartilage repair device. The device includes a cannula, surgical drill and implant delivery device. The cannula has a tubular body defining a proximal and a distal end a bore disposed in the tubular body and extending from the proximal end to the distal end, a blade disposed at a tip of the distal end of the tubular body and configured to incise about an articular cartilage area. The surgical drill has a drill shaft having a proximal end and a distal end, an attachment tip on the proximal end of the drill shaft and configured to be received in a rotation device, and a site preparation tip on the distal end of the drill shaft and configured to ream an incised area of the damaged articular cartilage and to simultaneously prepare a bore in the subchondral bone underneath the reamed area of the damaged articular cartilage. The implant delivery device has a handle defining a proximal end and a distal end, a shaft extending from the distal end of the handle and having an application end with a retention slot configured to releasably receive an articular cartilage repair assembly comprising an articular cartilage repair unit releasably retained on an articular cartilage implant retainer. The retaining sleeve is disposed on the insert and is operative in a first mode to allow the articular cartilage implant retainer to be received in the retention slot, and in a second mode that prevents egress of the articular cartilage implant retainer from the retention slot.
According to yet another aspect of the principles of the present invention, there is provided a method of implanting an articular cartilage repair device into an area of damaged articular cartilage. The technique includes the steps of (a) providing access to a joint space having damaged articular cartilage through an arthroscopic portal in the body of a patient, (b) using an obturator to insert a combination instrument guide and articular cartilage cutter cannula through the arthroscopic portal, (c) removing remnants of damaged articular cartilage at a damaged articular site through the inserted cannula, (d) simultaneously preparing the damaged articular cartilage site and underlying bone with a surgical drill having a combination reaming and boring tip through the cannula, and (e) implanting an articular cartilage repair assembly onto the prepared articular cartilage site through the cannula.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Referring now to
The cannula 40 is made from a suitable surgical material such as metal and, preferably, but not necessarily, from stainless steel. Other suitable materials, however, can be used and are contemplated. The cannula 40 is defined by a cylindrical, tubular or similarly shaped body 42 having a first portion 44 and a second portion 46. A bore 50 extends the axial length of the body 42 through the first portion 44 and the second portion 46. The bore 50 defines a first opening 52 in an axial (proximal) end of the first portion 44 and a second opening 54 in an axial end (distal tip 56) of the second portion 46.
While the bore 50 may have the same diameter throughout the first portion 44 and the second portion 46, the outer diameter of the first portion 44 is greater than the outer diameter of the second portion 46. This creates an annular ledge 48 defining a boundary between the outer diameter of the first portion 44 and the outer diameter of the second portion 46. The bore 50, and thus the cannula 40 itself, serves as a guide to pass and/or utilize the various instruments of the present instrument set (and other instruments not shown and/or described herein) through an incision in the body. While the incision and the procedure is preferably arthroscopic in nature, the various instruments of the present instrument set may be utilized in surgical procedures that are not arthroscopic in nature.
It should be appreciated that the bore 50 may be made in various diameters. As such, the outer diameter of the first and second portions 44, 46 may be fashioned in various diameters. A surgical set of cannula tubes 40 of various outer diameters and/or various diameter bores may be provided. In this manner, a surgeon may have a choice of sizes of cannula 40 in order to accommodate ACRU implant assemblies of varying diameters.
Referring additionally to
The distal tip 56 also has an annular cutting section 60. The cutting section 60 is here formed as a reduced diameter portion and as such, defines an annular rim 62. At the end of the cutting section 60 is a blade 64. The blade 64 is annular and defined by a tapered, angled or beveled edge 66. The blade 64 is shown as annular, but may be fashioned in other shapes if desired. Typically, the blade has the same shape as a cross section of the body of the cannula. The blade 64 is adapted, configured, and/or operative to cut an area of cartilage (e.g. a focal lesion or damaged cartilage) from the articular cartilage site. The length of the blade 64 determines the maximum depth of articular cartilage cut. The incised area of cartilage corresponds to the shape of the blade 64 and thus corresponds, as well, to the size of the bore 50 at the distal bore end 54. The cannula 40 is both a guide for instruments via passing of an instrument through the bore 50 thereof, and an articular cartilage cutter through utilization of the distal tip 56. The cannula 40 is thus a dual purpose instrument.
Referring now to
The body 72 is of a diameter that permits the body 72 to pass through the bore 50 of the cannula 40. As well, the body 72 is of sufficient length to allow the tip 76 to either extend beyond or be at/near the end 55 (see
A handle 78 is provided at a proximal end of the body 72. The body 72 is also of sufficient length to allow the bulb 78 to be sufficiently beyond the end 53 (see
Referring now to
The body 92 further includes an elongated shaft 98 that is connected to the opposite side of the stop portion 96. The shaft 98 is preferably cylindrical and has a diameter that is able to be accommodated in the bore 50 of the cannula 40. The diameter of the elongated shaft 98, however, is less than the diameter of the stop portion 96. As such, a stop surface 97 is defined at the junction of the stop portion 96 and the elongated shaft 98. The stop surface 97 provides a stop for insertion of the reamer 90 in the cannula 40. Particularly, when the reamer 90 is fully inserted into the bore 50 of the cannula 40, the stop surface 97 abuts the end 53 of the first portion 44 of the body 42 of the cannula 40.
The reamer 90 includes a cutting or reaming head or portion 100 at the distal end of the elongated shaft 92 that is adapted, configured and/or operative to cut through cartilage (e.g. meniscus and articular) and to simultaneously bore a hole in subchondral bone. As such, the reaming head 100 has helical blades 102 and 103. Of course, it should be appreciated that while two helical blades are shown, the reaming head 100 may have more helical blades and/or other styles of blades.
A cutting tip 104 axially extends from an end 106 of the blades 102, 103. The cutting tip 104 is adapted, configured and/or operative to bore a hole in the subchondral bone underneath the reamed articular cartilage. The size and length of the cutting tip 104 is selected so as to bore a hole appropriate for receiving the stem of an articular repair device such as is known in the art. Thus, as the reamer 90 is rotated, the appropriate sized hole is bored into the subchondral bone while the blades 102, 103 ream out the previously incised area of articular cartilage.
The reamer 90 (i.e. the various parts thereof) may be fashioned in various dimensions in order to be accommodated in a particular cannula and/or to effect appropriate cutting depths of both the bore in the subchondral bone for the shaft of the articular cartilage repair device and the cartilage at the cartilage repair site (having been previously cut via the cutting blade 66 of the cutting head 56 of the cannula 40). In all cases, however, the length L of the elongated shaft portion 98 including the cutting portion 100 (i.e. from the stop surface 97 to the end 106) is sized such that when the stop surface 97 abuts the end 53 of the cannula 40, a portion of the blades 102, 103 (from the end 106 rearward toward the stop surface 97) extends beyond the end 55 of the cutting portion 56 of the cannula 40. The amount of blade extension is sufficient to ream out the incised depth of the articular cartilage.
While the cannula 40 of
The cannula 110 is one of a set of instruments or devices for performing a surgical procedure on articular cartilage, the other instruments of the set being shown in the other figures and described herein. Again, while described more fully below, the surgical procedure and one or more of the various instruments of the present instrument set, guides the various instruments through an incision of the body, gauges the depth of articular cartilage at a cartilage defect or focal lesion (site) of a joint that is proximate the incision, prepares the site, and allows implanting of an ACRU at the site.
The cannula 110 is made from a suitable surgical material such as metal and, preferably, but not necessarily, from stainless steel. Other suitable surgical materials, however, can be used and are contemplated. The cannula 110 is defined by a cylindrical, tubular or similarly shaped body 112 having a first portion 114 and a second portion 116. A bore 120 extends the length of the body 112 through the first portion 114 and the second portion 116. The bore 120 defines a first opening 122 in a proximal end of the cannula 110 and a second opening 124 in a distal end of the cannula 110.
While the bore 120 has the same diameter throughout the first portion 114 and the second portion 116, the outer diameter of the first portion 114 is greater than the outer diameter of the second portion 116. This creates an annular ledge 118 defining a boundary between the outer diameter of the first portion 114 and the outer diameter of the second portion 116. The bore 120, and thus the cannula 110 itself, serves as a guide to pass and/or utilize the various instruments of the present instrument set (and other instruments not shown and/or described herein) through an incision in the body. While the incision and the procedure is preferably arthroscopic in nature, the various instruments of the present instrument set may be utilized in surgical procedures that are not arthroscopic in nature.
It should be appreciated that the bore 120 may be made in various diameters. As such, the outer diameter of the first and second portions 114, 116 may be fashioned in various diameters. A surgical set of cannula tubes of various outer diameters and/or various diameter bores may be provided. In this manner, a surgeon may have a choice of sizes of cannula.
In like manner to the cannula 40 of
The distal tip 126 also has an annular cutting section 130. The cutting section 130 is here formed as a reduced diameter portion and as such, defines an annular rim 132. At the end of the cutting section 130 is a blade 134. The blade 134 is annular and defined by a tapered, angled or beveled edge 136. The blade 134 may be fashioned in another shape if desired. The blade 134 is adapted, configured, and/or operative to cut an area of cartilage (e.g. a focal lesion or damaged cartilage) from the articular cartilage site. The length of the blade 134 determines the maximum depth of articular cartilage cut. The incised area of cartilage corresponds to the shape of the blade 134 and thus corresponds, as well, to the size of the bore 120 at the distal bore end 124. The cannula 110 is both a guide for instruments via passing of an instrument through the bore 120 thereof, and an articular cartilage cutter through utilization of the distal tip 126. The cannula 110 is thus a dual purpose instrument.
In order for the obturator 70 (see
Because the cannula 110 is bent or curved, it is not possible for the rigid reamer 90 of
The reamer 140 includes a flexible shaft 142 fabricated from a braided, segmented, coiled or similar construction material suitable for surgical use. The flexible shaft 142 is constructed such that the shaft 142 may bend to fit the curvature of the bore of the selected cannula, while still allowing rotation of the shaft to effect reaming/cutting by rotation of a reaming/cutting head 146 attached to a distal end of the shaft 142. The proximal end of the shaft 142 is non-rotatably connected to an attachment device 144 that is adapted, configured and/or operative to be attached to a rotation device (not shown). The attachment device 144 includes an attachment shaft 148 for receipt by the rotation device. A socket portion 150 extends from an end of the attachment shaft 148 and includes a bore 152 that receives an end of the shaft 142. The shaft 142 is non-rotatably received in the bore 152 such that as the attachment device 144 is rotated, the shaft 142 is also rotated.
The reamer 140 also includes a reaming, cutting and/or site preparation head or tip 146 that is provided on a distal end of the shaft 142. The reaming/cutting head 146 is non-rotatably attached to the end of the shaft 142 and is configured and/or operative to cut through cartilage (e.g. meniscus and articular) and to simultaneously bore a hole in subchondral bone. As seen in
Referring additionally to
The reamer 140 (i.e. the various parts thereof) may be fashioned in various dimensions in order to be accommodated in a particular length of cannula and/or to effect appropriate cutting depths of both the bore in the subchondral bone for the shaft of the articular cartilage repair device and the cartilage at the cartilage repair site (having been previously cut via the cutting blade of the cutting head of the cannula). In all cases, however, the length of the elongated shaft 142 including the reaming/cutting head 146 (i.e. from a stop surface 153 defined on the socket head 150, see
Referring now to
The articular cartilage thickness gauge 170 includes a tube 172 that is preferably, but not necessarily, made of a resilient material. The tube 172 has an inner bore 173 in which is disposed a needle, probe or the like 174. The probe 174 terminates in a tip 176 and includes a number of gauge marks 177. The gauge marks correspond to various depths measured from the end of the tip 176. Such gauge marks may be demarcated in millimeters or other small increments. An end of the probe 174 that is not seen in
Referring additionally to
Referring now to
The implant delivery device 190 is adapted, configured and/or operative to receive, hold, implant, and release an articular cartilage repair unit (ACRU) or device and articular cartilage matrix (collectively, ACRU device) such as that shown in
The implant delivery device 190 further includes a pusher rod or cylinder 196 disposed within the bore 194 of the sleeve 192. The pusher rod 196 is axially slidable within the sleeve 192, the purpose of which will become evident with the below description. The pusher rod 196 includes a configured cutout 198 for receiving and holding an implant retainer (see
The implant delivery device 190 is depicted in
Referring to
The retainer 218 may be formed of a suitable, surgical appropriate plastic in which case the J-wire 220 may be integrally molded therein, such as via insert molding. Alternatively, the retainer 218 may be formed of a suitable, surgical appropriate metal in which case the retainer 218 may be crimp-fit around the J-wire 220. Other materials and/or methods of attachment, however, may be used. The retainer 218 is shaped at least substantially the same as the retainer slot 200, while the wire slot 202 is configured to receive the J-wire 220.
It should be appreciated that the retainer of the implant retainer may take different forms.
Referring now to
In
Referring now to
The shaft 264 includes a retainer slot 272 configured to receive one of the retainers of the implant retainers described herein. A wire slot 268 extends from the retainer slot 272 to the end 270. A sliding sleeve 274 is disposed around the shaft 264 between the seating ring 266 and the handle 262. The sliding sleeve 274 is biased such as by spring loading to be in a closed position as depicted in
Referring now to
A cylindrical sleeve 294 is disposed around the shaft portion 284 and includes a retainer port 296 and a wire channel 298 that extends from the retainer port 296. The cylindrical sleeve 294 is limitedly rotatable about the shaft portion 284. In
Preferably, but not necessarily, the sleeve 294 is biased into the closed position by a spring mechanism or the like. Therefore, in order to position the sleeve 294 into the open position as depicted in
Referring to
Referring now to
The implant retainer 404 is sized to receive and releasably retain an ACRU.
Referring now to
It should be appreciated that the various implant delivery devices as described above are usable only with the axially straight (non-curved) cannula. This is due to the rigid nature of the components. In order to alleviate this problem and thus be able to utilize any one of the various implant delivery devices, any of the above-described implant delivery devices may be formed as shown in
The flexible implant delivery device 310 has a distal tip 312 that is made of a hard, surgical-appropriate material. The tip 312 includes a retainer cutout or slot 318 that is configured to receive a retainer portion of an implant retainer. A wire slot 320 extends from the retainer cutout 318 to the end 319 of the tip 312. The flexible implant delivery device 310 also includes a proximal end 314 that is fabricated of a hard, surgical-appropriate material. A shaft 316 is disposed between the tip 312 and the end 314. The shaft 316 is fabricated from a flexible, surgical-appropriate material. The flexible shaft 316 is thus operative to bend or curve in any direction and/or amount in order to be accommodated in a cannula of any curvature. The flexible shaft 316 is also resilient such that the shaft will, without external bias, tend to remain in (or go back into) a straight configuration.
The ability to flex or bend is illustrated in
An exemplary method or technique of preparation of an articular cartilage site and implantation of an articular cartilage repair unit/device or ACRU in accordance with an aspect of the principles of the subject invention will now be described utilizing a set of instruments as described herein that includes at least some, if not all of the present instruments. As well, reference will be made to
In block or step 352, an incision or incisions is first made in the body of a patient proximate to the affected joint in a manner known in the art. The incision(s) may be for an arthroscopic procedure or not. Once the incision(s) has been made, in block 354, an obturator is used to insert a selected cannula in accordance with the principles of the subject invention through the incision (or one of the incisions). The selected cannula may be a straight cannula or may be a curved cannula. If the selected cannula is a curved cannula, the surgeon must select the degree of curvature. Additionally, the size (diameter) of the cannula must be selected. Therefore, the instrument set should include a plurality of cannula from straight to variously curved cannula each coming in various sizes.
In block 354, the selected cannula is inserted through the incision using the obturator and situated adjacent (i.e. over) the affected or damaged articular cartilage site. This positions the cutting tip/blade of the cannula around the damaged articular cartilage site. The obturator is then removed from the cannula (block 355).
In block 356, once the cannula is in a proper position over the damaged articular cartilage site, the damaged articular cartilage is cut or incised by the cannula blade. The cartilage is incised to the proper depth. The depth of cutting may first be ascertained by use of the articular cartilage depth gauge instrument that may be part of the instrument set.
Thereafter, in block 358, an appropriate reamer is selected and inserted into the cannula. The reamer is attached to a rotation device for rotation of the reamer. In block 360, the articular cartilage incised by the cannula is then reamed by the blades of the reamer. The reamer also reams the subchondral bone under the articular cartilage flat or smooth. Simultaneously, in block 362, a bore is drilled in the subchondral bone for receipt by the stem of the ACRU fixation device. In block 364, the reamer is then removed from the cannula. The site is now ready to receive the ACRU implant.
In block 366, an ACRU assembly is attached to an implant retainer. Thereafter, in block 368, the ACRU implant assembly is attached to the implant delivery device. In block 370, the implant delivery device is then inserted through the cannula to the prepared site. The ACRU assembly, in block 372, is then implanted into the prepared site. In block 374, the implant delivery device is then removed from the cannula. Thereafter, the cannula 376 is removed from the incision.
While not specifically mentioned in the above procedure, typical and necessary measures and procedures (e.g. closing the incision(s)) would be performed. Such are known in the art.