PATELLA RESECTION GUIDE
A method and apparatus for resectioning a patella without everting it includes a resection guide which grips the patella with gripping members, one of which can also function as an alignment guide for a surgeon using a saw for the resectioning. Means engageable with the resection guide are provided for aligning drills and/or reamers used in resectioning. Under one embodiment, a pair of reamers are provided for reaming the patella in two reaming operations.
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This application is based upon and claims priority under Provisional Patent Application No. 60/359,631 filed Feb. 26, 2002.
SUMMARY OF THE INVENTIONThe present patent application is directed to a patella resection guide for permitting precise measurement of the depth of a resection cut of the patella which may be used to support the patella and perform a precise resection cut from the dome portion without everting the patella.
BACKGROUND OF THE INVENTIONIn performing knee surgery, it is frequently necessary to resect the patella preparatory to inserting a patellar prosthesis therein. Heretofore it has been necessary to evert the patella in order to have it positioned such that the resectioning can be effectively performed. The resection device of the present invention permits the patella to be resectioned without the necessity of everting it thereby simplifying the procedure and permitting it to be performed in a less invasive manner than was heretofore the case. Additionally, the resection device of the present invention permits other arthroplasty procedures to be performed without everting the patella including preparation of the distal end of the femur and the proximal end of the tibia.
BRIEF DESCRIPTION OF THE DRAWINGS
The patella engagement end 103 extends longitudinally beyond the forward central slot 105 and is enlarged to extend laterally outwardly from the central axis of the forward central slot 105. A pair of upstanding tabs 110 are mounted in spaced-apart relationship on the enlarged patella engagement end 103. Supported on each of the tabs 110 is a tapered patella engagement pin 111 each of which points rearwardly and inwardly toward the axis of the forward central slot 105.
A secondary guide member 108 is secured to the slide support 102 for slideable movement relative thereto. The secondary guide member 108 includes a slide 112 on one side of the slide support 102 and a base 107 on the opposite side of the slide support 102. A support pin 106 is secured to the leading end of the slide 112 and extends through the slot 105 and through the base 107, extending upwardly from the base 107. A slideable cutting guide/support member 113 is pivotally mounted on the end of the support pin 106 for pivotal movement thereon.
The cutting guide/support 113 has a V-shaped configuration with a pair of patella engagement pins 111A extending toward the patella engagement end 103 and the patella engagement pins 111 supported on the tabs 110. One of the patella engagement pins 111A is located on one side of the support pin 106 and the other patella engagement pin 111A is on the opposite side of such support pin 106. Since the shape of a patella is not perfectly circular in the area to be gripped by the patella engagement pins 111 and 111A, the feature of permitting the cutting guide/support 113 to pivot about the support pin 106 assures that both of the patella engagement pins 111A, as well as both of the patella engagement pins 111, will engage the patella P.
Extending upwardly from the opposite end of the slide 112 from the pivot pin 106 is a threaded screw 124 which extends through the rear slot 125. Encircling the rear slot 125 is a ledge 138 which is recessed from the upper surface of the slide support 102. A flat head cap screw 117 is engaged to the threaded screw 124 and rests upon the ledge 130 for sliding engagement therewith thereby providing support and guidance for that end of the slide 112.
Supported on the opposing end 104 of the slide support 102 is a base assembly 115 having a pair of gripping handles 116 extending from opposite sides thereof. Extending longitudinally through an opening in the base assembly 115 is a slideable plunger 118 having a gripping member 145 at the opposing end. The plunger 118 is connected to the end of the slide 112 adjacent the screw 124 by means of a connector which permits the plunger 118 to be rotated 90° from the position shown in
Housed within the enlarged base 115 is a pawl spring and pawl positioned to engage the ratchet teeth 119. The pawl and spring are so positioned within the base assembly 115 as to permit the plunger 118 to readily be moved forwardly toward the patella engagement end 103 (to the right as viewed in
When it is desired to grip the patella P, the patella resection guide 100 is positioned such that the enlarged area adjacent the patella engagement end 103 supports the anterior side of the patella P and then is moved to a position at which the patella engagement pins 111 supported on the tabs 110 engage the central portion of the patella. The plunger 118 is then moved forward by pushing the gripping member 145 while holding the gripping handles 116 thereby causing the slide 112 to move toward the patella engagement end 103 and to grip the patella P with the patella engagement pins 111A carried on the slideable cutting guide 113. As previously discussed, the slideable cutting guide 113 is pivotally mounted on the support pin 106 to assure that the patella engagement pins 111A both engage the patella P notwithstanding any irregularities in the central portion of the patella P.
In order to release the ratchet teeth 119 from the pawl, there is provided a spring loaded lock release 123 which may be depressed to permit the plunger 118 to be rotated 90° to thereby disengage the ratchet teeth 119 from the pawl. Such rotation can be accomplished because the plunger 118 is rotatably secured to the slide 112. In order to prevent the plunger 118 from rotating when it is desired to be maintained in the patella gripping position shown in
If desired, the plunger 118 may have longitudinally extending line 147 embossed on the side opposite the ratchet teeth 119 in order to permit the surgeon to readily determine that the ratchet teeth 119 are facing in a position to engage the pawl. A similar line 147A may also be embossed in the upper surface of the enlarged base 115 to assist the surgeon in rotatable alignment.
Extending upwardly from a central portion of the slide support 102, between the forward central slot 105 and rear slot 125 is a support post 127 which may be used to assist in proper preparation of the patella.
Under one embodiment of the present invention, the patella resection guide as thus far described can be used for guiding a resectioning saw to cut the desired amount of the dome on the posterior surface of the patella. Thus, the sizing of the slideable cutting guide/support 113 and its positioning of its upper surface above the surface of the enlarged area of the slide support 102 adjacent the patella engagement end 103 upon which the anterior surface of the patella P rests is designed to leave a predetermined amount of patella P, 13 to 16 mm, between such upper surface and the supported portion of the anterior surface resting upon the enlarged end adjacent the end 103. As will be appreciated, in performing such resecting, the surgeon simply uses such upper surface of the slideable cutting guide/support 113 as a guide determining the plane of movement of the cutting saw.
In the event that the surgeon, upon engaging the patella P with the resection guide 100, ascertains that a lesser amount of bone should be resected from the dome of the patella, there is provided an adjustment member 114 (see
The slideable cutting guide/support 113, as shown in
Referring to
Referring to
The sizing/alignment guide 130 is useable both for drilling a hole in the central portion of the patella P either prior to any resecting of the dome portion thereof as shown in
Each of the first enlarge head 170 and second enlarge head 171 is provided with a central passageway 126 for receiving and guiding a combination drill/guide rod 128 and three larger passageways 129 for receiving and guiding drills for drilling peg holes in the flat prepared surface (see
Extending downwardly from each of the first and second enlarged heads 170 and 171 are three alignment pins 135 which may rest upon the resected surface of the patella P prior to drilling an aperture for positioning the drill guide 128 when the patella is resected with a saw as described with reference to
The outside diameter of the enlarged head, for example, the first enlarged head 170 or the second enlarged head 171 of the sizing alignment guide 130 is selected based upon the diameter of the patellar prosthesis implant intended for the patella P, which size depends upon the size of the patient and the condition of the patella being prepared. The sizes of the enlarged heads 170, 171 may vary from 26 to 41 mm. The positioning of the apertures 129 for each size of enlarged head 170 or 171 is determined by the positioning of the peg lugs of the patellar prosthesis to be implanted. Although the sizing alignment guide 130 is shown as having two enlarged heads (first enlarged head 170 and the second enlarged head 171), this is done simply to reduce the number of sizing alignment guides 130 required for a set with varying sizes from 26 to 41 mm in diameter. Only a single enlarged head 170, 171 will be used for guiding the drilling and reaming in the preparation of a specific patella.
The support post 127 is positioned at right angles to the slide support 102. When the sizing/alignment guide 130 is so positioned on the support post 127, the pin alignment guide aperture 126 and the guide holes 129 for drilling the peg holes will be parallel to the support post 127. Preparatory to tightening the upper and lower adjustment members 174, 175 onto the support post 127, the sizing/alignment guide 130 may be moved to the right or to the left as shown in
With the drill/guide pin 143 engaged to the patella P, the sizing/alignment guide 130 may then be removed from the support posts 127 or rotated out of alignment with the patella P to provide room for a circumferential patella reamer to be positioned over the drill/guide pin 143. Although not shown in
As shown in
The circumferential reamer 180 is provided with a tubular member 189 attached to the head 184 and an enlarged power means gripping portion 190 engageable with a drill or other power means in a manner well known in the art. A central passageway 191 extends completely through the circumferential patella reamer 180 from the proximal end 192 to the upper interior wall 188 so that the circumferential patellar reamer 180 can be telescoped over the drill/guide pin 143 as shown in
In the event the surgeon determines that the size or condition of the patella being reamed is such that reaming to a depth of 10 mm as measured from the dome 159 of the patella P to the cut surface 154 would be excessive, he may insert a washer such as the washer 193 shown in
Referring to
A tubular shaft 166 and power engaging means 167 extend from the enlarged head 195. A cannulation passageway 169 extends completely through the finishing reamer 194.
Following reaming of the patella P with the circumferential patella reamer 180 and removal of the circumferential patella reamer from the drill/guide pin 143, the finishing reamer 194 is telescoped over the drill/guide pin 143. As shown in
Following completion of reaming with the finishing reamer 194 as shown in
Referring
Extending upwardly from the upper leg 222A is a post 232 having a recess 233 sized to receive and support a member to be hereinafter described. The post 232 is provided with a radially extending threaded aperture 234 in which is received a threaded stem 235 of a tightening handle 236. The lower leg 222B is also provided with an axially extending slot 238 having a widened area adjacent the lower surface defining a downwardly facing shoulder 239.
The slideable guide member 240 includes an upper leg 240A slidingly engaged to the lower surface of the upper leg 222A of the slide support 222 and a lower leg 240B slidingly engaged to the upper surface of the lower leg 222B and a third leg 240C joining the legs 240A and 240B. Secured to and extending upwardly from the leading end of the upper leg 240A is a support pin 242 (See
The lower leg 240B is slideably engaged to the upper surface of the lower leg 222B of the slide support 222. The lower leg 240B has a pin 246 extending downwardly therefrom through the slot 238. The pin 246 has an enlarged head 248 which engages the shoulder 239.
Supported on the end of the lower leg 222B of the slide support 222, at the end opposite the leg 222C, is a base assembly 250 similar to the base assembly 115 of the embodiment of
When it is desired to grip the patella P, the patella resection guide 220 is positioned such that the anterior surface of the patella P rests on the support surface 228. The resection guide 220 is moved to a position at which the patella engagement pins 227 supported on the upstanding tabs 226 engage the central portion of the patella P. The slideable plunger 254 is then moved in a direction (to the right as viewed in
Referring to
The pin 262 may be supported in the cavity 233 of the post 232. Tightening of the handle 236 and its threaded stem 235 will firmly engage the pin 262 in the cavity 233.
If desired, the adjustment member 114 could also be provided with slots through which the saw could be guided.
The above detailed description of the present invention is given for explanatory purposes. It will be apparent to those skilled in the art that numerous changes and modifications can be made without departing from the scope of the invention.
Claims
1-22. (canceled)
23. A device for use in resectioning a patella having an anterior surface, a posterior surface and a circumferential edge between said anterior surface and said posterior surface comprising:
- (a) a fixed engagement member having (i) a support upon which said patella anterior surface may rest and (ii) first patella engagement means for engaging said circumferential edge; and
- (b) a movable engagement member having second patella engagement means for engaging at least a portion of said circumferential edge of a patella resting upon said support, said movable engagement member being slideably attached to said fixed engagement member for movement toward said first patella engagement means to engage at least a portion of the circumferential edge of said patella.
24. A device according to claim 23 wherein said movable engagement member has a planar surface spaced from said support, said planar surface being useable for guiding a cutting tool.
25. A device according to claim 24 wherein said planar surface defines one surface of a guide slot on said movable engagement member.
26. A device according to claim 24 further including an adjustment member engageable with said planar surface, said adjustment member having a second planar surface useable for guiding a cutting tool.
27. A device according to claim 23 wherein said fixed engagement member includes an arm terminating at said support and a post mounted on said arm at substantially right angles to said arm and further including a guide member supported on said post, said guide member having a passageway for guiding movement of a drill into said patella, and means for positioning said guide member on said post to position said passageway over a central portion of a patella engaged by said first and second patella engagement means.
28. A device according to claim 23 further including gripping means engaged to said movable engagement member, said gripping means includes an arm extending to a gripping portion, said arm positioned on the opposite side of said support from said first and second patella engagement means.
29. A device according to claim 28 wherein said fixed engagement member includes a first arm extending from said support in a direction away from said first patella engagement means to an area of juncture, said first arm having a longitudinal slot and a second arm spaced from and parallel to said first arm and wherein said movable engagement member includes a first slider member slideably engaged to said first arm on the opposite side of said first arm from said second patella engagement means and a second slider member slideably engaged to said second arm.
30. A device according to claim 29 further including a guide member secured to said fixed engagement member, said guide member having a passageway for guiding movement of a drill into said patella, and means for positioning said guide member on said fixed engagement member to position said passageway over a central portion of a patella engaged by said first and second patella engagement means.
31. A device according to claim 30 wherein (i) said means for positioning said guide member on said fixed engagement means includes a receptacle engaged to said first arm and (ii) said guide member being supported on a post engageable in said receptacle.
32. A device according to claim 31 wherein said guide member is adjustably supported on said post.
33. A combination of a device according to claim 23 and first and second reamers useable with said device, said first reamer having a circumferential cutter, inner and outer cylindrical walls extending from said circumferential cutter, said inner cylindrical wall defining a portion of a cavity terminating in an end wall spaced from said circumferential cutter and engageable with a central portion of said patella posterior surface to limit the depth to which said circumferential cutter can ream said patella, said second reamer having a central cutter and a circumferential non-cutting surface encircling said central cutter and sized to engage the portion of said patella reamed by said first reamer to limit the depth to which said central cutter can ream said patella.
34. A resection device for a patella comprising a reamer having a circumferential cutter, inner and outer cylindrical walls extending from said circumferential cutter, said inner cylindrical wall defining a portion of a cavity terminating in an end wall spaced from said circumferential cutter and engageable with a central portion of said patella to limit the depth to which said circumferential cutter can ream said patella.
35. A reamer for resectioning a patella partially reamed to leave a circumferential reamed surface comprising a central cutter and a circumferential non-cutting surface encircling said central cutter and sized to engage the partially reamed portion of said patella to limit the depth to which said reamer can ream said patella.
36. A device for resectioning a patella comprising a combination of first and second reamers, said first reamer having a circumferential cutter, inner and outer cylindrical walls extending from said circumferential cutter, said inner cylindrical wall defining a portion of a cavity terminating in an end wall spaced from said circumferential cutter, said end wall engageable with a central portion of said patella posterior surface to limit the depth to which said circumferential cutter can ream said patella, said second reamer having a central cutter and a circumferential non-cutting surface encircling said central cutter, said non-cutting surface sized to engage the portion of said patella reamed by said first reamer to limit the depth to which said second reamer can ream said patella.
Type: Application
Filed: Jan 21, 2008
Publication Date: May 15, 2008
Applicant: ZIMMER, INC. (Warsaw, IN)
Inventors: Donald Smucker (Perrysburg, OH), Richard Van Zile (Bryan, OH)
Application Number: 12/017,104
International Classification: A61B 17/58 (20060101); A61F 5/00 (20060101);