Patent Publication Number: US-11376020-B2

Title: Expandable reamers

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of U.S. patent application Ser. No. 15/596,309, now U.S. Pat. No. 10,456,145, which was filed on May 16, 2017, the entire disclosure of which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     This disclosure relates to expandable reamers that can be introduced into a bone tunnel for removing diseased bone. 
     Diseased areas of bone may need to be removed from patients suffering from bone degeneration. For example, treating avascular necrosis (AVN) of the hip or osteochondritis dissecans (OCD) of the knee requires removing diseased bone from the patient. Various surgical cutting devices have been used for this purpose. However, advancements in this field of technology are desired for improving the procedure for removing diseased bone. 
     SUMMARY 
     This disclosure relates to expandable reamers that can be used to remove diseased bone. The expandable reamers include a blade that can be advanced to form a socket in bone. The blade is non-deployed as the expandable reamers are positioned relative to the diseased bone, and the blade is then deployed to a cutting position for removing the diseased portions of the bone. 
     According to an exemplary aspect of this disclosure, an expandable reamer includes, inter alia, an outer tube, an inner shaft within the outer tube, a blade hinged to the inner shaft and movable between a first position in which the blade is inside the outer tube and a second position in which the blade is exposed outside of the outer tube, and an actuator assembly configured to move the blade between the first position and the second position. The actuator assembly includes a selector sleeve, an actuator, and a first pin movable within a helical groove of the actuator to linearly translate either the inner shaft or the outer tube as the selector sleeve is rotated. A ratcheting assembly includes an engaged position in which the selector sleeve is prevented from rotating and a disengaged position in which the selector sleeve is free to rotate. A pawl of the ratcheting assembly engages a gear in the engaged position and is released from the gear in the disengaged position 
     According to another exemplary aspect of this disclosure, an expandable reamer includes, inter alia, an outer tube, an inner shaft within the outer tube, a blade movable between a first position in which the blade is inside the outer tube and a second position in which the blade is exposed outside of the tube, and an actuator assembly configured to move the blade between the first position and the second position. The actuator assembly includes a selector sleeve, an actuator, and a first pin movable within a groove of the actuator to linearly translate either the inner shaft or the outer tube as the selector sleeve is rotated. 
     A method for removing diseased bone includes, inter alia, positioning an expandable reamer relative to diseased bone with a blade of the expandable reamer positioned in a non-cutting position, and incrementally advancing the blade to a cutting position relative to the diseased bone by rotating a selector sleeve of the expandable reamer. As the selector sleeve is rotated, a pin of the selector sleeve travels within a groove of an actuator to linearly translate the actuator. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings that accompany the detailed description can be briefly described as follows: 
         FIGS. 1 and 2  illustrate an expandable reamer according to a first embodiment of this disclosure. 
         FIG. 3  is an enlarged view of a portion of the expandable reamer of  FIGS. 1 and 2 . 
         FIGS. 4 and 5  illustrate an actuator assembly of the expandable reamer of  FIGS. 1 and 2 . 
         FIGS. 6 and 7  illustrate an expandable reamer according to a second embodiment of this disclosure. 
         FIGS. 8, 9, and 10  illustrate an actuator assembly of the expandable reamer of  FIGS. 6 and 7 . 
         FIGS. 11 and 12  illustrate an expandable reamer according to a third embodiment of this disclosure. 
         FIG. 13  illustrates a blade of the expandable reamer of  FIGS. 11 and 12 . 
         FIGS. 14 and 15  illustrate a cam cap of the expandable reamer of  FIGS. 11 and 12 . 
         FIGS. 16, 17, and 18  illustrate an actuator assembly of the expandable reamer of  FIGS. 11 and 12 . 
         FIGS. 19 and 20  illustrate an expandable reamer according to a fourth embodiment of this disclosure. 
         FIG. 21  is an exploded view of the expandable reamer of  FIGS. 19 and 20 . 
         FIGS. 22, 23, and 24  illustrate an actuator assembly of the expandable reamer of  FIGS. 19 and 20 . 
         FIGS. 25, 26, 27, 28, and 29  illustrate a ratchet assembly of the expandable reamer of  FIGS. 19 and 20 . 
         FIGS. 30, 31, 32, 33, 34, and 35  schematically illustrate an exemplary method of removing areas of diseased bone. 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure describes expandable reamers that can be used to remove diseased bone. The expandable reamers include at least one blade that can be incrementally advanced to form a socket in bone. The blade is held in a non-cutting positon as the expandable reamers are positioned relative to the diseased bone, and the blade is then deployed to a cutting position for removing the diseased portions of the bone. 
     According to an exemplary aspect of this disclosure, an expandable reamer includes, inter alia, an outer tube, an inner shaft within the outer tube, a blade hinged to the inner shaft and movable between a first position in which the blade is inside the outer tube and a second position in which the blade is exposed outside of the outer tube, and an actuator assembly configured to move the blade between the first position and the second position. The actuator assembly includes a selector sleeve, an actuator, and a first pin movable within a helical groove of the actuator to linearly translate either the inner shaft or the outer tube as the selector sleeve is rotated. A ratcheting assembly includes an engaged position in which the selector sleeve is prevented from rotating and a disengaged position in which the selector sleeve is free to rotate. A pawl of the ratcheting assembly engages a gear in the engaged position and is released from the gear in the disengaged position. 
     According to another exemplary aspect of this disclosure, an expandable reamer includes, inter alia, an outer tube, an inner shaft within the outer tube, a blade movable between a first position in which the blade is inside the outer tube and a second position in which the blade is exposed outside of the tube, and an actuator assembly configured to move the blade between the first position and the second position. The actuator assembly includes a selector sleeve, an actuator, and a first pin movable within a groove of the actuator to linearly translate either the inner shaft or the outer tube as the selector sleeve is rotated. 
     According to another exemplary aspect of this disclosure, an expandable reamer includes, inter alia, an outer tube, an inner shaft within the outer tube, a blade movable between a first position in which the blade is inside the outer tube and a second position in which the blade is exposed outside of the tube, and an actuator assembly configured to move the blade between the first position and the second position. The actuator assembly includes a selector sleeve, an actuator, and a first pin movable within a groove of the actuator to linearly translate either the inner shaft or the outer tube as the selector sleeve is rotated. 
     In a further embodiment, a cam cap is configured to guide movement of a blade outwardly of an outer tube. 
     In a further embodiment, a cam cap is positioned within a distal portion of an outer tube. 
     In a further embodiment, a cam cap includes a slanted wall that guides a blade along an arced path as the blade is moved between a first position and a second position. 
     In a further embodiment, a cam cap includes grooved tracks disposed on each side of a slanted wall, and a blade includes projections that are guided within the grooved tracks. 
     In a further embodiment, a blade is hinged to a distal portion of an inner shaft. 
     In a further embodiment, a groove is a helical groove. 
     In a further embodiment, a helical groove includes a plurality of detents. 
     In a further embodiment, a first pin is movable from a first detent to a second detent to alter a cutting diameter of a blade. 
     In a further embodiment, a ridge is disposed between a first detent and a second detent of an actuator. 
     In a further embodiment, a ratcheting assembly locks a selector sleeve from rotational movement. 
     In a further embodiment, a ratcheting assembly includes an engaged position in which a selector sleeve is prevented from rotating and a disengaged position in which the selector sleeve is free to rotate. 
     In a further embodiment, a ratcheting assembly includes a pawl and a gear, and the pawl engages the gear in the engaged position and is released from the gear in the disengaged position. 
     In a further embodiment, a selector sleeve is movable longitudinally forward to move the ratcheting assembly from an engaged position to a disengaged position. 
     In a further embodiment, an outer tube and an inner shaft are disposed along a longitudinal axis, and a blade is parallel to the longitudinal axis in a first position and transverse to the longitudinal axis in a second position. 
     A method for removing diseased bone according to another exemplary aspect of this disclosure includes, inter alia, positioning an expandable reamer relative to diseased bone with a blade of the expandable reamer positioned in a non-cutting position, and incrementally advancing the blade to a cutting position relative to the diseased bone by rotating a selector sleeve of the expandable reamer. As the selector sleeve is rotated, a pin of the selector sleeve travels within a groove of an actuator to linearly translate the actuator. 
     In a further embodiment, a method includes rotating an expandable reamer with a blade in a cutting position to remove diseased bone. 
     In a further embodiment, a method includes reaming a tunnel into a bone that includes diseased bone prior to positioning an expandable reamer. 
     In a further embodiment, a method includes backfilling a bone tunnel with a biologic after removing diseased bone. A biologic includes, inter alia, bone marrow aspirate, bone marrow concentrate, platelet rich plasma, bone morphogenetic proteins (e.g., BMP-2), demineralized bone matrix, growth factors (e.g., TGF-β), autologous or allogeneic ex vivo cultured bone marrow cells, and the like, and combinations thereof. 
     In another embodiment, a method includes backfilling a bone tunnel with a bone cement after removing diseased bone. Bone cements are known and include, inter alia, calcium phosphate cements (CPC). Bone cements can have varying formulations to provide different characteristics and can be injectable. In an example, a nanocrystalline calcium phosphate formulation can be mixed with saline and implanted in a bone tunnel where the formulation hardens and converts to nanocrystalline hydroxyapatite. Specifically, a CPC can comprise tricalcium phosphate (e.g., α-TCP or β-TCP), tetracalcium phosphate, hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 , fluoroapatite (Ca 5 (PO 4 ) 3 F), monocalcium phosphate monohydrate (MCPH), dicalcium phosphate dehydrate (DCPD), dicalcium phosphate anhydrous, calcium deficient apatite CDA), tricalcium silicate, and combinations thereof. CPC formulations will also commonly include polysaccharides, and salts and mixtures thereof. For example, common polysaccharides in CPC formulations include hydroxypropylmethylcellulose (HPMC) and carboxymethylcellulose (CMC). In an example formulation, a CPC comprises at least 70 wt % α-TCP. In an embodiment, a CPC comprises 88 wt % α-TCP, 10 wt % DCPD, and 2 wt % HPMC. 
     In a further embodiment, a method includes incrementally advancing a blade by moving the blade along an arced path to a position radially outward from an outer tube of an expandable reamer. 
       FIGS. 1-5  illustrate an exemplary expandable reamer  10 . The expandable reamer  10  is an orthopedic surgical device that may be part of a surgical instrumentation set designed for removing diseased bone from a patient. In an embodiment, the expandable reamer  10  is used to treat avascular necrosis (AVN) of the hip. In another embodiment, the expandable reamer  10  is used to treat osteochondritis dissecans (OCD) of the knee. The expandable reamers described in this disclosure could be used for any surgical procedure that requires removing diseased bone in either human or animal patients. 
     The expandable reamer  10  may include an outer tube  12 , an inner shaft  14 , one or more blades  16 , and an actuator assembly  18 . The blades  16  may be incrementally advanced between a first position P 1  (see  FIG. 1 ) and a second position P 2  (see  FIG. 2 ). The first position P 1  is a non-cutting position in which the one or more blades  16  are not exposed outside of the outer tube  12 , and the second position P 2  is a cutting position in which the one or more blades  16  are exposed outwardly of the outer tube  12  for removing diseased bone. In an embodiment, the one or more blades  16  are incrementally advanced to bore a socket into bone that is any diameter. In an embodiment, the diameter is a range between about 5 mm to about 10 mm, about 5 mm to about 15 mm, about 5 mm to about 18 mm, or about 5 mm to about 20 mm. Of course, the expandable reamer  10  could be configured to bore a socket of any size. 
     The outer tube  12  and the inner shaft  14  are disposed along a longitudinal axis A. The inner shaft  14  extends inside the outer tube  12  and is thus at least partially surrounded by the outer tube  12 . In an embodiment, the outer tube  12  and the inner shaft  14  are concentric relative to one another. 
     In another embodiment, the inner shaft  14  is fixed and the outer tube  12  is movable along the longitudinal axis A of the expandable reamer  10 . However, an opposite configuration is also contemplated in which the outer tube  12  is fixed and the inner shaft  14  moves along the longitudinal axis A. Movement of either the inner shaft  14  or the outer tube  12  relative to the other of the inner shaft  14  and the outer tube  12  positions the one or more blades  16  in the second positions P 2  for reaming diseased tissue, as discussed in greater detail below. 
     The expandable reamer  10  shown in  FIG. 1  includes two blades  16 . However, the expandable reamer  10  could include a single blade or greater than two blades within the scope of this disclosure. 
     Referring to  FIG. 3 , the blades  16  may be attached near a distal portion  20  of the outer tube  12  by a first pin  22 . In an embodiment, the first pin  22  extends through a first arm  24  of the distal portion  20  of the outer tube  12 , then through both blades  16 , then through a slot  26  formed in the inner shaft  14 , and finally through a second arm  28  of the distal portion  20  of the outer tube  12 . As the outer tube  12  is moved along the longitudinal axis A in the direction of arrow  15 , the first pin  22  moves within the slot  26  of the inner shaft  14 . This linear movement forces the blades  16  to push against a second pin  30 , thereby moving the blades  16  radially outward from the outer tube  12  toward the second position P 2 . The second pin  30  may travel within a slot  27  of one of the blades  16  as the blades  16  are pushed against the second pin  30 . In an embodiment, the second pin  30  extends between walls  32  of a cap  34  of the outer tube  12 . 
     In an embodiment, the blades  16  are incrementally advanced through windows  36  that extend between the walls  32  of the cap  34  and between the first and second arms  24 ,  28  of the outer tube  12 . Thus, in the first position P 1 , the expandable reamer  10  provides an atraumatic device that substantially reduces risks of inadvertent damage to surrounding tissue as the expandable reamer  10  is positioned within bone. The blades  16  of the expandable reamer  10  may be advanced radially outward from the outer tube  12  to the second position P 2 , or any position between the first position P 1  and the second position P 2 , for preparing a socket in bone. In the second position P 2 , the blades  16  are non-parallel to the longitudinal axis A and are exposed outside of the outer tube  12 . 
     The actuator assembly  18  is configured for moving the blades  16  in the manner described above. As best illustrated in  FIG. 4 , the actuator assembly  18  may include a selector sleeve  38 , an actuator  40 , and a connector hub  42 . The selector sleeve  38  is connected to the actuator  40 , such as at a threaded connection  44 . The selector sleeve  38  may be rotated relative to the connector hub  42  to linearly move the actuator  40  along the longitudinal axis A. In other words, rotational movement of the selector sleeve  38  translates the actuator  40  linearly. 
     The actuator  40  is connected (e.g., welded, etc.) to the outer tube  12 , and therefore, in this example, linear movement of the actuator  40  results in linear movement of the outer tube  12 . Linear movement of the outer tube  12  pushes the blades  16  against a second pin  30  in the manner described above and shown in  FIG. 3  to move the blades toward the second position P 2 . Rotation of the selector sleeve  38  in the opposite direction retracts the blades  16  toward the first position P 1 . 
     The selector sleeve  38  may include a knurled surface  46 . The knurled surface  46  is designed to improve a user&#39;s grip when turning the selector sleeve  38 . 
     An extension  48  of the actuator  40  extends forward of the selector sleeve  38 . The extension  48  supports the selector sleeve  38  and may provide a visual indication of the amount the blades  16  have been moved. 
     The connector hub  42  may be mounted relative to the selector sleeve  38  using a snap ring  50 . In an embodiment, the connector hub  42  is connected to the inner shaft  14  via one or more set screws  52  (see  FIG. 5 ). 
     The clutch assembly  18  may additionally include a connector  54 . In an embodiment, the connector  54  is an integral component of the inner shaft  14 . In another embodiment, the connector  54  is as a Jacobs connector. Powered equipment, such as a drill, may be connected to the connector  54  for rotating the entire expandable reamer  10  after the blades  16  have been positioned in the second position P 2  to achieve a desired bore diameter in bone. 
       FIGS. 6-10  illustrate another exemplary expandable reamer  110 . The expandable reamer  110  may include an outer tube  112 , an inner shaft  114 , a blade  116 , and an actuator assembly  118 . Using the actuator assembly  118 , the blade  116  may be incrementally advanced between a first position P 1  (see  FIG. 6 ) and a second position P 2  (see  FIG. 7 ). The first position P 1  is a non-cutting position in which the blade  116  is generally parallel to the outer tube  112 , and the second position P 2  is a cutting position in which the blade  116  is transverse to the outer tube  112 . 
     The outer tube  112  and the inner shaft  114  are disposed along a longitudinal axis A. The inner shaft  114  extends inside the outer tube  112  and is thus at least partially surrounded by the outer tube  112 . In an embodiment, the outer tube  212  is fixed and the inner shaft  114  moves along the longitudinal axis A. Movement of the inner shaft  114  relative to the outer tube  112  moves the blade  116  toward the second position P 2  for reaming diseased tissue. 
     The expandable reamer  110  includes a single blade  116 , although additional blades could be provided within the scope of this disclosure. In an embodiment, the blade  116  is movably connected to a distal portion  120  of the inner shaft  114  by a pin  122  (i.e., the blade  116  is hinged to the inner shaft  114 ). In another embodiment, the blade  116  includes one or more cutting edges  117  for cutting bone once positioned in the second position P 2 , or any position between the first and second positions P 1 , P 2 . 
     The blade  116  may be incrementally advanced (e.g., pivoted) through an opening  124  formed in the distal portion  121  of the outer tube  112  to create a retrograde socket in bone that can subsequently be backfilled with biologics. The opening  124  extends through a sidewall  126  of the outer tube  112 , and the blade  116  may be moved radially outward of the outer tube  112  through the opening  124  of the sidewall  126 . 
     The actuator assembly  118  is configured for pivoting the blade  116  between the first position P 1  and the second position P 2 . The actuator assembly  118  may include a hub  128 , an actuator  130 , a depth stop dial  132 , a release  134 , and a lock  136 . 
     The depth stop dial  132  may be rotated to a desired position on a threaded portion  138  of the actuator  130 . This sets the diameter that is to be cut by the blade  116 . The threaded portion  138  is located inside the hub  128 , and the depth stop dial  132  extends inside the hub  128  but is partially exposed outside of the hub  128 . The depth stop dial  132  can be rotated when the lock  136  is positioned in the unlocked position shown in  FIG. 9 . 
     The actuator assembly  110  may be positioned within a bone socket with the blade  116  in the first position P 1 . Once properly positioned, the release  134  may be actuated. This forces the hub  128  forward until a wall  140  of the hub abuts the depth stop dial  132 . This action also activates a spring  142  (see  FIG. 8 ) housed inside the hub  128  to force the inner shaft  114  forward, thus pivoting the blade  116  toward the second position P 2 . 
     The lock  136  may be actuated to lock the hub  128  and the depth stop dial  132  together. This may be done, for example, when using the expandable reamer  110  to ream a socket in bone. In the locked position, a pawl arm  144  of the lock  136  engages one or more notches  146  formed in the depth stop dial  132  (see  FIG. 10 ). 
     The clutch assembly  118  may additionally include a connector  154 . In an embodiment, the connector  154  is an integral component of the inner shaft  114 . In another embodiment, the connector  154  is as a Jacobs connector. Powered equipment, such as a drill, may be connected to the connector  154  for rotating the entire expandable reamer  110  after the blade  116  has been positioned in the second position P 2  to achieve a desired bore diameter in bone. 
       FIGS. 11-18  illustrate another exemplary expandable reamer  210 . The expandable reamer  210  may include an outer tube  212 , an inner shaft  214 , a blade  216 , and an actuator assembly  218 . The blade  216  may be incrementally advanced between a first position P 1  (see  FIG. 11 ) and a second position P 2  (see  FIG. 12 ). The first position P 1  is a non-cutting position in which the blade  216  is not exposed outwardly from the outer tube  212 , and the second position P 2  is a cutting position in which the blade  216  is exposed outwardly of the outer tube  212  for removing diseased bone. In an embodiment, the blade  216  may be incrementally advanced to bore a socket into bone that is any diameter (e.g., between about 5 mm to about 10 mm, about 5 mm to about 15 mm, about 5 mm to about 18 mm, or about 5 mm to about 20 mm). Of course, the expandable reamer  210  could be configured to bore a socket of any size. 
     The outer tube  212  and the inner shaft  214  are disposed along a longitudinal axis A. The inner shaft  214  extends inside the outer tube  212  and is thus at least partially surrounded by the outer tube  212 . In an embodiment, the outer tube  212  and the inner shaft  214  are concentric relative to one another. 
     In another embodiment, the outer tube  212  is fixed and the inner shaft  214  moves along the longitudinal axis A. Movement of the inner shaft  214  relative to the outer tube  212  positions the blade  216  in the second position P 2  for reaming diseased tissue, as discussed in greater detail below. 
     The expandable reamer  210  includes a single blade  216 , although additional blades could be provided within the scope of this disclosure. In an embodiment, the blade  216  is movably connected to a distal portion  220  of the inner shaft  214  by a pin  222  (i.e., the blade  216  is hinged to the inner shaft  214  as best shown in  FIG. 13 ). In another embodiment, the blade  216  includes one or more cutting edges  217  for cutting bone after the expandable reamer  210  has been positioned in the second position P 2 , or any position between the first and second positions P 1 , P 2 . 
     A cam cap  224  is received within a distal portion  226  of the outer tube  212  for guiding movement of the blade  216  between the first position P 1  and the second position P 2 . In an embodiment, the cam cap  224  is press fit within the distal portion  226  of the outer tube  212 . As best illustrated in  FIGS. 14 and 15 , for example, the cam cap  224  includes a slanted wall  228  and grooved tracks  230  positioned on each side of the slanted wall  228 . The grooved tracks  230  are sized to receive projections  232  of the blade  216 . As the inner shaft  214  is moved in a direction D 1  along the longitudinal axis A, the projections  232  of the blade  216  are guided within the grooved tracks  230  of the cam cap  224 . This movement causes the blade  216  to slide against the slanted wall  228 , thus forcing the blade  216  along an arced path to a position that is radially outward of the outer tube  212 . In an embodiment, the slanted wall  228  is positioned in a plane that is transverse to the longitudinal axis A. 
     In another embodiment, the blade  216  is incrementally advanced through a window  234  formed through a sidewall  236  of the outer tube  212 . Thus, in the first position P 1 , the expandable reamer  210  provides an atraumatic device that substantially reduces risks of inadvertent damage to surrounding tissue as the expandable reamer  210  is positioned within bone. The blade  216  of the expandable reamer  210  may be advanced radially outward from the outer tube  212  to the second position P 2  for preparing a socket in bone. In the second position P 2 , the blade  216  is non-parallel to the longitudinal axis A and is exposed outside of the outer tube  212 . 
     The actuator assembly  218  is configured for moving the blade  216  in the manner described above. As best illustrated in  FIGS. 16-18 , the actuator assembly  218  may include a selector sleeve  238 , an actuator  240 , and a hub  242 . The selector sleeve  238  is movably connected to the actuator  240  by a pair of pins  244  that extend between these two components (see  FIG. 17 ). The selector sleeve  238  may be rotated relative to the hub  242  to linearly move the actuator  240  along the longitudinal axis A. In other words, rotational movement of the selector sleeve  238  results in linear movement of the actuator  240 . The hub  242  may include tactile indicators  243  (see  FIG. 17 ) for indicating a dimeter of the socket to be bored in bone by the blade  216 . 
     A positioning of the inner shaft  214  is locked relative to the actuator  240  by a set screw  246 , and therefore, linear movement of the actuator  240  results in linear movement of the inner shaft  214 . Linear movement of the inner shaft  214  pushes the blade  216  against a slanted wall  228  of the cam cap  224  in the manner described above to move the blade  216  to the second position P 2 . Rotation of the selector sleeve  238  in the opposite direction retracts the blade  216  toward the first position P 1 . 
     A spring  248  is housed between the actuator  240  and a compression cap  250  that is secured to the selector sleeve  238 . The spring  248  pushes against the actuator  240  as the selector sleeve  238  is turned, thus causing the actuator  240  to piston back and forth inside the selector sleeve  238  during diameter selection (i.e., during positioning of the blade  216  between the first position P 1  and the second position P 2 ). 
     The selector sleeve  238  may include a knurled surface  252 . The knurled surface  252  is designed to improve a user&#39;s grip when turning the selector sleeve  238 . 
     The outer tube  212  is connected to the hub  242 . The hub  242  supports the selector sleeve  238  and provides for single plane rotation of the selector sleeve  238  during diameter selection. 
     Referring now primarily to  FIGS. 17 and 18 , the pins  244  may travel within a helical groove  254  formed in the actuator  240  as the selector sleeve  238  is rotated during diameter selection. Movement of the pins  244  within the helical groove  254  forces translational movement of the inner shaft  214 . In an embodiment, the helical groove  254  extends along a helical path that wraps at least partially around the body of the actuator  240 . Thus, the helical path of the helical groove  254  is non-linear. 
     In another embodiment, the helical groove  254  includes a plurality of detents  256 . A ridge  258  extends between adjacent detents  256 . The pins  244  must travel over the ridges  258  to move from one detent  256  to an adjacent detent  256 . This may provide tactile feedback to the user of a change in the diameter setting. In an embodiment, the force required to move the pins  244  from one detent  256  to another is large enough to prevent inadvertent movement of the selector sleeve  238 , and thus, the blade  216 . Therefore, the detents  256 /ridge  258  configuration of the helical groove  254  helps maintain the selector sleeve  238 , and thus the blade  216 , at a desired diameter setting during a bone cutting procedure. 
     The clutch assembly  218  may additionally include a connector  253 . In an embodiment, the connector  253  is an integral component of the inner shaft  214 . In another embodiment, the connector  253  is as a Jacobs connector. Powered equipment, such as a drill, may be connected to the connector  253  for rotating the entire expandable reamer  210  after the blade  216  has been positioned in the second position P 2  to achieve a desired bore diameter in bone. 
       FIGS. 19-29  illustrate yet another exemplary expandable reamer  310 . The expandable reamer  310  may include an outer tube  312 , an inner shaft  314 , a blade  316 , and an actuator assembly  318 . The blade  316  may be incrementally advanced between a first position P 1  (see  FIG. 19 ) and a second position P 2  (see  FIG. 20 ). The first position P 1  is a non-cutting position in which the blade  316  is concealed inside the outer tube  312 , and the second position P 2  is a cutting position in which the blade  316  is exposed outwardly of the outer tube  312  for removing diseased bone. In an embodiment, the blade  316  may be incrementally advanced to bore a socket into bone that is any diameter. In an embodiment, the blade  316  is incrementally advanced to bore a socket into bone that is any diameter. In an embodiment, the diameter is a range between about 5 mm to about 10 mm, about 5 mm to about 15 mm, about 5 mm to about 18 mm, or about 5 mm to about 20 mm. Of course, the expandable reamer  310  could be configured to bore a socket of any size. 
     The outer tube  312  and the inner shaft  314  are disposed along a longitudinal axis A. The inner shaft  314  is at least partially surrounded by the outer tube  312 . In an embodiment, the outer tube  312  and the inner shaft  314  are concentric relative to one another. 
     In another embodiment, the outer tube  312  is fixed and the inner shaft  314  is movable along the longitudinal axis A. Movement of the inner shaft  314  relative to the outer tube  312  positions the blade  316  in the second position P 2  for reaming diseased tissue, as discussed in greater detail below. 
     The expandable reamer  310  includes a single blade  316 , although additional blades could be provided within the scope of this disclosure. In an embodiment, the blade  316  is movably connected to a distal portion  320  of the inner shaft  314  by a pin  322  (i.e., the blade  316  is hinged to the inner shaft  314  as best shown in  FIG. 21 ). The blade  316  may include one or more cutting edges  317 . 
     A cam cap  324  is received within a distal portion  326  of the outer tube  312  for guiding movement of the blade  316  along an arced path between the first position P 1  and the second position P 2 . The cam cap  324  is substantially similar to the cam cap  224  described above and shown in  FIGS. 14 and 15  and therefore its features are not repeated here. 
     In an embodiment, the blade  316  is incrementally advanced through a window  334  formed through a sidewall  336  of the outer tube  312 . Accordingly, in the first position P 1 , the expandable reamer  310  provides an atraumatic device that substantially reduces risks of inadvertent damage to surrounding tissue during the positioning of the expandable reamer  310  within bone. The blade  316  of the expandable reamer  310  may be advanced radially outward from the outer tube  312  to the second position P 2  for preparing a socket in bone. In the second position P 2 , the blade  316  is non-parallel (i.e., transverse) to the longitudinal axis A and is exposed outside of the outer tube  312 . 
     The actuator assembly  318  is configured for moving the blade  316  in the manner described above. As best illustrated in  FIGS. 22, 23, and 24 , the actuator assembly  318  may include a selector sleeve  338 , an actuator  340 , and a hub  342 . The selector sleeve  338  is movably connected to the actuator  340  by a pair of pins  344  (see  FIG. 23 ). The selector sleeve  338  may be rotated relative to the hub  342  to linearly translate the actuator  340  along the longitudinal axis A. In other words, rotational movement of the selector sleeve  338  results in linear movement of the actuator  340 . 
     In an embodiment, a snap bushing  345  rotationally connects the selector sleeve  338  to the hub  342 . The snap bushing  345  may be snapped into the hub  342  and is connected to the selector sleeve  338  by the pins  344  (see  FIG. 23 ). 
     Although not shown, the hub  342  could include tactile indicators for indicating a dimeter of the socket that is to be bored in bone by the blade  316 . 
     A positioning of the inner shaft  314  is locked relative to the actuator  340  by a set screw  346 , and therefore, linear movement of the actuator  340  results in linear movement of the inner shaft  314 . Linear movement of the inner shaft  314  pushes the blade  316  against a slanted wall (see feature  228  of  FIG. 15 ) of the cam cap  324  in the manner described above to move the blade  316  toward the second position P 2 . Rotation of the selector sleeve  338  in the opposite direction retracts the blade  316  toward the first position P 1 . 
     A stop cap  350  (see  FIG. 22 ) is secured to the selector sleeve  338 . The stop cap  350  establishes a positive stopping surface for the actuator  340  during diameter selection. In an embodiment, the stop cap  350  is removable to disassemble the actuator assembly  318 . 
     The selector sleeve  338  may include a knurled surface  352 . The knurled surface  352  is designed to improve a user&#39;s grip when turning the selector sleeve  338 . 
     The outer tube  312  is connected to the hub  342 . The hub  342  supports the selector sleeve  338  and provides for a single plane rotation of the selector sleeve  338  during diameter selection. 
     Referring now primarily to  FIGS. 23 and 24 , the pins  344  may travel within a helical groove  354  formed in the actuator  340  as the selector sleeve  338  is rotated during diameter selection. Movement of the pins  344  within the helical groove  354  forces translational movement of the inner shaft  314 . In an embodiment, the selector sleeve  338  is rotated in a clockwise direction to move the inner shaft  314  forward and advance the blade  316 , and is rotated in a counterclockwise direction to move the inner shaft  314  backward and retract the blade  316 . In an embodiment, the helical groove  354  extends along a helical path that wraps at least partially around the body of the actuator  340 . Thus, the helical path of the helical groove  354  is non-linear. 
     The actuator assembly  318  may additionally include a ratcheting assembly  360 , which is best illustrated in  FIGS. 25-29 . The ratcheting assembly  360  controls the ability to rotate the selector sleeve  338 . 
     In an embodiment, the ratcheting assembly  360  includes a gear  362 , a pawl  364 , a spring  366 , and a pin  368 . The pin  368  mounts the pawl  364  within a recess  370  of the selector sleeve  338 . The pawl  364  includes a projection  372  that selectively engages between teeth  374  of the gear  362  to lock a positioning of the selector sleeve  338  relative to the hub  342 . The selector sleeve  338  cannot be rotated to move the blade  316  when the pawl  364  is engaged with the gear  362 . The pawl  364  is biased toward the gear  362  by the spring  366 . The engaged position of the pawl  364  is shown in  FIGS. 26 and 29 . 
     The selector sleeve  338  may be unlocked relative to the hub  342  by disengaging the pawl  364  from the gear  362 . For example, the selector sleeve  338  may be pushed forward toward the hub  342 , thus overcoming a biasing force of a spring  376  housed between the hub  342  and the selector sleeve  338  (see  FIG. 22 ). As the selector sleeve  338  is moved forward, the pawl  364  is moved out of engagement with the gear  362  such that the projection  372  is no longer engaged between the teeth  374 . The disengaged position of the pawl  364  is shown in  FIGS. 27 and 28 . 
     The selector sleeve  338  may then be rotated relative to the hub  342  to actuate the blade  316 . Once a desired diameter has been selected and the user releases the forward force on the selector sleeve  338 , the spring  376  forces the selector sleeve  338  rearward, thus forcing the pawl  364  back into engagement with the gear  362  (see  FIGS. 26 and 29 ) and again locking the selector sleeve  338  from rotational movement. The ratcheting assembly  360  therefore substantially prevents inadvertent movement of the blade  316  once a desired diameter setting has been selected and during bone reaming. 
     The clutch assembly  318  may additionally include a connector  353 . Powered equipment, such as a drill, may be connected to the connector  353  for rotating the entire expandable reamer  310  after the blade  316  has been positioned in the second position P 2  to achieve a desired bore diameter in bone. 
       FIGS. 30-35  schematically illustrate a method for removing diseased bone using an expandable reamer. In these figures, the method is illustrated using the expandable reamer  310  of  FIGS. 19-29 ; however, any of the expandable reamers described in this disclosure could be utilized in the proposed method for removing diseased bone. It should be understood that the method described herein and shown in  FIGS. 30-35  could include a greater or fewer number of steps and that the steps could be performed in a different order within the scope of this disclosure. 
     Referring first to  FIG. 30 , the method begins by inserting a guide pin  80  into a bone  82 . In an embodiment, the bone  82  is a femur that includes a femoral head  84 , although the method may be beneficially used elsewhere in a patient (e.g., the knee, etc.). A surgeon or other medical professional would be able to select an appropriate positioning and/or placement of the guide pin  80  and could use fluoroscopic guidance and/or a targeting guide to achieve proper placement within the bone  82 . 
     The guide pin  80  is inserted into diseased bone  86  (e.g., a lesion). In an embodiment, the guide pin  80  is positioned such that it does not violate the articular cartilage overlying the lesion. In other words, the method may be performed subchondrally. 
     Once the guide pin  80  has been positioned, a cannulated drill bit  88  is placed over the guide pin  80  to ream a tunnel  90  (i.e., void) into the bone  82 , as shown in  FIG. 31 . The size of the guide pin  80  and the cannulated drill bit  88  may vary depending upon the size of the patient, among other criteria. The tunnel  90  could alternatively be formed without using the guide pin  80 . Once the bone  82  has been reamed, the cannulated drill bit  88  and guide pin  80  are removed. 
     Next, as illustrated by  FIG. 32 , the expandable reamer  310  may be inserted into the tunnel  90  and positioned within the bone  82  such that it extends into the diseased bone  86 . During positioning, the cutting blade  316  of the expandable reamer  310  is concealed inside of the outer tube  312  (see position P 1  of  FIG. 19 ). 
     Referring now to  FIG. 33 , the cutting blade  316  of the expandable reamer  310  may next be incrementally moved to a cutting position. For example, the cutting blade  316  can be advanced by turning the selector sleeve  338  in the Z direction to effectuate axial movement of the inner shaft  314 , which is converted to rotational movement of the blade  316  by the cam cap  324  to position the cutting blade  316  in the desired cutting position. The desired cutting position may vary depending on the amount of diseased bone  86  that is present. 
     The entire expandable reamer  310  may then be rotated, such as using power equipment (not shown) that is connected to the connector  353 , to create a retrograded socket  92  in the bone  82  with the blade  316 , thereby removing the diseased bone  86 . The cutting blade  316  may then be retracted (by disengaging the pawl  364  from the gear  362  of the ratcheting assembly  360  by moving the selector sleeve  338  forward in a direction toward the hub  342  and subsequently turning the selector sleeve  338  in an opposite direction) and the expandable reamer  310  removed from the bone  82  after the socket  92  has been adequately formed as shown in  FIG. 34 . The tunnel  90  and the socket  92  may be aspirated, such as with a combination of suction and irrigation, to remove any debrided tissue that may exist after reaming. 
     Finally, as shown in  FIG. 35 , the tunnel  90  and the socket  92  may be backfilled with a biologic  94 . In an embodiment, the biologic  94  includes bone marrow concentrate (BMC) or BMC mixed with demineralized bone matrix (DBM). In another embodiment, the biologic  94  is injected with a delivery cannula  96  working from the socket  92  backwards toward the tunnel  90 . In yet another embodiment, the tunnel  90  and the socket  92  are completely filled with the biologic  94 . 
     The expandable reamers of this disclosure are atraumatic surgical devices that substantially reduce the risks of inadvertent damage to surrounding tissue during the positioning of the expandable reamers within bone. The blades of the expandable reamers may be incrementally positioned to achieve a multitude of socket diameters using novel actuator assemblies. 
     Although the different non-limiting embodiments are illustrated as having specific components or steps, the embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from any of the non-limiting embodiments in combination with features or components from any of the other non-limiting embodiments. 
     It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should further be understood that although a particular component arrangement is disclosed and illustrated in these exemplary embodiments, other arrangements could also benefit from the teachings of this disclosure. 
     The foregoing description shall be interpreted as illustrative and not in any limiting sense. A worker of ordinary skill in the art would understand that certain modifications could come within the scope of this disclosure. For these reasons, the following claims should be studied to determine the true scope and content of this disclosure.