Abstract:
An surgical apparatus and method are described for manipulating one or more osteochondral plugs, including, but not limited to, extracting and/or impacting the one or more osteochondral plugs.

Description:
BACKGROUND  
       [0001]     The present disclosure relates to osteochondral implants or plugs and, more particularly, to a surgical apparatus and method for manipulating one or more osteochondral plugs, including, but not limited to, extracting and/or impacting the one or more osteochondral plugs.  
         [0002]     Osteochondral plugs may be extracted from, and/or impacted into, various locations in the human body. For example, one or more osteochondral plugs may be impacted into the knee of the human body. More particularly, in the human body, the knee consists of three bones—a femur, a tibia, and a patella—that are held in place by various ligaments. The chondral surfaces of the femur and the tibia form a hinge joint, and the patella protects the joint. Portions of the chondral surfaces of the femur and the tibia, as well as the underside of the patella, are covered with an articular cartilage which allow the femur and the tibia to smoothly glide against each other without causing damage. A menicus sits between the articular cartilage and the bone to distribute weight and to improve the stability of the joint. The articular cartilage often tears, usually due to traumatic injury (often seen in athletics) and degenerative processes (seen in older patients). This tearing does not heal well due to the lack of nerves, blood vessels and lymphatic systems and the resultant knee pain and swelling and limited motion of the bone(s) and must be addressed.  
         [0003]     Damaged adult cartilage has historically been treated by a variety of surgical interventions including lavage, arthroscopic debridement, and repair stimulation, all of which provide less than optimum results. Another known treatment involves removal and replacement of the damaged cartilage with a prosthetic device. However, the known artificial prostheses have largely been unsuccessful since they are deficient in the elastic, and therefore in the shock-absorbing, properties characteristic of the cartilage. Moreover, the known artificial devices have not proven able to withstand the forces inherent to routine knee joint function.  
         [0004]     In an attempt to overcome the problems associated with the above techniques, osteochondral transplantation, also known as “mosaicplasty” has been used to repair articular cartilage. This procedure involves removing injured tissue from the articular defect and drilling openings such as, for example, cylindrical holes in the base of the defect and underlying bone. Osteochondral plugs such as, for example, cylindrically shaped osteochondral plugs of healthy cartilage and bone, are obtained from another area of the patient, typically from a lower-bearing region of the joint under repair, or from a donor patient, and are implanted in the drilled holes. (The term “autograft” refers to tissue or cells which originate with or are derived from the recipient, whereas the term “allograft” refers to cells and tissue which originate with, or are derived from, a donor of the same species as the recipient, in this case, another human.)  
         [0005]     However, one or more problems or issues may arise in connection with an osteochondral transplantation procedure. For example, multiple instruments may be required during the osteochondral transplantation, with one or more instruments being used for each step in the procedure, thereby possibly increasing the time spent during, and the overall costs and/or complexity of, the procedure. Moreover, in procedures involving multiple osteochondral plugs, the one or more sites containing healthy bone and cartilage may need to be revisited several times, from the articular defect, in order to complete the transplantation, thereby also possibly increasing the time spent during, and the overall costs and/or complexity of, the procedure. Also, during the impacting of one or more osteochondral plugs, the operator may not be able to adequately determine the amount of force that is being applied to each of the osteochondral plugs, and therefore may not be able to know whether enough force has been applied to suitably impact each of the osteochondral plugs, or whether too great a force is being applied against the osteochondral plugs during the impacting.  
         [0006]     In view of all of the above and/or other considerations, what is needed is an apparatus and/or method for manipulating one or more osteochondral plugs, including, but not limited to, extracting and/or implanting the one or more osteochondral plugs, that overcomes one or more of the above-described problems, among other problems.  
       SUMMARY  
       [0007]     According to an embodiment, a surgical method is provided that includes positioning a first osteochondral plug within a tubular member, positioning at least one other osteochondral plug within the tubular member, and impacting the at least one other osteochondral plug into a defect site. According to another embodiment, a surgical method is provided that includes positioning at least one osteochondral plug within a tubular member and coupling a pressure sensor to the at least one osteochondral plug. According to another embodiment, a surgical apparatus is provided that includes a tubular member defining a longitudinal passage wherein at least one osteochondral plug is adapted to be positioned within the longitudinal passage, and a pressure sensor adapted to be coupled to the at least one osteochondral plug so that the at least one osteochondral plug and the pressure sensor are positioned within the longitudinal passage of the tubular member at the same time. According to another embodiment, a surgical apparatus is provided that includes a tubular member sized to receive and hold in place a first osteochondral plug and at least one other osteochondral plug, and a protrusion adapted to be received by the tubular member.  
         [0008]     Various embodiments of the invention may possess one or more of the above features and advantages, or provide one or more solutions to the above problems existing in the prior art, among other problems. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1A  is a sectional view of an apparatus according to an embodiment and including a cannula according to an embodiment.  
         [0010]      FIG. 1B  is a sectional view of the cannula of  FIG. 1  taken along line  1 B- 1 B.  
         [0011]      FIG. 2  is an elevational view of a pusher device according to an embodiment and adapted to be received by the cannula depicted in  FIGS. 1A and 1B .  
         [0012]      FIGS. 3A, 3B ,  3 C and  3 D are top plan views depicting the preparation of an articular cartilage defect site.  
         [0013]      FIGS. 4A, 4B ,  4 C,  4 D,  4 E and  4 F are sectional views depicting the extraction of osteochondral plugs from respective donor sites using the apparatus of  FIGS. 1A and 1B .  
         [0014]      FIG. 5  is a partial sectional/partial diagrammatic view of the cannula of  FIGS. 1A and 1B  with a plurality of osteochondral plugs positioned in the cannula, and a sensor system adapted to be coupled to one of the osteochondral plugs.  
         [0015]      FIGS. 6A, 6B ,  6 C,  6 D,  6 E and  6 F are sectional views depicting the impacting of the osteochondral plugs of  FIG. 5  into the articular cartilage defect site of  FIGS. 3A, 3B ,  3 C and  3 D, using the apparatus of  FIGS. 1A and 1B .  
         [0016]      FIG. 6G  is a top plan view of the osteochondral plugs of  FIG. 5 , after the osteochondral plugs have been impacted into the articular cartilage defect site of  FIGS. 3A, 3B ,  3 C and  3 D, using the apparatus of  FIGS. 1A and 1B .  
         [0017]      FIG. 7A  is a sectional view of a cannula according to another embodiment.  
         [0018]      FIG. 7B  is a top plan view of a plurality of osteochondral plugs, after the osteochondral plugs have been impacted into an articular cartilage defect site, using the cannula of  FIG. 7A .  
         [0019]      FIG. 8A  is a sectional view of a cannula according to another embodiment.  
         [0020]      FIG. 8B  is a top plan view of a plurality of osteochondral plugs, after the osteochondral plugs have been impacted into an articular cartilage defect site, using the cannula of  FIG. 8A .  
         [0021]      FIG. 9A  is a sectional view of a cannula according to another embodiment.  
         [0022]      FIG. 9B  is a top plan view of a plurality of osteochondral plugs, after the osteochondral plugs have been impacted into an articular cartilage defect site, using the cannula of  FIG. 9A . 
     
    
     DETAILED DESCRIPTION  
       [0023]     Referring to  FIGS. 1A and 11B , a surgical apparatus is generally referred to by the reference numeral  10  and includes a cannula  12  having a handle  14  and a generally transparent tubular member  16  extending therefrom. The tubular member  16  defines a longitudinal passage  16   a , and includes a tapered distal end portion  16   b  and a circular cross-section defining an inside diameter  16   c . A stop  18  is movably coupled to the tubular member  16  of the cannula  12 , and is adapted to translate longitudinally, relative to the tubular member  16  and for reasons to be described.  
         [0024]     Referring to  FIG. 2 , the apparatus  10  further includes a pusher device  20  having a gripping or handle portion  22  and a protrusion  24  extending therefrom, which is adapted to be received by the tubular member  16  and extend within the passage  16   a  for reasons to be described. In an exemplary embodiment, the pusher device  20  may be in the form of an obturator.  
         [0025]     In operation, the apparatus  10  may be used to, inter alia, extract one or more osteochondral plugs from donor bone and/or cartilage, and/or impact the one or more osteochondral plugs into, for example, an articular cartilage defect site to at least partially repair the articular cartilage, as described below. In an exemplary embodiment, as illustrated in  FIGS. 3A, 3B ,  3 C and  3 D, an articular cartilage defect site is prepared before the one or more osteochondral plugs are impacted into the articular cartilage defect site. Referring to  FIG. 3A , a defect area such as, for example, a cartilage defect area  26  is present in bone and/or cartilage such as, for example, in articular cartilage  28  having a top surface  28   a . In an exemplary embodiment, the articular cartilage  28  may be on, for example, the lateral femoral condyle of a human knee, any chondral surface on the femur, tibia and/or patella of a human knee, and/or on any other chondral and/or bone surface in the human body.  
         [0026]     Referring to  FIG. 3B , a diameter D 1  of a defect site  30  is determined in response to determining the size of the cartilage defect area  26 . In an exemplary embodiment, the size of the diameter D 1  may be determined by, for example, determining a diameter of a circle  32  suitable to circumscribe the cartilage defect area  26  and sizing the diameter D 1  to be at least as great as the diameter of the circle.  
         [0027]     Referring to  FIGS. 3C and 3D , the defect site  30  is prepared in a conventional manner using one or more defect debridement devices and/or defect debridement techniques, procedures and/or methods. As a result, and in an exemplary embodiment, the defect site  30  is in the form of a generally cylindrically-shaped blind bore in the articular cartilage  28 , having the diameter D 1  and defining a depth or height H 1  from the top surface  28   a  of the articular cartilage.  
         [0028]     In an exemplary embodiment, as illustrated in  FIGS. 4A, 4B ,  4 C,  4 D,  4 E and  4 F, the one or more osteochondral plugs are extracted from donor bone and/or cartilage before the one or more osteochondral plugs are impacted into the defect site  30 . Referring to  FIGS. 4A and 4B , the stop  18  may be adjusted and moved either upwards or downwards, relative to the tubular member  16 , so that a distance or height H 2  is defined between the distal end of the tubular member  16  and the stop  18 .  
         [0029]     In an exemplary embodiment, the height H 2  may be substantially equal to the height H 1  defined by the defect site  30 , and the stop  18  may be adjusted and the height H 2  may be set by inserting the tubular member  16  into the defect area  30  so that the distal end of the tubular member  16  contacts the bottom surface of the defect area. The stop  18  may then be adjusted downwards until the stop  18  contacts the surface  28   a  of the articular cartilage  28 , thereby causing the height H 2  to be substantially equal to the height H 1 .  
         [0030]     After the stop  18  has been adjusted relative to the tubular member  16 , the position of the stop  18  is fixed relative to the tubular member  16 . The stop  18  may be fixed in a wide variety of manners such as, for example, by using one or more set screws to set the stop  18  against the tubular member  16 , and/or by using one or more clamps to engage both the stop  18  and the tubular member  16 . In an exemplary embodiment, the stop  18  may be in the form of an adjustable clamp that extends about the tubular member  16 , and the clamping force of the stop  18  against the tubular member  16  may be increased to fix the stop  18  to the tubular member  16  by, for example, tightening one or more fasteners.  
         [0031]     After the position of the stop  18  has been fixed relative the tubular member  16 , the cannula  12  is driven downwards into a donor site  34 , which is composed of donor bone and/or cartilage, and the tubular member  16  is punched into the donor site  34 . The tapered distal end portion  16   b  of the tubular member  16  facilitates the entrance and penetration of the tubular member  16  into the donor site  34 . The tubular member  16  penetrates the donor site  34  until the stop  18  contacts the external surface of the donor site  34 . As a result, the distal end of the tubular member  16  penetrates the donor site  34  to a depth substantially equal to the height H 2 . As another result, a portion of the donor site  34  is disposed within the passage  16   a  of the tubular member  16 , thereby defining an osteochondral plug  36 .  
         [0032]     Referring to  FIG. 4C , and after the osteochondral plug  36  has been defined, the cannula  12  is gently rocked back and forth so that the tubular member  16  rocks back and forth, causing the osteochondral plug  36  to separate from the remainder of the donor site  34 . At this point, the cannula  12  is moved upwards so that the tubular member  16  moves upwards and away from the donor site  34 . The osteochondral plug  36  remains positioned in the tubular member  16  and therefore is extracted from the donor site  34 , moving upwards and away from the donor site  34 . The cross-section of the osteochondral plug  36  generally corresponds to the cross-section of the tubular member  16 , and the osteochondral plug  36  is generally cylindrically shaped, having a diameter substantially equal to the inside diameter  16   c  of the tubular member  16 , and a height substantially equal to the height H 2 . Due to its diameter and/or the material properties of bone and/or cartilage, of which the osteochondral plug  36  is composed, the osteochondral plug  36  fits snugly within the tubular member  16  and thus is prevented from sliding relative to, and exiting, the tubular member  16 . The transparency of the tubular member  16  permits observance and inspection of the osteochondral plug  36  through the tubular member  16 . As a result of the extraction of the osteochondral plug  36  from the donor site  34 , an opening  38  is formed in the donor site  34 .  
         [0033]     Referring to  FIGS. 4D and 4E , the cannula  12  is again driven downwards into another donor site  40 , which is composed of donor bone and/or cartilage and which may be adjacent to, or remote from, the donor site  34 . The tubular member  16  is punched into the donor site  40 , and the tapered distal end portion  16   b  of the tubular member  16  facilitates the entrance and penetration of the tubular member  16  into the donor site  40 . The tubular member  16  penetrates the donor site  40  until the stop  18  contacts the external surface of the donor site  40 . As a result, the distal end of the tubular member  16  penetrates the donor site  40  to a depth substantially equal to the height H 2 . As another result, a portion of the donor site  40  is disposed within the passage  16   a , thereby defining an osteochondral plug  42 . The disposal of the osteochondral plug  42  within the passage  16   a  forces the osteochondral plug  36  to slide upwards within the passage  16   a . More particularly, one or more forces associated with punching the tubular member  16  into the donor site  40  are greater than and/or overcome the one or more frictional forces between the osteochondral plug  36  and the inside surface of the tubular member  16 , thereby causing the osteochondral plug  36  to slide upwards within the passage  16   a.    
         [0034]     Referring to  FIG. 4F , and after the osteochondral plug  42  has been defined, the cannula  123  is gently rocked back and forth so that the tubular member  16  rocks back and forth, causing the osteochondral plug  42  to separate from the remainder of the donor site  40 . At this point, the cannula  12  is moved upwards so that the tubular member  16  moves upwards and away from the donor site  40 . The osteochondral plug  42  remains positioned in the tubular member  16  and therefore is extracted from the donor site  40 , moving upwards and away from the donor site  40 . The osteochondral plug  42  is about the same size and shape as the osteochondral plug  36 , being generally cylindrically shaped, having a diameter substantially equal to the inside diameter  16   c  of the tubular member  16 , and having a height substantially equal to the height H 2 . Due to its diameter and/or the material properties of bone and/or cartilage, of which the osteochondral plug  42  is composed, the osteochondral plug  42  fits snugly within the tubular member  16  and thus is prevented from sliding relative to, and exiting, the tubular member  16 . Moreover, the osteochondral plug  36  is adjacent to, and further abuts, the osteochondral plug  42 . The osteochondral plug  36  is prevented from sliding relative to the tubular member  16  due to the presence of the osteochondral plug  42  in the tubular member  16 , the diameter of the osteochondral plug  36  and/or the material properties of bone and/or cartilage, of which the osteochondral plug  36  is composed. The transparency of the tubular member  16  permits observance and inspection of the osteochondral plugs  36  and/or  42  through the tubular member  16 . As a result of the extraction of the osteochondral plug  42  from the donor site  40 , an opening  44  is formed in the donor site  40 .  
         [0035]     Referring to  FIG. 5 , osteochondral plugs  46 ,  48 ,  50  and  52  are extracted from respective donor sites, and are positioned in the tubular member  16 , in a manner substantially identical to the manner in which the osteochondral plugs  36  and  42  are extracted from the donor sites  34  and  40 , respectively, and are positioned in the tubular member  16 . As a result, and in an exemplary embodiment, the cannula  12  holds six osteochondral plugs. In an exemplary embodiment, the height H 1 , the height H 2 , and the height of each of the osteochondral plugs  46 ,  48 ,  50  and  52  may be about 15 mm. In an exemplary embodiment, the height H 1 , the height H 2 , and the height of each of the osteochondral plugs  46 ,  48 ,  50  and  52  may be less than, about or greater than 15 mm. The transparency of the tubular member  16  permits observance and inspection of the osteochondral plugs  36 ,  42 ,  46 ,  48 ,  50  and/or  52  through the tubular member  16 .  
         [0036]     After the osteochondral plugs  46 ,  48 ,  50  and  52  are extracted from respective donor sites, and are positioned in the tubular member  16 , a pressure sensor  54  is coupled to the osteochondral plug  52 . In an exemplary embodiment, the pressure sensor  54  includes a capacitor having a pair of spaced plates, and a resonant frequency of the pressure sensor  54  is dependent upon the spacing between the plates of the capacitor. The pressure sensor  54  is in communication with a receiver  56 . In an exemplary embodiment, the pressure sensor  54  is in wireless communication with the receiver  56 . In several exemplary embodiments, the pressure sensor  54  may be in the form of one or more of the pressure sensors disclosed in U.S. Pat. No. 6,855,115, the disclosure of which is incorporated herein by reference, or in any combination thereof. In an exemplary embodiment, the pressure sensor  54  may be coupled to the osteochondral plug  52  by, for example, being disposed in the interior of the osteochondral plug  52 . In an exemplary embodiment, the pressure sensor  54  may be delivered into the interior of the osteochondral plug  52  via, for example, the distal end of a delivery catheter. In several exemplary embodiments, the pressure sensor  54  may be delivered into the interior of the osteochondral plug  52  via one or more of the delivery techniques, procedures and/or methods disclosed in U.S. Pat. No. 6,855,115, the disclosure of which is incorporated herein by reference.  
         [0037]     In an exemplary embodiment, the osteochondral plugs  36 ,  42 ,  46 ,  48 ,  50  and  52  are impacted into the defect site  30 . Referring to  FIG. 6A , the stop  18  is adjusted so that a surface of the stop  18  is aligned with the distal end of the tubular member  16 . After the pressure sensor  54  is coupled to the osteochondral plug  52 , the cannula  12  is positioned so that the stop  18  contacts the top surface  28   a  of the articular cartilage  28 , and so that the tubular member  16  is above the defect site  30 .  
         [0038]     Referring to  FIGS. 6B and 6C , the pusher device  20  is received by the tubular member  16  so that the protrusion  24  extends within the passage  16   a  of the tubular member  16 . The handle portion  22  is gripped and the protrusion  24  is pushed downwards, as viewed in  FIG. 6B , so that the distal end of the protrusion  24  contacts the osteochondral plug  36 . The protrusion  24  is pushed further downward, causing a force to be applied against the osteochondral plug  36 , which, in turn, applies a force against the osteochondral plug  42 , which, in turn, applies a force against the osteochondral plug  46 , which, in turn, applies a force against the osteochondral plug  48  which, in turn, applies a force against the osteochondral plug  50  which, in turn, applies a force against the osteochondral plug  52 . As a result, the osteochondral plugs  36 ,  42 ,  46 ,  48 ,  50  and  52  all translate downwards in the passage  16   a , and at least a portion of the osteochondral plug  52  exits the tubular member  16  and extends into the defect site  30 . The protrusion  24  is pushed further downwards and, as a result, the osteochondral plug  52  entirely exits the tubular member  16  and is impacted into the defect site  30 , as illustrated in  FIG. 6C . In an exemplary embodiment, the osteochondral plug  52  may be impacted into the defect site  30  so that the osteochondral plug is positioned in about the middle of the defect site  30 . The transparency of the tubular member  16  permits observance or inspection of the osteochondral plugs  36 ,  42 ,  46 ,  48 ,  50  and  52  in the tubular member  16  during the impacting of the osteochondral plug  52 .  
         [0039]     During the impacting of the osteochondral plug  52 , the osteochondral plug  52  undergoes a pressure associated with, or in response to, the pushing of the protrusion  24  and the resulting application of a pushing force against the osteochondral plug  52  via the osteochondral plugs  36 ,  42 ,  46 ,  48  and  50 . The pressure sensor  54  measures the amount of pressure that the osteochondral plug  52  undergoes during this force application. More particularly, the spacing between the plates of the above-described capacitor in the pressure sensor  54  changes in response to the application of the pushing force against the osteochondral plug  52  and, as a result, the resonant frequency of the pressure sensor  54  changes. The pressure sensor  54  sends one or more signals, one or more of which correspond to the change in resonant frequency of the pressure sensor  54 , to the receiver  56 . The receiver  56  receives the one or more signals and converts, conditions and/or processes the one or more signals to determine the amount of pressure that the osteochondral plug  52  is undergoing during its impacting into the defect site  30 . In an exemplary embodiment, the receiver  56  outputs this pressure amount via, for example, a display screen. In response to an operator&#39;s reading of the pressure measurement provided by the pressure sensor  54 , the force applied to the osteochondral plug  52  via the pusher device  20  may be increased, decreased or stopped altogether by increasing, decreasing or stopping altogether, respectively, the pushing force that the operator applies to the protrusion  24 . As a result, the operator is able to adequately gage the amount of force that is being applied to the osteochondral plug  52  during its impacting, and may accordingly adjust the amount of applied force as needed and/or desired.  
         [0040]     In several exemplary embodiments, the pressure sensor  54  may measure the amount of pressure that the osteochondral plug  52  is undergoing according to one or more of the techniques, procedures and/or methods disclosed in U.S. Pat. No. 6,855,115, the disclosure of which is incorporated herein by reference.  
         [0041]     Referring to  FIG. 6D , after the osteochondral plug  52  has been impacted into the defect site  30 , the cannula  12  and the pusher device  20  are both lifted upwards and away from the defect site  30 . During this movement, the osteochondral plugs  36 ,  42 ,  46 ,  48  and  50  remain positioned in the tubular member  16 , but the protrusion  24  does not apply an appreciable force against the osteochondral plug  36 . In an exemplary embodiment, after the osteochondral plug  52  has been impacted into the defect site  30 , the protrusion  24  of the pusher device  20  may be removed from the passage  16   a  of the tubular member  16  of the cannula  12 .  
         [0042]     Referring to  FIG. 6E , the cannula  12  and the pusher device  20  are repositioned, relative to the radial center of the defect site  30 , and the protrusion  24  is again pushed downwards within the passage  16   a  of the tubular member  16  so that the distal end of the protrusion  24  contacts and applies another force against the osteochondral plug  36 . The osteochondral plug  36 , in turn, applies a force against the osteochondral plug  42 , which, in turn, applies a force against the osteochondral plug  46 , which, in turn, applies a force against the osteochondral plug  48  which, in turn, applies a force against the osteochondral plug  50 . As a result, the osteochondral plugs  36 ,  42 ,  46 ,  48  and  50  all translate downwards in the passage  16   a , and the osteochondral plug  50  exits the tubular member  16  and is impacted into the defect site  30 , as illustrated in  FIG. 6E . In an exemplary embodiment, the osteochondral plug  50  may be impacted into the defect site  30  so that the osteochondral plug  50  is positioned adjacent the osteochondral plug  52 , contacting or nearly contacting the osteochondral plug  52 . The transparency of the tubular member  16  permits observance or inspection of the osteochondral plugs  36 ,  42 ,  46 ,  48  and  50  in the tubular member  16  during the impacting of the osteochondral plug  50 .  
         [0043]     During the impacting of the osteochondral plug  50 , the osteochondral plug  50  undergoes a pressure associated with, or in response to, the pushing of the protrusion  24  and the resulting application of a pushing force against the osteochondral plug  50  via the osteochondral plugs  36 ,  42 ,  46  and  48 . The pressure sensor  54 , which remains coupled to the osteochondral plug  52 , measures the amount of pressure that the osteochondral plug  50  undergoes during this force application, at least with respect to when the osteochondral plug  50  extends in the defect site  30 , in a manner substantially identical to the above-described manner in which the pressure sensor  54  measures the amount of pressure that the osteochondral plug  52  undergoes during the impacting of the osteochondral plug  52  into the defect site  30 . The pressure sensor  54 , which is disposed in the interior of the osteochondral plug  52 , is able to measure the amount of pressure that the osteochondral plug  50  undergoes because of the one or more forces that propagate through the osteochondral plug  50 , the osteochondral plug  52  and the defect site  30  in response to the application of the pushing force against the osteochondral plug  50 . For example, one or more forces may be transferred from the osteochondral plug  50  to the osteochondral plug  52  because of the contact between the adjacent osteochondral plugs  50  and  52 . In an exemplary embodiment, the radial range of pressure-amount detection by the pressure sensor  54  may be about 5 cm. That is, the pressure sensor  54  may be able to detect pressure amounts in the defect site  30 , and in the osteochondral plugs  50  and  52 , within a range of about 5 cm in any radial direction from the pressure sensor  54 .  
         [0044]     Referring to  FIG. 6F , after the osteochondral plug  50  has been impacted into the defect site  30 , the cannula  12  and the pusher device  20  are both lifted upwards and away from the defect site  30 . During this movement, the osteochondral plugs  36 ,  42 ,  46  and  48  remain positioned in the tubular member  16 , but the protrusion  24  does not apply an appreciable force against the osteochondral plug  36 . In an exemplary embodiment, after the osteochondral plug  50  has been impacted into the defect site  30 , the protrusion  24  of the pusher device  20  may be removed from the passage  16   a  of the tubular member  16  of the cannula  12 .  
         [0045]     Referring to  FIG. 6G , the osteochondral plugs  48 ,  46 ,  42  and  36  are each impacted into the defect site  30 , and are each positioned adjacent the osteochondral plug  52 , contacting or nearly contacting the osteochondral plug  52 , in a manner substantially identical to the manner in which the osteochondral plug  50  is impacted into the defect site  30 . During the impacting of each of the osteochondral plugs  48 ,  46 ,  42  and  36 , the pressure sensor  54  measures the amount of pressure that the respective plug undergoes during its impacting into the defect site  30 , in a manner substantially identical to the manner in which the pressure sensor  54  measures the amount of pressure that the osteochondral plug  50  undergoes during its impacting into the defect site  30 .  
         [0046]     As a result of the above-described impacting of the osteochondral plugs  52 ,  50 ,  48 ,  46 ,  42  and  36  into the defect site  30 , the articular cartilage  28  is at least partially repaired. In several exemplary embodiments, the cannula  12  is used to both extract and impact the osteochondral plugs  52 ,  50 ,  48 ,  46 ,  42  and  36 . Moreover, in several exemplary embodiments, since all of the osteochondral plugs  52 ,  50 ,  48 ,  46 ,  42  and  36  are positioned in the tubular member  16  prior to any impacting, the cannula  12  does not have to return to any donor sites after being positioned in the vicinity of the defect site  30 .  
         [0047]     Referring to  FIGS. 7A and 7B , instead of the tubular member  16 , the cannula  12  may include an alternate tubular member  57  defining a longitudinal passage  57   a  including a generally slice-of-pie-shaped cross-section. That is, the cross-section of the tubular member  57  includes walls  57   b  and  57   c , respective ends of which meet at a common vertex, and a curved, circumferentially-extending wall  57   d  extending between respective other ends of the walls  57   b  and  57   c.    
         [0048]     In operation, the alternate tubular member  57  may be used to extract and impact osteochondral plugs  58 ,  60 ,  62 ,  64 ,  66  and  68  into the defect site  30 , with each of the osteochondral plugs being generally slice-of-pie shaped, that is, generally corresponding to the generally slice-of-pie-shaped cross-section of the passage  57   a . The osteochondral plugs  58 ,  60 ,  62 ,  64 ,  66  and  68  may be extracted and impacted into the defect site  30  in a manner substantially similar to the above-described manner in which the osteochondral plugs  36 ,  42 ,  46 ,  48 ,  50  and  52  are extracted and impacted. The pressure sensor  54  is coupled to the osteochondral plug  68  so that the amount of pressure that each of the osteochondral plugs  58 ,  60 ,  62 ,  64 ,  66  and  68  undergoes during the impacting may be measured.  
         [0049]     As a result of the generally slice-of-pie-shaped cross-section of the osteochondral plug  58 , an increased amount of the external surface area of the osteochondral plug  58  engages the immediately adjacent osteochondral plugs  60  and  68 . Likewise, an increased amount of the external surface area of each of the remaining osteochondral plugs  60 ,  62 ,  64 ,  66  and  68  engages the osteochondral plugs immediately adjacent thereto. Also, the quantity and sizes of any gaps between and among the osteochondral plugs  58 ,  60 ,  62 ,  64 ,  66  and  68 , and the defect site  30 , are minimized. As a result, any short or long-term bonding among the osteochondral plugs  58 ,  60 ,  62 ,  64 ,  66  and  68  may be strengthened or improved, and/or bonding may be initiated, and/or the repair of the defect site  30  may be facilitated.  
         [0050]     Referring to  FIGS. 8A and 8B , instead of the tubular member  16 , the cannula  12  may include an alternate tubular member  70  defining a longitudinal passage  70   a  including a generally hexagonal cross-section. In operation, the alternate tubular member  70  may be used to extract and impact osteochondral plugs  72 ,  74 ,  76 ,  78 ,  80 ,  82  and  84  into the defect site  30 , with each of the osteochondral plugs having a hexagonal cross-section that generally corresponds to the generally hexagonal cross-section of the passage  70   a . The osteochondral plugs  72 ,  74 ,  76 ,  78 ,  80 ,  82  and  84  may be extracted and impacted into the defect site  30  in a manner substantially similar to the above-described manner in which the osteochondral plugs  36 ,  42 ,  46 ,  48 ,  50  and  52  are extracted and impacted. The pressure sensor  54  is coupled to the osteochondral plug  84  so that the amount of pressure that each of the osteochondral plugs  72 ,  74 ,  76 ,  78 ,  80 ,  82  and  84  undergoes during the impacting may be measured.  
         [0051]     As a result of the generally hexagonal cross-sections of the osteochondral plugs  72 ,  74 ,  76 ,  78 ,  80 ,  82  and  84 , an increased amount of the external surface area of each of the osteochondral plugs  72 ,  74 ,  76 ,  78 ,  80 ,  82  and  84  engages the osteochondral plugs immediately adjacent thereto. Also, the quantity and sizes of any gaps between and among the osteochondral plugs  72 ,  74 ,  76 ,  78 ,  80 ,  82  and  84 , and the defect site  30 , are minimized. As a result, any short or long-term bonding among the osteochondral plugs  72 ,  74 ,  76 ,  78 ,  80 ,  82  and  84  may be strengthened or improved, and/or bonding may be initiated, and/or the repair of the defect site  30  may be facilitated.  
         [0052]     Referring to  FIGS. 9A and 9B , instead of the tubular member  16 , the cannula  12  may include an alternate tubular member  86  defining a longitudinal passage  86   a  including a generally square cross-section. In operation, the alternate tubular member  86  may be used to extract and impact osteochondral plugs  88 ,  90 ,  92 ,  94 ,  96  and  98  into a rectangular defect site  100  in articular cartilage  102 , with each of the osteochondral plugs having a square cross-section that generally corresponds to the generally square cross-section of the passage  86   a . The osteochondral plugs  88 ,  90 ,  92 ,  94 ,  96  and  98  may be extracted and impacted into the defect site  100  in a manner substantially similar to the above-described manner in which the osteochondral plugs  36 ,  42 ,  46 ,  48 ,  50  and  52  are extracted and impacted into the defect site  100 . The pressure sensor  54  is coupled to the osteochondral plug  98  so that the amount of pressure that each of the osteochondral plugs  88 ,  90 ,  92 ,  94 ,  96  and  98  undergoes during the impacting may be measured.  
         [0053]     As a result of the generally square cross-sections of the osteochondral plugs  88 ,  90 ,  92 ,  94 ,  96  and  98 , an increased amount of the external surface area of each of the osteochondral plugs  88 ,  90 ,  92 ,  94 ,  96  and  98  engages the osteochondral plugs immediately adjacent thereto. Also, the quantity and sizes of any gaps between and among the osteochondral plugs  88 ,  90 ,  92 ,  94 ,  96  and  98 , and the defect site  100 , are minimized. As a result, any short or long-term bonding among the osteochondral plugs  88 ,  90 ,  92 ,  94 ,  96  and  98  may be strengthened or improved, and/or bonding may be initiated, and/or the repair of the defect site  100  may be facilitated.  
       Variations  
       [0054]     It is understood that variations may be made in the foregoing without departing from the scope of the disclosure. For example, any of the osteochondral plugs may be in the form of an allograft, an autograft, a composite plug having polyactide-coglycolide, calcium sulfate and/or polyglycolide fibers, other types of composite plugs and/or any combination thereof. Also, one or more portions of the tubular members  16 ,  57 ,  70  and  86  may be transparent or at least partially transparent, or may include a window portion to provide at least partial transparency. Moreover, in addition to, or instead of the foregoing, the pressure sensor  54  may be in the form of a wide variety of other pressure sensors, which may include a wide variety of transducers and/or a wide variety of micro-electro-mechanical systems (MEMs). Also, the pressure sensor  54  may be coupled to any of the above-described osteochondral plugs such as, for example, the osteochondral plug  52 , before the osteochondral plug  52  is extracted. That is, the pressure sensor may be coupled to the material of the donor site  34 , of which the osteochondral plug  52  is composed, prior to the extraction of the osteochondral plug  52 . Further, the pressure sensor  54 , and/or one or more pressure sensors that are similar to the pressure sensor  54 , may be coupled to any one of the above-described osteochondral plugs.  
         [0055]     Still further, the sizes, dimensions and cross-sections of the above-described tubular members  16 ,  57 ,  70  and  86 , and/or of the above-described osteochondral plugs, may be varied. For example, the diameter of one or more of the osteochondral plugs  36 ,  42 ,  46 ,  48 ,  50  and  52  may be 5 mm, 8 mm or 11 mm. For another example, the osteochondral plugs  36 ,  42 ,  46 ,  48 ,  50  and  52  may have rectangular, triangular, star-shaped or octagonal cross-sections. Also, osteochondral plugs of different sizes and shapes may be impacted into the same defect site such as, for example, the defect site  30  or  102 . Moreover, the length of the tubular member  16 ,  57 ,  70  or  86  may be increased or decreased so that number of osteochondral plugs that may be positioned within the tubular member at the same time may be increased or decreased, respectively.  
         [0056]     In an exemplary embodiment, an automatic feedback control system may be added to the apparatus  10 , using the pressure measurement provided by the pressure sensor  54  as a feedback control signal, so that the amount of force applied by the protrusion  24  may be automatically adjusted in response to the pressure measurement provided by the pressure sensor  54 .  
         [0057]     Any spatial references such as, for example, “upper,” “lower,” “above,” “below,” “between,” “vertical,” “angular,” “upwards,” “downwards,” “side-to-side,” “left-to-right,” “right-to-left,” “top-to-bottom,” “bottom-to-top,” etc., are for the purpose of illustration only and do not limit the specific orientation or location of the structure described above.  
         [0058]     In several exemplary embodiments, one or more of the operational steps in each embodiment may be omitted. Moreover, in some instances, some features of the present disclosure may be employed without a corresponding use of the other features. Moreover, one or more of the above-described embodiments and/or variations may be combined in whole or in part with any one or more of the other above-described embodiments and/or variations.  
         [0059]     Although several exemplary embodiments have been described in detail above, those skilled in the art will readily appreciate that many other modifications, changes and/or substitutions are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of the present invention. Accordingly, all such modifications, changes and/or substitutions are intended to be included within the scope of this invention as defined in the following claims. In the claims, any means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.