Abstract:
An acetabular cup shell inserter has a first end with a handle and a wire coupling element. The inserter has a shell insertion end opposite the first end having a radial expandable element for contacting an inner surface of the acetabular cup shell. A tubular portion is provided extending between the handle end and the insertion end. The tubular portion may be curved. A wire having a first end coupled to the coupling element at the first end is provided. The wire extends through the tubular portion and into the insertion end, the wire having a second end coupled to a moveable element for expanding the expandable element. The inserter includes a system for applying tension to the wire, such as by moving the wire in a direction towards the first end, the tension causing the expandable element to expand and grip the inner surface of the shell.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates to a prosthetic acetabular cup inserter which is particularly, although not exclusively, applicable for minimally invasive surgery (MIS) with small incisions. The inserter can also be used to orient the cup outer shell in the acetabulum and to impact it. The outer shell generally receives a polyethylene or ceramic bearing which in turn receives the spherical head of a femoral component. The invention allows the inserter to have a curved shape although the invention can be applied to inserters with a substantially axially straight shape. 
   WO 2004/010882 shows a surgical impactor which is intended for engagement with a threaded implant. The cup holder is provided with a collet which carries a screw thread and the collet can be opened or closed by operation of a tapered cam. The cam is resiliently biased into its operative position to open the collet to collapse which reduces or collapses a screw thread to detach the impactor from the implant. 
   A fundamental problem with this construction is that the cam is not forceably held in its operative position but merely relies upon a spring so that the cam can move backwards against the spring in certain circumstances thus reducing the grip on the implant. Moreover, the available area of the collet for engaging the implant is restricted by the cover which must extend over the collet to locate it in place. 
   Curved acetabular cup impactors/inserters/reamers are shown in U.S. Patent Publications 2003/0050645, 2003/0229356 and 2004/0153063. 
   Straight impactors showing devices for gripping the outer shell of the acetabular cup system are shown in U.S. Pat. Nos. 4,632,111, 5,169,399, 5,571,111, 5,540,697 and 5,954,727. 
   U.S. Pat. No. 4,632,111 shows apparatus for positioning a prosthetic acetabular cup within an acetabulum and relies upon an expandable elastomeric annular collar. The collar is expanded by operation of a hand retainer nut which acts on a threaded stem to provide pressure against the annular collar so that it can be compressed and its diameter increased to grip the inner surface of the cup to be implanted. 
   It would be very difficult to use this device where there is little available room for the surgeon to operate, especially for minimally invasive surgery (MIS) with a short incision. The present invention is intended to overcome the difficulties of both the above earlier disclosures and to provide a prosthetic acetabular cup inserter which is easier to operate. 
   As used herein, when referring to bones or other parts of the body, the term “proximal” means closer to the heart and the term “distal” means more distant from the heart. The term “inferior” means toward the feet and the term “superior” means towards the head. The term “anterior” means towards the front part of the body or the face and the term “posterior” means towards the back of the body. The term “medial” means toward the midline of the body and the term “lateral” means away from the midline of the body. 
   SUMMARY OF THE INVENTION 
   According to the present invention a prosthetic acetabular cup inserter includes an adjustable cup holder having a resilient ring which can be expanded to grasp the cup outer shell with which it is to be used by operation of an elongated flexible element by a tensioning device which tensions, for example, a cable which causes the resilient ring to expand. 
   Thus, the adjustable cup holder can be carried on an operating handle and the elongated flexible element can be operable from the handle. In a preferred embodiment, the handle is connected to the adjustable cup holder by an extension and this can be curved or substantially straight. The elongated flexible element may conveniently be carried within the extension. 
   In a preferred embodiment, the tension is applied to the elongated flexible element by an operating element carried on a ramp or screw thread so that rotation thereof causes lengthwise movement of the elongated flexible element. 
   In an alternative embodiment, the force can be applied to the elongated flexible element by a pivoted trigger mechanism, angular movement of which causes lengthwise movement of the elongated flexible element. 
   A device can be included for adjusting the operative length and tension of the elongate flexible element. In a preferred arrangement the trigger mechanism can include a rotatable cam which can be operated to apply the tension to the elongate flexible element. 
   The adjustable cup holder can include a backing member, a movable operating member and a resilient deformable member which is deformed to grasp and inner surface of the cup to be inserted when the movable operating member is moved in relation to the backing member. The resilient ring can be made from an elastomeric material and can be axially compressed to cause it to expand radially to grip the cup. 
   A system can be included for adjusting the operative length and tension of the elongate flexible element. 
   In a preferred arrangement the trigger mechanism can include a rotatable cam which can be operated to apply the tension to the elongate flexible element. 
   The adjustable cup holder can include a backing member, a movable operating member and a resilient deformable member which is deformed to grasp an inner surface of the cup to be inserted when the movable operating member is moved in relation to the backing member. 
   The resilient ring can be made from an elastomeric material and can be axially compressed to cause it to expand radially to grip the cup. 
   The adjustable cup holder can include a backing member and a movable operating member to which the flexible element is connected and between which the resilient ring is located so that it is axially compressed when the movable operating member is moved towards the backing member when tension is applied to the flexible element. Thus, the resiliently deformable member may be arranged to grasp the inner rim of the cup or an area adjacent thereto. 
   In an alternative construction the resiliently deformable member can be in the form of split ring and the movable operating member can include a tapered portion which acts against the inner surface of the ring to cause it to expand to engage and grip the cup to be inserted. 
   The backing member can be removably secured to the handle or extension thereof to allow the cup holder to be removed and the backing member can be provided with a system for securing it in a predetermined angular position in relation to the axis of the handle and/or extension thereof. 
   In the above constructions one end of the elongated flexible element can be secured to the movable operating member and the other end secured to the operating element carried on the operating handle or extension. A system can be included to apply a first tension to the flexible cable to hold the backing member and movable operating member in position in the adjustable cup holder and then to apply a second tension to cause the resilient ring to expand. The first tension can be achieved in a first position of the trigger and the second tension when the trigger is in a second position. The elongated flexible element can be made of any suitable material and in a convenient construction is in the form of a metal cable. 
   The invention also includes a prosthetic acetabular cup inserter as set forth above including in combination therewith one or more alternative cup holders which have different dimensions and are for use with cups of different dimensions from the first and which can be fitted in place of the first cup. 
   It will be appreciated that the use of such an elongated flexible element provides the designer with a wide range of possibilities due to the ability of the cable to extend around curves and corners between an operating position, for example on the handle of the device, and the adjustable cup holder, and the use of the flexible element in tension ensures a sufficiently powerful operation for the expansion of the resilient ring. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention can be performed in various ways and two embodiments will now be described by way of example and with reference to the accompanying drawings in which: 
       FIG. 1  is a side elevation of a prosthetic acetabular cup inserter but without an adjustable cup holder; 
       FIG. 2  is a plan view of the cup inserter shown in  FIG. 1 ; 
       FIG. 3  is a cross-sectional side elevation of the other side of the inserter from that shown in  FIG. 1  and with the adjustable cup holder in place on a prosthetic acetabular cup; 
       FIG. 4  is an enlarged cross-sectional elevation of part of the inserter shown in  FIGS. 1 to 3 ; 
       FIG. 5  is a plan view of the elongated flexible element used in the construction shown in  FIG. 3 ; 
       FIG. 6  is a pictorial isometric view from the other end of the elongated flexible element as shown in  FIG. 5 ; 
       FIGS. 7 to 11  are pictorial isometric views showing how the various parts of the adjustable cup holder are assembled together; 
       FIG. 12  is an isometric view of an alternative construction of part of the adjustable cup holder; 
       FIG. 13  is a pictorial exploded isometric view of the various parts of another alternative construction of adjustable cup holder; 
       FIG. 14  is an isometric view showing the adjustable cup holder shown in  FIG. 13  ready to receive the acetabular cup with which it is to be used; 
       FIG. 15  is another isometric view of the adjustable cup holder shown in  FIG. 13  ready to receive the acetabular cup; 
       FIG. 16  is an isometric view of the adjustable cup holder shown in  FIGS. 1 to 12  or  12  to  15 ; 
       FIG. 17  is a cross-sectional side elevation of part of another alternative construction; 
       FIG. 18  is a plan view from above of the construction shown in  FIG. 17 ; 
       FIG. 19  is an isometric view of the construction shown in  FIGS. 17 and 18 ; 
       FIG. 20  is a sectional side elevation of an alternative construction with an operating trigger lever in a free position and in which the handle can receive the adjustable cup holder; 
       FIG. 21  is a view similar to  FIG. 20  of the same construction with the operating trigger lever in a position to cause a first tension to hold the adjustable cup holder in position; 
       FIG. 22  is a view similar to  FIGS. 20 and 21  of the same construction with the operating trigger lever in a position to grasp the cup to be inserted; 
       FIG. 23  is a exploded isometric view of the various parts which make up an alternative construction of an adjustable cup holder; 
       FIG. 24  shows the parts illustrated in  FIG. 23  assembled together and ready for assembly onto a shaped end piece on the handle and stem; 
       FIG. 25  shows the parts shown in  FIGS. 23 and 24  in position and ready for rotation to a locked position; 
       FIG. 26  shows the parts locked in position on the handle and stem; 
       FIG. 27  is an isometric view of the parts shown in  FIGS. 23 to 26  in position on the handle and stem and ready to receive the acetabular cup which is to be used; and 
       FIG. 28  is a view similar to view  27  with the acetabular cup in place on the inserter. 
   

   DETAILED DESCRIPTION 
   As shown in  FIGS. 1 to 12  the preferred prosthetic acetabular cup inserter, according to the present invention, comprises an adjustable cup holder  1  which can be operated to grasp the cup  2  with which it is to be used from a position remote from the cup holder  1  through an elongated flexible element  3  which is in the form of a steel cable. 
   The adjustable cup holder  1  is carried on an operating handle  4  which can be rubberized and from which the flexible element  3  is operated. The free end of handle  4  may have a knob  6  with a striker area  6   a . The handle  4  is connected to the adjustable cup holder by a hollow extension  5  within which the flexible element  3  is carried. As will be seen from the drawings the extension is of a curved shape to assist the surgeon during surgery. 
   A tension force is applied to the flexible element  3  by an operating element  6  which is in the form of a grooved knob and which has a screw threaded axial bore  7 . An extended portion  8  of the knob  6  is located in a top hat shaped bearing  9  and in which it can freely rotate. The inner end of the bearing  9  is closed but has a shaped bore  10 , provided with three flats which are angularly spaced apart by 120°, and within which a shaped nipple  11  (shown in  FIGS. 5 and 6 ) provided on the flexible element  3  can slide but not rotate. From  FIGS. 5 and 6  it will be seen that the shaped nipple is substantially cylindrical apart from a set of three flats  12  which are angularly spaced apart by 120° and this portion of the nipple  11  also carries a screw thread which can co-operate with the screw thread in the bore  7  on the operating knob  6 . Thus, rotation of the operating knob  6  will cause the screw threaded nipple to move backwards and forwards in the screw threaded bore  7  and it is held against rotation by the flats  12  acting against the flats in shaped bore  10  in the bearing  9 . Rotational movement of the knob  6  can therefore be in a direction to create a tensional force in the flexible element  3 . 
   As shown in  FIG. 4 , in order to facilitate location of the extended portion  8  in the bearing  9  a ring  13  is provided in a groove  14  which holds it in place when the flexible element  3  is not assembled, but which can be dismantled for cleaning. 
   The end of the extension  5  spaced away from the handle  4  includes a substantially conically shaped end piece  15  which is rigidly secured to the hollow extension  5 . As is best seen in  FIGS. 7 and 8  the end piece  15  has a flat substantially circular bearing surface  16  which is provided with a pair of spaced apart shaped abutments  17  and which are arranged diametrically opposed to each other on each side of a bore  18  which communicates with the bore of the hollow extension  5 . 
   A backing member in the form of a pressure plate  19  has a shaped opening  20  adapted to fit over the abutments  17  which act to prevent plate  19  from rotating on the end piece  15 . The backing plate  19  has an outer rim  21  which is shaped and adapted to align with the outer rim  22  of the acetabular cup shell to be inserted. The inner edge of the outer rim  21  of the plate  19  is shaped to receive a resiliently deformable member in the form of a flexible ring  23 . This can be square, rectangular or circular shaped as required. The outer diameter of flexible ring  23  is very slightly less than the inner diameter of the rim  22  of the cup  2  so that it can extend over it. 
   The flexible ring  23  is located on a movable operating member  24  which has an outer rim  25  shaped to extend over and engage the outer rim of the ring  23 . The movable operating member  24  is also provided with a shaped opening  26  and which is of substantially the same shape and dimensions as the opening  20  in the backing member  19 . 
   As seen in  FIG. 6 , the end of the flexible element  3  displaced from the nipple  11  carries a shaped locking head  30  which has a shaped part-circular collar  31  and a cylindrical stem portion  32 . The locking head  30  has a bore  36  which also extends through the cylindrical portion  32  and the outer end of which is substantially rectangular. This engages with a substantially rectangular nipple  35  (and shown in  FIG. 3 ) and prevents the head  30  from rotating on the element  5 . The collar  31  is shaped to locate within the abutment  17  with its flat sides  37  aligned with the edges  38  of the abutments, as will be clearly seen from  FIG. 9 , and so that when the backing plate  19  is placed in position over the abutments  17  it will prevent rotation of the collar  31  on the head  30  and cylindrical extension  32 . The spring  33  engages against a shoulder  39  in the bore  36  in the conically shaped end  15  so that the head  31  is biased outwardly from the extension  5  into the position shown in  FIG. 9 . 
   The parts are assembled together as shown in  FIGS. 7 ,  8 ,  9 ,  10  and  11 .  FIG. 7  shows the end piece  15  ready to receive the flexible element  3 . This is inserted so that the end carrying the nipple  11  is pushed through the extension and handle and until it engages with the screw threaded bore  7  in the operating knob  6 . Rotation of the operating knob in the appropriate direction now causes the nipple  11  to move up the bore  7 . 
   With the head  30  in position, as shown in  FIG. 8 , the backing plate  19  can be added by passing it over the projections  17  where it also acts to prevent rotation of the collar  31  as shown in  FIG. 9 . 
   The movable operating member  24  is now placed in position, as indicated in  FIG. 10 , and is then rotated through 90° so that its opening  26  lies at right angles to the head  31  and thus locks the assembly together, as shown in  FIG. 11 . 
   The edge of the inner rim  25  now rests against the flexible deformable ring  23  which has been placed in position prior to the movable operating member  24 . 
   With the parts in the position indicated above the cup  2  to be inserted is placed over the rim of the ring  23  and the operating knob  6  is rotated appropriately which causes a tension and axial movement of the flexible element  3  thus pulling the movable operating member  24  against the resiliently deformable ring  23  so that it is compressed and is forced radially outwardly against the inner surface of the outer edge of the cup thus grasping the rim of the cup and holding it in position in relation to the inserter, as shown in  FIG. 3 . 
   The cup can now be inserted in the acetabulum as required and the cup can also be held in this position if impaction is required. 
   With the cup positioned it can be easily released merely by rotating the operating knob  6  appropriately which will release the pressure on the resiliently deformable ring  23  and allow the inserter to be removed. 
     FIG. 12  shows an alternative embodiment in which the same reference numerals are used to indicate similar parts but in this arrangement the shaped abutments  17  are of different dimensions, one,  17 ′, being larger than the other. The shaped opening  20  is shaped to accommodate the abutments  17  to ensure that the pressure plate  19  can only be fitted in one predetermined position. This construction is for use with prosthetic cups which have a particular anatomic shape and which require insertion in a particular position in the acetabulum. 
     FIGS. 13 ,  14  and  15  show an alternative embodiment in which the same principles are employed as that set forth in  FIGS. 1 to 12  but in this construction the adjustable cup holder is designed to operate with a cup  40  which has an internal groove  41  displaced inwardly from its immediate inner rim which carries a ring of depressions. With this construction the shape of the conical end  15  of the apparatus is similar to that described with regard to  FIGS. 1 to 12  but the shaped head  30  on the flexible element  3  is replaced by a head carrying a pair of cylindrical abutments  42 . A backing or pressure member  43  of similar construction to but of different shape to that shown in  FIG. 9  is employed and located on this is a circlip or split ring  44  which replaces the deformable ring  23  shown in  FIGS. 1 to 12 . The circlip can be made of metal or any other suitable material. The removable operating member in this construction is in the form of a dished member  45  which has a conical outer wall  46  and a shaped opening  47  which is dimensioned to pass over the abutments  42 . The shape of the abutments  17  can be as shown in  FIG. 12 . 
   The assembly is placed together in a similar manner to that described with regard to the earlier construction and the removable operating member  45  is again rotated through 90° to hold it in position. When the operating knob  60  is rotated the flexible element  3  again acts to pull the removable operating member  45  towards the backing member  43  but in this case the tapered sides of the operating member engage the inner surface  48  of circlip  44  forcing it apart. Thus, when the cup  40  is placed on the assembly operation of the flexible element  3  causes the circlip  44  to expand into the groove  41  on the cup  40  and thus hold it in position. The cup can be released by again operating the knob  6 . 
   As shown in  FIG. 1  a guide  50  can also be provided on or adjacent the handle to assist the surgeon. 
     FIG. 16  shows how the rear face of the pressure plate  19  can be marked with a landmark  55  to indicate the position of a trial cup (not shown) to the definitive cup  2  to be inserted using a bistoury marking on the rim of the acetabulum. Reference numeral  56  indicates an area to position the trial cup following the anterial rim of the acetabulum. The markings are desirable for use with cups which have a particularly shaped rim. 
     FIGS. 17 to 19  show another alternative construction in which the same reference numerals are used to indicate similar parts to those shown in  FIGS. 1 to 12 . 
   In this construction a trigger mechanism is employed the pivotal movement of which is used to tension the flexible element  3 . The trigger mechanism comprises an operating trigger lever  60  which is located within a slot  61  in the handle  4  and carried on a pivot pin  62  which extends transversely across the handle  4 . The trigger lever  61  has a pair of flanges  64  each of which has a bore  65  to accept one of the pivot pin  62 . The flanges  64  each have a cam surface  66  which extends around the end of the trigger lever  60 . Thus, when the lever  60  is pivoted about the pivot pin  62  the cam surfaces  66  are also rotated. Cam surfaces  66  bear against a cylindrical bearing block  67  carried on an adjustment hand wheel  68 . The hand wheel  68  has an extension  69  which locates in a bearing bore  70  provided in a handle end cap  71 . 
   The end of the flexible element  3  is provided with a screw threaded nipple  72  which is carried in a screw threaded bore  73  in the adjusting wheel  68  and extends through an opening  74  in the pivot pin  62  and between the cam flanges  64 . 
   As will be seen from  FIG. 19  the handle  4  is cut away at  75  and  76  to provide an extension of the slot  61  to enable the hand wheel  68  to be rotated by the operator. The adjustable cup holder  1  can be similar to that shown in  FIGS. 1 to 12  and the flexible element  3  can be attached in a similar manner, preferably however an alternate cup holder construction is used which is shown in  FIGS. 19 to 28  as further described below. 
   To operate the trigger mechanism the trigger is first lifted to the position shown in  FIG. 19 . In this position the height of the cam surface is their lowest so that there is the maximum relaxation of the flexible element  3 . This enables the cup to be placed in position on the cup holder. The lever is now rotated in an anticlockwise direction when viewed in  FIG. 17  which moves the cam surfaces round their highest position which in turn forces the bearing block  67  towards the right (as shown in  FIG. 17 ) thus tensioning the flexible element  3  which is connected to the bearing block  67  and the hand wheel  68 , the axial movement being accommodated in the bore  70 . The tension of the flexible element  3  is sufficient for the flexible ring  23  in the cup holder  1  to grasp the cup. The trigger mechanism can also be employed with the cup holder construction shown in  FIGS. 13 to 16 . 
   The applied tension at the closed position of the trigger, that is in the position shown in  FIG. 17 , can be adjusted by rotating the hand wheel  68 . This can be rotated on the threaded nipple  72  which will cause the nipple to move axially in either direction depending upon the direction of rotation of the hand wheel. The effect is to vary the operative length of the flexible element  3  and to increase or decrease the applied tension. 
   The hand wheel can thus be used when different sized cups are employed which, depending upon their dimensions, may require slightly more or less movement of the resilient ring to grasp the cup. 
   If required the trigger mechanism can include a locking mechanism to allow it to be locked in the position shown in  FIG. 17 . This, for example, can be in the form of a simple rotating clasp indicated by reference numeral  78  and shown in broken lines in  FIG. 18 . 
     FIGS. 20 and 22  show a construction in which the same reference numerals are used to indicate similar parts as in  FIGS. 17 to 19  and the constructions of the handle  4  is generally similar to that described in  FIGS. 17 ,  18  and  19  but the operating trigger lever can be moved to three operative positions. The operating trigger lever is indicated by reference numeral  81  and its cams, indicated by reference numeral  82 , have three operating surfaces, indicated by reference numerals  83 ,  84  and  85  respectively. 
     FIG. 20  shows the operating trigger lever  81  in a first position where the cam surface  83  bears against the cylindrical bearing block  67  on the hand wheel  68 . In this position the flexible element can be assembled onto the handle. Before assembling the cup holder  1  to the end piece on the extension  5  the hand wheel  68  is tightened up to the cam surface  83  and the operating trigger lever  81  is then moved to the second position, as shown in  FIG. 21 , and the second cam surface  84  bears against the cylindrical bearing block  67 . This cam surface is 1.5 mm lower than cam surface  83  and allows the adjustable cup holder assembly to be fitted to the end piece of the extension  5  and for the locking head  30  to be located in place. 
   The assembly is now ready to receive the cup with which it is to be used. 
   When the cup is placed in position on the adjacent cup holder  1  the operating trigger lever  81  is moved to the third position as shown in  FIG. 22 . This causes cam surface  85  to engage the cylindrical bearing block  67  and thus tension the flexible element  3 . The cam surface  85  is 1 mm higher than the cam surface  84  and this provides sufficient tensioning in the flexible element  3  to compress the flexible ring  23  to cause it to expand and grasp the rim of the cup. 
   Due to the dimensions of the cam surface this now allows the surgeon 0.5 mm movement if he wishes to further tighten the grip on the cup by operating the hand wheel  68 . 
   To release the cup the operating trigger lever  81  is moved back to the position shown in  FIG. 21  which allows the release of the inserter from the cup and the operating trigger lever can be moved further counterclockwise to a position shown in  FIG. 20  to allow the various parts of the cup holder  1  to be released from the end piece  15 . 
   As described above, the construction as shown in  FIGS. 17 to 21  can be used with the arrangements shown in  FIGS. 7 to 15 . 
     FIGS. 19 to 28  show an alternative form of releasable cup holder which can not only be used with the construction shown in  FIGS. 17 to 22  but also with the arrangement shown in  FIGS. 1 to 8 . In this construction the releasable cup holder comprises a backing member  90  which has an outer rim  91  shaped and adapted to align with the outer rim of the acetabular cup to be inserted. The backing member  90  is adapted for use with an end piece  92  as shown in  FIGS. 19 ,  24 ,  25  and  26 . This end piece, which is rigidly secured to the hollow extension  5 , has a substantially flat circular bearing surface  93  similar to the bearing surface  16  of the construction shown in  FIGS. 7 and 8 . It also has a pair of spaced apart shaped abutments  94  which are arranged diametrically opposed to each other on each side of a bore which communicated through the bore of the hollow extension  5 . 
   In addition to the abutments  94  the end piece  92  has a projection  95  adjacent its outer rim and best seen in  FIGS. 24 ,  25  and  26  and a shaped locking head  30 , similar to that shown in the other constructions, is also provided. 
   The backing member  90  has a first radial groove  96  from which extends a ramp  97 . This terminates in a flat circumferentially extending surface  98  and leads to a second radially extending groove  99  with which is aligned a cut-out  100 . 
   The movable operating member  110  in this construction comprises a flanged circular plate  111  the flange  112  having a radially projecting rim  113 . A shaped opening  114 , similar to the shaped opening  26  in the construction shown in  FIGS. 7 to 12 , is provided and the circular plate  111  has a projecting pin  115 . 
   The flexible element  120  in this arrangement is shaped to extend over the flange  112  and rest against the outer rim  113 . 
   This construction is assembled by placing the flexible element  120  in position on the flange  112  and pushing the operating member  110  onto the backing member  90 , at the same time engaging the pin  115  in a bore  116  in the backing member. It will be appreciated that the pin  115  aligns and holds the parts together. The assembled parts are presented to the end piece  92  as shown in  FIG. 24  and then pressed against the end piece  92  as shown in  FIG. 25 . The flexible element is dimensioned so that it is slightly compressed when the parts are pushed into positions as shown in  FIG. 25  with first groove  96  aligned with the projection  95  on the end piece  92 . The parts are now rotated in the direction of the arrow shown in  FIG. 25  moving the projection  95  up the ramp  97  and around until it engages the second groove  99  as shown in  FIG. 26 . 
   Prior to assembling the parts onto the end piece  92  the operating trigger lever  81  of the construction shown in  FIG. 19  or  FIGS. 20 to 22  is moved to the free position. With the construction shown in  FIG. 19  the hand wheel  68  is rotated to a position in which there is maximum movement and the handle is then closed which produces a reduced tension force and enables the end piece  30 , which has been passed through a circular opening  121  in the backing member  90  and through the shaped opening  114  in the movable operating member  110  which acts to hold the parts in position. 
   In the construction shown in  FIGS. 20 ,  21  and  22  this position is achieved by moving the operating trigger lever  81  to its first tension position. 
   The inserter is now assembled and ready to receive the cup  2  with which it is to be used. The shaped cup is aligned with the shaped edge  91  of the backing member  90  as shown n  FIG. 27 . The cup is then placed onto the cup holder  1  as shown in  FIG. 28  with the flexible element within the outer rim of the cup in a similar manner to that described with the earlier embodiments. 
   When used with the arrangement shown in  FIGS. 17 to 19  the adjustment hand wheel is adjusted to provide maximum tension in the flexible element  3  and operating trigger level  60  is then moved to provide the maximum tension of the flexible elements  3  which thus acts to expand the flexible ring  120  by compressing it between the backing member  90  and the operating member  110 , the ring thus expanding radially to grasp the cup  2 . 
   It will be understood that the flexible ring  23  now performs two functions. It not only provides a resilient bias to hold the parts in position when they are first located on the end piece  92  but, on further compression, it also acts to grasp the cup  2 . 
   A number of alternative cup holders can be provided of different dimensions for use with cups of different dimensions so that a modular construction is achieved. Thus, one handle and extension can be used with a large number of different shaped and sizes adjustable cup holders. 
   The various parts can be made from any convenient material, for example the various parts of the adjustable cup holder can be made from metal or a synthetic plastics material. Again, the handle and extension can be metal or a synthetic plastics material as can the end piece. It is also possible to use different materials for the other parts, for example the flexible element could be made from a suitably strong synthetic material as well as from metal. 
   Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.