Abstract:
A mount usable with an implantable extra-articular system including a body having a first end opposite a second end. The mount includes a coupling connection positioned at the first end of the mount for attaching the mount to a base component. The mount also includes a multi-dimensional articulating connection component configured at the second end of the mount. The body of the mount offsets the articulating connection component away from body anatomy when coupled to the base component. The mount also orients and aligns a link absorber that is coupled to the articulating connection component.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. application Ser. No. 11/743,097, filed May 1, 2007, a continuation-in-part of U.S. application Ser. No. 11/743,605, filed May 2, 2007, a continuation-in-part of U.S. application Ser. No. 11/775,139, filed Jul. 9, 2007, a continuation-in-part of U.S. application Ser. No. 11/775,149, filed Jul. 9, 2007 and a continuation-in-part of U.S. application Ser. No. 11/775,145, filed Jul. 9, 2007, the entire disclosures of which are expressly incorporated herein by reference. 
     
    
     FIELD OF EMBODIMENTS 
       [0002]    Various embodiments disclosed herein relate to structure for attachment to body anatomy, and more particularly, towards approaches for providing mounting members for implantable extra-articular systems. 
       BACKGROUND 
       [0003]    Joint replacement is one of the most common and successful operations in modern orthopedic surgery. It consists of replacing painful, arthritic, worn or diseased parts of a joint with artificial surfaces shaped in such a way as to allow joint movement. Osteoarthritis is a common diagnosis leading to joint replacement. Such procedures are a last resort treatment as they are highly invasive and require substantial periods of recovery. Total joint replacement, also known as total joint arthroplasty, is a procedure in which all articular surfaces at a joint are replaced. This contrasts with hemiarthroplasty (half arthroplasty) in which only one bone&#39;s articular surface at a joint is replaced and unincompartmental arthroplasty in which the articular surfaces of only one of multiple compartments at a joint (such as the surfaces of the thigh and shin bones on just the inner side or just the outer side at the knee) are replaced. Arthroplasty as a general term, is an orthopedic procedure which surgically alters the natural joint in some way. This includes procedures in which the arthritic or dysfunctional joint surface is replaced with something else, procedures which are undertaken to reshape or realigning the joint by osteotomy or some other procedure. As with joint replacement, these other arthroplasty procedures are also characterized by relatively long recovery times and their highly invasive procedures. A previously popular form of arthroplasty was interpositional arthroplasty in which the joint was surgically altered by insertion of some other tissue like skin, muscle or tendon within the articular space to keep inflammatory surfaces apart. Another previously done arthroplasty was excisional arthroplasty in which articular surfaces were removed leaving scar tissue to fill in the gap. Among other types of arthroplasty are resection(al) arthroplasty, resurfacing arthroplasty, mold arthroplasty, cup arthroplasty, silicone replacement arthroplasty, and osteotomy to affect joint alignment or restore or modify joint congruity. When it is successful, arthroplasty results in new joint surfaces which serve the same function in the joint as did the surfaces that were removed. Any chodrocytes (cells that control the creation and maintenance of articular joint surfaces), however, are either removed as part of the arthroplasty, or left to contend with the resulting joint anatomy. Because of this, none of these currently available therapies are chondro-protective. 
         [0004]    A widely-applied type of osteotomy is one in which bones are surgically cut to improve alignment. A misalignment due to injury or disease in a joint relative to the direction of load can result in an imbalance of forces and pain in the affected joint. The goal of osteotomy is to surgically re-align the bones at a joint and thereby relieve pain by equalizing forces across the joint. This can also increase the lifespan of the joint. When addressing osteoarthritis in the knee joint, this procedure involves surgical re-alignment of the joint by cutting and reattaching part of one of the bones at the knee to change the joint alignment, and this procedure is often used in younger, more active or heavier patients. Most often, high tibial osteotomy (HTO) (the surgical re-alignment of the upper end of the shin bone (tibia) to address knee malalignment) is the osteotomy procedure done to address osteoarthritis and it often results in a decrease in pain and improved function. However, HTO does not address ligamentous instability—only mechanical alignment. HTO is associated with good early results, but results deteriorate over time. 
         [0005]    Other approaches to treating osteoarthritis involve an analysis of loads which exist at a joint. Both cartilage and bone are living tissues that respond and adapt to the loads they experience. Within a nominal range of loading, bone and cartilage remain healthy and viable. If the load falls below the nominal range for extended periods of time, bone and cartilage can become softer and weaker (atrophy). If the load rises above the nominal level for extended periods of time, bone can become stiffer and stronger (hypertrophy). Finally, if the load rises too high, then abrupt failure of bone, cartilage and other tissues can result. Accordingly, it has been concluded that the treatment of osteoarthritis and other bone and cartilage conditions is severely hampered when a surgeon is not able to precisely control and prescribe the levels of joint load. Furthermore, bone healing research has shown that some mechanical stimulation can enhance the healing response and it is likely that the optimum regime for a cartilage/bone graft or construct will involve different levels of load over time, e.g. during a particular treatment schedule. Thus, there is a need for devices which facilitate the control of load on a joint undergoing treatment or therapy, to thereby enable use of the joint within a healthy loading zone. 
         [0006]    Certain other approaches to treating osteoarthritis contemplate external devices such as braces or fixators which attempt to control the motion of the bones at a joint or apply cross-loads at a joint to shift load from one side of the joint to the other. A number of these approaches have had some success in alleviating pain but have ultimately been unsuccessful due to lack of patient compliance or the inability of the devices to facilitate and support the natural motion and function of the diseased joint. The loads acting at any given joint and the motions of the bones at that joint are unique to the body that the joint is a part of. For this reason, any proposed treatment based on those loads and motions must account for this variability to be universally successful. The mechanical approaches to treating osteoarthritis have not taken this into account and have consequently had limited success. 
         [0007]    Prior approaches to treating osteoarthritis have also failed to account for all of the basic functions of the various structures of a joint in combination with its unique movement. In addition to addressing the loads and motions at a joint, an ultimately successful approach must also acknowledge the dampening and energy absorption functions of the anatomy, and be implantable via a minimally invasive technique. Prior devices designed to reduce the load transferred by the natural joint typically incorporate relatively rigid constructs that are incompressible. Mechanical energy (E) is the action of a force (F) through a distance (s) (i.e., E=F×s). Device constructs which are relatively rigid do not allow substantial energy storage as the forces acting on them do not produce substantial deformations—do not act through substantial distances—within them. For these relatively rigid constructs, energy is transferred rather than stored or absorbed relative to a joint. By contrast, the natural joint is a construct comprised of elements of different compliance characteristics such as bone, cartilage, synovial fluid, muscles, tendons, ligaments, etc. as described above. These dynamic elements include relatively compliant ones (ligaments, tendons, fluid, cartilage) which allow for substantial energy absorption and storage, and relatively stiffer ones (bone) that allow for efficient energy transfer. The cartilage in a joint compresses under applied force and the resultant force displacement product represents the energy absorbed by cartilage. The fluid content of cartilage also acts to stiffen its response to load applied quickly and dampen its response to loads applied slowly. In this way, cartilage acts to absorb and store, as well as to dissipate energy. 
         [0008]    With the foregoing applications in mind, it has been found to be necessary to develop effective structures for mounting to body anatomy. Such structures should conform to body anatomy and cooperate with body anatomy to achieve desired load reduction, energy storage, and energy transfer. These structures should include mounting means for attachment of complementary structures across articulating joints. 
         [0009]    For these implant structures to function optimally, they must not cause a disturbance to apposing tissue in the body, nor should their function be affected by anatomical tissue and structures impinging on them. Moreover, there is a need to reliably and durably connect a link or an energy absorbing structure at an interventional site and to provide a durable surface for articulating motion without restricting natural ranges of motion of body anatomy. Therefore, what is needed is an approach which addresses both joint movement and varying loads as well as complements underlying anatomy and provides an effective mount for a link or energy manipulating assembly. 
       SUMMARY 
       [0010]    Briefly, and in general terms, the present disclosure is directed to mounting components that are used in connection with implantable extra-articular systems. The mounting components are intended to provide reliable and durable connections. The components are also intended to provide a durable bearing surface and a secure engagement between moving parts without substantially restricting ranges of motion as well as be removable and/or adjustable. 
         [0011]    According to one embodiment, the mount includes a body having a first portion opposite a second portion, the second portion providing an articulating connection. The mount can further include a coupling connection in the form of a locking stem that is configured at the first portion of the mount for attaching the mount to a base component. The mount can also include a multi-dimensional articulating connection component (for example, a socket for receiving a ball) defining a bearing surface formed at the second portion of the mount. The body of the mount offsets the multi-dimensional articulating connection component away from body anatomy when coupled to the base component. The mount also orients and aligns a link or absorber that is coupled to the articulating connection component. In one aspect, the link or absorber to bearing surface connection is arranged so that the link or absorber is easily inserted or removed. In another aspect, the contemplated structure is intended to withstand maximum stresses at maximum loading conditions for a high number of cycles. 
         [0012]    In another embodiment, the mount includes a locking coupling connection that is positioned at a first end of the mount for attaching the mount to a base component. The mount also includes an adjustable multi-dimensional articulating connection component slidably affixed to a second end of the mount, the articulating connection defining a bearing surface. The body of the mount offsets the multi-dimensional articulatable connection component away from body anatomy when coupled to the base component. The mount also orients and aligns a link or absorber that is coupled to the articulatable connection component. 
         [0013]    Various other approaches and embodiments include deformable material which facilitates an engagement between mounting structure and a base component. Such deformable material can be configured as a separate sleeve or formed integral with a mount assembly. Additionally, the sleeve can include surface ridges facilitating relative movement between parts as well as a desired locking engagement. 
         [0014]    In one particular embodiment, a mount component is formed from cobalt chromium. Additionally, a sleeve can be made from titanium and portions of the mount can be coated with a ceramic material. Tapered structure is employed to act as a funnel to aid in guiding parts to proper positions. In this regard, one or more of a locking stem, deformable sleeve or stem receiving hole can be tapered. Tabs and receiving slots are also contemplated to aid in proper orientation between parts. 
         [0015]    Moreover, a highly refined, polished surface finish is contemplated for the bearing surfaces. Tight tolerances respecting diameter clearances with structure received by the bearing surface as well as the spherecity of the pocket defined by the bearing surfaces are required in certain applications. Symmetrical as well as asymmetrical bearing surfaces are also contemplated for example in a knee application the surfaces accomplish articulating limb flexion/extension rotation of up to 130°, varus/valgus rotation up to 10° and internal/external rotation of 75°. 
         [0016]    Other features and advantages will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate by way of example, the features of the various embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a perspective view, depicting a preferred embodiment of an implantable mechanical energy absorber system with a protective housing or sheath removed to show the components; 
           [0018]      FIG. 2  is an enlarged perspective view, depicting a first mount component; 
           [0019]      FIG. 3  is a perspective view, depicting the first mount component rotated with respect to  FIG. 2 ; 
           [0020]      FIG. 4  is a perspective view, depicting a socket portion of the first mount component of  FIG. 2 ; 
           [0021]      FIG. 5  is an enlarged perspective view, depicting a second mount component; 
           [0022]      FIG. 6  is a perspective view, depicting the second mount component rotated with respect to  FIG. 5 ; 
           [0023]      FIG. 7  is a perspective view, depicting a socket portion of the second mount component; 
           [0024]      FIG. 8  is a perspective view, depicting the system of  FIG. 1  with an absorber element and first and second mount components removed; 
           [0025]      FIG. 9  is an enlarged side view, depicting the energy absorber element removed from  FIG. 8 ; 
           [0026]      FIG. 10  is an enlarged perspective view, depicting a deformable sleeve; 
           [0027]      FIG. 11  is a perspective view of one embodiment of a mounting member coupled to a base component that is fixed to a bone; 
           [0028]      FIG. 12  is a back perspective view of one embodiment of an extra-articular implantable mechanical energy absorbing system coupled to base components via mounting members; 
           [0029]      FIG. 13A  is a top perspective view of one embodiment of a coupling connection between a mounting member and a base component; 
           [0030]      FIG. 13B  is a cross-section view of the coupling connection of  FIG. 13A ; 
           [0031]      FIG. 13C  is a top view of another embodiment of a lockable connection between a mounting member and a base component in an unlocked position; 
           [0032]      FIG. 13D  is a top view of the lockable connection of  FIG. 13C  in a locked position; 
           [0033]      FIG. 14A  is a perspective view of another embodiment of a coupling connection between a base component and a mounting member; 
           [0034]      FIG. 14B  is a perspective view of yet another embodiment of a coupling connection between a base component and a mounting member; 
           [0035]      FIG. 15  is a perspective view of another embodiment of a coupling connection between a base component and a mounting member; 
           [0036]      FIG. 16  is a perspective view of another embodiment of a coupling connection between a base component and a mounting member; 
           [0037]      FIG. 17A  is an exploded view of another embodiment of a coupling connection between a base component and a mounting member; 
           [0038]      FIG. 17B  is a top view of the coupling connection of  FIG. 17A  fully assembled; 
           [0039]      FIG. 18A  is a top view of one embodiment of a articulatingable connection usable with a mounting member; 
           [0040]      FIG. 18B  is a top view of another embodiment of a articulatingable connection usable with a mounting member; 
           [0041]      FIG. 18C  is a perspective view of yet another embodiment of a articulatingable connection usable with a mounting member; 
           [0042]      FIG. 19  is a perspective view of another embodiment of a articulatingable connection provided on a mounting member; 
           [0043]      FIG. 20  is a side view of one embodiment of an adjustable articulating connection provided on a mounting member; 
           [0044]      FIG. 21  is a side view of another embodiment of an adjustable articulating connection provided on a mounting member; 
           [0045]      FIG. 22A  is a cross-sectional view of yet another embodiment of an adjustable articulating connection provided on a mounting member; 
           [0046]      FIG. 22B  is a perspective view of one embodiment of a shim used in the adjustable articulating connection of  FIG. 22A ; 
           [0047]      FIG. 23  is a cross-sectional view of another embodiment of an adjustable articulating connection provided on a mounting member; 
           [0048]      FIG. 24  is a cross-sectional view of another embodiment of an adjustable articulating connection provided on a mounting member; 
           [0049]      FIG. 25A  is a cross-sectional view of another embodiment of an adjustable articulating connection provided on a mounting member; 
           [0050]      FIG. 25B  is a top view of a lever used with the adjustable articulating connection of  FIG. 25A ; 
           [0051]      FIG. 25C  is a side view of a ball component used with the adjustable articulating connection of  FIG. 25A ; 
           [0052]      FIG. 26A  is a cross-sectional view of another embodiment of an adjustable articulating connection provided on a mounting member; 
           [0053]      FIG. 26B  is a cross-sectional view of a locking washer of  FIG. 26A  in a locked position; 
           [0054]      FIG. 26C  is a cross-sectional view of a locking washer of  FIG. 26A  in an unlocked position; 
           [0055]      FIG. 27A  is a side view of another embodiment of an adjustable articulating connection provided on a mounting member; 
           [0056]      FIG. 27B  is a top perspective view of the adjustable articulating connection provided on a mounting member of  FIG. 27A ; 
       
    
    
     DETAILED DESCRIPTION 
       [0057]    Various disclosed embodiments are directed to mounting members for implantable medical devices. In one particular aspect, the mounting members are attachable to base components that are mounted to a bone as well as to a link mechanism for an implantable extra-articular system. The mounting member includes a first portion performing a coupling connection for mounting to the base component. A second portion of the mounting member includes a socket for coupling to the link mechanism. According to one approach, the socket is a fixed mechanism. In other embodiments, a portion of the socket mechanism is one or more of adjustable and removable. The two part base/mounting member components provide a method for good attachment of the base to the bone and a more simple surgical technique for installing the link. It also allows a protective sheath (not shown) and/or the wear components of the link/mount assembly to be removeable and/or replaceable without removing or replacing the base components. It further allows the wear components of the link/mount assembly and the base components to be different materials. For example, the base components can be titanium or titanium alloy which promote osteo-integration and the wear components can be much harder materials such as cobalt chrome (e.g., Biodur CCM Plus), ceramic, or other durable materials that produce a minimal amount of particulate material or, if particulate material is generated, the smallest size of particulate material. 
         [0058]    Thus, the disclosed mounting assemblies provide reliable and durable connections between moving parts. Since moving parts wear, the contemplated approaches facilitate easy and reliable removal and replacement of wearing elements. Accordingly, removal methods, features and tools are contemplated. Moreover, there has been a recognition of varying kinematics of an implant by altering juxtapositional relationships with anatomy and the same has been considered in certain of the mount approaches. 
         [0059]    Referring now to the drawings, wherein like reference numerals denote like or corresponding parts throughout the drawings and, more particularly to  FIGS. 1-27B , there are shown various embodiments of a mounting member. With specific reference to  FIGS. 1-10 , there is shown a preferred embodiment of an implantable mechanical energy absorbing system  10 . In the application shown, the system is extra-articular in nature in that it is connected exterior of the joint capsule and across a knee joint; however, features of the present disclosure can be applied to various body anatomy. 
         [0060]    In the particular embodiment depicted, the implantable mechanical energy absorbing system  10  includes a femoral base component  12  attached to a femur  14  and a tibial base component  16  attached to a tibia  18 . Configured between the bases  12 ,  16  is an absorber  20 . To connect the absorber  20  to the bases  12 ,  16 , in one approach, a first mount  22  is employed to attach a first end of the absorber  20  to the femoral base  12  and a second mount  24  is utilized to attach a second end of the absorber to the tibial base  16 . 
         [0061]    The mounts  22 ,  24  are designed to reliably and durably connect the absorber  20  to the base components  12 ,  16 . Additionally, the mounts  22 ,  24  define a socket  25  configured to provide durable bearing surfaces  26 ,  28  (best seen in  FIGS. 4 and 7 ) for a ball joint  30  (See  FIG. 9 ) configured at the ends of the absorber  20 . Moreover, the structure of the mounts  22 ,  24  provide a secure engagement of the ball joints  30  within the sockets  25  without overly restricting ranges of motion. 
         [0062]    Each of the mounts  22 ,  24  define slightly different structures but have aspects in common. The mounts  22 ,  24  each include a generally cylindrical locking stem  32  having a tapered terminal end  33 . Moreover, the stems can include a mid-section  34  having a slightly reduced diameter. Also, in one approach, the overall profile of the stems can be tapered along its length toward their terminal ends. 
         [0063]    The stems  32  extend from a base of the socket portion  25  of the mounts  22 ,  24 . A longitudinal axis  36  extends through the stem  32 . Extending in an opposite direction from the stem are curved walls which define the socket portion  25 . Although the walls are contiguous with each other, for purposes of description, two walls  38 ,  40  are identified. Moreover, while the walls of the first and second mounts  22 ,  24  have different configurations, they are described together here to the extent they have common features. It is to be recognized that the walls  38 ,  40  are sized and shaped for receiving oppositely oriented ball joints  30  extending from the absorber  20 . In this regard, the hooked shape of the ball joints  30  facilitate the insertion of the ball joint  30  within the socket  25 . Moreover, the inter-relationship of the shapes of the ball joints  30  and the socket  25  function to securely retain the structures together when a complete implantation energy absorber  10  is attached at an interventional site. 
         [0064]    The first and second curved walls  38 ,  40  include interior surfaces which, in conjunction, define the bearing surface  26  of the socket  25 . As such, the walls  38 ,  40  provide the bearing surface  26  with a contour defining a portion of a spherical surface. In one aspect, this spherical surface is machined to provide a 0.002 inch diametrical clearance with the ball joint  30 . A highly fine  2  surface finish is contemplated for the bearing surface. 
         [0065]    The curved walls  38 ,  40  also define a gap or opening to the socket  25 . The opening is off-center when considering the longitudinal axis  36  extending through the mount. To accomplish this, the first wall  38  has a longer longitudinal, curved dimension as compared to the second wall  40 . As such, the walls define an asymmetric socket. In an alternative embodiment, the walls are mirrored images and define a symmetrical socket. Moreover, each of the walls  38 ,  40  include curved reliefs  42 ,  44  removed from the respective walls, a first relief  42  formed in the first wall  38  being deeper than a second relief  44  of the second wall  40 . A transition structure  46  having an irregular surface area (best seen in  FIGS. 3 and 6 ) is formed between the walls  38 ,  40 . Since the base of the tibial mount  24  is larger than the base of the femoral mount  22 , the transition structure  46  of the tibial mount  24  assumes a larger area than that of the femoral mount  22 . 
         [0066]    It is the specific shapes of this transitional structure area  46  as well as that of the curved walls  38 ,  40  which define the opening to the socket  25 . In this regard, the curved walls  38 ,  40  and the transitional area  46  provide the mounts  22 ,  24  with structure to secure the ball joints without overly restraining ranges of motion. In one particular aspect, the mounts  22 ,  24  of system  10  affixed to a knee joint can provide 130 degrees of flexion/extension rotation, 10 degrees of varus/valgus rotation and an internal/external rotation of 75 degrees. The mount connector is also desired to withstand a greater than 260 pound pullout force and contact stress exceeding 325 MPa. 
         [0067]    Additionally, the walls  38 ,  40  are configured to permit easy insertion and removal of the ball joints upon twisting of the same relative to the sockets  25  during assembly or disassembly. The mounts  22 ,  24  can be formed from any durable material. In a preferred approach, the mounts are machined from CoCr Biodur CCM plus material. In certain approaches, a ceramic material can be coated or otherwise formed on exterior surfaces of the mounts  22 ,  24  such as within the socket  25 . Ceramic materials may be used to minimize the generation of particulate matters due to prolonged interfacing between parts. Moreover, in certain applications, the structures are contemplated to be designed to maintain functionality for greater than two million loading cycles. 
         [0068]    In order to accomplish a secure attachment between the mounts  22 ,  24  and the bases  12 ,  16 , an interference fit can be employed. As stated, the stem  32  of the mounts  22 ,  24  can be tapered. Also, recesses  50  formed in the bases  12 ,  16  can be tapered to a different degree. Moreover, the stems  32  and recesses  30  can assume other interfering structures such one being tapered with respect to the other, the first structure having a straight profile. In either approach, it is contemplated that a connection between the pieces be facilitated by a funneling action. Also, tabs  52  can be formed on the bases which register into recesses provided in the mounts to aid in proper orientation between the parts. It is also to be noted that such structures can be placed on opposite parts or each part can include tabs and recesses. 
         [0069]    In a preferred embodiment, a deformable sleeve  60  is contemplated to facilitate accomplishing a secure engagement between the mounts  22 ,  24  and the bases  12 ,  16 . Thus, the sleeve  60  can act as a sacrificial structure, giving up its original shape to accomplish a locking function. In one embodiment, the sleeve is formed of titanium or a titanium alloy. As with the recesses  50  formed in the bases  12 ,  16  and the stems  32  themselves, the sleeve  60  can have a tapered profile. The tapered profile can either be on an exterior of the sleeve or within its bore. As shown in  FIG. 8 , the sleeve can be sized to be placed within the base recesses  50 , its internal bore configured to securely receive a stem  30 . 
         [0070]    In its assembled configuration, the sleeve  30  deforms about the stem  30  and within the base recesses  50 . To facilitate its insertion into the recesses  50 , the sleeve  30  can include variously spaced and sized annular recesses  62  which present a smaller surface area while the sleeve is moved relative to the recess  50 . The slightly reduced mid-section  34  of the stem  30  also aids in both the relative movement and secure engagement between the sleeve  60  and stem  30 . 
         [0071]    In certain approaches, locking forces ranging between 60-450 pounds or within a smaller range of 60-150 pounds have been found useful. Since taper lock forces are proportional with taper dimensions and surface area, reducing surface area can result in reducing locking forces. Unlocking forces can be 50-150% of locking forces and controlled in a similar fashion. The mount  22  can be unlocked and removed from base  12  by inserting a pry tool between the joining interface of mount  22  to base  12  or by inserting a tool into the opening  13  on base  12  that allows access to the end  33  on the mount  22  such that rotation of the tool (such as an oval-shaped shaft) acts as a cam to push on the end  33  and force the stem  30  out of the base  12 . Similarly, mount  24  can be unlocked and removed from base  16  by inserting a pry tool between the joining interface or by inserting a tool into the opening  17 . 
         [0072]    Next is described various other embodiments and approaches to mounts. The above described features as well as materials, surface finishes, coatings and design requirements can be incorporated as needed into such approaches. 
         [0073]    With reference now to  FIG. 11 , in a further embodiment, a mounting member  110  is coupled to a base component  112  at a first end portion and a link member (not shown) at a second end portion. At the first end, the mounting member  110  includes a coupling connection  116  for securing the mounting member to the base component  112 . As shown in  FIG. 11 , the coupling connection  116  is a dovetail connection. At the second end, the mounting member  110  terminates at a ball component  114 , which is one portion of a ball-and-socket mechanism. Alternatively, the mounting member  110  terminates at a socket component at the second end. 
         [0074]    The mounting member  110  as shown in  FIG. 11  has a generally tapered shape. The body of the mounting member  110  narrows when moving distally (i.e., the mounting member is wider at the connection point between the base component as compared to the width of the mounting member at the ball component  114 ). As shown in  FIG. 12 , the mounting member  110  may also be configured to further offset the ball component  114  (or socket component) away from the bone thereby allowing the link or absorber  118  to avoid bone structures, ligaments, muscles, and the like. The mounting member  110  also allows for proper alignment and orientation of a link or absorber  118  so that the link or absorber can freely move and reduce or remove forces on articulating surfaces of a joint. Comparing the mounting members  110  of  FIGS. 11 and 12 , the mounting members have different shapes. As those skilled in the art will appreciate, different shapes of the mounting members  110  accommodate different types of links or absorbers and allow varying load reduction at a joint. Accordingly, the link or absorber  118  and the mounting member  110  may be varied to better fit patient needs. 
         [0075]      FIGS. 13A-13D  illustrate various embodiments of a coupling connection  120  between the mounting member  110  and a base component  112 .  FIG. 13A  illustrates one embodiment of a tapered dovetail connection  120  between the mounting member  110  and a base component  112 . As shown in  FIG. 13A , the dovetail is provided on the mounting member  110  and a corresponding recess is provided on the base component  112 . Alternatively, the dovetail may be provided on the base component  112  and the corresponding recess is provided on the mounting member  110 . As shown in  FIG. 13A , a set screw  122  is also provided to further secure the dovetail connection  120 . Additionally, a plurality of relief cuts  124  are provided on the dovetail connection  120  in order to reduce the stress concentrations at the root of the dovetail. The dovetail can also include rounded edges to further reduce stress concentrations. 
         [0076]      FIG. 13B  is a cross-sectional view of the dovetail connection  120  of  FIG. 13A . As shown in  FIG. 13B , the set screw  122  forces the mounting member  110  down onto the base component  112 , thereby tightening the dovetail connection  120 . The set screw  122  is inserted into the base component  112  at an angle to improve access to tighten or loosen the screw. 
         [0077]      FIG. 13C  illustrates another locking dovetail connection  120 . The dovetail and corresponding recess are similar as to the dovetail connection shown in  FIG. 13A . As shown, the connection  120  includes a recess  126  adjacent to the connection. A captured cam  128  is provided within the recess  126 . The cam  128  has a rounded edge  130  and a flattened edge  132 . As shown in  FIG. 13C , the mounting member  10  may be separated from the base component  112  since the flattened edge  132  of the cam  128  is aligned with the edge of the mounting member  110 . As shown in  FIG. 13D , the cam  128  can be rotated approximately 90° to 180° to have the rounded edge  130  engage a portion of the mounting member  110  thereby securing the connection between the mounting member  110  and the base component  112 . 
         [0078]      FIG. 14A  illustrates another embodiment of a coupling connection  140  between a base component  112  and a mounting member  110 . The coupling connection  140  is a snap fit connection between the base component  112  and the mounting member  110 . The base component  112  has a shaped protuberance  140  that mates with a corresponding slot  142  on the mounting member  110 . In an alternate embodiment, the mounting member  110  includes the shaped protuberance and the corresponding slot is provided on the base component  112 . Optionally, the snap connection  40  may incorporate locking mechanisms as shown in  FIGS. 13A-13D . 
         [0079]    With reference to  FIG. 14B , yet another embodiment of a coupling connection  144  between a base component  112  and a mounting member  110  is depicted. As shown, the edges of the mounting member  110  and the base component  112  are overlapping. One or more screws  146  to secure the connection between the mounting member  110  and the base component  112 . Again, alternatively, the connection  144  may incorporate locking mechanisms as shown in  FIGS. 13A-13D . 
         [0080]    A friction-fit coupling connection  150  approach between a base component  112  and a mounting member  110  is shown in  FIG. 15 . In this embodiment, the end of the base component  112  includes a bore  152 . The mounting member  110  includes a tapered shaft having a first diameter at a first end (at the tip of the shaft) and a second diameter at a second end (at the base of the shaft) where the second diameter is larger than the first diameter. Locking mechanisms can also be incorporated here. 
         [0081]      FIG. 16  illustrates another embodiment of a coupling connection  160  between a base component  112  and a mounting member  110 . The base component  112  includes a tongue  162  that engages a groove  164  provided on the mounting member  110 . Additionally, the base component  112  and the mounting member  110  may include additional interlocking surfaces  166 ,  168  to further secure the two surfaces together. The tongue  162  includes a tapered locking screw hole  170 , and the groove  164  also includes a screw hole. When the tongue  162  and groove  164  are properly aligned, a screw or other fastening means may be used to secure the tongue within the groove. 
         [0082]    Yet another approach of a coupling connection  172  between a base component  112  and a mounting member  110  is shown in  FIGS. 17A-B . Here, the coupling structure  172  is a dovetail connection where the dovetail is provided on the base component  112  and a corresponding recess is provided on the mounting member  110 . Alternatively, the dovetail may be provided on the mounting member  110  and the corresponding recess is provided on the base component  112 . The dovetail connection includes through holes  174  in the walls of the recess and the dovetail  176 . According to one embodiment, a locking pin  178  having locking threads is threaded through the through holes  174 ,  176  to secure the dovetail connection  172 . In another embodiment, the locking pin  178  is tapered, and the locking pin is press fitted through the holes  174 ,  176  to secure the connection  172 . 
         [0083]    Turning now to  FIGS. 18A-18C , various embodiments of a ball-and-socket connection  180  are depicted. As shown, the connection  180  includes a ball component  182  that is secured within a socket that includes a first socket portion  186  that is secured to a second socket component  188  with one or more screws  190 . As those skilled in the art will appreciate, any fastening means known or developed in the art may be used to couple to the first and second socket portions  186 ,  188 .  FIG. 18C  illustrates a universal connection  192  where the ball component  194  is secured within a one-piece socket  196  via a pin  198 . 
         [0084]    A mounting member  110  terminating at a socket component  200  is shown in  FIG. 19 . The socket component  200  includes a first portion that is integral with the mounting body and a second portion  202  that may be fastened to the first portion via a screw  204  or other securing means. As shown, a ball component  206  is inserted and secured within the socket component  200 . The ball component  206  is coupled to one end of the link or absorber  118 . 
         [0085]    Other ball-and-socket connections that may be used on the end of the mounting member  110  are disclosed in U.S. patent application Ser. No. ______, Attorney docket number 83456.0024, filed on the same date herewith, and entitled “Ball and Socket Assembly,” which is hereby incorporated herein by reference in its entirety, may also be used in combination with the mounting member  110 . 
         [0086]    Referring back to  FIG. 11 , the ball component  114  is provided on the mounting member  110 . In alternate embodiments, the socket portion may be provided on the mounting member as shown in  FIG. 12 . In other embodiments, a portion of other articulating or articulatinging surfaces as disclosed in U.S. patent application Ser. No. 11/775,145, filed on Jul. 9, 2007, which is hereby incorporated herein by reference, may be provided on the mounting member  110 . Additionally, as shown in  FIGS. 11-12 , the ball or socket component is fixed to the mounting member  110 . Accordingly, the ability to adjust the ball or socket location in these embodiments is dependent upon changing the shape of the mounting member  110  or moving the base component  112 . 
         [0087]      FIGS. 20-27B  illustrate various embodiments of a mounting member  110  having an adjustable articulating connection component. The adjustable articulating connection allows a ball or socket component to be moved thereby providing adjustability in the location, alignment, or range of motion of the articulating connection. The adjustability can be used to alter the load carrying capacity of the link or absorber and/or to alter the displacement range of the link or absorber. For example,  FIG. 20  illustrates one embodiment of a rotatable mounting member  110  having a ball component  210  at one end of the member. The mounting member  110  is rotatably fixed to the base component  112 . Accordingly, rotation of the mounting member  110  allows for shifting the connection point for the ball component  210  and socket component (not shown). 
         [0088]      FIG. 21  illustrates another embodiment of a mounting member  110 , which is coupled to a base component  112  which has an adjustable articulating connection component. As shown in  FIG. 21 , the adjustable articulating connection component is a ball component  212 , but the ball component may be a socket component in alternate embodiments. The ball component  212  is coupled to a movable arm  214 . The movable arm  214  is operably connected to a thumbscrew  216  such that rotation of the thumbscrew relative to the teeth  218  causes the movable arm to translate upwards or downwards as indicated by arrow A. Optionally, detents (not shown) may be provided along the mount surface  220 . The detents may be spaced approximately 1 mm apart (or any other fixed distance) thereby providing a plurality of locations for registering the arm  214 . As the movable arm  214  passes the detents, an audible click is emitted thereby providing the end user with an indication that the arm (and ball component) is being linearly translated. In alternate embodiments, a rack and pinion mechanism (not shown) may be used to move the ball component  212 . 
         [0089]    With reference to  FIG. 22A , another embodiment of a mounting member  110  having an adjustable articulating connection is depicted. As shown, the mounting member  110  includes a movable ball component  212 . In an alternate embodiment, the mounting member  110  includes a socket component in place of the movable ball component  212 . A plurality of shims  222  are provided in a recessed area  224  of the mounting member  110 . The shims  222  may be slid in the recess to engage or disengage the ball component  212 . Accordingly, the ball component  212  is raised to the mounting member  110  as shims  222  are positioned below the ball component. Placement of additional shims  222  engaging the ball component  212  moves the ball component away from the body of the mounting member  110 . The shim  222  has a body portion  226  and a lever portion  228 . Optionally, a radiopaque coating is applied to the lever portion  228  and/or the body portion  226  so that the shim may be seen under a fluoroscope to visualize the shims after the mounting member  110  has been fixed within a patient. 
         [0090]    A mounting member  110  having a movable ball component  212  that is positioned above a plurality of compartments  232  is shown in  FIG. 23 . In an alternate embodiment, the mounting member  110  can include a socket component in place of the movable ball component  212 . The compartments  232  are separated by flexible dividers  230 . The dividers  230  are separated at a fixed distance such as, but not limited to, approximately 1 mm. According to one embodiment, one or more of the compartments  232  may be filled with bone paste or other material to set a desired height of the ball component  212  relative to the mounting member  110 . Additionally, a retaining member  234  secures the ball component  212  to the mounting member  110 . 
         [0091]    Turning to  FIG. 24 , a mounting member  110  having a movable ball component  212  is shown. In an alternate embodiment, the mounting member  110  includes a socket component in place of the movable ball component  212 . The ball component  212  is coupled to a shaft having a bore  250 . The shaft of the ball component  212  is deflectable and may compress and expand when a force is applied to the shaft. The bore  250  also includes an annular stop  242 . Additionally, a release pin  248  is slidably coupled within the bore  250 . A spring  244  is coupled to the base of the bore  250  at one end and the release pin  248  at a second end. The shaft includes a plurality of rings  242  on the outer diameter. The rings  242  are spaced a fixed distances such as, but not limited to, approximately 1 mm. The ball component  212  is placed within the bore of the mounting member  110 . The bore of the mounting member  110  also includes a ring stop  246  that extends into the bore of the mounting member. 
         [0092]    In operation, the release pin  248  is depressed until the pin contacts the annular stop  242  with the bore  250 . Any additional force causes the ball component  212  to move from one ring  246  to an adjacent ring. As the force is applied to the release pin  248 , the walls of the shaft deflect to move around king stop  246 . Alternatively, the release pin  248  may be pulled downward until the stop on the outer diameter of the release pin contacts the annular stop  242 . As the downward force is applied to the ball component  212 , the ball component may be lowered from one ring  240  to the next ring. 
         [0093]      FIGS. 25A-C  illustrate another approach to a mounting member  110  having a movable ball component  212 . Again, in an alternate embodiment, the mounting member  110  includes a socket component in place of the movable ball component  212 . In  FIG. 25A , the mounting member  110  includes a ball component  212  that is movable within a main bore  254 . The ball component  212  includes a plurality of rings  254  spaced apart on the shaft of the ball component. As shown in  FIGS. 25A and 25C , the shaft of the ball component  212  has two diameters D 1  and D 2 . 
         [0094]    The mounting member  110  also includes a secondary bore  258  is generally perpendicular to and intersects the main bore  254 . A release lever  256  is slidably mounted within the secondary bore  258 . The release lever  256  is also biased in a closed (or locked) position via a spring  260  provided at end of the secondary bore  258 . As shown in  FIG. 25B , the release lever  256  includes two overlapping openings  260 ,  262  having different radii, R 1  and R 2 , where R 1 &gt;R 2 . 
         [0095]    In order to unlock the ball component  212  (i.e., allow for adjustment of the ball component), the release level is pushed in direction A, which causes the release lever to slide toward the end of the secondary bore  258 . As the lever  256  slides in direction A, the smaller opening  262  is displaced in favor of the larger opening  260 . As a result, the larger opening  260  is centered in the bore  254 . When the larger opening  260  is centered in the bore  254 , the ball component  212  is free to move within the bore  254  as the outer diameter D 1  is able to pass through the larger opening  260  of the lever  256 . Once the height of the ball component  212  is adjusted, the lever  256  is released and the smaller opening  262  is centered in the bore  254  thereby locking the ball component in place. 
         [0096]    Referencing  FIGS. 26A-C , a mounting member  110  having an adjustable articulating connection component includes a bore  267  that accommodates a ball component  212  having a shaft  264  coupled thereto. A socket component can replace the movable ball component  212 . To adjust the height of the ball component  212 , the release lever  266  is actuated upwards (direction of arrow). The upward movement of the release lever  266  articulates a washer  270  such that the inner diameter  268  of the washer is concentric with the shaft  264  as shown in  FIG. 26C . Accordingly, the shaft  264  (and the ball component  212 ) is able to freely move upwards or downwards. On reactivation of the lever  264  (i.e., downward movement of the lever), the inner diameter  268  of the washer  270  portion of the lever is angled with respect to the shaft  264  thereby locking the shaft in place as shown in  FIG. 26B . 
         [0097]      FIGS. 27A-B  depict a mounting member  110  having an adjustable articulating connection similar to the mounting member shown in  FIGS. 26A-C . The mounting member  110  in  FIGS. 27A-B , however, includes a ball component  114  having a shaft  274  coupled thereto. In an alternate approach, the adjustable ball component  212  is substituted for a socket component. The shaft  274  includes a plurality of teeth  276  or ridges on the outer diameter. The shaft  274  can have an elliptical cross-section, but other embodiments of the shaft may have a square, circular, or other polygonal-shaped shaft. 
         [0098]    As shown in  FIGS. 27A-B , the mounting member  110  has a lever  272  that generally follows the contour of the mounting member. The large size of the lever  272  relative to the mounting member  110  allows the lever to be palpitatable through the skin after the device has been implanted, thereby allowing further adjustments after implantation. A first portion  278  of the lever  272  is generally perpendicular to the shaft  274  and includes an opening (not shown) through which the shaft passes. In a default position (i.e., locked position), the first portion of the lever  278  engages the teeth  276  on the shaft  274 . When a force F is applied to the lever  272 , the lever moves downward thereby making the opening of the lever concentric with the shaft  274 . Accordingly, the location of the ball component  212  may be adjusted. Once the lever  272  is released, the walls of the opening on the first portion  278  of the lever engage the teeth  276  thereby locking the ball component  114  in position. 
         [0099]    Accordingly, various embodiments of an articulating assembly which reliably and durably connects a link or an energy absorber structure to an interventional site have been described. The contemplated approaches provide durable surfaces for accomplishing articulating motion without restricting natural ranges of motion of anatomy at the interventional site. Features of certain of the disclosed approaches such as material and surface finishes as well as specific sub-structure can be incorporated into any other of the approaches to provide a patient with a desirable mount assembly and the assemblies can be employed in relevant medical as well as non-medical applications. 
         [0100]    The various embodiments described above are provided by way of illustration only and should not be construed to limit the claimed invention. Those skilled in the art will readily recognize various modifications and changes that may be made to the claimed invention without following the example embodiments and applications illustrated and described herein, and without departing from the true spirit and scope of the claimed invention, which is set forth in the following claims.