Patent Abstract:
An orthopaedic fixation component attachable to a femur, said femur defining a femur shaft, a femur head and a femur neck extending therebetween, said femur further defining a greater trochanter limiting laterally said femur neck, said orthopaedic fixation component comprising: a shaft section fixation portion and an end section fixation portion extending substantially longitudinally therefrom, said shaft section and end section fixation portions being respectively securable to said femur shaft and said greater trochanter; said end section fixation portion including a pair of end arms, said end arms being configured, sized and positioned to delimit a trochanter receiving recess for receiving a prominent portion of said greater trochanter.

Full Description:
[0001]    The present application claims priority from U.S. Provisional Patent Application Ser. No. 61/129,221 filed on Jun. 12, 2008. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to the general field of orthopaedic surgery components and methods and is particularly concerned with an orthopaedic fixation component and method. 
       BACKGROUND 
       [0003]    There exists a wide variety of situations wherein it is desirable to fixate adjacent bone pieces or segments to promote healing of a fracture. Such situations occur, for example, whenever a fragment of the greater trochanteric portion of the femur bone needs to be fixated to the shaft of the femur. 
         [0004]    With the aging demographics of many industrialized countries, hip related surgical procedures are becoming increasingly prevalent. An example of such procedures is the so-called total hip replacement surgery or arthroplasty which is typically performed as a consequence of osteoarthritis of the hip joint. The procedure involves replacing the diseased cartilage and bone of the hip joint with artificial materials including an artificial prosthesis. 
         [0005]    During the procedure, a segment of the greater trochanteric portion of the femoral bone is typically temporarily osteotomized, that is a the greater trochanter is surgically separated from the proximal end of the femur so that the soft tissue attached to the greater trochanter can be moved aside in preparation for implantation of the femoral stem of the replacement prosthesis into the medullar canal of the femoral shaft. Once the femoral stem of the prosthesis is seated within the medullar canal in the femur, the greater trochanter is re-attached to the proximal end of the femur. 
         [0006]    The greater trochanter is subjected to considerable stress imparted thereon by anatomical structures such as muscles attachments during normal use of the hip. Accordingly, mechanical fixation of the greater trochanter to the femoral shaft is mandatory in order to promote healing of the fracture created by the osteotomizing step of the hip replacement procedure or traumatic injury. 
         [0007]    Also, because of the considerable stress imparted on the greater trochanter as a consequence of the total hip arthroplasty procedure, it is estimated that this type of procedure is associated with a relatively high percentage of greater trochanter post-surgical fractures, which, in turn, may require fixation. 
         [0008]    Other examples of situations wherein fixation of the greater trochanter to the femur shaft is required include trochanter and/or proximal femur reconstruction, corrective or revision hip surgery and the like. 
         [0009]    One relatively common prior art method for fixating the greater trochanter to the proximal femur shaft is a so-called “cerclage” fixation technique wherein a flexible member, such as a cable, is drawn tight and clamped in order to encircle the target fixation site and to hold the bone portions together until they have time to heal. 
         [0010]    Typically, the surgical cables are implanted using tensioning devices which apply tension to a surgical cable looped around the bone. Crimps are then added and deformed to clamp the cable loop in place. 
         [0011]    The so-called “cerclage” methods, although somewhat useful, are associated with a number of drawbacks. For example, such procedures are typically considered relatively complex. Furthermore, cable failure, migration or loosening may lead to fixation loss and non-union of the bone fragments with clinical consequences such as pain, lack of functionality and the like. 
         [0012]    Other types of components have been devised in attempts to provide solutions for fixating the greater trochanter to the femur shaft. For example, some components include a bone grip for engaging over the trochanter and a plate portion for extending down over the shaft of the femur. 
         [0013]    A well known typical example of such type of component is the so-called “Cable-Ready” (a registered trade mark) greater trochanteric re-attachment system developed by Zimmer. This system involves the use of a component which has a substantially straight, flat and elongated plate portion, integral with a hooked portion terminating in a spike. Ideally, the hooked grip portion lies over the greater trochanter, and the plate portion overlies the shaft of the femur. Both portions have apertures to receive “cerclage” cables, which are passed around the bone, to secure the device in place. 
         [0014]    Again, although somewhat useful, such devices also suffer from numerous drawbacks. Indeed, as is well known, the greater trochanter lies laterally, close to the skin, and can be easily palpated on the lateral side of the thigh. Because it is the most lateral point of the hip region, the greater trochanter may cause discomforts when lateral pressure is exerted on the side of the body such as when an individual lies on his or her side on a hard surface. Most prior art fixation plates increase the discomfort by being located over the most prominent portion of the greater trochanter. Also, some prior art devices require that relatively large incisions be performed in large leg muscles to position them properly over the greater trochanter, with all the discomfort and risk for complications associated with such operations. 
         [0015]    Accordingly, there exists a need for an improved orthopaedic fixation component and it is a general object of the present invention to provide such an improved orthopaedic fixation component. 
       SUMMARY OF THE INVENTION 
       [0016]    In a broad aspect, the invention provides an orthopaedic fixation component attachable to a femur, said femur defining a femur shaft, a femur head and a femur neck extending therebetween, said femur further defining a greater trochanter limiting laterally said femur neck, said orthopaedic fixation component comprising: a shaft section fixation portion and an end section fixation portion extending substantially longitudinally therefrom, said shaft section and end section fixation portions being respectively securable to said femur shaft and said greater trochanter; said end section fixation portion including a pair of end arms, said end arms being configured, sized and positioned to delimit a trochanter receiving recess for substantially fittingly receiving a prominent portion of said greater trochanter. 
         [0017]    The proposed orthopaedic fixation component is intended to be used in particular with generally elongated bones such as the femur and in particular for greater trochanteric re-attachment although other applications are within the scope of the present invention. 
         [0018]    The proposed orthopaedic fixation component provides a variety of advantages for both the surgeon and the intended patient, some of which are disclosed in greater details at the end of the detailed description portion of the present application. In short, the proposed orthopaedic fixation component is designed so as to improve fixation while reducing post-operative complications. 
         [0019]    The present invention also relates to a method of using an orthopaedic fixation component in order to also improve fixation while reducing post-operative complications. 
         [0020]    Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    An embodiment of the present invention will now be disclosed, by way of example, in reference to the following drawings, in which: 
           [0022]      FIG. 1 , in a perspective view, illustrates an orthopaedic fixation component in accordance with an embodiment of the present invention operatively mounted on a femoral bone, only a proximal portion of which is shown; 
           [0023]      FIG. 2 , in a front view, illustrates the orthopaedic fixation component and femoral bone shown in  FIG. 1 ; 
           [0024]      FIG. 3 , in a perspective view similar to that of  FIG. 1 , illustrates the insertion within the bone of some of the attachment screws used with the orthopaedic fixation component in accordance with the present invention; 
           [0025]      FIG. 4   a , in a transversal cross-sectional view taking along arrows A-A of  FIG. 3 , illustrates the spatial relationship between the inserted attachment screws shown in  FIG. 3 ; 
           [0026]      FIG. 4   b , in a transversal cross-sectional view taking along arrows B-B of  FIG. 3 , illustrates the spatial relationship between shaft attachment screws shown in  FIG. 3  and the stem of a replacement prosthesis; 
           [0027]      FIG. 5 , in a top view, illustrates some of the features of the proximal portion of the orthopaedic fixation component in  FIGS. 1 through 4  when the latter is anchored to the femoral bone shown in  FIGS. 1 through 3 ; 
           [0028]      FIG. 6 , in a front view, illustrates the orthopaedic fixation component shown in  FIGS. 1 through 5 ; 
           [0029]      FIG. 7 , in a transversal cross-sectional view, illustrates the cross-sectional configuration of an end arm, part of the orthopaedic fixation component, the cross-section being taken across line C-C of  FIG. 6 ; and 
           [0030]      FIG. 8 , in a transversal cross-sectional view, illustrates the cross-sectional configuration of an end arm, the cross-section being taken along lines D-D of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    Referring to  FIG. 1 , there is shown, in a perspective view, a fixation component in accordance with an embodiment of the present invention, generally indicated by the reference numeral  10 . The fixation component  10  is shown, by way of example, mounted to a femur generally indicated by reference numeral  12 . It should, however, be understood that the fixation component  10  is only shown mounted to a femur  12  by way of example and that the fixation component  10  could be used for fixating or securing bone segments located at other anatomical regions without departing from the present invention. 
         [0032]    More specifically, the fixation component  10  is particularly well adapted to be used at anatomical regions involving substantially elongated bones defining a corresponding bone end region. By way of non limitative examples, the fixation component  10  could, for example, be used in applications involving the distal femur, the proximal tibia as well as the proximal and distal humerus regions. 
         [0033]    As is well known, the femur  12  is an elongated bone. As shown in  FIGS. 1 through 3 , the femur  12  includes a body or shaft  14  defining a pair of longitudinally opposed extremities or ends (only the proximal one of which is shown in the Figures). The body or shaft  14  of the femur is slightly bowed inferiorly and is narrowest at its mid-point. Its middle two quarters are approximately circular in transverse section. The distal end (not shown) of the femur shaft  14  is broadened by medial and lateral condyles where it articulates with the tibia and patella to form the knee joint. 
         [0034]    The proximal end, shown in  FIG. 1 , includes a femur head  16 , a femur neck  18 , a greater trochanter  20  and a lesser trochanter  22 . As is also well known, the femur head  16  is typically smooth and forms 2/3  of a sphere. It is directed medially, superiorly, and slightly inferiorly to fit into the acetabulum of the hip bone (not shown). 
         [0035]    The femur neck  18  connects the femur head  16  to the femur body or shaft  14 , typically at an angle of approximately 125 degrees. The femur neck  18  is limited laterally by the greater trochanter  20  and is narrowest in diameter at its mid-section. A broad, rough inter-trochanteric line runs infero-medially from the greater trochanter. This inter-trochanteric line passes inferior to the lesser trochanter and becomes continuous with the spiral line on the posterior aspect of the femur. 
         [0036]    The inter-trochanteric line is produced by the attachment of the massive illio-femoral ligament (not shown). The inter-trochanteric line separates the interior surface of the femur neck  18  from the femur body or shaft  14  of the femur  12 . A prominent ridge, the inter-trochanteric crest, unites the two trochanters  20 ,  22  posteriorly. 
         [0037]    In the anatomical position, a line joining the tips of the greater trochanters  20  normally passes through the center of the femur heads  16  (only on of which is shown) and the pubic tubercles (not shown). As shown more specifically in  FIG. 2 , the greater trochanter  20  of the femur  12  is a substantially large, somewhat rectangular projection from the junction of the femur neck  18  and the femur body  14 . It provides an attachment for several muscles of the gluteal region. Some of these muscular attachments are illustrated schematically in  FIG. 1 . 
         [0038]    As is well known, both the gluteus medius and the gluteus minimus are used for abduction and medial rotation of the thigh as well as to steady the pelvis. The distal attachment of the gluteus medius is typically located on the lateral surface of the greater trochanter  20  while the distal attachment of the gluteus minimus is typically located on the anterior surface of the greater trochanter  20 . 
         [0039]    The obturator internus and the gemelli, superior and inferior, are used for laterally rotating the extended thigh and abducting the flexed thigh. They are also used to steady the femur head  16  in the acetabulum (not shown). Both the obturator internus and the gemini superior and inferior have their distal attachment on the medial surface of the greater trochanter  20 . 
         [0040]    Another muscle having its distal attachment on the greater trochanter  20  is the piriformis muscle attached to the superior border of the greater trochanter  20 . It should be understood that the muscular insertions illustrated in  FIG. 1  are rough schematic representations of the three major muscle groups hereinafter discussed and should only be considered an approximation of the actual anatomical reality. 
         [0041]    Referring now more specifically to  FIG. 6 , there is shown in greater details some of the features of the fixation component  10 . In general terms, the fixation component  10  includes a shaft section fixation portion  24  and a substantially longitudinally and integrally extending end section fixation portion  26  for being respectively secured to a corresponding shaft section and a corresponding end section of bone such as the femur shaft  14  and the greater trochanter  20  shown in  FIG. 1 through 3 . 
         [0042]    In the preferred embodiment, the fixation component  10  has a generally asymmetrical “Y”-shaped configuration defining a shaft arm generally indicated by the reference numeral  28  attached to a pair of end arms generally indicated by the reference numerals  30  and  32 . 
         [0043]    The end arms  30 ,  32  typically extend integrally from the shaft arm  28  although they may be permanently or reversibly attached to the latter without departing from the scope of the present invention. Also, in the embodiment shown throughout the Figures, the shaft arm  28  and the end arms  30 ,  32  are rigidly secured to each other in a substantially stable spatial relationship relative to each other. 
         [0044]    However, in other embodiments of the invention (not shown) the shaft arm  28  and the end arms  30 ,  32  could be pivotally, slidably or otherwise movably connected to each other so as to allow for selective spatial movement therebetween in predetermined combinations. For example, both end arms  30 ,  32  could be fixedly secured to each other while being movably secured to the shaft arm  28 . Alternatively, the end arms  30 ,  32  could be movable relative to each other. 
         [0045]    In instances wherein the shaft arm  28  and/or the end arms  30 ,  32  are movable relative to each other, the fixation component  10  may further be provided with arm movement preventing means for either permanently or releasably selectively preventing the relative movements between the shaft arm  28  and one or both of the end arms  30 ,  32 . 
         [0046]    The end arms  30 ,  32  are typically configured, sized and positioned so as to diverge away from each other, together forming a substantially asymmetrical V-shaped configuration. Each one of the end arms  30 ,  32  has a substantially elongated configuration defining a corresponding end arm proximal section  34  and a longitudinally opposed end arm distal section  36 . Typically, the end arm distal sections  36  of each end arm  30 ,  32  merge integrally with each other. 
         [0047]    Each one of the end arms  30 ,  32  also defines a corresponding end arm outer edge  38  and a substantially transversely opposed end arm inner edge  40 . The end arm inner edges  40  together define a trochanter receiving recess  42  extending therebetween for receiving at least a selected portion of the greater trochanter  20 . The selected portion of the greater trochanter  20  adapted to be received within the trochanter receiving recess  42  is typically a particularly prominent or protruding portion  44  (seen in  FIG. 1 ) of the greater trochanter  20 . 
         [0048]    One of the main features of the present invention resides in that the end arms  30 ,  32  are configured, sized and positioned such that the trochanter receiving recess  42  substantially fittingly receives the prominent portion  44  of the greater trochanter  20 . More specifically, the end arms  30 ,  32  are configured, sized and positioned such that the opposed end arms inner edges  40  substantially partially encircle the prominent portion  44  of the greater trochanter  20 . 
         [0049]    The end arm inner edges  40  typically merge with each other about their respective end arm distal sections  36  so as to form a nadir  46 . The end arms  30 ,  32  are typically further configured, sized and positioned such that the nadir  46  is located substantially underneath the prominent portion  44  of the trochanter  20  when the fixation component  10  is operatively mounted on the femur  12 . 
         [0050]    Another feature of the present invention resides in that the end arms  30 ,  32  are configured, sized and positioned relative to each other so as to optimize the retaining action exerted thereby on the greater trochanter  20  so as to prevent relative movement between trochanteric portions and lessen the probability of creating a secondary fracture. 
         [0051]    The end arms  30 ,  32  provide a multi-directional holding action adapted to cancel out the tendency of the three major muscles of which the distal insertion is shown in  FIG. 1  tending to exert a pulling action upon the greater trochanter  20  along multiple vectorial directions. This holding action prevents the trochanteric portions from being pulled in any one of the vectorial directions and, in particular, any one of the three major directions illustrated in  FIG. 1 . The specific configuration, size and position of the end arms  30 ,  32  is also adapted to take into account that there is an intense and strong pull, particularly of the abductor muscles of the hip during normal activities of daily living such as ambulation. 
         [0052]    The end arms  30 ,  32  are each provided with an end arm attachment means for attaching or anchoring the end arms  30 ,  32  to the greater trochanter  20 . In the preferred embodiment, the end arm attachment means includes at least one and preferably two end arm fastening apertures  48  extending through corresponding end arms  30  or  32 . 
         [0053]    Each end arm fastening aperture  48  is adapted to receive a corresponding fastening component such as an end arm bone screw  50  (seen for example in  FIG. 1 ). Typically, each end arm fastening aperture  48  has a substantially countersunk portion. Typically, although by no means exclusively, the end arm bone screws  50  are of the self-locking type. Self-locking type screws are typically preferred, at least in part, because of the relatively thin layer of the cortex of the bone in the regions of the greater trochanter  20 . 
         [0054]    As illustrated more specifically in  FIG. 3 through 5 , the configuration, size and position of the end arms  30 ,  32  and their corresponding end arm fastening apertures  48  is such that the end arm bone screws  50  provide an entrapment effect for further preventing trochanteric portions from being fractured or pulled out by various forces acting thereon. 
         [0055]    The configuration, size and position of the end arms  30 ,  32  is also chosen in order to take into consideration the position of the insertion of the main muscle attachments on the greater trochanter  20 . 
         [0056]    Referring back to the schematically illustrated muscular insertions of  FIG. 1 , it can be seen, the end arms  30 ,  32  are configured, sized and positioned so that their respective inner and outer peripheral edges  40 ,  38  substantially clear these muscular attachments or, at least, minimally interfere therewith so as to reduce the risks of clinical problems once the fixation component  10  is operationally attached to the femur  12  and also so as to facilitate the anchoring of the fixation component  10  to the femur  12  during surgery. 
         [0057]    As shown more specifically in  FIG. 6 , the end arms  30 ,  32 , typically diverge away from each other in a proximal direction so as to define an end arm angle “A” therebetween, Typically, although by no means exclusively, the end arm angle “A” has a value of between 60 and 120 degrees. 
         [0058]    Another feature of the present invention resides in the cross-sectional configuration of at least one and preferably both end arms  30 ,  32 . As illustrated more specifically in  FIGS. 7 and 8 , each end arm  30 ,  32  preferably has a substantially concave end arm inner surface  51  and a substantially convex end arm outer surface  52 . Also, each of the end arms  30 ,  32  is also provided with substantially rounded end arm inner and outer edges  40 ,  38 . 
         [0059]    The substantially concave end arm inner surface  51  is typically variable along the length of the end arms  30 ,  32  and adapted to allow for an improved contact engagement between the end arm inner surfaces  51  and the substantially convex outer surface of the greater trochanter  20 . 
         [0060]    The substantially arc-shaped cross-sectional profile of the end arms  30 ,  32  is also adapted to increase the structural strength thereof and, hence, allow for minimization of the overall thickness of the end arms  30 ,  32  for a given material and considering given auxiliary geometrical variables. The optimized fit between the contact surfaces of the end arm inner surface  51  and the outer surface of the greater trochanter  20  combined with the relatively small cross-sectional distance between the end arm inner and outer surfaces  51 ,  52  is adapted to provide greater comfort to the patient with reduced risks of clinical complications. 
         [0061]    As illustrated more specifically in  FIGS. 1 through 5 , the end arm proximal portion  34  of at least one and typically both end arms  30 ,  32  typically curves inwardly so as to substantially override at least a portion of the greater trochanter  20  and in operational position provide a retaining means against axial displacement of portions thereof. 
         [0062]    Also, at least one and preferably both of the end arms  30 ,  32  typically taper proximally so as to define a corresponding substantially pointed anchoring apex  53 . Typically, the pointed apex  53  is adapted to be inserted into the cortical portion of the upper portion of the greater trochanter  20 . Typically, although by no means exclusively, the distance D between the apex  53  and the nadir  46  has a value of between 40 and 70 millimetres. 
         [0063]    Alternatively, in an embodiment of the invention not shown, the end arm proximal portion  34  of at least one of the end arms  30 ,  32  could be deprived of a pointed apex  53  and/or made out of a substantially deformable material so as to allow the surgeon to bend the latter to a suitable shape for increasing the retention characteristics thereof. 
         [0064]    Referring back to  FIGS. 1 through 3  and  6 , there is shown that the shaft arm  28  typically has a substantially elongated configuration defining a shaft arm longitudinal axis  55  (shown in  FIG. 6 ). Another feature of the present invention resides in that the substantially V-shaped configuration formed by the end arms  30 ,  32  is preferably substantially or laterally offset relative to the shaft arm longitudinal axis  55 . 
         [0065]    Since the main muscular attachments to the greater trochanter  20  are located substantially anteriorly, the end arms  30 ,  32  are typically offset substantially posteriorly relative to the shaft arm longitudinal axis  55  so as to reduce the risk of interference or obstruction with the muscles attached to the greater trochanter  20 . Typically, as illustrated throughout the Figures, the end arm  32  being operatively mounted more anteriorly than the end arm  30 , the end arm  32  is positioned so as to extend at lesser angle relative to the shaft longitudinal axis  55  than the end arm  30 . 
         [0066]    The shaft arm  28  is provided with a suitable shaft arm attachment means for attaching the shaft arm  28  to the femur shaft  14 . In the embodiment shown throughout the Figures, the shaft arm attachment means includes shaft arm attachment apertures  54  for receiving suitable attachment components such as shaft arm screws  56  (seen for example in  FIG. 1 ). The shaft arm attachment apertures  54  are typically provided with a countersunk section. 
         [0067]    Each shaft arms attachment aperture  54  typically extends through a corresponding shaft arm flange or tab  58  extending integrally and substantially laterally from the shaft arm  28 , The shaft arm flanges or tabs  58  and their corresponding shaft arm attachment apertures  54  are positioned in an offset relationship relative to each other so as to prevent the shaft arm screws  56  from interfering with each other when the fixation component  10  is operatively mounted. 
         [0068]    Typically, the shaft arm tabs  58  and corresponding shaft arm attachment apertures  54  are grouped in pairs with members of a given pair extending in laterally opposite and longitudinally offset relationships relative to each other. 
         [0069]    As illustrated more specifically in  FIG. 4   b , the shaft arm attachment apertures  54  are positioned so as to no only provide sufficient clearance between the shaft arm screws  56  but also to so as to reduce the risks of interference with the femoral stem  60  of a hip replacement prosthesis when the fixation component  10  is used on a femur  12  having such a prosthesis. 
         [0070]    The shaft arm attachment means typically further includes “cerclage” cable channels  66  extending substantially transversely across the shaft arm  28  for receiving “cerclage” cables  68 . Typically, although by no means exclusively, a pair of cerclage cable channels  66  extends through the shaft arm  28  proximally to each pair of shaft arm attachment apertures  54 . 
         [0071]    The fixation component  10  could be provided with “cerclage” cables  68  already having a portion thereof secured to the shaft arm  28  or be simply adapted to receive conventional “cerclage” cables such as the Zimmer Co—Cr cables. 
         [0072]    Alternatively, the fixation component  10  could be provided with or used in conjunction with a “cerclage” cable  68  made out of a super-elastic material. Preferably, although by no means exclusively, the super-elastic “cerclage” cable could be of the type having a braided tuberous structure. Such a cable is described in the PCT application bearing Serial No. PCT/CA2005/001859, naming Brailovski et al as inventors, the entire content of which is expressly incorporated herein by reference thereto. 
         [0073]    Super-elastic cables having a braided tuberous structure provide a synergistic advantage when used with the hereinabove disclosed fixation component  10  by reducing the contact pressure on connected bones and maintaining compression between fragments during the fracture healing period. 
         [0074]    In use, the specific configuration and size of the various sections of the fixation component  10  allows a surgeon to position the fixation component  10  on the femur  12  of an intended patient in such a manner that the end arms  30 ,  32  are strategically positioned to reduce the risk of having portions or fragments of the greater trochanter  20  being displaced or pulled out of alignment relative to their optimal anatomical relationship with the femur shaft  14 . 
         [0075]    The configuration, size and relative position of the end arms  30 ,  32  relative to the shaft arm  28  take into consideration both the orientation and magnitude of the forces exerted by the muscles attached to the greater trochanter  20  and the insertion location of such muscles in order to reduce the risk of interference therewith. 
         [0076]    The retaining action exerted by the end arms  30 ,  32  on portions or fragments of the greater trochanter  20  is compounded by the strategic location of end arm fastening apertures  48  adapted to receive self-locking bone screws oriented to provide an entrapment effect. 
         [0077]    Furthermore, the configuration of the fixation component  10  is designed in such a manner that the outward radial protrusion of the end arms  30 ,  32  away from the greater trochanter  20  is also minimized. Indeed, as mentioned previously, the end arms  30 ,  32  are configured, sized and positioned relative to the shaft arm  28  in such a manner that they create a trochanter receiving recess therebetween, the trochanter receiving recess  42  being, in turn, configured and sized for substantially fittingly circumventing the prominent portion  44  of the greater trochanter  20 . 
         [0078]    Also, as mentioned previously, the configuration of the end arms  30 ,  32 , including their cross-sectional configuration, is such that the fit with the surface of the greater trochanter  20  is optimized and the structural characteristics of the end arms  30 ,  32  is improved, allowing for a thinner structure. The avoidance of the prominent portion  44  of the greater trochanter  20  synergistically combined with the improved contact with the greater trochanter  20  and the relatively thin profile reduces the protrusion of the end arms  30 ,  32  from the femur  12  translates not only into an improved aesthetical appearance but also a greater comfort for the patient. 
         [0079]    The shaft arm attachment means provided with the fixation component  10  allows the latter to be used with a wide variety of patients including patients requiring total hip arthroplasty prosthesis. Indeed, the strategic positioning of the shaft arm attachment apertures  54  allows for a suitable number of shaft arm screws  56  to be used in order to solidly anchor the shaft arm  28  to the femur shaft  14  while reducing the risk of interference of the shaft arm screws  56  not only with adjacent shaft arm screws  56  but also with the femoral stem  60  of a hip replacement prosthesis inserted within the medullary canal of the femur  12  such as shown in  FIG. 4   b.    
         [0080]    Furthermore, the “cerclage” cable channels  66  allow for the use of either conventional “cerclage” cables  68  or so-called super-elastic cables  68 . The use of super-elastic cables  68  and, in particular, super-elastic cables  68  having a braided tubular structure provides a synergistic effect when combined with the other features of the fixation component  10 . 
         [0081]    By reducing the contact pressure on contacted bones, these cables  68  allow for the fixation component  10  to be used with patients having particularly fragile bone structures. Also, such cables  68  are adapted to maintain a compression force between fragments during the fracture healing period which is particularly crucial with such patients. 
         [0082]    Furthermore, the positioning of the “cerclage” cable channels  66  in an alternating fashion with pairs of shaft arm attachment apertures  54  provides an optimal distribution of force exerted on the bone structure for obtaining secure anchorage while reducing the risk of traumatizing the femur shaft  14 . 
         [0083]    The present invention also relates to a method of using an orthopaedic fixation component such as the hereinabove disclosed fixation component  10  or other suitable fixation components. The orthopaedic method, in accordance with the present invention, includes positioning a fixation component to a bone structure defining a bone shaft and a bone end section having a prominent region in such a manner that the fixation component substantially avoids the prominent section while providing an efficient retaining action for preventing relative displacement between the bone structures. 
         [0084]    The proposed orthopaedic method also includes as an independent or combined step the use of a “cerclage” cable made out of a super-elastic material for attaching the fixation component to the bone. Preferably, the step of using a “cerclage” cable includes using a super-elastic “cerclage” cable having a braided structure for attaching the fixation component to the bone structure. 
         [0085]    Although the present invention has been described hereinabove by way of preferred embodiments thereof, it can be modified, without departing from the spirit and nature of the subject invention as defined in the appended claims.

Technology Classification (CPC): 0