Abstract:
A curved positioning and insertion instrument for inserting a guide wire into the femur has a curved guide tube with a distal end to be placed on the trochanter and/or the medial muscle and a proximal end for inserting a guide wire. The instrument also has a holding arm that links the guide tube to a handle. A positioning hook fitted with at least one correction bore for receiving the guide wire or another guide wire is arranged at the distal end of the guide tube. This structure makes it possible to easily insert further or additional guide wires relative to a reference guide wire.

Description:
RELATED APPLICATION DATA 
     The present application is a continuation of the U.S. National Stage designation of co-pending International Patent Application No. PCT/IB2004/000624, filed Mar. 8, 2004, which claims priority to Swiss Patent Application Nos. 01395/03, filed Aug. 13, 2003, and 00026/04, filed Dec. 23, 2003, the entire content of which are expressly incorporated herein by reference thereto. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a curved positioning and insertion instrument for inserting a guide wire into the femur for precise bone opening. 
     BACKGROUND OF THE INVENTION 
     Precise bone opening requires a reliable reference in position and direction which a surgeon with a drill or cutter can use as a guide. It is known that guide wires which are inserted (drilled or tapped) into the femur prior to drilling in order to guide the drill safely are used for this purpose. 
     U.S. Pat. No. 6,074,392 describes such a curved positioning and insertion instrument for inserting a guide wire into the femur, comprising a curved guide tube having a distal end for placing on the trochanter and a proximal end for pushing in a guide wire, comprising a retaining arm for the connection between the guide tube and a handle. This design has been chosen because the insertion of a guide wire along a curve is advantageous with regard to the anatomy of the human femora, and the tissue in the affected region is therefore impaired to a lesser extent during an operation. 
     U.S. Pat. No. 6,074,392 therefore describes an instrument design comprising a key element which consists of a curved guide tube for a curved guide wire. This guide wire is inserted into the bone and serves as a guide path for a hollow and flexible drill. The guide wire is mounted with the aid of a positioning and insertion instrument, the curved guide tube being mounted by means of a support part on a handle which can be properly held by the surgeon. The exact positioning of the guide tube is implemented by means of X-rays or by direct inspection. After positioning, the guide wire is hammered in along the longitudinal axis of the bone or driven in in another manner. Thereafter, the insertion instrument is removed and the flexible drill or cutter is passed over the guide wire. After drilling is complete, everything is removed. 
     However, the weak point of this solution is that there is no particular possibility for correction if the X-ray image shows that the guide wire is not optimally positioned. 
     In a completely different design, for example according to U.S. Pat. No. 5,951,561, a guide instrument which has the possibility of correction of guide wires is also described. However, this design consists of a bulky sheath which receives a rotary cylindrical component comprising a plurality of discs each having a plurality of holes, which have to be oriented concentrically with one another in a complicated production process and in addition provide no possibility for tapping a guide wire along a curve into the femur. To this extent, this design offers no improvement for a design according to the generic type. 
     It is now the object of the invention to permit corrections by means of a simple device, the intention being to impair the tissue in the affected region as little as possible. For this reason, as already noted above, the person skilled in the art would not at all have used U.S. Pat. No. 5,951,561 as prior art for achieving the present object. It is also comprehensible that U.S. Pat. No. 6,074,392 published in 1998 is itself a further development of U.S. Pat. No. 5,624,447 published in 1997, while U.S. Pat. No. 5,951,561 was published in the same year as U.S. Pat. No. 6,074,392 and therefore followed another parallel route for setting guide wires. 
     Further but less relevant documents relating to the prior art are U.S. Pat. Nos. 4,466,429; 3,439,671; 5,135,527; 5,112,336; 4,712,541; and 6,273,892. 
     SUMMARY OF THE INVENTION 
     In order to achieve the object, the inventor now presents a novel positioning and insertion instrument which comprises a handle which is arranged by means of a retaining arm on a curved guide tube. At the end thereof there is a positioning hook with, if appropriate, a guide bore which is oriented at an angle of 6°-30°, preferably 7°-20°, in particular about 8°, relative to the guide tube. In addition to this bore, various correction bores are present, according to an improved further development. Furthermore, a T-handle is required when the instrument according to the invention is used. The invention thus makes it possible to insert at least one guide wire which subsequently guides an opening drill. Instead of a T-handle or a motorized drilling or tapping drive, it is also possible to provide an impact head so that the guide wire can be hammered in. 
     According to the invention, during use in practice, the guide tube is, if appropriate, first loaded with a reference guide wire. The handle of the positioning and insertion instrument is then aligned by visual inspection approximately parallel to the longitudinal axis of the femur and with the extension of the intramedullary canal thereof. The positioning hook is placed on the trochanter and the nose of the hook is forced by pressure in the medial direction into the muscle (gluteus medius), the reference guide wire being inserted parallel to the longitudinal axis of the femur. The instrument is removed. Thereafter, the guide tube of the positioning and insertion instrument is loaded with an opening guide wire and, according to this method of use, the guide bore in the positioning hook is pushed over the reference guide wire and thus once again placed on the trochanter. Because the guide bore in the positioning hook is set at about 8°, the positioning and insertion instrument becomes aligned accordingly in order to give the opening guide wire the correct angle. This procedure is carried out because it is more difficult to estimate a certain angle visually than a parallelism. If, however, the reference guide wire were to happen to fit the first time, it would also be possible to use it as an opening guide wire. As a rule, however, it is expected that a second guide wire has to be set as the opening guide wire. 
     A number of embodiments without a guide bore dispenses with the insertion of the reference guide wire and ensures the placing of the positioning and insertion instrument at the correct site and angle by the particular characteristics of its positioning hook which are adapted to the anatomical conditions. The design of these hooks is therefore chosen so that, when gently pressed into the medial muscle and when placed on the trochanter, the hook comes to rest in the optimum position for insertion of the opening guide wire in the majority of applications. The nose is designed so that it can be pressed into the medial muscle while protecting soft tissue. Its thickness is about 0.5-10 mm, preferably about 1-5 mm and in particular about 2.5 mm. The length between the centre of the guide tube and the tip of the nose of the positioning hook may vary, depending on the soft tissue situation, between about 10-30 mm, preferably about 15-25 mm, and is in particular about 20 mm. The correction bores have a diameter of about 1-5 mm, preferably about 1.8-3.6 and in particular about 3.3 mm. The receptacle for the guide tube is about 3-20 mm, preferably about 6-10 mm and in particular about 8 mm. 
     If the opening guide wire is also inserted into the trochanter, it is approximately at an optimum angle of about 8° relative to the reference guide wire in the frontal plane at its insertion point. X-ray images can now confirm whether the opening guide wire is in the correct position for implementing the opening. However, if it is, for example, too close to the lateral cortex there is according to the invention the possibility of a correction with the aid of the positioning and insertion instrument. This is then pushed with one of its correction bores over the reference or opening guide wire and a further, previously loaded, opening guide wire is inserted in a new position into the trochanter. The old opening guide wire which was not correctly positioned can then be removed. If required, such a correction measure can be made on the basis of the only set reference guide wire by directly pushing a correction bore, instead of the guide bore, onto the reference guide wire. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further developments of the invention are indicated in the figures and in the dependent patent claims. The list of reference numerals following the detailed description is part of the disclosure. The invention is explained in more detail schematically and by way of example on the basis of the figures. 
       The figures are described in relation to one another and as a whole. Identical reference numerals denote identical components, and reference numerals with different indices indicate functionally identical or similar components. 
         FIG. 1  schematically shows the positioning and insertion instrument having a T-handle, guide wires and an opening drill; 
         FIG. 2  schematically shows the positioning and insertion instrument with loaded guide wire; 
         FIG. 3   a  schematically shows the positioning hook of the positioning and insertion instrument with its guide and correction bores and the nose for retention in the medial muscle in frontal view or anterior/posterior view. 
         FIG. 3   b  schematically shows the positioning hook of the positioning and insertion instrument with its guide and correction bores and the nose for retention in the medial muscle in view A according to  FIG. 3   a;    
         FIG. 4  schematically shows the positioning and insertion instrument with guide wire and T-handle, placed on the trochanter and ready for drilling, in frontal view or anterior/posterior view; 
         FIG. 5  schematically shows the positioning and insertion instrument loaded with the opening guide wire and pushed over the reference guide wire; 
         FIG. 6  schematically shows the positioning and insertion instrument with T-handle, loaded with the opening guide wire, moved over the reference guide wire and placed again on the trochanter and ready for drilling; 
         FIG. 7  schematically shows the opening drill pushed over the opening guide wire and with T-handle ready for drilling; 
         FIG. 8  schematically shows an X-ray image of the femur with inserted guide wire; 
         FIG. 9  schematically shows an X-ray image of the femur with inserted reference guide wire and opening guide wire to be inserted; 
         FIG. 10  schematically shows an X-ray image of the femur with inserted reference guide wire and inserted opening guide wire; 
         FIG. 11  schematically shows an X-ray image of the femur with inserted opening guide wire and without or optionally with removed reference guide wire; 
         FIG. 12  schematically shows an X-ray image of the femur with non-optimally positioned first opening guide wire and second opening guide wire for correction; 
         FIG. 13  schematically shows an X-ray image of the femur with correctly set opening guide wire; 
         FIG. 14  schematically shows an X-ray image of the femur with opening bore; 
         FIG. 15   a  schematically shows the positioning hook of the positioning and insertion instrument without guide bore and with its correction bores and the nose for retention in the medial muscle in frontal view or anterior/posterior view; 
         FIG. 15   b  schematically shows the positioning hook of the positioning and insertion instrument without guide bore and with its correction bores and the nose for retention in the medial muscle in view A according to  FIG. 15   a;    
         FIG. 16   a  schematically shows the positioning hook of the positioning and insertion instrument without guide bore and with its correction bores and the nose for retention in the medial muscle in frontal view or anterior/posterior view; 
         FIG. 16   b  schematically shows the positioning hook of the positioning and insertion instrument without guide bore and with its correction bores and the nose for retention in the medial muscle in view A according to  FIG. 16   a;    
         FIG. 17   a  schematically shows the positioning hook of the positioning and insertion instrument without guide bore and with its correction bores and the nose for retention in the medial muscle in frontal view or anterior/posterior view; 
         FIG. 17   b  schematically shows the positioning hook of the positioning and insertion instrument without guide bore and with its correction bores and the nose for retention in the medial muscle in view A according to  FIG. 17   a;    
         FIG. 18   a  schematically shows the positioning hook of the positioning and insertion instrument without guide bore and with its correction bores and the nose for retention in the medial muscle in frontal view or anterior/posterior view; 
         FIG. 18   b  schematically shows the positioning hook of the positioning and insertion instrument without guide bore and with its correction bores and the nose for retention in the medial muscle in view A according to  FIG. 18   a;    
         FIG. 19   a  schematically shows the positioning hook of the positioning and insertion instrument without guide bore and with its (additional) correction bores and the nose for retention in the medial muscle in frontal view or anterior/posterior view; and 
         FIG. 19   b  schematically shows the positioning hook of the positioning and insertion instrument without guide bore and with its (additional) correction bores and the nose for retention in the medial muscle in view A according to  FIG. 19   a.    
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows the individual components which as a rule are required in using the instrument according to the invention. The positioning and insertion instrument  1  consists of a curved guide tube  2 , at the distal end of which a positioning hook  3  is arranged. The curvature of the guide tube  2  describes a radius of about 300 to 800 mm, preferably 500 to 700 mm, in particular about 600 mm. The positioning hook  3  is formed in such a way that it is retained on the tip of the greater trochanter and the medial muscle. In the region of the proximal end of the guide tube  2 , mounted approximately perpendicularly thereto, is a retaining arm  4  which then curves in order to run approximately parallel to the guide tube  2 . A handle  5 , the longitudinal axis of which is approximately parallel to a tangent to the guide tube  2  in the region of the positioning hook  3 , is present at the end of the retaining arm  4 . Furthermore,  FIG. 1  shows two guide wires  50  which are such that they can be inserted into the guide tube  2  and can be used either as reference guide wire  50   a  or as opening guide wire  50   b . In addition a hollow opening drill  20  is shown, which is formed in such a way that it can be passed over a guide wire  50  and can be operated by a T-handle  30 . Finally,  FIG. 1  shows the above mentioned T-handle  30  with a lever  32  and a drill chuck, which fits both onto the guide wires  50  and on to the opening drill  20 . Of course, motor-driven drilling and tapping drives are of course also possible as an alternative to the T-handle. 
       FIG. 2  shows the positioning and insertion instrument  1  with a guide wire  50  loaded into the guide tube  2 . The guide wire  50  can be inserted at the proximal or distal end of the positioning and insertion instrument  1 , which leads to at least temporary curvature of the guide wire  50 . 
       FIG. 3   a  and  FIG. 3   b  show the positioning hook  3  of the positioning and insertion instrument  1 , comprising a guide bore  6 , which is set at an angle of about 8° in the nose  11  relative to the guide tube  2  and the central bore thereof. In addition to this bore, various correction bores are present, in particular an anterior/posterior correction bore  7 , a medial correction bore  8 , a posterior/anterior correction bore  9  and a lateral correction bore  10 . 
       FIG. 4  shows the positioning and insertion instrument  1  with a guide wire  50  lowered into the guide tube  2 , which instrument is placed on the greater trochanter  41  of a femur  40 . The characteristics of the positioning hook  3  ensure proper non slip positioning on the surface of the trochanter  41  and in the medial muscle  45 . The handle  5  of the positioning and insertion instrument  1  is aligned parallel to the longitudinal axis of the femur  40  and parallel to the extension of the intramedullary canal thereof. The T-handle  30  is shown in the position in which it is capable of inserting the guide wire  50 . 
       FIG. 5  shows the positioning and insertion instrument  1  which is just being pushed along its guide bore  6  on the reference guide wire  50   a  already inserted into the trochanter  41  of the femur  40 . The positioning and insertion instrument  1  or its guide tube  2  is loaded with an opening guide wire  50   b.    
       FIG. 6  shows the positioning and insertion instrument  1  which has been pushed through the guide bore  6  over the reference guide wire  50   a  already inserted into the trochanter  41  of the femur  40 . The positioning and insertion instrument  1  is correctly positioned corresponding to the angle of about 8° in the frontal plane of the guide bore  6 , in order to insert the already loaded opening guide wire  50   b . The T-handle  30  is shown in the position in which it is capable of inserting the opening guide wire  50   b.    
       FIG. 7  shows the opening drill  20  when it has been pushed over the inserted opening guide wire  50   b . The T-handle  30  is shown in the position in which it is capable of inserting the opening drill  20  into the trochanter  41  of the femur  40 . 
       FIG. 8  shows an X-ray image which shows the positioning hook  3  of the positioning and insertion instrument  1  and a guide wire  50  loaded in the guide tube  2  and inserted into the trochanter  41  of the femur  40 . Proper positioning by means of the characteristics of the positioning hook  3  on the surface of the trochanter  41  is evident. The guide wire  50  has been inserted parallel to the longitudinal axis of the femur  40  and in the intramedullary canal thereof. 
       FIG. 9  shows an X-ray image which shows the positioning hook  3  of the positioning and insertion instrument  1 , which has been pushed via its guide bore  6  over the reference guide wire  50   a  already inserted into the trochanter  41  of the femur  40 . The positioning and insertion instrument  1 , is optimally correctly positioned, corresponding to the angle of about 8°, in the frontal plane of the guide bore  6 , in order to insert the already loaded opening guide wire  50   b.    
       FIG. 10  shows an X-ray image which shows the reference guide wire  50   a  and opening guide wire  50   b  inserted into the trochanter  41  of the femur  40 . The desired insertion angle  42  of about 8° between reference guide wire  50   a  and opening guide wire  50   b  is clearly recognisable. 
       FIG. 11  shows an X-ray image which shows the remaining opening guide wire  50   b  optionally after removal of the reference guide wire  50   a . In this example, the opening guide wire  50   b  is located too close to the lateral cortex to implement the opening and has to be corrected. 
       FIG. 12  shows an X-ray image which shows the correction of the opening guide wire  50   b . A second opening guide wire  50   b  is inserted into the trochanter  41  parallel to the guide wire  50   b.    
       FIG. 13  shows an X-ray image which shows the corrected opening guide wire  50   b  after removal of the first opening guide wire  50   b . It is now located optimally for implementing the opening by means of opening drill  20 . 
       FIG. 14  shows an X-ray image which shows the implemented opening  43  of the trochanter  41  of the femur  40 . 
       FIG. 15   a  and  FIG. 15   b  show the positioning hook  3  of the positioning and insertion instrument  1 , which positioning hook has no guide bore, comprising various correction bores, in particular an anterior/posterior correction bore  7 , a medial correction bore  8 , a posterior/anterior correction bore  9  and a lateral correction bore  10 . In comparison with the variant shown in  FIG. 3   a  and  FIG. 3   b , the nose  11  is also markedly thinner. 
       FIG. 16   a  and  FIG. 16   b  show the positioning hook  3  of the positioning and insertion instrument  1 , which positioning hook has no guide bore, comprising various correction bores, in particular an anterior/posterior correction bore  7 , a medial correction bore  8 , a posterior/anterior correction bore  9  and a lateral correction bore  10 . In comparison with the variant shown in  FIG. 15   a  and  FIG. 15   b , the nose  11  tapers somewhat more sharply and is longer. 
       FIG. 17   a  and  FIG. 17   b  show the positioning hook  3  of the positioning and insertion instrument  1 , which positioning hook has no guide bore, comprising various correction bores, in particular an anterior/posterior correction bore  7 , a medial correction bore  8 , a posterior/anterior correction bore  9  and a lateral correction bore  10 . This variant differs in comparison with the variants shown in  FIG. 15   a  and  FIG. 15   b ,  FIG. 16   a  and  FIG. 16   b , substantially through a smaller cross-sectional area. The correction bores are enclosed by the outer contour. 
       FIG. 18   a  and  FIG. 18   b  show the positioning hook  3  of the positioning and insertion instrument  1 , which positioning hook has no guide bore, comprising various correction bores, in particular an anterior/posterior correction bore  7 , a medial correction bore  8 , a posterior/anterior correction bore  9  and a lateral correction bore  10 . In comparison with the variant shown in  FIG. 17   a  and  FIG. 17   b , the nose tapers somewhat more sharply and is longer. This variant differs in comparison with the variants shown in  FIG. 15   a  and  FIG. 15   b ,  FIG. 16   a  and  FIG. 16   b , substantially through a smaller cross-sectional area. The correction bores are enclosed by the outer contour. 
       FIG. 19   a  and  FIG. 19   b  show the positioning hook  3  of the positioning and insertion instrument  1 , which positioning hook has no guide bore, comprising various correction bores, in particular an anterior/posterior correction bore  7 , a medial correction bore  8 , a posterior/anterior correction bore  9 , a lateral correction bore  10  and four additional correction bores. 
     
       
         
               
             
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 List of reference numerals 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                  1 
                 Positioning and insertion instrument 
               
               
                   
                  2 
                 Guide tube 
               
               
                   
                  3 
                 Positioning hook 
               
               
                   
                  4 
                 Retaining arm 
               
               
                   
                  5 
                 Handle 
               
               
                   
                  6 
                 Guide bore 
               
               
                   
                  7 
                 Anterior/posterior correction bore 
               
               
                   
                  8 
                 Medial correction bore 
               
               
                   
                  9 
                 Posterior/anterior correction bore 
               
               
                   
                 10 
                 Lateral correction bore 
               
               
                   
                 11 
                 Nose 
               
               
                   
                 12 
                 Additional correction bore 
               
               
                   
                 20 
                 Opening drill or cutter 
               
               
                   
                 30 
                 T-handle 
               
               
                   
                 31 
                 Drill chuck 
               
               
                   
                 32 
                 Lever 
               
               
                   
                 40 
                 Femur 
               
               
                   
                 41 
                 Trochanter 
               
               
                   
                 42 
                 Angle 
               
               
                   
                 43 
                 Opening 
               
               
                   
                 44 
                 Femur axis 
               
               
                   
                 45 
                 Medial muscle 
               
               
                   
                 50 
                 Guide wire 
               
               
                   
                 50a 
                 Reference guide wire 
               
               
                   
                 50b 
                 Opening guide wire 
               
               
                   
                 50b1 
                 Further opening guide wire 
               
               
                   
                   
               
             
          
         
       
     
     While the present invention has been described with reference to the preferred embodiments, those skilled in the art will recognize that numerous variations and modifications may be made without departing from the scope of the present invention. Accordingly, it should be clearly understood that the embodiments of the invention described above are not intended as limitations on the scope of the invention, which is defined only by the following claims.