DE3542016C2 - - Google Patents

Description

The invention relates to a thigh part Hip joint endoprosthesis, with one shaft, one adjoining it proximally, to the shaft axis inclined neck and one arranged on the neck Head with the outer contour of the shaft of the Hal ses and head the corresponding section of the Bone cavity or the head of the patient femur is adjusted.

A method of making such thighs kelteile is known from DE-OS 32 13 434, in which using computer tomography, several to scale Area images of the endoprosthesis the body part are generated; that this way generated area data are saved and cleared Combined and, if necessary, in advance level criteria such as cavity formation or cross cut taper in the direction of implantation etc. fit and after a corresponding modification to Production of an individually multidimensional shape endoprosthesis. Through the shape adaptations endoprostheses to the individual anatomy the use of bones cement to be kept to a minimum or completely become superfluous and a particularly firm one Anchoring the endoprosthesis in the concerned Bones can be realized.

DE-OS 33 40 024 is a device and a Known method, which for the production of a Pro serve the individual with individual adaptation  should. In a first step, the Kno measurement of the cavity in three dimensions. Subsequently a solid model of the bone cavity is created. Then one through the model of the bone cavity displaceable shaft model generated, the outer Ab measurements correspond to the prosthetic blank. The Shank model is placed on a through the insertion opening Path of smallest volume displacement - possibly under on conclusion of rotational movements and changes of direction gene - introduced into the bone cavity model, the distance covered including the spatial alignment of the prosthesis in this way to be recorded. Then the Festig of the remaining prosthetic socket, based on the real prosthesis material, checked. In the end the volume that is displaced in the shaft model also in the real prosthesis blank by cutting Deformation using a numerically controlled movement machine removed. In this way indi viduelle, to the found or created kno optimally adapted prosthetic stems in can be generated individually and also used taking into account bone curvatures be possible. The key criterion of this known manufacturing process is, for. B. means Simulation by a computer the way of the optimal Insertion and to determine the best shape of the shaft men whose shape is determined in such a way that the this shaft on this "way of optimal insertion" then can also be introduced. The known in this Process considered necessary prerequisite condition, the endoprosthesis through an insertion opening in the axial direction of the bone into the bone cavity the form of the  Shaft - and thus also the dimension of the form fit between the shaft and the supporting cortex. Also in the so manufactured and customized prosthetic stems - because of the constraint that Insert the prosthesis through the insertion opening - a form closure only takes place locally.

The object of the invention is the prosthetic upper leg part of the type mentioned in such a white to train that a particularly large and uniform application of force in natural Pa tientfemur is realized.

This task is for the prosthetic thigh kelteil of the type mentioned in the invention solved by dividing the thigh part is in a lower head section that is integral in the neck and shaft merges, and a separate one upper head section.

The thigh part according to the invention can always be then implant when the patient is on his proximal end in the axial direction in two halves bowls or lids split, and one of the two half-shells or lids by means of one Neten incision separated from the rest of the femur and from is taken; also during this operations technology only the defective upper part of the na removed the femoral head and then the Broken bone cavity. Then it is invented appropriate thigh part in the prepared, half-open bone cavity inserted positively whereupon the removed half-shell form placed conclusively on the thigh part and in the  anatomically correct position in a known manner with the underlying solid bone section, e.g. B. with bone nails or circumferential cuffs or Screw connections, is firmly connected. The advantage of prosthetic thigh part according to the invention lies in the fact that in addition to the shaft and neck a lower, form-fitting head section is integrally formed on the thigh part, which itself form-fitting in the lower head section of the natural supports patient femurs and - according to how the growing of the temporarily removed and again attached half-shell-shaped bone section - a large-scale support through the neck tapered patient experience. To this Ways are transferred to the thigh part forces large and uniform on the un transfer the lower head section of the patient femur, which ensures a particularly firm anchoring of the Endo prosthesis in patient femur - only with resection of the defective head section - is achieved.

While the lower head section prefers the ent speaking section of the patient's bone cavity tenfemurs is individually adapted to a particular good form fit in the lower head area of the Fe The upper head section is to be realized spherical and has about the outer Diameter of the natural femoral head.

The lower head section preferably has in its top end face an inward conical narrowing bore, and the upper head portion be sits a corresponding cone shoulder on the un tere head portion facing end face. Cone  The bore and cone shoulder form one at Bela jamming plug connection.

Advantageously, different top headers cuts with different lengths of the cone set as well as with different ball diameters kept available to choose the appropriate one a suitable head and neck length to be able to manufacture.

According to a preferred embodiment of the invention is the top face of the bottom head section formed perpendicular to the neck axis. The axis of the conical bore and the conical shoulder align this embodiment advantageously with the Neck axis. The resection line runs on the femoral head advantageously at the same height as the edge edge of the lower head section, and the open stuck upper head section covered when a ge suitable head diameter is chosen, the resec surface of the bone.

According to an alternative embodiment of the invention the upper face of the lower head section at a predetermined angle of about 70 ° to 135 °, particularly preferably from 90 ° to the shaft axis.

The opposite end faces of the two Head sections can be flat or match each other be curved.

Advantageous developments of the invention are characterized by the features of the subclaims.

Exemplary embodiments of the invention are described below dung explained with reference to the drawing. It shows

Figure 1 is a side view of an implanted upper leg part of a hip joint endoprosthesis, partly in section.

2 shows a section along the line II-II of Figure 1, but with again being set front half-shell of Patientenfemurs..;

Fig. 3 is a section along the line III-III of Figure 1 with reattached front half-shell of the patient femur.

Fig. 4 is a side view of a second embodiment of the thigh part; and

Fig. 5 is a side view of a third embodiment of the thigh portion in the implanted state.

In Figs. 1 to 4 show different views are individually displayed one at the matched to prothetisierenden Patientenfemur hip-joint endoprosthesis, whereby the Patientenfemur, in which the hip joint Endopro synthesis is fitted, is shown in various stages of operation. In Fig. 1 the femur 1 is cut axially into two approximately the same half-shells, and the front half-shell is separated and removed at its lower end by means of a corresponding circumferential cut. An upper section of the femoral head has also been resected. In the rear half-shell 1 a shown in Fig. 1 a , the thigh part 2 of the hip joint endoprosthesis is inserted. The thigh part 2 has an elongated shaft 3 which extends in the direction of the shaft axis 5 and at its proximal end merges into a relatively thin neck 4 . The neck 4 is inclined towards the shaft 3 in such a way that an acute angle is formed between the shaft axis 5 and the neck axis 13 which, depending on the shape of the patient femur to be prosthetic, lies in the range between 20 ° and 50 °. At the transition between shaft 3 and neck 4 , a trochanter attachment 8 is adapted.

The neck 4 merges proximally into a lower head section 6 , which approximately has the shape of a Kugelab section and has at its proximal end an upper end face 10 which is flat and extends perpendicular to the neck axis 13 . In the upper end face 10 is aligned with the neck axis 13 - a conical bore 12 which tapers conically towards the shaft 3 .

The shaft 3 , the trochanter attachment 8 , the neck 4 and the lower head section 6 have an outer contour which, over the entire length of the thigh part 2, corresponds three-dimensionally to the previously three-dimensionally measured contour of the cooking cavity of the individual patient's bone to be prostheticized. The measurement of the shape or contour of the bone cavity is carried out for this purpose by means of a known X-ray or tomographic method, and the contour obtained in this way is e.g. B. by means of numerically controlled cutting tools on a prosthesis blank. This ensures that the shape of the thigh part 2 to be inserted into the femur corresponds to the contour of the actually existing bone cavity of the individual patient femur to be prostheticized so precisely that a reliable large-area, form-fitting anchoring in the shaft and neck area and in the lower head section of the bone is realized.

The thigh part 2 carries on its lower head portion 6 an upper head portion 20 , which has the shape of a spherical section, the upper outer surface 22 is spherical, and the lower end face 24 runs just ver. Perpendicular and centrally to the lower end face 24 is a conical neck molded onto 26 which tapers towards the outside with the cone angle of the bore 12 and forms a plug connection with the conical bore 12th The diameter of the outer surface 22 of the upper Kopfab section 20 approximately coincides with the outer diameter of the femoral head and can also be selected appropriately.

For this purpose, various top sections 20 are kept available with different outer diameters and different lengths of the conical extension 26 in order to enable head-neck length compensation and a precise adaptation of the upper head section to the acetabular cup.

As shown in FIGS. 2 and 3, the neck 4 and the shaft 3 are adapted in their entire circumference to the contour of the bone cavity of the patient femur. In Figs. 2 and 3, the front half-shell 1 b is of the femur was removed for insertion of the implant, reattached, and with means of - not shown - fixing means with the rear half-shell 1 a and possibly the well with the unte ren section Femurs firmly connected.

Fig. 5 shows a second embodiment of the prosthetic thigh part 2 , wherein if the front half-shell 1 b of the proximal femur is removed. The upper defective area of the femoral head is separated in a resection plane running perpendicular to the shaft axis 5 . Shaft 3 , neck 4 , lower head section 6 and trochanter attachment 8 are - as in the exemplary embodiment according to FIGS. 1 to 4 - three-dimensional to the previously three-dimensionally measured contour of the bone cavity of the individual patient femur to be prosthetic by numerically processing a corresponding prosthesis. Blanks are fitted so that a large-area form fit between the thigh part 2 and the femur is guaranteed. The upper end face 10 of the lower head section 6 extends in the resection surface perpendicular to the shaft axis 5th The conical bore 12 and the conical extension 26 run parallel to the shaft axis 5 .

Claims (8)

1.Thigh part of a hip joint endoprosthesis, with a shaft, a proximally attached to it, the neck inclined to the shaft axis and a head arranged on the neck, in which the outer contour of the shaft of the neck and head corresponds to the corresponding section of the bone cavity or the head adapted to the patient's femur, characterized in that the thigh part ( 2 ) is subdivided into a lower head section ( 6 ) which integrally merges into the neck ( 4 ) and shaft ( 3 ), and a separate upper head section ( 20 ). 2. Thigh part of a hip joint endoprosthesis according to claim 1, characterized in that the lower head section ( 6 ) is adapted to the corresponding section of the bone cavity of the patient femur, and that the upper head section ( 20 ) sits in the form of a spherical section, the diameter of which is approximately that corresponds to the outer diameter of the natural femoral head. 3. thigh part of a hip joint endoprosthesis according to one of the preceding claims, characterized in that the lower head portion ( 6 ) has an inwardly conically narrowing bore ( 12 ) in the upper end face ( 10 ), and that the upper head portion ( 20 ) one corre sponding cone extension ( 26 ) on the lower Kopfab section ( 6 ) facing end face ( 24 ). 4. Thigh part of a hip joint endoprosthesis according to one of the preceding claims, characterized in that
that the end face ( 10 ) of the lower head section ( 6 ) extends perpendicular to the neck axis ( 13 ), and and that the axis of the conical bore ( 12 ) and the conical extension ( 26 ) are aligned with the neck axis ( 13 ). 5. thigh part of a hip joint endoprosthesis according to one of claims 1 to 3, characterized in that the end face ( 10 ) of the lower head portion ( 6 ) extends perpendicular to the shaft axis ( 3 ). 6. thigh part of a hip joint endoprosthesis according to one of the preceding claims, characterized in that the end face ( 10 ) of the lower head portion ( 6 ) extends at a predetermined angle of 70 ° to 135 ° to the shaft axis ( 3 ). 7. thigh part of a hip joint endoprosthesis according to one of the preceding claims, characterized in that the opposing end faces ( 10, 24 ) of the lower and upper head portion ( 6, 20 ) are flat. 8. Hip joint endoprosthesis according to one of the preceding claims, characterized in that the shaft ( 3 ) has a natural trochanter cavity adapted Trochanter approach ( 8 ).