Cutting tool for cleaning out the femur medullary space and artificial hip to be inserted into this space

The invention relates to a milling tool for clearing Of the femoral marrow to create a space for the Shaft of a hip prosthesis and one for insertion into the latter Space suitable hip prosthesis.

Insertion of one shaft and one angled On this attached ball existing hip prosthesis A frequent, regularly relatively uncomplicated surgical Intervention.

Difficulties arise, however, in the cases in which Before the insertion of the shaft of the hip prosthesis Using a cutter tool Femur medullary space is not stretched, but curved, Since then in the use of the usual - stretched Trained milling tools regularly in Undesirably also bone material to be preserved Is milled.

DE 29 14 455 discloses a device for manufacturing Of the cavity in a bone for the insertion of a Artificial gel member, in which two of the mold Of the bone cavities adapted to be produced On a flexible rotary drive shaft The two rasp halves being arranged in the axial direction Are movable relative to one another.

Furthermore, WO 94/275 discloses a milling cutter tool for the Clearing out the femoral cavity to create a Space for the hip of a hip prosthesis, with one Flexible core and having a plurality of tapered, With central perforations, Superimposed on the soul, rotationally symmetrical Milling segments, one open to the soul Applied rotational force.

The features of the preamble of claim 7 are exemplary From EP-A-0,359,485.

The object of the invention is to provide a milling cutter tool To create a room for The shaft of a hip prosthesis, corresponding to the respective course Of the femoral medulla, as well as a hip prosthesis, Which are placed in such an extent, not stretched Femur-medullary space. Can be used.

According to the invention, this object is achieved by the features Of claims 1 and 7, respectively. The subclaims Preferred embodiments of the invention.

The invention is described in the following by means of a drawing Is explained. FIG.<dl tsize="6"><dt>FIG</dt><dd>A schematic representation of a Such milling tool Not-stretched soul,</dd><dt>FIG</dt><dd>1 is a view corresponding to FIG With a strained soul, </dd><dt>FIG</dt><dd>The hip prosthesis in non - tensioned soul and soul</dd><dt>FIG</dt><dd>3 is a view corresponding to FIG With a strained soul.</dd></dl>

The milling cutter shown in FIGS Consists of a flexible soul and a plurality of With a central through hole (not shown) , Placed one above the other on the core 10, Conical, rotationally symmetrical milling segments.

The soul is unrounded in the cross-section and the Bore of the milling segments 12 with a corresponding one Non-round axial bore (additive Or alternatively the mutually facing end faces Of the individual milling segments 12 also with one inside one another Engaging toothed teeth).

The soul is with one on the top of the milling segments 12, the tightening thereof Against the upper cutting segment 12, the core 10 is tensioned And thereby a stiffening of the milling segments 12 relative to each other (And thus of the individual milling segments 12).

The drawing also indicates that the mutually pointing ones End faces of the milling segments are slightly convex So that they roll on each other can.

The bottom of the milling segments 12 is fixed to the core 10.

The milling tool is used to clear the femoral cavity With a non-tensioned core 10 in the usual manner Respectively. In this case, the distal milling segment 12 (the With the soul 10 firmly connected) the path of the (Relatively soft) femur mark space, the following Milling segments follow this path in each case, whereby, at The rotation of the milling cutter, A rotational force on the soul and / or the upper Of the milling segments, predominantly only the soft Material of the femoral cavity clears the bone Spares The milling tool "snakes" with it The curved femur medullary space and clears it Protection of the bone material.

The hip prosthesis shown in FIGS. 3 and 4 is Appropriately constructed:

It consists of a flexible core 10, a plurality Which are provided with a central perforation, one above the other Conical, rotationally symmetrical Segments and a device 14 To a stiffening of the part formed by the individual segments 12 Formed shafts of the core 10.

The shaft of the hip prosthesis is shown in FIG State in which the core 10 is not tensioned, In the previously trimmed (not strictly linear) Femur medullary cavity. In this process The individual segments 12 will align themselves (Ie tilt to the - imaginary axis of the shaft), That the shaft adapts to the femur medullary space.

After driving the shaft, the soul 10 of the Tense, whereby the shaft stiffens and in Direction is subjected to increasing stretching, Which is due to the elasticity of the bone material A large area of ​​the segments forming the shaft On the obtained bone substance and thus A considerably greater force transmission of the prosthesis On the femur than when used Would be attainable.