DE7235643U - Femoral head prosthesis - Google Patents

Description

Artur Fischer Den, September 20, 1S72

72 ^ 41 Tumlingen Ju / Sl

PM 12 * 41

Femoral head prosthesis

The invention relates to a hip joint head prosthesis with a spherical part forming the joint head and an anchoring part that engages in the bone canal of the thigh and can be fixed there.

Hip joint head prostheses are known to be required when the hip joint head is destroyed, as is the case, for example can occur with athrosis.

The currently most common way of anchoring the spherical head part in the thigh is this A shaft plate bearing the head part is cemented in place into the bone canal of the thigh. The special cement methyl methacrylate is used for this, which, however, has the undesirable property that V / poor is released during curing. This heat development requires a complicated surgical technique, since it protects the bone substance and the other neighboring ones Tissue parts must be cooled.

In addition to these difficulties during the operation itself, there is also a technical disadvantage. The constant Loading of the head part leads to a loosening of the cemented shaft plate in the bone canal and thus to a constant withdrawal of the entire hip joint head prosthesis. One tried to

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restrict that the shaft plate is offset in cross section relative to the head part of the hip joint head prosthesis. This creates a support surface with which the head part can also be supported on the corticalis of the thigh bone. Because this additional If the support is not sufficient to prevent the prosthesis from becoming detached, this leads to it in the long run a destruction of the bone. Apart from the fact that the prosthesis of the hip joint head does not function properly loses, this can possibly mean that the thighbone is the basis for further hip joint head prostheses becomes unusable.

The invention is therefore based on the object of a hip joint head prosthesis to create, which can be used without much difficulty and iir. Case of infections as well can be taken out again, and the cvi-ch an even Pressure distribution enables an anchoring that is gentle on the bone substance and enables the prosthesis to be set down in prevents the thighbone.

According to the invention this is achieved in that the anchoring part consists of several expansion elements lined up one behind the other, "'e by pulling in an expansion body in the lowermost Sprt element can be expanded by means of a pull rod and displaced relative to the longitudinal axis of the pull rod are.

When the expansion body is drawn in through the pull rod, the expansion elements are pushed together. While the bottom Spreading element is spread open by the spreading body itself, the spreading of the remaining spreading elements takes place in each case through the upstream expansion element, the face of which penetrates into the conical bore of the downstream expansion element

The number of cer -prei 7.el enienl.t · int can be freely selected · and can be based on <] <r body size, weight or other frictors.

With anchoring (: i lon with an i.'pre.i.zhü] re, the entire Prc ■ ρ r is centered; pressure on this; an opreirte.il and with a v-ferr.ir/-r: on: - pr ^f 'i even only to the outermost Kr.di- c: ie :: <r.'. "pr. i: · '. ei ler. Ii er · then results in very boring 1 point a; · ι ur. gi ·!., the: ··. u a ^ pror.gurg of the bone leader, ki'nn · -) :. P * · .: -it r erfi t] dur.L "f - ger.i! '-i;: I-! üftgelnkkc'pfpr'C't her; e vei-part ·. L'ich dr r} 'rt sr'druck only on several Γ ρ: -ei ? Λ 1 <v.:> R: te, vo , ■.; .. ^r - r.cht η da.iuT'ch cir ; e up-

can ^: ■ ;. eic tincelnen Γρ: · ι. · ί: ^- t -I ·. ■; · ..- ntc »a ;;; ■} ■■ g (gi nübcr d '. r' ^r ! r. '/ ,: · .. ·· (· ■ · .; ·> dir "u. R '.-. (. Gf · <\ ■}.'. ·. '·! .Kr · ;; and thus the. Y *. ! '! on Ί'r. YilcI.- ik ::! ⁿ ' · '.- 1: ■■:: -r; i'V. "■■ * - ■ bone! ·:.'.:. al , dei 'zur Pe ff. f ⁴ i Γ'-'- Γ vc ^- ~;} - 'rr t b.-.- se:. that have a single :: ..:' t 1 err η! · Γ ·.:;. T igung ": ■■ '.'. Ft au fv: c ir <: ■!"., At 'tigt v: "! Rd, irt in den v; · r; .gs'rn; . ^;: l "! c !. ger.ai: z \ lindr ;; - ch mu: straight. Dc · ..- Ki nfvlir · - ■■ ::« .ir. · :. "Yv r: .nke : - ..; -. _L ·. · - part rr. ⁴ te ~ ner and cJalu r en 'rsprech nc; i:.:. Rer. .'R: v :: - sleeve he *.: Tet CcM .n rcl "v: i (rigkei t er. cd ·: ¹ ir ··. o:" \ ::. · Is

Part of the successful i'r · γ. ! ":;:.;: ■ (: .uh if not ^ eradver j auferden Kr.cchenkar. · ''! ·: Τ. Leic:". Introduce urid anchor. Pie individual ;: limbs y :: .. · .:. The. course of the Kr.cchGr.kr-ncilt-E :: -λ- .. / c-Zli ·: with larger bone drills Then support the individual spreader eggs in a zigzag shape on the wall of the bone canal V'eite des Knoeher.kar.ales correspond.

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When the individual spreading elements are spread apart, they form one compared to the previous spreading element Step or ledge that digs into the bone wall. These steps correspond to the number of expansion elements together with the friction of the spreading elements on the bone wall, prevent the prosthesis from settling. The position of the prosthesis thus remains the same even with constant load, so that even over a longer period of time No deterioration in walking ability is to be feared over a period of time. An even better step formation and Pressure distribution is possible in that the individual expansion elements are rotated against each other so that their longitudinal slots offset by 90 to each other are.

According to a further embodiment of the invention, each expansion element of the hip joint head prosthesis can over have part of its length at least one longitudinal slot guided from below and also with be provided with a downward widening conical bore. The number and length of the longitudinal slots of the expansion elements depends on the hardness and strength and thus on the expandability of the material. When using titanium as the material for the expansion elements, there is another advantage that it is light Machinability of the parts of this difficult-to-process material is added. The pivotability • of the individual elements depends on the difference in diameter between the cone hole and the tie rod. A large difference in diameter results in a large one, and conversely a small difference in diameter results in one less swiveling of the expansion elements. The selection of the correct expansion elements therefore depends on the course of the Bone canal egg.

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In a further addition to the invention, the one penetrating into the conical bore of the preceding expansion element can be used The end face of each expansion element may be hemispherical. This configuration too promotes the pivotability of the expansion elements. In addition, the rounding of the end faces facilitates penetration the expansion elements in the conical bores of the preceding expansion elements facilitated. The need for strength for the pushing together / h of the expansion elements is thus reduced to a minimum.

Finally, according to a further addition to the invention, it is also possible to attach the expansion elements to their Grooving or roughening the outer surface. This serves to increase the friction and thus the reinforcement the anchoring effect.

In a further embodiment of the invention, the joint head can form directly on the Connect an angled shaft plate to the spherical part of the femoral head prosthesis, the end face of which serves as a support for the head of the pull rod. The shaft plate forms the joint head on the axis of the bearing part an angle of about 120. This angle roughly corresponds to the natural specific angle between the femoral neck and Thighbones. The vertical part of the shaft plate has a bore into which the pull rod is pushed through. The head of the pull rod is supported by the retraction of the expansion body End face of the shaft plate. To secure the drawbar Spring washers or the like can be used, which also act as tension compensation and elastic Cushions are used when the joint head prostheses are loaded.

72356 A3 2 7.6.74

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Furthermore, according to a further addition to the invention, the end face of the uppermost expansion element with a Be provided groove in which engages the underside of the shaft plate. The shaft plate with its rectangular Cross-section serves as an additional fixation against rotational movements of the prosthesis and is therefore in for example the elliptically enlarged bone canal in the upper part Part of the thigh bone adapted. Through the groove on the face of the uppermost expansion element and the engagement the underside of the shaft plate in this groove, this expansion element is secured against twisting.

Finally, in a further embodiment of the invention, the outer surface of at least the topmost spreading element can also be used be tapered conically in adaptation to the bone canal in the direction of the introducer. The topmost expansion element is also still in the enlarged part of the bone canal, so that the tapering of the Spreading element and the adaptation to the bone canal a better support and anchoring is given.

In a further advantageous embodiment of the invention, the pull rod can be curved to adapt to the bone canal. As a rule, each bone canal in the femur is slightly curved. It facilitates the introduction of the anchoring part _} if the pull rod has already been bent beforehand according to the curvature of the bone canal. With more pronounced curvatures of the bone canal,

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would be the pivotability of the individual Sprc-ir.eler.ente can no longer compensate for the curvature.

In the case of a curved tie rod, it is particularly advantageous in a further addition to the invention if the Drawbar and the expansion body that can be attached to the drawbar via one on the face of the shaft plate supporting head nut are retractable. The curvature makes it difficult to turn the pull rod and thereby the retraction of the expansion body into the lowermost expansion element. When pulling in a pull rod through a head nut this only moves in the axial direction, so that the twisting movement of the pull rod is eliminated.

Finally, the length of the head nut can also be at least the length necessary for spreading the anchoring part The retraction path of the expansion body correspond. The front end of the pull rod remains after it has been spread open in any case still within the head nut and can therefore not form any painful pressure points.

Finally, in an advantageous embodiment of the invention, the tie rod and the bore of the Spreading elements have the same cross-section that excludes mutual twisting. For example the tie rod and the opening of the expansion elements can be rectangular. However, it is also possible to provide the pull rod with a spring and the opening of the expansion elements with the corresponding groove.

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In the patent drawing sine! Execution:-! ei: ■ [..: < ¹ Ie ': · - · Invention shown.

Figure 1 shows the in the Obr? Rscli'M.k · ■ Ikric: ^ 'η inserted hip joint head prosthesis

FIG. 2 shows the lowest spreading line. Ent it: section.

The üüftgelcrikkci: "prothf.'f.; -? 1 consists of your kugclfcr: r..i gen head part 2 and thorn anchoring part 3- Unrr.ittcllar on da :: head part 2 sleeps a v.ir.k-lte Sch : · Ftp ^{': ptto h} - ar., Which is partly already set in Ohf-r .'- ci.-'- r.ki.-lkr.Ov'heri Π eit. The front side d-'f-rr : · Rchai't ρ]?. ■ -1 ed: ei.t the head cover. ^C ; e C als / vuf-] f: [y!: Eir. ". rl: r. : ■: '■: .er. the tie rod 7 and the; m the

· R-ur.t ". I'i 1 3 consists of several, one behind the other- · '..:.." J. : ··. ·: Re] <-? · .En * er., D; o opposite the :: · '·: ■ 7 ·.; Rrt? Ir.ge 7 swivel! .Ar are. Rhyme - "r: -e '.; · / ' Ivv <~ : · ;: cv: er egg, serve spro: i zelernente · rcl-o! <· ::, se · ü? Rf, the lower spreading element each-

. ^r ■: ■] ..- \ ■ "': er: '■;.: ■. element lying on top of '.'."'.'ir.-ci ν ^c Ί err.er.te 9 a longitudinal slot: · !, r. ■ ·'. ··. at: erv: eiterr.ce Konunsbohrung

.: ■ ::!:: ·:; Rr: ■■ ": · .-: ■ through the pull rod 7 up-:.. · '. ·: R; ··':: ·; ■:; ■■ : ft, and the better Schvenk- ·:. :: ^r :.: :: ·: Γ ti rnseit en 12 of the expansion elements

ha]:>·.; ■. · Z Γ · ν: ■. ". '; - -: -ge -rvr.dt. You penetrate more easily ir. ν.' · Kcru:: ■ · -'-. ·. £: 1 ''>; · γ of the preceding expansion element. I-'e Γ ::.: ■■: ■: ■ '.r> - -1'. Depends also from the r.-urcr.rr.erserui .- ': ·. ■ .hlec of the tie rod 7 and the hole of the ei ;;;: ei: ".': - r. 3p: eizeleri.erite 9 from.

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When drawn in, the spreading elements pivot and thereby adapt to the course of the bone canal. Dc: i stronger curves of the bone channel 14 may even bccccre adjustment Sos Veranker-unn-steep ~ *> be achieved in that the pull rod 7 is curved to match the bone canal fourteenth In such cases, a head sleeve 6 is used to pull in the pull rod 7, so that twisting the pull rod 7 is no longer necessary. The expansion body 8 can be connected in one piece with the pull rod 7 in this case. The head sleeve 6 'is somewhat longer than the retraction path of the expansion body necessary for spreading the anchoring part 3, so that the end face of the tie rod 7 remains within the head sleeve 6 even after the anchoring.

The cross section of the shaft plate 4 corresponds approximately the elliptical shape of the bone canal 14 in the uppermost area of the thigh bone 5 · The same is also the topmost chaff element 9a is still conical adapted to the tapering bone canal. Furthermore, this expansion element 9a is provided with a groove on its end face provided, in which the shaft plate engages with its underside to prevent rotation.

In Figure 2, the lowermost expansion element 9b is shown, the expansion body is drawn into the conical bore 11 by means of the pull rod 7. It will this spreading element 9b spread open, which is caused by the guided from below and over part of the spreading element extending longitudinal slot 10 is made possible. Simultaneously with the spreading is this expansion element also in the next

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higher expansion element retracted, so that also diesec as well as the still following expanded and is anchored in the bone canal. The resulting steps 16, together with the friction of the Spreading areas for safe and non-slip anchoring the prosthesis. They are in the conical bore for better swiveling and sliding properties 11 penetrating end faces 12 of the individual expansion elements are rounded in a hemispherical shape. An anti-twist device between the pull rod 7 and the expansion elements 9 is created by profiling the pull rod 7 and the expansion gap bore adapted to it 13 reached. In the example ή Gt for this purpose, the pull rod 7 is provided with a spring strip 17, which is inserted into corresponding grooves 18 of the expansion element mente 9 fit.

Claims (1)

Artur Fischer Den, September 20, 1972 Tumlingen Ju / Sl £ —a— £ ρι Proverbs 1 = hip joint head prosthesis with a thin joint head forming spherical part and one engaging and iort in the bone canal of the thigh fixable anchoring part, characterized thereby, that the anchoring part (3) consists of several spreading elements (9> Tn, 9b), which by pulling in an expansion body (8) in the lowermost spreading element (9b) by means of a pull rod (7) spreadable and opposite to the longitudinal axis the tie rod (7) are displaceable. 2. Hip joint head prosthesis according to claim 1, characterized in that each expansion element (9, 9a> 9b) has at least one longitudinal slot (10) guided from below over part of its length and is also provided with a downwardly widening conical bore (11). 3. Hip joint head prosthesis according to claim 1, characterized in that the in the conical bore (11) of the preceding expansion element penetrating end face (12) of each expansion element hemispherical is trained. ^. Hip joint head prosthesis according to claim 1, characterized in that that the expansion elements (9, 9a, 9b) are corrugated or roughened on their outer surface. PM 12m - 2 - Hip joint head prosthesis according to claim l _f, characterized in that ar. the spherical toilet (2) forming the joint head is connected to an angled shaft plate (4), the end face of which serves as a support for the head of the tie rod (7). 6. Hip joint head prosthesis according to claim 1, characterized in that the end face of the uppermost expansion element (9a) is provided with a groove (Ib) into which the underside of the shaft plate ( ¹ O engages. 7. femoral head prosthesis according to claim 1, characterized characterized in that at least the outer surface of the uppermost spreading element (9a) in adaptation is tapered conically on the bone canal (14) in the direction of the insertion end. 8. Hip joint head prosthesis according to claim 1 _/ characterized in that the pull rod (7) is curved in adaptation to the bone joint. 9. femoral head prosthesis according to claim 1 and 8 characterized _s that the pull rod (7) and attachable to the pull rod expansion body (8) are retractable over a supported on the end face of the stem plate (4) head nut (6). PM 12 * 41 - 3 - 10. Hüftcelenkkopfprüthe ^ w. · According to claim 1, 8 and thereby ge ken η scr! chnet, wet the L.'ince the KcpfiiiutU'r (, D ^ iiixiiUL'H th ;; üun. zum Aui'Lijji'f-. 'izen Uta Verankerurigstciloc (3) necessary r'.inzi ehv.oc des Sprrizkor'pcr; - (8). 11. lü'ftcc'l ^ r.kkopfpi'o ^ hcr, e ni; ch claim 8 and 9 _y dacuich guker.r. :: el chn ( ^j t that the Zuc-tnge (7) and the opening (13) of the Spre j zeleir: duck one equal ·. '·!'., the tre ^ cnr.ei ti £ e twisting the end- ε ch 1 ϊ <-. ? .. '. "' r. d ο π C u <■ rsch η i 11 au fv: iron.