SI9600304A

SI9600304A - Reconstructional cement-free hip endoprosthesis with breech

Info

Publication number: SI9600304A
Application number: SI9600304A
Authority: SI
Inventors: Samo K. Fokter; Karl Fokter
Original assignee: Samo K. Fokter
Priority date: 1996-10-17
Filing date: 1996-10-17
Publication date: 1998-04-30

Abstract

Subject of the invention is the thighbone section of a hip revisional endoprosthesis which provides a solid joint between the remaining bone in the middle and lower third of the thighbone as well as the prosthesis itself. The upper third of the thighbone is due to the decay of the bone along the primary prostheses unsuitable for stable application of the prosthesis during its replacement process. In the lower third the thighbone channel is featuring a horn-like extension, therefore sinking of standard cylinder-shaped revision trunks towards the knee is often encountered. The concept of the solution is, that after implantation the lower geared part of the prosthesis (8) can be expanded from the upper side (3) to the internal diameter of the thighbone in its lower and/or middle third with the help of the screw (6) and the cylinder (2) as well as winglets (7), leaving the thighbone channel accessible to the operator even after the prosthesis has been applied. Alternatively the construction is made in such a way that after inserting the trunk (1), the screwing of the cylinder shaped screw (11) in the upper part of the prosthesis (3) spreads into the lower part (8) the transversely inserted plugs (13) in order to firmly grab to the surrounding bone.

Description

REKONSTRUKCIJSKA BREZCEMENTNA KOLČNA ENDOPROTEZA NA ZAKLEPRECONSTRUCTIVE FREE CIRCULAR ENDOPHESTHESIS ON CONCLUSION

Predmet izuma je rekonstrukcijska brezcementna kolčna endoproteza, ki je izdelana tako, da omogoča čvrst spoj med deblom proteze in spodnjim (distalnim) delom stegnenice, kjer je kost tudi pri omajani primarni kolčni endoprotezi še čvrsta. Na ta način je preprečeno posedanje debla proteze v stegnenični kanal.The subject of the invention is a reconstructive cementless hip endoprosthesis, which is designed to allow a firm connection between the prosthesis trunk and the lower (distal) part of the femur, where the bone is still rigid even in the affected primary hip endoprosthesis. This prevents the denture trunk from settling into the femoral canal.

Menjava omajane kolčne endoproteze predstavlja v rekonsrukcijki ortopediji zaradi izgube okolišnje kostnine, povzročene vsled tujkovega drobiija, ki se iz umetnega sklepa sprošča, velik problem. Izguba kostnine je lahko tolikšna, da čvrsta fiksacija nove endoproteze ni več možna. Poznana so revizijska debla kolčnh endoprotez (H. Wagner Femur Revision Prosthesis, Protek AG, CH-3001 Bern; MP-Reconsruction Prosthesis, cementless, Waldemar Link GmbH & Co, D-22339 Hamburg), ki izkoriščajo še intaktno kost v distalnem delu stegnenice, kamor primarna proteza običajno ni segala in do resorbcije kostnine ni prišlo. Tovrstna debla so dolge konične oblike in narejena iz titanovih legur mikroporozne strukture za katero je znano, da omogoča dobro vezavo kostnega tkiva pri brezcementni tehniki inplantacije. Sama vsaditev takega debla v stegnenični kanal zahteva precejšnje povrtavanje le-tega s koničnimi svedri, kar ima znane neugodne posledice in povzroči dodatno izgubo kostnine. Pri bolnikih z dolgim deblom primarne endoproteze, krajšimi in/ali trobljastimi stegnenicami ter tistih, ki ne obvladajo večmesečne razbremenilne hoje z opornicami, pride pogosto do pogrezanja debla revizijske proteze v stegnenični kanal, kar otežuje normalno hojo, povzroči prikrajšavo okončine ali celo izpah stegneničnega vsadka iz sklepne ponvice.Replacement of the stiff hip endoprosthesis is a major problem in reconstructive orthopedics due to the loss of surrounding bone, caused by a foreign body rub, which is released from an artificial joint. Bone loss may be such that firm fixation of the new endoprosthesis is no longer possible. Auditory trunks of hip endoprosthesis (H. Wagner Femur Revision Prosthesis, Protek AG, CH-3001 Bern; MP-Reconsruction Prosthesis, cementless, Waldemar Link GmbH & Co, D-22339 Hamburg) are known to exploit intact bone in the distal part of the femur where the primary prosthesis did not usually reach and bone resorption did not occur. Such trunks are long conical shapes and made of titanium alloys with a microporous structure that is known to allow good bone tissue to be bonded in the cementless implantation technique. Immediately implanting such a trunk in the femoral canal requires considerable rotation of the trunk with conical drill bits, which has the known unfavorable consequences and results in additional bone loss. In patients with a long trunk of the primary endoprosthesis, shorter and / or truncated femurs, and those who do not control the months of relieving walking with braces, the implant prosthesis trunk is often submerged in the femoral canal, which impairs normal walking, leads to limb shortening, or even femoral collapse. from the concave pan.

Iz tehnike operativnega zdravljenja zlomov z intramedulamimi žeblji so po drugi strani poznane rešitve, ki omogočajo vsaditev tovrstnega inplantata brez povrtavanja, saj ima žebelj v svojem zgornjem (proksimalnem) in spodnjem (distalnem) delu prečne odprtine, kamor lahko s pomočjo rentgena (AO/ASIF Unreamed Femoral Nail, Synthes, Paoli, PA 193011222, USA) ali posebnega vodila (Citieffe Interlocking Nail for Femur, 40012 Calderara di Reno, Bologna, Italy) zavijemo vijake, ki preprečujejo dislokacijo zlomljenih delov kosti, dokler ne pride do njenega zaraščanja. Na podoben način je dosežena stabilizacija stegneničnega vsadka pri kolčni endoprotezi Kent Hip (Biomet Ltd, Waterton Industrial Estate, Bridgend, CF 31 3ΧΑ, South Wales, U.K.), kjer po vstavitvi debla proteze enakomernega preseka v stegnenični kanal s pomočjo posebnega vodila zavijemo prečne vijake skozi cevasto kost in vrtine v sami protezi. Spoj proteza - kost ostaja pri tem ohlapen.The technique of surgical treatment of fractures with intramedullary nails, on the other hand, are known solutions that allow implantation of this implant without rotation, since the nail has a transverse opening in its upper (proximal) and lower (distal) port, where it can be X-rayed (AO / ASIF) Unreamed Femoral Nail, Synthes, Paoli, PA 193011222, USA) or a special guide (Citieffe Interlocking Nail for Femur, 40012 Calderara di Reno, Bologna, Italy) wrap screws to prevent the dislocation of broken bones until its healing occurs. Similarly, femoral implant stabilization is achieved with a Kent Hip hip arthroplasty (Biomet Ltd, Waterton Industrial Estate, Bridgend, CF 31 3ΧΑ, South Wales, UK), where after inserting a prosthesis trunk of uniform cross section into the femoral canal, using a special guide, the transverse screws through tubular bone and holes in the prosthesis itself. The prosthesis joint - the bone remains loose.

Deblo revizijske kolčne endoproteze naj bo torej tako, da bo omogočalo primarno čvrsto vsaditev brez obsežnega povrtavanja kosti in pogrezanja vsadka v stegnenični kanal. Ta naloga je v smislu izuma rešena tako, da je modularno ali kompaktno poljubno dolgo in poljubno debelo deblo revizijske endoproteze 1 iz ali prevlečeno z osteokonduktivnim materialom izdelano tako, da ima v svojem distalnem delu mehanizem za čvrst stik z obdajajočo kostjo, ki je prednostno izveden s koničnim elementom 2, ki ob zategnitvi ob vratu proteze 3 razpre njene ozobljene nožiče 4 tako, da ni potrebna nobena dodatna rana distalno na stegnu. Deblo revizijske endoproteze je mogoče na podoben način izdelati tudi iz meteriala s spominom, to je takega materiala, ki omogoča, da so nožiče 4 na nižji temperaturi od telesne zaprte, po vstavitvi v kost in ogretju na telesno temperaturo pa se samodejno razpro. Pravtako je možno nožiče razpreti z elektromagnetno silo, ako so izdelane iz materiala s spominom, ki se trajno deformira pod tovrstno silo.The trunk of the revision hip endoprosthesis should therefore be such that it allows primary firm implantation without extensive bone rotation and implantation into the femoral duct. This object of the invention is solved by having a modular or compact arbitrarily long and arbitrarily thick trunk of revision endoprosthesis 1 made of or coated with osteoconductive material so as to have in its distal part a mechanism for firm contact with the surrounding bone, which is preferably implemented with a tapered member 2 which, when tightened at the neck of the prosthesis 3, opens its toothed blades 4 so that no additional wound is distal to the thigh. The trunk of the revision endoprosthesis can similarly be made from a material with memory, which is such a material that allows the blades 4 to be kept at a lower temperature than the body closed, and then automatically expanded after insertion into the bone and heated to body temperature. It is also possible to open the blades with electromagnetic force if they are made of a material with a memory that is permanently deformed under such force.

Primer izvedbe rekonstrukcijske brezcementne kolčne endoproteze s koničnim elementom po izumu je prikazan v Sliki 1, primer izvedbe s čepi pa v Sliki 2. Sliki kažeta vertikalni presek proteze v stegnenici.An example embodiment of a reconstructive cementless hip endoprosthesis with a tapered element according to the invention is shown in Figure 1 and an example of a plug-in design in Figure 2. The figures show a vertical section of a denture in the femur.

Deblo endoproteze 1 je v bistvu konični femoralni žebelj cevastega profila iz biološko inertne snovi in take površinske makro- in mikrostrukture, za katero je znano dobro vraščanje kosti (npr. titanove legure z mikroporami okoli 70um) ali biološko inertne snovi, na katero je nanesena kosti kemično sorodna snov (npr. kalcijev hidroksiapatit) oz. biološko aktivna snov (npr. BMP - bone morphogenic protein). Na njenem vratu 3 je standardni konus 12/14 mm za standardno glavo 5, s katero je stegenski del proteze v artikulaciji s sklepno ponvico. Deblo 1 (Slika 1) omogoča prehod vijaka z glavo 6, ki seže v navoj konusa 2 s krilci 7, ki preprečujejo njegovo rotacijo. Ob pritegovanju vijaka 6 drsi konus navzgor in razpira ozobljene nožiče 4 distalnega dela proteze 8 tako, da se zagozde v okolišnjo kost. Alternativno je fiksacija izvedena tako (Slika 2), da distalno v stožec oblikovani vijak 11 s proksimalnimi navoji 12 ob pritegnitvi v deblo proteze 1 z navojem na njenem proksimalnem delu 3 razrine ustrezno poševno brušene čepe 13 iz njihovega ležišča v prečnih vrtinah distalnega dela debla proteze 8, da se čvrsto vtisnejo v okolišnjo kost 14.The endoprosthesis 1 trunk is essentially a conical femoral nail of a tubular profile of biologically inert material and of such superficial macro- and microstructures known to have good bone ingrowth (eg, titanium alloys with micropores of about 70um) or biologically inert material to which the bone is applied a chemically related substance (eg calcium hydroxyapatite) or. biologically active substance (eg BMP - bone morphogenic protein). On her neck 3 is a standard cone 12/14 mm for standard head 5, with which the femoral part of the prosthesis is in articulation with a joint pan. Trunk 1 (Figure 1) allows the passage of a screw with a head 6 extending into the thread of the cone 2 with the wings 7, which prevent its rotation. By tightening the screw 6, it slides the cone upwards and opens the toothed blades 4 of the distal portion of the prosthesis 8 so that it wedges into the surrounding bone. Alternatively, the fixation is performed (Fig. 2) such that a distally screw-shaped cone 11 with proximal threads 12, when screwed into the trunk of the prosthesis 1 with a thread on its proximal part 3, breaks a properly obliquely milled plug 13 from their position in the transverse holes of the distal portion of the trunk of the prosthesis. 8 to press firmly into the surrounding bone 14.

Pri operativnem posegu kirurg najprej odstrani omajan vstavek, kostni cement in granulacijsko tkivo. Z zaporednimi koničnimi svedri pripravi stegnenični kanal brez agresivnejšega povrtavanje na ustrezno debelino. Nato vstavi rekonstrukcijsko deblo ter ga zabije do odgovarjajoče globine v stegnenični kanal z ozirom na dolžino spodnje okončine. S pritegom vijaka 6 oz. 11 ob vratu debla proteze 3, ko je le-to še v izpahnjenem položaju, povzroči čvrst spoj distalnega dela rekonstrukcijskega debla in zdrave kostnine stegnenice, tako da dodatno pogrezanje vstavka ni več možno. Zaradi stabilnosti spoja je pričakovati še hitrejšo tvorbo nove kosti ob deblu proteze, kot je iz literature znano pri podobnih protezah. Zavoljo svoje lokacije sta vijaka kirurgu jasno vidna in dostopna skozi običajno operativno rano, ki se rutinsko uporablja pri tovrstnih posegih. Separatna rana za distalno fiksacijo oz. dodatno vrtanje in uvajanje vijakov ni potrebna.In surgery, the surgeon first removes the stained insert, bone cement and granulation tissue. With successive tapered drill bits, prepare the femoral canal without turning more aggressively to the proper thickness. He then inserts the reconstruction trunk and inserts it to the proper depth into the femoral duct with respect to the length of the lower limb. With 6 oz bolt tightening. 11 at the neck of the trunk of the prosthesis 3, when it is still in the inflated position, causes a firm connection of the distal part of the reconstructive trunk and a healthy femur bone, so that additional insertion of the insert is no longer possible. Due to the stability of the joint, the formation of new bone at the denture trunk is expected to be even faster than is known in the literature for similar dentures. Because of their location, the screws are clearly visible to the surgeon and accessible through a normal surgical wound, which is routinely used in such procedures. Separate wound for distal fixation. no additional drilling and screwing is required.

Čvrstost vstavitve omogoča uporabo rekonstrukcijske brezcementne kolčne endoproteze na zaklep tudi za premostitev s strani primarnega ali sekundarnega tumorja oslabljene proksimalne stegnenice ali za sanacijo zlomov v tem področju.Insertion strength allows the use of reconstructive, cementless hip endoprosthesis on the lock also for bridging the primary or secondary tumor of the weakened proximal femur or for repair of fractures in this area.

Claims

PATENT APPLICATION

Reconstructive, cementless hip endoprosthesis on lock, characterized in that the prosthesis trunk (1) is designed to allow the passage of a screw (6) along the longitudinal axis, which tightening at the upper part of the prosthesis causes the conical element (7) to approach and thereby open the blades. (4) in the lower part of the prosthesis; or so as to allow passage below into the cone of the milled screw (11) which, when tightened, breaks the obliquely milled studs (13) from their transverse beds in the lower part of the prosthesis; or made of memory material which, upon insertion into the body of the patient, due to a change in temperature or under the influence of another harmless force or field to the patient, permanently alters its shape so as to allow a firm anchorage of the endoprosthesis in the medulla of the femur.