Total hip arthroplasty in young patients : with special references to patients under 55 years of age and to patients with developmental dysplasia of the hip

There is an ongoing controversy as to which methods in total hip arthroplasty (THA) could provide young patients with best long-term results. THA is an especially demanding operation in patients with severely dysplastic hips. The optimal surgical treatment for these patients also remains controversial. The aim of this study was to evaluate the long-term survival of THA in young patients (<55 years at the time of the primary operation) on a nation-wide level, and to analyze the long-term clinical and radio-graphical outcome of uncemented THA in patients with severely dysplastic joints. Survival of 4661 primary THAs performed for primary osteoarthritis (OA), 2557 primary THAs per-formed for rheumatoid arthritis (RA), and modern uncemented THA designs performed for primary OA in young patients, were analysed from the Finnish Arthroplasty Register. A total of 68 THAs were per-formed in 56 consecutive patients with high congenital hip dislocation between 1989-1994, and 68 THAs were performed in 59 consecutive patients with severely dysplastic hips and a previous Schanz osteotomy of the femur between 1988-1995 at the Orton Orthopaedic Hospital, Helsinki, Finland. These patients underwent a detailed physical and radiographical evaluation at a mean of 12.3 years and 13.0 years postoperatively, respectively. The risk of stem revision due to aseptic loosening in young patients with primary OA was higher for cemented stems than for proximally porous-coated or HA-coated uncemented stems implanted over the 1991-2001 period. There was no difference in the risk of revision between all-poly cemented-cups and press-fit porous-coated uncemented cups implanted during the same period, when the end point was defined as any revision (including exchange of liner). All uncemented stem designs studied in young patients with primary OA had >90% survival rates at 10 years. The Biomet Bi-Metric stem had a 95% (95% CI 93-97) survival rate even at 15 years. When the end point was defined as any revision, 10 year survival rates of all uncemented cup designs except the Harris-Galante II decreased to <80%. In young patients with RA, the risk of stem revision due to aseptic loosening was higher with cemented stems than with proximally porous-coated uncemented stems. In contrast, the risk of cup revision was higher for all uncemented cup concepts than for all-poly cemented cups with any type of cup revision as the end point. The Harris hip score increased significantly (p<0.001) both in patients with high con-genital hip dislocation and in patients with severely dysplastic hips and a previous Schanz osteotomy, treated with uncemented THA. There was a negative Trendelenburg sign in 92% and in 88% of hips, respectively. There were 12 (18%) and 15 (22%) perioperative complications. The rate of survival for the CDH femoral components, with revision due to aseptic loosening as the end point, was 98% (95% CI 97-100) at 10 years in patients with high hip dislocation and 92% (95% CI, 86-99) at 14 years in patients with a previous Schanz osteotomy. The rate of survival for press-fit, porous-coated acetabular components, with revision due to aseptic loosening as the end point, was 95% (95% CI 89-100) at 10 years in patients with high hip dislocation, and 98% (95% CI 89-100) in patients with a previous Schanz osteotomy. When revision of the cup for any reason was defined as the end point, 10 year sur-vival rates declined to 88% (95% CI 81-95) and to 69% (95% CI, 56-82), respectively. For young patients with primary OA, uncemented proximally circumferentially porous- and HA-coated stems are the implants of choice. However, survival rates of modern uncemented cups are no better than that of all-poly cemented cups. Uncemented proximally circumferentially porous-coated stems and cemented all-poly cups are currently the implants of choice for young patients with RA. Uncemented THA, with placement of the cup at the level of the true acetabulum, distal advancement of the greater trochanter and femoral shortening osteotomy provided patients with high congenital hip dislocation good long-term outcomes. Most of the patients with severely dysplastic hips and a previous Schanz osteotomy can be successfully treated with the same method. However, the subtrochanteric segmental shortening with angular correction gives better leg length correction for the patients with a previous low-seated unilateral Schanz osteotomy.Väitöskirjatutkimuksessa osoitettiin ensimmäistä kertaa väestötasolla, että lonkan tekonivelleikkauksella voidaan saavuttaa hyvät pitkäaikaistulokset myös nuorilla potilailla. Lisäksi todettiin, että sairaala Ortonissa kehitetyllä, teknisesti erittäin vaativalla lonkan tekonivelleikkauksella voidaan merkittävästi vähentää kipua ja parantaa kävelykykyä myös niillä potilailla, joilla lapsuudessa hoitamatta jäänyt lonkan synnynnäinen korkea sijoiltaanmeno on johtanut nivelen vaikeaan kehityshäiriöön. Tutkimus tuo uutta tietoa nuorten potilaiden tekonivelleikkausten tuloksista. Lonkan tekonivelleikkaus on tehokas kirurginen toimenpide, jolla on pääsääntöisesti hyvät lyhyt- ja pitkäaikaisseurantatulokset, ja jonka on osoitettu merkittävästi vähentävän kipua ja parantavan potilaiden elämänlaatua. Tyypillinen lonkan tekonivelleikkaukseen joutuva potilas on 60-80 -vuotias nainen. Aiemmissa tutkimuksissa lonkkatekonivelten kiinnipysyvyystulokset ovat olleet väestötasolla nuorilla potilailla vanhempia heikommat. On ollut kiistanalaista, minkä tyyppinen lonkkatekonivel kestäisi parhaiten nuorilla, aktiivisilla potilailla. Hoitamatta jääneen lonkan korkean synnynnäisen sijoiltaanmenon vaurioittaman lonkkanivelen hoito aikuisiällä lonkan tekonivelleikkauksella on vaativaa ja komplikaatio-altista. Näistä tekonivelleikkauksista on raportoitu hyvin vähän pitkäaikaistuloksia, minkä vuoksi eri leikkausmenetelmien asema on ollut selkiytymätön. Tutkimusta varten analysoitiin Suomen endoproteesirekisterin tietojen perusteella 4661 nuoren, alle 55-vuotiaan nivelrikkopotilaan ja 2557 nuoren reumaatikon lonkan tekonivelleikkausten pitkäaikaistulokset. Lisäksi sairaala Ortonissa jälkitarkastettiin 87 potilasta, joille oli tehty erittäin vaativa lonkan tekonivelleikkaus joko lapsuudessa hoitamatta jääneen korkean synnynnäisen lonkan sijoiltaanmenon vuoksi tai lonkan kehityshäiriön johdosta tehdyn reisiluun muovausleikkauksen jälkeen. Tutkimuksen perusteella sekä nuorille nivelrikko- että reumapotilaille kannattaa valita lonkan tekonivelleikkauksessa reisiluun puolelle moderni sementitön poroosi- tai hydroksiapatiittipinnnoitettu varsiosa. Lonkkamaljakon puolella sementtikiinnitteisellä polyetyleenikupilla saavutettiin paras kiinnipysyvyys nuorilla reumaatikoilla, kun taas nuorilla nivelrikkopotilailla modernien sementittömien ja sementtikiinnitteisten kuppiosien tuloksissa ei ollut eroa. Vaikean lonkkanivelen kehityshäiriön hoidossa sementitön tekonivelleikkaus, jossa reisiluu lyhennettiin iso sarvennoinen alas siirtäen, ja kuppiosa implantoitiin alkuperäisen lonkkamaljakon alueelle, vähensi merkittävästi kipua ja paransi potilaiden kävelykykyä

Nanoscale Assembly Using DNA and Electromagnetic Fields

In this work we demonstrate the control of nanoparticles and nanostructures with the help of the DNA origami method and dielectrophoresis. DNA nanotechnology is a subfield of nanotechnology where DNA is used as a construction material. The DNA origami method is a recent development in the field which enables the assembly of nanoparticles with nanometer scale accuracy through self-assembly. Here we take advantage of the method for efficient deposition and alignment of single-walled carbon nanotubes (SWCNTs). Especially the alignment of SWCNTs on substrates has been a major challenge for commercialization of SWCNT based devices, to which our approach could offer a potential solution. As an example, a crossed carbon nanotube junction, a basic geometry for a carbon nanotube transistor, is constructed. The high yields of assembled structures as well as correct alignment of SWCNTs are verified with atomic force microscopy. The DNA origami method is used also for assembling a bow-tie antenna configuration from silver nanoparticles. The optical response of the system is based on the hybridization of the individual nanoparticle surface plasmon resonance modes. The formation of the structures is verified with transmission electron microscopy and complemented with agarose gel electrophoresis. The configuration could have potential use as an optical DNA sensor. The sensor performance is investigated with finite-difference time-domain numerical simulations. In addition to assembling nanoparticles, control over the DNA origami structure itself is demonstrated with dendrons and external trigger signals. Efficient control over the structure formation is investigated with atomic force microscopy, agarose gel electrophoresis and dynamic light scattering experiments. The external trigger signals can be chosen by choosing the dendron structure. We demonstrate our concept with dendrons which can be triggered either with UV-radiation or with a mild reducing agent such as dithiothretoil. Dielectrophoresis is an electromechanical technique for manipulating micro-and nanoparticles. Here the method is used for developing a new nanoimprint lithographic technique named field-induced nanoimprint lithography. In this technique nanoelectrodes are used for producing dielectrophoretically a pattern of nanoparticles on a re-usable master stamp, which is then used for transferring the nanoparticle pattern on a target substrate by mechanical contact. Dielectrophoresis is also used for producing chains of gold nanoparticles between nano- and microelectrodes. The chains are investigated for sensing purposes with impedance studies.Tämä väitöskirja käsittelee nanohiukkasten ja nanorakenteiden kontrollointia nanomittakaavassa DNA-origami-tekniikan sekä dielektroforeesin avulla. DNA-origami-tekniikka on DNA-nanoteknologian viimeaikaisimpia saavutuksia, jossa DNA:a käytetään geneettisen informaation säilömisen sijaan rakennusmateriaalina. Tässä väitöskirjassa DNA-rakenteita käytetään etenkin erilaisten nanopartikkelien kiinnittämiseen ja asemoimiseen. Ensimmäisenä DNA-origamien sovellutuskohteena osoitamme menetelmän yksiseinäisten hiilinanoputkien kontrolloituun asemoimiseen. Osoitamme lähestymistavan tehokkuuden muun muassa rakentamalla ristiliitoksen kahdesta yksiseinäisestä hiilinanoputkesta - rakenteen, jota voi käyttää hiilinanoputkitransistorina. Vastaavanlaisia rakenteita on erittäin vaikea tuottaa kontrolloidusti perinteisillä menetelmillä, mikä on ollut yksi este hiilinanoputkiin perustuvien laitteiden kaupallistamisessa. Hiilinanoputkien asemoinnin lisäksi sovellamme DNA-origami-tekniikkaa antennirakenteen kokoamiseen hopeananohiukkasista. Todistamme rakenteiden syntymisen atomivoima- sekä läpäisyelektronimikroskoopin avulla. Varmennamme tuloksemme myös geelielektroforeesin avulla. Yhtenä antennirakenteemme sovellutuksena voi olla DNA-anturi; tutkimme myös rakenteemme soveltuvuutta kyseiseen tarkoitukseen numeeristen simulaatioiden avulla. Viimeisenä DNA-origami-tekniikkaan liittyvänä tutkimuksena osoitamme, kuinka DNA-rakennetta itseään voidaan kontrolloida dendronien sekä ulkoisten signaalien avulla. Osoitamme atomivoimamikroskooppi-, geelielektroforeesi- sekä dynaamisten valonsirontakokeiden avulla pystyvämme tehokkaasti kontrolloimaan DNA-rakenteiden muodostumisen. Kontrollisignaalit määräytyvät käytettyjen dendronirakenteiden mukaan. Kokeissamme kontrollisignaaleja ovat ultraviolettivalo sekä mieto redusoiva aine dithiothretoil. Dielektroforeesi on elektromekaaninen menetelmä, jonka avulla voi kontrolloida mikro- sekä nanokokoluokan hiukkasia sähkökenttien gradienttien avulla. Käytämme metodia uuden nanopainamismenetelmän kehittämiseen. Menetelmän pääkomponentti on leimasin, johon kuvioimme nanoelektrodit. Käytämme näitä elektrodeja muodostamaan haluttuja kuvioita nanohiukkasista sähkökenttien gradienttien avulla. Lopulta siirrämme kyseisen kuvion halutulle alustalle mekaanisen painamisen avulla. Nanopainamismenetelmän lisäksi käytämme dielektroforeesia muodostaaksemme nanohiukkasketjuja kultananohiukkasista mikro- sekä nanoelektrodien avulla. Teemme myös impedanssimittauksia kyseisillä ketjuilla anturisovellutusta varten

Outcomes of the rotating hinge knee in revision total knee arthroplasty with a median follow-up of 6.2years

BackgroundThe purpose of this study was to determine the mid-term clinical, radiographic and health-related quality of life (HRQoL) outcomes and define the survival rate in patients who had undergone revision total knee arthroplasty (TKA) using the single rotating hinged knee (RHK) design.MethodsBetween January 2004 and December 2013, 125 revision TKAs were performed at our institution using the single RHK implant. We conducted both a retrospective analysis of prospectively collected outcome data of these patients and a prospective follow-up study of all 39 living patients (41 knees). The follow-up phase included an optional extra follow-up visit, PROM questionnaires, and plain radiographs.ResultsThe ten-year Kaplan-Meier survival rate of the revision RHK knees was 81.7% (95% CI 71.9-91.6%) with re-revision for any reason as the endpoint. Overall, 15 knees (12% of the total) underwent re-revision surgery during the follow-up. The median follow-up was 6.2years (range, 0-12.7years) post-operatively for the baseline group. One mechanical hinge mechanism-related failure occurred without any history of trauma or infection. At the time of the final follow-up, the majority of patients evinced a fairly good clinical outcome measured with patient-reported outcome measures and none of the components were radiographically loose.ConclusionWe found that in patients undergoing complex revision TKA, fairly good functional outcome and quality of life can be achieved using an RHK implant. Further, it seems that in this type of patient cohort, revision TKA using an RHK implant relieves pain more than it improves ability to function. The NexGen (R) RHK design can be regarded as a suitable option in complex revision TKA.Peer reviewe

Good mid-term outcome of the rotating hinge knee in primary total knee arthroplasty - Results of a single center cohort of 106 knees with a median follow-up of 6.3 years

Background: The prognosis of complex primary total knee arthroplasty (TKA) with severe deformity and ligament deficiency is not clear. There is a paucity of evidence in the current literature on treatment outcomes of the rotating hinge knee implants in primary TKA. The aim of this study was to determine the mid-term clinical, radiographic, and health-related quality of life (HRQoL) outcomes in patients who had undergone complex primary TKA using single hinged knee replacement. Methods: In total, 106 complex primary TKAs (101 patients) were performed using the single rotating hinged knee (RHK) implant design at our institution between January 2004 and December 2013. We conducted a retrospective analysis of prospectively collected outcome data of these patients, obtaining also information on all possible revision surgeries from the Finnish Arthroplasty Register, and conducted a prospective follow-up study of all living patients. Results: The 10-year Kaplan-Meier survival rate of the RHK knees was 91.6% (95% CI 86.0% to 97.2%) with revision for any reason as the endpoint. Overall, eight knees (7.5 %) underwent revision surgery during the follow-up. None of the unrevised RHK knees were radio-graphically loose. The majority of patients evinced good clinical outcome and quality of life as measured with patient reported outcome measures. Conclusion: The hinge knee replacement which was assessed current study can be regarded as a suitable option in complex primary TKA, provided adequate attention is paid to the correct indications and patient selection. (C) 2020 Elsevier B.V. All rights reserved.Peer reviewe

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Midterm risk of cancer with metal-on-metal hip replacements not increased in a Finnish population

Background and purpose - Metal-on-metal (MoM) total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA) have been widely used during the early 21st century. We assessed the midterm risk of cancer of patients treated with modern MoM hip implants compared with patients with non-MoM hip implants and the general Finnish population with special interest in soft tissue sarcomas and basalioma due to the findings of our previous report. Patients and methods - All large-diameter head MoM THAs and hip resurfacings performed in Finland between 2001 and 2010 were extracted from the Finnish Arthroplasty Register (10,728 patients). Patients who underwent conventional THA formed the non-MoM reference cohort (18,235 patients). Data on cancer cases up to 2014 were extracted from the Finnish Cancer Registry. The relative risk of cancer in the general population was expressed as the ratio of observed to expected number of cases, i.e., standardized incidence ratio (SIR). Poisson regression analysis was used to compare the cancer risk between the cohorts. The mean follow-up was 7.4 years (1-14) in the MoM cohort and 8.4 years (1-14) in the non-MoM cohort. Results - The overall risk of cancer in the MoM cohort was comparable to the general Finnish population (SIR 0.9, 95% CI 0.9-1.0). Risk of basalioma in the MoM cohort was higher than in the general Finnish population (SIR 1.2, CI 1.1-1.4) and higher than in the non-MoM cohort in the stratified regression analysis (RR 1.2, CI 1.0-1.4, p = 0.02). The SIR of soft-tissue sarcoma in the MoM cohort was 1.4 (CI 0.6-2.8); the incidence was same as in the non-MoM cohort. Interpretation - Metal-on-metal hip implants are not associated with an increased overall risk of cancer during midterm follow-up.Peer reviewe