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Polven eturistisiteen (ACL) katkeaminen on vakava polven ligamenttivamma, joka yleensä johtaa toistuviin polven alta pettämisoireisiin, turvotteluun ja kipuiluun. Hoitona on rekonstruktio käyttäen esim. potilaan omia Hamstring-jänteitä tai patellajänteen keskikolmannesta siirteenä. Tämän tutkimuksen tarkoituksena oli tutkia kliinisiä paranemistuloksia tähystysleikkauksessa tehdyn eturistisiteen rekonstruktion jälkeen. Myös siirteen paikan, lihasvoimien sekä polven leikkaushetkisen kunnon yhteys paranemistuloksiin selvitettiin. Lisäksi kartoitettiin leikkauksenjälkeisen nivelrikon esiintyvyys sekä siihen liittyviä tekijöitä. Prospektiivisessa randomoidussa tutkimuksessa verrattiin uutta eturistisiteen tuplasiirretekniikkaa perinteisesti käytettyyn yhden siirteen tekniikkaan. Magneettitutkimuksella arvioitiin biosulavien ruuvien ja metalliruuvikiinnityksen eroja paranemistuloksissa. Yhteenvetona tästä tutkimuskokonaisuudesta voitiin todeta, että ACL-rekonstruktiopotilailla on lihasvoimavajauksia vielä 6 vuotta leikkauksen jälkeen, joskin voimavajaukset näyttävät pienenevän ajan myötä. Yhden siirteen leikkaustekniikkaa käytettäessä sekä femoraalisen että tibiaalisen siirteen paikan yhtäaikainen arviointitulos korreloi sekä etu-takasuuntaisen että kiertosuuntaisen polven tukevuuden kanssa. Polvissa joissa oli kierukkavamma ACL-korjausleikkauksen aikaan, on odotettavissa enemmän polven kulumamuutoksia. Eturistisiteen rekonstruktion uusi tuplasiirretekniikka näyttää johtavan parempaan polven kiertosuuntaiseen tukevuuteen kuin yhden siirteen leikkaustekniikka. Se näyttää suojaavan polvea myös uusintavamman aiheuttamalta siirteen pettämiseltä. Biosulavien ruuvien käyttö yhden siirteen tekniikassa johtaa suurempaan femoraalisen tunnelin laajenemiseen kuin metalliruuvien käyttö, sekä useammin siirteen pettämiseen. The objective of this thesis was to evaluate the clinical outcome of the anterior cruciate ligament (ACL) reconstruction with a hamstring autograft. The associations of the graft placement, muscle strength, and the condition of the knee at the time of the operation with the clinical outcome were studied. Also, the prevalence of osteoarthritis in mid-term and the factors associated with it were characterized. In addition, in a prospective, randomized study, a novel double-bundle reconstruction technique was compared to a conventional technique, and magnetic resonance imaging (MRI) was used to evaluate the outcome of bioabsorbable versus metal screw fixation. Patients clinical assessment included evaluation of the anteroposterior and rotational knee stability, and the knee scoring system of the International Knee Documentation Committee (IKDC). The anteroposterior stability testing was done with a KT-1000-arthrometer. The subjective-functional assessment of the knee was done by a Lysholm knee score, and patients activity level was evaluated using the Tegner score. The functional performance of the knee was evaluated using the one-leg-hop -test, and muscle strengths of the lower extremities were measured by Dynacom testing apparatus. The radiographic knee assessment of the osteoarthritic changes and ACL-graft placement was done. MRI was used to study the extent of graft-tunnel widening, absorption of the bioabsorbable screws, and possible adverse tissue reactions. The study I showed that the muscle strength deficits at the injured lower extremity persisted even 3 to 7 years after the ACL reconstruction. However, they seemed to recover with time, especially the quadriceps strength of the patients with a bone-patellar tendon-bone (BTB) autograft. This suggested that in BTB patients the quadriceps strength was lower postoperatively compared to those treated with a hamstring autograft. The knee flexion (hamstring), and knee extension (quadriceps) strength deficits were associated with the subjective Lysholm score indicating that the smaller the strength difference between the operated and the non-operated limb, the less the patient experienced symptoms in the knee. Also, the knees with no instability had less flexion torque deficit than the knees with nearly normal or abnormal stability. The study II revealed a correlation between the femoral graft position and the Lysholm score, so that the more posterior the graft was placed, the higher was the score. Simultaneous evaluation of the femoral and tibial graft placements proved useful by predicting both the anteroposterior and rotational stability of the knee. The study III showed that meniscectomy at the time of the ACL reconstruction resulted in more severe osteoarthritic changes in the knee than reconstruction without meniscectomy. Also, the Lysholm score was higher when meniscectomy was not done. The prospective, randomized study IV comparing a novel double-bundle ACL-reconstruction technique to a conventional single-bundle technique indicated that the new technique resulted in better rotational stability of the knee and was able to protect the patients from a reinjury-induced graft failure. No between-groups difference was noted in the occurrence of complications, or IKDC or Lysholm scores. The study V showed that postoperative femoral tunnel widening was larger with the bioabsorbable screws than metal screws, as judged with the MRI 2-years postoperatively. In the tibia, no difference was noted. The use of bioabsorbable screws resulted in more graft failures compared to the use of metal screws. After excluding the graft failures, the clinical outcome of the patients was equally good in the two groups. The follow-up tibial tunnel diameter correlated with the stability. In conclusion, the studies I-V of this thesis showed that muscle strength deficits in the injured extremity 6 years after the ACL reconstruction were associated with inferior clinical outcome of the patient. However, the muscular performance seemed to improve by time, also in long-term. The graft placements (as assessed by simultaneous evaluation of the femoral and tibial graft placements) had an effect on both anteroposterior and rotational knee stability so that optimal graft positioning improved the stability. More severe osteoarthritic changes could be expected in the knees showing accompanying meniscal injury at the time of the reconstruction. A new double-bundle ACL reconstruction technique resulted in better rotational stability of the knee than the conventional single-bundle technique, and, it seemed to protect the knee from reinjury-induced graft failures. Finally, the use of bioabsorbable screws with the single-bundle technique resulted in larger femoral tunnel widening than the use of metal screws, and more graft failures.

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Multicomponent standard submicron particles for EM microanalysis have been produced via combined sol-gel and aerosol methods. The particles were found suitable for microanalysis standard materials and for the study of mass size effect. Particles with uniform composition containing silicon, titanium, iron and oxygen were produced at 800 ºC. Thermal treatment at higher temperatures resulted in formation of separate rutile and hematite phases and iron clusters. Cluster size of the separated phases can be altered via temperature control.

We have investigated the development of crystal morphology and phase in ultrafine titanium dioxide particles. The particles were produced by a droplet-to-particle method starting from propanolic titanium tetraisopropoxide solution, and calcined in a vertical aerosol reactor in air. Mobility size classified 40 nm diameter particles were conveyed to the aerosol reactor to investigate particle size changes at 20-1200°C with 5-1 s residence time. In addition, polydisperse particles were used to study morphology and phase formation by electron microscopy. According to differential mobility analysis, the particle diameter was reduced to 21-23 nm at 600°C and above. Precursor decomposition occurred between 20°C and 500°C. The increased mobility particle size at 700°C and above was observed to coincide with irregular particles at 700°C and 800°C and faceted particles between 900°C and 1200°C, according to transmission electron microscopy. The faceted anatase particles were observed to approach a minimized surface energy by forming {101} and {001} crystallographic surfaces. Anatase phase was observed at 500-1200°C and above 600°C the particles were single crystals. Indications of minor rutile formation were observed at 1200°C. The relatively stable anatase phase vs. temperature is attributed to the defect free structure of the observed particles and a lack of crystal-crystal attachment points.

Multicomponent standard submicron particles have been produced via aerosol method combined with sol-gel chemistry. Suitability of the particles for EM microanalysis standard material use was studied. Particles with uniform composition containing Si, Ti, Fe and O were produced at 800 ºC. Thermal treat-ment at higher temperatures resulted in formation of separate rutile and hematite phases and iron clusters. Cluster size of the separated phases can be altered via temperature control.

A method to produce titanium oxide powders by in-droplet hydrolysis of metal alkoxide precursor was studied. Onset of titanium dioxide crystallization on the aerosol particles was investigated. Titanium hydrous oxide particles were prepared starting from an acetic acid modified titanium alkoxide precursor solution aerosol at 200 °C in tube flow reactor. Titanium n-tetrabutoxide, hydrolysis water, and acetic acid were included in the ethanolic precursor solution that was nebulized. The droplets were transported to a tubular flow reactor where the chemical reactions formed solid particles. The powders were characterized by XRD, TG-SDTA, BET, SEM, TEM, EDS, XRF, IR- spectroscopy, and with aerosol impactor. Micron sized powder particles were amorphous, smooth on the surface, and either spherical or deflated in shape. Subsequently, titanium dioxide particles were produced by thermal post-annealing of the powders in air. The onset of crystallization of aerosol particles to nanocrystalline TiO2 was investigated at 500 °C reactor temperature. Thinned particles were studied and the initial crystallization was observed to be localized on the surface of the particles.

We have studied the ultrafine TiO2 particle morphology and phase transformation from anatase to rutile in aerosol reactor. The particles were prepared via aerosol decomposition of titanium tetraisopropoxide (TTIP) droplets. Aerosol was produced by dispersing precursor solution by aerosol nebulizer and subsequently evaporating the propanol solvent. The TTIP droplets were size selected using a differential mobility analyzer (DMA). The 45 nm mobility size fraction was transported to a tube reactor in air carrier gas with a flow rate of 1.0 lpm. Experimental runs were made between 600 and 900 °C. In the flow reactor the TTIP droplets were thermolyzed to TiO2 particles. The particle size was measured with a second DMA downstream of the flow reactor. Particle microstructure was investigated with transmission electron microscope (TEM). Computer simulations of the reactor temperature and flow fields were made. The tandem-DMA results show how particle size is reduced during the aerosol decomposition and subsequently by TiO2 densification and phase change. The original TTIP droplet size is reduced by 30 % at 700 °C reactor temperature and finally by 35 % at 900 °C to reach 30 nm rutile particle size. The high resolution TEM (HR-TEM) and electron diffraction (ED) results of the nanosized TiO2 particles reveal the crystallite size and phase transformation at different reactor temperatures.

Mustalipeän poltossa muodostuvien tuhkahiukkasten ominaisuuksia tutkittiin käyttämällä alipaineimpaktoria (BLPI), ionikromatografiaa (IC) ja pyyhkäisyelektronimikroskopiaa (SEM). BLPI:n avulla saatiin selvitettyä hiukkasten aerodynaaminen kokojakauma 0,01-100 µm:n alueella. Eri kokoluokista tehtiin kemialliset analyysit IC:llä. Hiukkasten keskimääräinen halkaisija kolmessa eri kokoluokassa määritettiin SEM-kuvista. SEM:iin yhdistetyllä röntgenanalysaattorilla määritettiin näytteiden kemiallinen koostumus, jota verrattiin IC:llä saatuihin tuloksiin.