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The anterior cruciate ligament (ACL) contributes to normal knee function, but it is commonly injured and has poor healing capabilities. Of the current treatments available for ACL reconstruction, none replicate the long-term mechanical properties of the ACL. It was hypothesized that tissue-engineered scaffolds comprised of reconstituted type I collagen fibers would have the potential to yield a more suitable treatment for ACL reconstruction. Ultra-violet (UV) radiation and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) were investigated as possible crosslinking methods for the scaffolds, and EDC crosslinking was deemed more appropriate given the gains in strength and stiffness afforded to individual collagen fibers. Scaffolds were composed of 54 collagen fibers, which were made using an extrusion process, organized in accordance with a braid-twist design; the addition of a hydrogel (gelatin) to this scaffold was also investigated. The scaffolds were tested mechanically to determine ultimate tensile strength (UTS), Young's modulus, and viscoelastic properties. Scaffolds were also evaluated for the cellular activity of primary rat lateral collateral ligament (LCL) and medial collateral ligament (MCL) fibroblast cells after 7, 14, and 21 days. The crosslinked scaffolds without gelatin exhibited mechanical and viscoelastic properties that were more similar to the human ACL. Cellular activity on the crosslinked scaffolds without gelatin was observed after 7 and 21 days, but no significant increase was observed with time. Although more studies are needed, these results indicate that a braid- twist scaffold (composed of collagen fibers) has the potential to serve as a scaffold for ACL replacement. / Master of Science

Objective-To assess the effect of 9 mm tibial tuberosity advancement (TTA) on cranial tibial translation (CTT) in cranial cruciate ligament (CCL) deficient canine stifles. Study Design-In vitro cadaveric study. Animals-Twelve canine pelvic limbs. Methods-Each stifle was placed in a jig at 135° with a simulated quadriceps force and tibial axial force, and the distance of CTT was measured with the CCL intact (iCCL), transected (tCCL), and after performing a TTA using a 9 mm cage. In addition, a material testing machine was used to assess the force required to elicit CTT in each scenario. Results-The mean CTT for iCCL was 0.42 mm, 1.58 mm after severing the CCL, and 1.06 mm post TTA. The tCCL CTT measured without any quadriceps force was 2.59 mm. Differences between the intact and tCCL (p<0.0001) and tCCL and TTA (p=0.0003) were significant. The difference between the tCCL with and without the quadriceps force was not significant (p=0.0597). The force required to cause CTT was greater in the TTA than the tCCL up to 6mm (p<0.0001). As axial load increased, the force required to advance the tibia increased in both treatment groups (p value for overall weight effect =0.0002). Conclusions- These data confirm that TTA does reduce CTT in tCCL stifles in this model. The addition of a simulated quadriceps force to a CCL deficient stifle prior to a TTA, by itself, may not significantly lessen CTT. Clinical Relevance- While this in vitro model demonstrated that TTA reduced CTT in canine stifles with CCL transected, the modular limitations preclude extrapolation to the effect of TTA on the live dog. / Master of Science

Objective: The aims of this prospective clinical cohort study were to determine the prevalence of asymptomatic bacteriuria in dogs with cranial cruciate ligament disease and to determine which clinical parameters and clinicopathologic data are associated with asymptomatic bacteriuria. Another aim was to determine the incidence of surgical site infections in dogs with and without asymptomatic bacteriuria. Results: In 156 dogs with cruciate ligament disease, the prevalence of asymptomatic bacteriuria was 7.1%. Furthermore, the prevalence was 12.4% in female dogs and 0% in male dogs. The most common bacterial isolate was Escherichia coli. Patient sex, urine white blood cells/ high-powered field, and microscopic bacteriuria were significantly different between dogs with and without asymptomatic bacteriuria. Only 60% of dogs with microscopic bacteriuria had growth on urine aerobic culture. No significant difference was found in age, body weight, body condition score, duration of lameness, limb affected, or other urinalysis values between dogs with and without asymptomatic bacteriuria. Of the dogs that had 8-week repeat cultures, 2/3 dogs with asymptomatic bacteriuria had negative urine cultures and 3/43 without asymptomatic bacteriuria had positive urine cultures. Of 57 dogs that received surgery and had sufficient follow-up, 15 developed surgical site infection. All surgical site infections occurred in dogs without AB. The incidence of surgical site infection in this population was 26.3% (15/57). Conclusions: Prevalence of asymptomatic bacteriuria in dogs presenting with cranial cruciate ligament disease was similar to previously reported values in male and female dogs. This suggests that dogs with cranial cruciate ligament disease are not more prone to asymptomatic bacteriuria than dogs in previously studied populations. Preliminary data suggests that AB does not predispose dogs to SSI however further research and continued data collection is warranted. / Master of Science / Asymptomatic bacteriuria is defined as having bacteria in the urine without signs of lower urinary tract disease. The aim of this study was to determine the prevalence asymptomatic bacteriuria in dogs with cranial cruciate ligament disease. Additionally, another aim was to determine the incidence of surgical site infections after cranial cruciate ligament surgery in dogs with and without asymptomatic bacteriuria. Prevalence of asymptomatic bacteriuria in dogs presenting with cranial cruciate ligament disease was found to be similar to previously reported values in male and female dogs. This suggests that dogs with cranial cruciate ligament disease are not more prone to asymptomatic bacteriuria than dogs in previously studied populations. Preliminary data suggests that dogs with bacteria in the urine does not predispose dogs to SSI however further research and continued data collection is warranted.

Objective - To compare preoperative tibial plateau leveling osteotomy planning using the common tangent method to the current conventional method and evaluate the effect on tibial translation and patellar ligament angle following rotation of the tibial plateau. Study Design – Cadaveric study. Seven paired canine pelvic limbs. Methods- Radiographs of the stifle were taken at 135° of extension prior to and following rotation of the tibial plateau under load (0N and 30N). The tibial plateau of each limb was rotated both according to the common tangent and conventional method. Tibial plateau angle (TPA), tibial translation, and the patellar ligament angles (PLA) were measured radiographically following rotation of the tibial plateau. Results- There was no significant difference between planning methods with regards to the amount of rotation of the tibial plateau or position of the tibia relative to the femur following rotation. There was no significant association between the postoperative tibial plateau angle and position of the tibia relative to the femur between groups. There was no significant difference between the patellar ligament angles following rotation based on the common tangent or conventional method preoperative TPLO planning. Conclusion- Both the conventional and common tangent TPLO planning results in adequate proximal tibial rotation to achieve a PLA of approximately 90°, thereby counteracting the compressive shear forces during ambulation. The TPA for both groups following rotation had no significant impact on the amount of cranial or caudal tibial translation relative to the femur. / Master of Science / Cranial cruciate ligament disease is one of the most common diseases of the stifle in dogs, and causes great discomfort. The tibial plateau leveling osteotomy (TPLO) procedure is designed to change the geometry of the tibia's articular surface, such that the femur no longer slides in a caudal direction during weight bearing. Conventional methods of planning do not consider the curved anatomical surface of the tibial condyles, but rather treat the condyles like a flat surface. The goal of this study was to compare the current conventional planning methods with a new technique, the common tangent method, and to evaluate if the common tangent method improves accuracy and tibial translation after surgery. Results of this study show that there was no statistically significant difference in rotation and tibial position between the two planning groups. However, it was found that the common tangent method consistently required less rotation of the tibial articular surface than the conventional method, but still achieved similar postoperative tibial translation. This implies that there may be overcorrection when performing the TPLO under the current conventional method, which could predispose the patients to strain on the caudal cruciate ligament and patellar ligament leading to discomfort. The common tangent method is a feasible way of planning for a TPLO procedure, and shows potential utility in cases where excessive tibial rotation would otherwise cause increased risk for complications or necessitate a more complex procedure.

Objective: To evaluate the effect of two tibial attachment sites for lateral suture stabilization (LSS) on the kinematics of the cranial cruciate ligament-deficient (CrCL-D) canine stifle during early, middle and late stance.<br />Study design: In vitro biomechanical study: 32 hind limbs from 16 canine cadavers.<br />Methods: Limbs were mounted in a testing jig and an electromagnetic tracking system was used to determine 3-D stifle kinematics under 33% body weight load during early, middle and late stance in the following sequence: CrCL intact, CrCL-D and LSS with the distal anchor through the tibial tuberosity (LSSTT) or through the cranial eminence of the extensor groove (LSSEG). The proximal anchor point was the lateral femoro-fabellar ligament.<br />Results: Transection of the CrCL resulted in significant changes in stifle kinematics during early, middle and late stance. Post-LSS stifle kinematics were more comparable to normal than post-transection kinematics for both techniques. Both LSS techniques restored stifle kinematics in CrCL-D stifles to varying amounts but neither technique successfully restored normal 3-D stifle kinematics. LSSEG improved kinematics of the CrCL-D stifle in the medial-lateral direction and axial rotation but performed poorly in restoring stifle kinematics in the cranial-caudal plane as compared to LSSTT.<br />Clinical significance: LSSTT and LSSEG techniques failed to completely restore normal stifle kinematics in CrCL-D stifles in vitro. / Master of Science

Majoriteten av idrottsskador inklusive skada på främre korsbandet (Anterior Cruciate Ligament, ACL) uppstår i slutet av träning/tävling när personen tenderar att vara trött. Nuvarande funktionstest inför återgång till idrott efter skada utvärderar ofta individens hoppförmåga i ett icke-uttröttat tillstånd. Syfte: Syftet med följande studie var att se huruvida prestationen i två olika enbenshopp kunde skilja sig mellan före och efter 25 minuters löpning, varav 15 minuter på hög-intensiv nivå och om hopprestationen skiljer sig mellan oskadade och ACL-opererade kvinnor. Metod: Totalt deltog 8 friska kvinnor, utan pågående besvär från nedre extremitet samt 6 färdigrehabiliterade ACL-opererade kvinnor som återgått till sin tidigare aktivitetsnivå. Deltagarna genomförde tester vid två olika tillfällen. Ett Pre-test-tillfälle då inträning av distans- och cross-overhopp samt ett max-pulstest (HRmax) på löpband utfördes. Ett Test-tillfälle där respektive hopp utfördes före och efter cirka 25 minuters löpning varav 15 minuter var på hög-intensiv nivå (&gt;RPE 15 eller &gt;85 % av HRmax). Total distans mättes, registrerades och analyserades för två godkända hopp per ben, tillstånd och hopptyp. Antal hopp-försök per ben och hopp registrerades. Ett symmetri index (LSI) beräknades för att bedöma om det förelåg en normal eller onormal sidoskillnad. Resultat: Cross-overhoppet var signifikant kortare efter löpning jämfört med före. Samma resultat syntes inte för distanshoppet. Ingen skillnad fanns mellan grupperna i hopplängd eller LSI-värden, före eller efter löpning. Ingen onormal sidoskillnad syntes före eller efter löpning i något utav hoppen. ACL-skadade behövde signifikant fler hoppförsök på det opererade benet i uttröttat tillstånd jämfört med det icke-opererade och jämfört med oskadade för att uppnå två godkända hopp. Slutsats: Cross-overhoppet försämrades av löpningen och kan därför sägas vara känsligt nog att kunna skilja uttröttat från icke-uttröttat tillstånd hos båda grupperna. Samma resultat syntes inte för distanshoppet. Det uttröttningsprotokoll och de hopptester som utfördes kunde inte frambringa några större förändringar eller olika sidoskillnader mellan färdigrehabiliterade ACL-opererade kvinnor som återgått till sin tidigare aktivitetsnivå och oskadade, generellt fysisk aktiva kvinnor. Viss osäkerhet kan ha funnits kvar hos det tidigare skadade benet eftersom fler hoppförsök krävdes i uttröttat tillstånd på det opererade benet jämfört med det icke-opererade benet eller jämfört med oskadade deltagare för båda hopptyperna. / Most sport injuries including anterior cruciate ligament-injury (ACL) occur at the end of sport events when the person tends to be fatigued. Despite this, the tests commonly used today to assess whether the individual should return to sports are performed in a non-fatigued state. Aim: The aim of this study was to compare effects of 25 minutes treadmill running, including 15 minutes at a level of high-intenisty on the performance of two different single-leg hop tests between un-injured women and women who underwent an ACL-reconstruction. Method: Eight un-injured women without any ongoing symptoms from either leg, and 6 women who had undergone an ACL-reconstruction, finished the rehabilitation program and returned to their pre-injury level of activity performed tests at two different occasions. The first occasion included technique training for each single-leg hop and a maximal heart rate test (HRmax) on a treadmill. On the second occasion subjects performed the single-leg hop for distance and the cross-over hop before and directly after 25 minutes running, including 15 minutes on a high-intensity level (&gt;RPE 15 and/or &gt;85 % HRmax). Total jump-distance was measured, registered and analysed for 2 approved trials per leg, condition and hop. A leg symmetry index (LSI) was calculated to assess side-to-side-differences. Results: The cross-over hop was significantly shorter after running in both groups, whereas no such effect was seen for the single-leg hop for distance. No difference was shown between groups in performed distance, side-to-side difference or LSI-values, before or after running any of the single-leg hops. Subjects in the ACL-group needed significantly more hop-trials on the operated leg compared to the non-operated leg and compared to un-injured subjects to achieve two qualified hops. Conclusions: Subjects jumped shorter in the cross-over hop after running. This hop can therefore be regarded as sensitive enough to tell fatigued state from a non-fatigued state in both groups. The fatigue protocol did not induce any side-to-side differences in subjects who had undergone ACL-reconstruction, finished their rehabilitation and returned to their pre-injury activity level. Some insecurity may still have been present in the previously injured leg since ACL-operated subjects needed more hop-trials for the operated leg compared to the non-operated leg or compared to un-injured subjects when fatigue.

Em uma tentativa de melhor restabelecer a função normal do ligamento cruzado anterior (LCA), foi proposta a técnica de reconstrução do LCA com feixe duplo (FD). Entretanto, a superioridade desta técnica frente à técnica com feixe simples (FS) ainda não está claramente demonstrada no cenário clínico. O propósito do presente estudo foi avaliar e comparar a amplitude de rotação tibial, o máximo de rotação interna e externa, e a força de reação ao solo de joelhos submetidos à reconstrução anatômica com feixe duplo, a joelhos submetidos à reconstrução com feixe simples, durante a realização de tarefas dinâmicas. Para isso, um total de 75 (setenta e cinco) indivíduos foram avaliados (26 reconstruções feixe duplo, 22 reconstruções feixe simples, 27 indivíduos sem lesão do LCA que formaram um grupo controle). Utilizando um sistema de análise do movimento humano, constituído por 4 câmeras para a análise do movimento, os indivíduos foram avaliados em três tarefas de demandas distintas. Utilizou-se a técnica TSACCAST para o cálculo da rotação interna e externa da tíbia. A média da amplitude de rotação tibial, máximo de rotação interna e externa, foi avaliada para cada joelho em cada um dos três grupos. A avaliação clínica destes pacientes foi realizada utilizando-se questionários subjetivo e objetivo (IKDC), assim como artrometria manual. Estas avaliações revelaram que ambos os grupos operados eram semelhantes no que se refere ao resultado clínico pós-operatório. A avaliação da amplitude de rotação tibial, máximo de rotação interna e externa, demonstrou que o joelho operado era semelhante ao joelho não operado e aos joelhos do grupo controle. Também não se verificou diferença significativa nos valores de amplitude de rotação tibial, máximo de rotação interna e externa, quando se comparou o grupo FS ao grupo FD. Desta forma, concluímos que a reconstrução do LCA com a técnica de FS e com a técnica de FD são similares no que se refere ao restabelecimento do controle da rotação da tíbia / In an attempt to better restore the normal function of the two ACL bundles, the ACL reconstruction with two bundles has been proposed. However, the superiority of the double-bundle technique has not been clearly demonstrated in the clinical setting. The purpose of this study was to compare the tibial rotational range, maximal internal and external rotation and ground reaction force of anatomical double-bundle anterior cruciate ligament reconstructed knees with single-bundle anterior cruciate ligament reconstructed knees during three different demanding tasks. A total of 75 subjects, (26 with double-bundle anterior cruciate ligament reconstruction, 22 with single-bundle anterior cruciate ligament reconstruction, and 27 healthy control individuals) were evaluated in this study. Using a 4-camera motion analysis system, motion subjects were recorded performing during three different tasks. Using the CAST technique, the internal-external tibial rotation of both knees was calculated. The mean tibial rotational range, maximum internal and external rotation, for each knee, was evaluated for the 3 groups (double-bundle group, single-bundle group, and control group). Clinical assessment, including objective and subjective IKDC scores, and knee arthrometric measurement, revealed restoration of the reconstructed knee stability with no differences between the two anterior cruciate ligament reconstruction groups. The results demonstrated that both groups resulted in tibial rotation range values that were similar to those in the non-injured knees and those in the healthy controls. There were also no significant differences in tibial rotational range, maximal internal and external rotation and ground reaction force between the DB group and the SB group. Therefore, anatomical double-bundle and single-bundle reconstruction are able to restore normal tibial rotation