Search results for "Cruciate ligament"
showing 10 items of 49 documents
Fractional order hereditariness of knee human ligament and tendon
2017
Anterior Cruciate Ligament (ACL) is one of the four major ligaments in the knee, playing a critical role in stabilizing the joint. ACL is highly susceptible to injury, overall during sport activities, often precipitating catastrophic long-term joint outcomes. The ideal replacement graft for a torn ACL would restore native anatomy and function to the knee. Most commonly used autograft and allograft, including patellar tendon (P) and hamstring tendon (H) graft, or bioengineered synthetic grafts, may substantially alter the biomechanics of the knee, permitting a return to only moderate physical activities [1]. Main issues are the sub-optimal graft properties [2] and a still incomplete biomecha…
How preconditioning and pretensioning of grafts used in ACLigaments surgical reconstruction are influenced by their mechanical time-dependent charact…
2021
Abstract Purpose Consensus about a pre-implant preparation protocol adaptable to any graft used in Anterior Cruciate Ligament reconstruction is still lacking. In fact, there is not agreement on reliable metrics that consider both specific graft dimensional characteristics, such as its diameter, and the inherent properties of its constitutive material, i.e. ligaments or tendons. Aim of the present study was to investigate and propose the applied engineering stress as a possible metrics. Methods Preconditioning and pretensioning protocol involved groups of grafts with different section (10 or 32 mm2) and materials (i.e. human patellar and hamstring tendons, and synthetic grafts). A 140 N load…
Influence of age on osteoarthritis progression after anterior cruciate ligament transection in rats.
2013
Abstract The anterior cruciate ligament transection (ACLT) model of osteoarthritis (OA) in young rats is widely used to study the pathogenesis of OA and possible treatment approaches. As aging is a key factor in the progression of this condition, it is hypothesized that animals may vary in their responses to ACLT according to their age. The histopathological features of young (2 month-old) and middle-aged (12 month-old) rats in the presence or absence of ACLT were compared. The results indicated that moderate degradative changes can be detected in the knee joints of sham-operated middle-aged rats compared with young animals. After ACLT, cartilage degradation was significantly higher in midd…
Regulation of the inflammatory response by tin protoporphyrin IX in the rat anterior cruciate ligament transection model of osteoarthritis
2010
The purpose of this study was to investigate several inflammatory mediators and cartilage degradation molecules as possible biomarkers of joint lesion in the anterior cruciate ligament transection (ACLT) model of osteoarthritis in rats. We also assessed whether the treatment with the anti-inflammatory agent tin protoporphyrin IX (SnPP) reduces the progression of disease. Our results indicate that serum levels of interleukin (IL)-6 and PGE2 are significantly increased in ACLT rats 10 weeks after surgery, whereas the increases in IL-1β and tumor necrosis-α were not significant. In addition, our data suggest that IL-17 is the main pro-inflammatory cytokine in the ACLT joint. We have shown that…
Faszikuläre und subfaszikuläre Architektur der Ligamenta cruciata
1992
Morphologie der Kollagenfaszikel und Vaskularisationsdichte von vorderem und hinterem Kreuzband wurden durch kombinierte histologische, transmissions- und rasterelektronenmikroskopische, morphometrische und immunhistochemische Studien analysiert. Die Fibrillendurchmesser im vorderen Kreuzband lagen zwischen 20 und 155 nm (x=74 nm, s=18.8 nm) und im hinteren Kreuzband zwischen 20 und 175 nm (x=82 nm, s=25,4 nm). Kollagen Typ III und VI besasen ein diffuses Verteilungsmuster mit einem Maximum in der Ansatzzone der Bander. Der Kollagen-Typ-IV-Gehalt des vorderen Kreuzbandes war gering. Die Anzahl der Kreuzbandarteriolen zeigte ein charakteristisches Verteilungsmuster (vorderes Kreuzband: unter…
A non-linear stochastic approach of ligaments and tendons fractional-order hereditariness
2020
Abstract In this study the non-linear hereditariness of knee tendons and ligaments is framed in the context of stochastic mechanics. Without losing the possibility of generalization, this work was focused on knee Anterior Cruciate Ligament (ACL) and the tendons used in its surgical reconstruction. The proposed constitutive equations of fibrous tissues involves three material parameters for the creep tests and three material parameters for relaxation tests. One-to-one relations among material parameters estimated in creep and relaxations were established and reported in the paper. Data scattering, observed with a novel experimental protocol used to characterize the mechanics of the tissue, w…
Anatomic Posterolateral Knee Reconstructions Require a Popliteofibular Ligament Reconstruction Through a Tibial Tunnel
2010
Background: No biomechanical study has been performed analyzing the merits of reconstructing the popliteofibular ligament (PFL) through a tibial tunnel with an anatomic reconstruction of the posterolateral knee. Hypothesis: There is no difference in an anatomic posterolateral knee reconstruction with or without a PFL reconstruction placed through a tibial tunnel in restoring knee motion to the intact, uninjured state, and the knee is not overconstrained with this reconstruction. Study Design: Controlled laboratory study. Methods: Eight paired knees were tested in the intact state and then sectioned to simulate a grade III posterolateral knee injury. The reconstruction for the first paired …
Unterschiede im Erhaltungszustand zwischen vorderem und hinterem Kreuzband bei rheumatoider Arthritis
2008
In rheumatoid arthritis (RA) we examined the cruciate ligaments of 16 patients by the use of light- and transmission electron microscopy. Considerable differences between the anterior (ACL) and the posterior cruciate ligament (PCL) were observed. The ACL showed dramatic ultrastructural changes, against that the PCL was compact and well conserved. The preservation of PCL in joint surgery can morphologically be recommended. Perhaps the greater inflammatory process on the surface of ACL is responsible for the observed differences.
MRT des Kniegelenkes: Fehleranalyse bezüglich der Meniskus- und Kreuzbanddiagnostik an einem arthroskopisch kontrollierten Patientenkollektiv
1998
PURPOSE To categorise discrepancies in findings of the menisci and anterior cruciate ligament (ACL) between arthroscopy and MRI. MATERIALS AND METHODS The MRIs of 236 patients were retrospectively analysed by an experienced radiologist without knowledge of clinical and/or operative findings. Discrepancies in arthroscopic findings were reevaluated together with the arthroscopist to determine their cause of error. RESULTS The diagnostic accuracies for injuries of the medial and lateral meniscus and the ACL were 92.4%, 92.4%, and 94.1%, respectively. For the menisci, causes for discrepancies in findings (n = 31) were: overinterpretation of central signal intensities with contact to the menisca…
Niederfeld-MR-Tomographie des Kniegelenkes: Ergebnisse einer prospektiven, arthroskopisch kontrollierten Studie
2008
PURPOSE To define the diagnostic accuracy of an open low-field MR unit (Magnetom Open, Siemens, Erlangen) in traumatic knee lesions. MATERIALS AND METHODS The MRIs of 150 patients were prospectively evaluated by two independent readers with different experience levels. The study protocol included a proton-density weighted SE-sequence in the sagittal, a T2.-weighted Flash-2D-sequence in the coronal, and a 3D-acquisition (DESS) in the axial plane. 75 patients were treated either conservatively or operatively. RESULTS Based on arthroscopy as the gold standard, the sensitivities, specificities, and diagnostic accuracies for lesions of the medial and lateral meniscus, the anterior cruciate ligam…