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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of this scientific investigation, made prior to 1977, was to determine the suitability of a polypropylene prosthetic ACL. The 3.6 mm diamond-braided prosthesis was implanted in 17 dogs. The device was passed through a trough on the anteromedial side of the tibial crest and over the top of the lateral femoral condyle. The device was internally fixed at both ends to bone using a bushing-lag screw technique which resulted in solid prosthesis immobilization at the time of surgery. Animals were necropsied at 3, 6, or 10 months after implantation. There was partial or total disruption of the prosthesis in all cases. Destruction of the prosthesis was attributed to excessive viscoelasticity of the device and fatigue failure. Based on this study, prosthetic ACL replacement using this device is not recommended.
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PMID:Evaluation of the polypropylene braid as a prosthetic anterior cruciate ligament replacement in the dog. 342 81

Reconstruction of the knee with a chronic injury to the anterior cruciate ligament is an unsolved problem. Biologic graft substitutes have failed to maintain knee stability in the longer postreconstruction intervals. In an attempt to overcome the limitations in graft performance, synthetic materials have been proposed to augment the biologic tissue. In this study, a 6-mm polypropylene braid Ligament Augmentation Device (LAD) possessing a tensile strength of 1500 N and excellent fatigue and creep properties was investigated as an adjunct to the MacIntosh/Marshall Over-the-Top repair. A two-year animal study of 54 adult goats was conducted in which experimental ACL defects were created and reconstructed with a transplant consisting of a portion of the rectus femoris tendon, prepatellar tissue, and the central one-third of the patellar tendon. The goats were equally divided between nonaugmented and LAD-augmented groups and sacrificed at three, six, 12, and 24 months after surgery. Mechanically, the augmented transplants were substantially stronger at the time of initial implantation (364N versus 26N) and again at two years (841N versus 528N). Intermediate times did not demonstrate a difference in strength. Histologically, the augmented transplants consisted of a loosely organized fibrous capsule surrounding the LAD. At 24 months, "insertion fibers" were noted to provide continuity between the fibrous tissue and bone on both the tibia and femur.
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PMID:Experimental mechanical and histologic evaluation of the Kennedy ligament augmentation device. 388 66

The purpose of this study was to determine muscle activities after ACL rupture during walking and running and to investigate the influence of mild fatigue (10 min walking) on these activities. A group of 12 patients with ACL-ruptures was compared with a control group (healthy volunteers) of 15 persons. Linear envelopes of EMG-activity from vastus medialis, vastus lateralis, biceps femoris and medial hamstrings were measured. Patients and control persons walked on a treadmill at speeds of 1.2 m/s (samples at t = 2 min and t = 12 min) and 2.8 m/s i.e. running (sample at t = 15 min). The patient group showed significantly lower muscle activities of vastus lateralis (p < 0.001) and medial hamstrings (p < 0.05) for both the injured and uninjured leg during running compared to the control group. After 10 minutes walking, the mean-EMG of biceps femoris (p < 0.05) and medial hamstrings (p < 0.01) decreased as did the activity time of biceps femoris (p < 0.05), medial hamstrings (p < 0.01) and vastus medialis (p < 0.001) for the injured leg of the patient group. Control persons showed no significant changes. Thus, mild fatigue did effect only the EMG-pattern of the patients. Patients with ACL-ruptures should be trained not only on strength and stabilisation, but also on endurance. A decrease in hamstrings activity during walking might be a sensitive measure for evaluation of the rehabilitation process, as those muscles may be able to substitute ACL-deficiency.
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PMID:EMG profiles of ACL-deficient patients during walking: the influence of mild fatigue. 789 Apr 66

Three Norwegian physicians crossed the inland glacier of Greenland on skis without any support. Body weight, fat and lean body mass was measured by dual X-ray absorptiometry scanning. Maximal oxygen uptake, lung capacity measurements, and various blood tests were recorded. Subjective health-related well-being and four transistory arousal states were also recorded (GHQ-30 and AD ACL, short form). One participant lost 1 kilo body weight, while the others gained 1 and 4 kilos, respectively, during the trip. Overall, lean body mass increased (1.2-4.0 kg), while body fat was reduced (0.4-2.7 kg). These changes reversed after four weeks. Bone mass, lung function and blood tests did not vary throughout the study period. The level of energy and calmness were high at baseline and even higher towards the end of the expedition, while the scores were low and stable for tiredness and tension. Subjective well-being increased for all participants towards the second half of the trip. We conclude that expeditions involving physical and mental strain can produce positive psychological changes. Catabolic conditions are avoidable. Changes in body mass composition revert quickly.
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PMID:[Skiing over Greenland--physical and psychological changes]. 941 73

The presence of antibodies to cardiolipin (ACL Abs) has been reported in some patients suffering from multiple sclerosis (MS), especially of the "neuromyelitic" type. In addition, bright T2-imaging foci (unidentified bright objects) are occasionally detected on brain magnetic resonance imaging (MRI) scans, in patients with antiphospholipid syndrome. From a cohort of 100 patients with a probable or definite diagnosis of MS according to Poser's criteria, we isolated a subgroup of 20 patients (8 males and 12 females) consistently positive for ACL Abs. These patients were followed up neurologically for 1 to 3 years and brain MRI scanning and a complete autoimmune screening were performed. Nineteen (19 of 20) of our patients had the classic neuroimaging features of MS (multiple white-matter T2 bright foci on the MRI scan). The most common neurological syndrome was chronic, slowly progressing myelopathy (presenting as myelopathy, neuromyelitis optica, or spinocerebellar syndrome; 15 of 20), and optic neuropathy (6 of 20). Headache was a dominant symptom in 8 of 20 patients. Less common symptoms included cognitive and psychiatric disorders and chronic fatigue. The mean levels of ACL Abs were 38.8+/-28.2 GPL (normal values up to 7.5). Oligoclonal bands in the cerebrospinal fluid were detected in only 3 of 20 patients. Patients were treated with acetylsalycilic acid and occasionally with short courses of steroids. The progression of the chronic myelopathic/spinocerebellar syndrome was slower than expected in MS (only 2 patients deteriorated whereas 4 improved during a mean follow-up period of 20.8+/-7.1 months). We conclude that patients with probable or definite diagnosis of MS, and consistently elevated levels of ACL Abs show a slower progression and some atypical (for MS) features, such as persistent headaches and absence of oligoclonal bands in the cerebrospinal fluid. In these patients, other, presumably vascular, mechanisms may be involved in the pathogenesis of the neurological symptoms. Therefore, management should include antiplatelet or even anticoagulant agents.
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PMID:A subgroup of multiple sclerosis patients with anticardiolipin antibodies and unusual clinical manifestations: do they represent a new nosological entity? 977 61

In view of the opposing theories regarding the arousing or de-arousing action of total sleep deprivation (TSD) in producing antidepressant effects, 23 patients with a major depressive disorder were deprived of a night's sleep twice weekly for two weeks, and self-rated their condition 38 times using von Zerssen's scale for depression and, concurrently, Thayer's Activation Deactivation Adjective Check List (AD ACL). Transient relief of depression after TSD, indicated by eight patients, was mimicked by their AD ACL scores, which revealed the same underlying factors as were found in Thayer's studies. TSD appears to be simultaneously arousing (giving more energy) and de-arousing (leading to less tension), while this response takes place against a background of increased tiredness/sleepiness. It is argued that TSD sets off a psychological disinhibition process on the basis of cerebral fatigue; in particular the prefrontal (orbital?) areas of the cerebral cortex may be implicated, possibly in relation to a dampening down of subcortical arousal systems.
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PMID:Self-rated arousal concurrent with the antidepressant response to total sleep deprivation of patients with a major depressive disorder: a disinhibition hypothesis. 1060 54

This biomechanical study analyzed the mechanical properties of different linkage systems commonly used in hamstring tendon ACL reconstruction. Two kinds of tapes, 5-mm braided polyester (Mersilene) and 3-mm woven polyester (Orthotape), were connected to a particular staple in bovine bone sections in single- and double-loop constructs with five replicates of each. These constructs underwent straight pull tensile tests, residual tensile tests, and fatigue tests at a loading regime of 540,000 cycles at 25 Hz frequency, using an Instron tensile test machine. Protrusion heights of the constructs were measured. The double-loop Mersilene-Fastlok construct was weaker than either single-loop or double-loop Orthotape-Fastlok construct. The mean failure strength of double-loop Orthotape-Fastlok was 93% higher and its mean stiffness was 40% greater at failure than that of Mersilene-Fastlok. At a 150-N load Mersilene-Fastlok was stiffer, while at 300 N Orthotape-Fastlok was stiffer. The thickness of Orthotape-Fastlok resulted in 1 mm more device protrusion. In hamstring tendon ACL reconstructions with indirect fixation we advocate the use of woven polyester (Orthotape) with Fastlok as a linkage material over braided polyester (Mersilene) with Fastlok because of its superior strength and stiffness.
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PMID:Hamstring graft tibial fixation: biomechanical properties of different linkage systems. 1244 8

This paper evaluates four highly cited measures of energy and fatigue moods. Substantial experimental and correlational evidence supports the conclusion that scores from the vitality scale of the SF-36 Health Survey can provide a valid measure of the recalled frequency of month-long feelings of energy and fatigue. Substantial experimental and correlational evidence supports the conclusion that scores from the fatigue and vigor scales of the Profile of Mood States (POMS) can provide reliable and valid measures the intensity of both week-long and "right now" fatigue and energy mood states, respectively. A smaller body of evidence supports the conclusion that scores from the energy scale of the Activation-Deactivation Adjective Checklist (AD-ACL) can provide a valid measure of the "right now" mood of energy; however, the energy scale of the AD-ACL has several limitations compared to the POMS vigor scale. All the measures lacked integration within a compelling theory of the mood of energy-fatigue. It is concluded that progress in understanding of energy and fatigue mood states will be aided by advances in both the psychobiological conceptualization of fatigue and energy mood states and their measurement.
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PMID:Evaluation of four highly cited energy and fatigue mood measures. 1558 46

This communication reports the results of a three-dimensional finite element (FE) model of stresses in a surgically altered femur and tibia. The model incorporated a novel approach in implementing orthotropic and inhomogeneous bone properties and non-uniform distributed loading. Cortical, cancellous, and subchondral bone of the femur and the tibia were modeled. Mechanical properties for the cortical and cancellous bone were mapped from published data characterizing the anisotropy and inhomogeneity of the bone properties. Mesh adequacy was determined using stress convergence and strain energy error convergence. Qualitatively, the results of the study compare well with experimental principal compressive strains from the literature. With respect to tunnel placement in anterior cruciate ligament reconstruction, the model predicted stress-shielding at the postero-lateral region of the tunnel wall, and increased stress at the postero-medial region of the tunnel wall. The stresses in the cancellous bone beneath the tunnel were, in general, lower than those above the tunnel. Prolonged stress shielding leads to bone resorption of the posterior tunnel wall leading to tunnel enlargement, and possible compromise of the ACL reconstruction. The stresses on the femoral cortex produced from a button-type fixation were noticeable for low levels of loading; the stress levels were very similar in models incorporating bone properties of patients aged 45 and 65. Repeated compression of the femoral cortex at these stress levels may cause microdamage to the cortex eventually resulting in fatigue failure.
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PMID:A three-dimensional finite element stress analysis for tunnel placement and buttons in anterior cruciate ligament reconstructions. 1571 4

The purpose of this study was to develop a test battery of hop tests with high ability to discriminate (i.e. high test-retest reliability, sensitivity, specificity and accuracy) between the hop performance of the injured and the uninjured side in patients with an ACL injury and in patients who have undergone ACL reconstruction. Five hop tests were analysed: three maximum single hop tests and two hop tests while developing fatigue. Fifteen healthy subjects performed the five hop tests on three separate occasions in a test-retest design. Thirty patients, mean 11 months after an ACL injury and 35 patients, mean 6 months after ACL reconstruction were tested. ICC values ranged from 0.85 to 0.97 for the five hop tests, indicating that all the tests had high test-retest reliability. Sixty-seven percent to 100% of the healthy subjects had normal symmetry (i.e. <10% side-to-side difference) in the five hop tests. Abnormal symmetry in the five hop tests ranged from 43 to 77% for patients with an ACL injury and from 51 to 86% for patients who had undergone ACL reconstruction respectively. The three tests with the highest ability to discriminate hop performance were chosen for the test battery; they were the vertical jump, the hop for distance and the side hop. The test battery revealed a high level of sensitivity and accuracy in patients with an ACL injury (87 and 84%) and in patients who had undergone ACL reconstruction (91 and 88%), when at least one of the three tests was classified as abnormal. To summarise, the test battery consisting of both maximum single hop performances: the vertical jump and the hop for distance and hop performance while developing fatigue: the side hop, produced high test-retest reliability, sensitivity and accuracy. Further, the test battery produced higher values compared with any of the three hop tests individually revealing that only one out of ten patients had restored hop performance 11 months after an ACL injury and 6 months after ACL reconstruction. It is concluded that this test battery showed a high ability to discriminate between the hop performance of the injured and the uninjured side both in patients with an ACL injury and in patients who have undergone ACL reconstruction.
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PMID:A test battery for evaluating hop performance in patients with an ACL injury and patients who have undergone ACL reconstruction. 1652 96


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