• Journal of Mechanical Science and Technology
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• v.18 no.4
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• pp.582-591
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• 2004

The purpose of this study was to determine the effects of elbow joint angle on mechanical properties, as represented by ultimate load, failure strain and elastic modulus, of bone-tendon specimens of common extensor tendon of the humeral epicondyle. Eight pairs of specimens were equally divided into two groups of 8 each, which selected arbitrarily from left or right side of each pair, positioned at 45$^{\circ}$ and 90$^{\circ}$ of elbow flexion and subjected to tension to failure in the physiological direction of the common extensor tendon. For comparison of the differences in the failure and elastic modulus between tendon and the bone-junction, data for both were evaluated individually. Significant reduction in ultimate load of bone-tendon specimens was shown to occur at 45$^{\circ}$. The values obtained from the bone-tendon junctions with regard to the failure strain were significant higher than those from tendon in both loading directions, but the largest failure strain at the bone-tendon junction was found at 45$^{\circ}$. The elastic modulus was found to decrease significantly at the bone-tendon junction when the loading direction switched from 90$^{\circ}$ to 45$^{\circ}$. Histological observation, after mechanical tensile tests, in both loading directions showed that failure occurred at the interface between tendon and uncalcified fibrocartilage in the thinnest fibrocartilage zone of the bone-tendon junction. We concluded that differences in measured mechanical properties are a consequence of varying the loading direction of the tendon across the bone-tendon specimen.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.141-147
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• 2012

Recently, the external prestressed concrete structures are increasingly being built. The mechanical behavior of prestressed concrete beams with external tendon is different from that of normal bonded PSC beams in that the increment of tendon stress was derived by whole member behavior. By this reason, the ultimate stress of external tendon is smaller than that of bonded tendon or internal unbonded tendon. The purposes of the present paper are therefore to improve the mechanical behavior of external unbonded tendon by using partially bonded external tendon and to evaluate the flexural behavior of partially bonded external tendon by the flexural member experiment. From the experimental results, before flexural cracking, there was no difference between external unbonded, partially bonded and bonded tendons. However, after cracking, yielding load of reinforcement, ultimate load, and tendon stress were increased in the sequence of external unbonded, partially bonded and bonded tendon members. The equation of ACI-318 and AASHTO 1994 were not matched with test results and had no correlations. So the newly proposed equation will be needed including the consideration of tendon profile, tendon bonded type, and so on. The proposed partially bonded external tendon in this paper will be a effective basis for the evaluation of external tendons in construction and design.

• Journal of the Korean Society of Safety
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• v.25 no.5
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• pp.44-53
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• 2010

Recently, the external prestressed concrete structures are increasingly being built. The mechanical behavior of prestressed concrete beams with unbonded tendon is different from that of normal bonded PSC beams in that the increment of tendon stress was derived by whole member behavior. By this reason, the ultimate stress of external tendon is smaller than that of bonded tendon or internal unbonded tendon. However, in the domestic and abroad code, the equation of ultimate stress of external tendon is not suggested yet, and the equation of ultimate stress of internal unbonded tendon is used instead of that of external tendon. Therefore, in this paper, after effective variables of ultimate stress of external tendon were analyzed, the analytical equation of ultimate stress of external tendon was proposed. And the reasonable coefficients were proposed by statistical work of test results of 25 beam with external tendon. Finally, the practical proposed equation of ultimate stress of external tendon was proposed with analytical and statistical model. The equation of ACI-318 and AASHTO 1994 were not matched with test results and had no correlations, and the proposed equation was well matched with test results. So the proposed equation in this paper will be a effective basis for the evaluation of external tendons in analysis and design.

• Journal of Korean Foot and Ankle Society
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• v.17 no.4
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• pp.309-315
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• 2013

Purpose: The purpose of the study was to investigate five cases with chronic Achilles tendon rupture that occurred after steroid injections. Materials and Methods: In our hospital, we experienced five cases of chronic Achilles tendon rupture from September 2010 to March 2012. All patients had got steroid injection for Achilles tendinitis at the other hospitals, and their heel pain was aggravated when they visited our outpatient department. After treatment, signs and symptoms of Achilles tendon rupture were developed and the diagnosis was confirmed by ultrasonography or magnetic resonance imaging (MRI). Surgical treatment was done for Achilles tendon rupture. Results: There was difference between intra-operative findings of Achilles tendon rupture and usual chronic Achilles tendon rupture. Unlike usual findings of chronic Achilles tendon rupture whose scar tissue or tissue attenuation are found around the defect area of Achilles tendon, there were partial necrosis of tendon severe adhesion with surrounding tissue, extensive defect and longitudinal rupture on ruptured area. Also, severe inflammation of paratenon, granulation and fibrinoid deposit were found on biopsy findings in four cases. Conclusion: Based on review of data about relative risk and benefit of local corticosteroid injection to inflammatory lesion in Achilles tendon, it requires more attention to Achilles tendon rupture following local corticosteroid injection.

• Journal of Korean Foot and Ankle Society
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• v.19 no.3
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• pp.114-117
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• 2015

Deep infection of Achilles tendon is one of the serious complications that occur after open repair of the tendon. It sometimes leads to a very large tendon defect during the course of treatment. We report on a case of massive defect in Achilles tendon, which was successfully treated with Achilles tendon allograft and flexor hallucis longus tendon transfer.

• Smart Structures and Systems
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• v.20 no.2
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• pp.181-195
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• 2017

In this study, the severity of damage in tendon anchorage caused by the loss of tendon forces is quantitatively identified by using the PZT interface-based impedance monitoring technique. Firstly, a 2-DOF impedance model is newly designed to represent coupled dynamic responses of PZT interface-host structure. Secondly, the 2-DOF impedance model is adopted for the tendon anchorage system. A prototype of PZT interface is designed for the impedance monitoring. Then impedance signatures are experimentally measured from a laboratory-scale tendon anchorage structure with various tendon forces. Finally, damage severities of the tendon anchorage induced by the variation of tendon forces are quantitatively identified from the phase-by-phase model updating process, from which the change in impedance signatures is correlated to the change in structural properties.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.1 no.1
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• pp.58-63
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• 2008

Mechanism of the peroneal tendon dislocation is mainly the ankle trauma and commonly caused by severe peroneal tendon contraction at ankle dorsiflexion state. Peroneal tendon tears are frequently combined in recurrent dislocation. The peroneal tendon dislocation from the fibula groove can be confirmed with ultrasound scanning. Recurrent dislocation needs surgical treatment and usually gains good clinical outcome with fibula groove deepening procedure. Tibialis anterior tendon rupture is frequently found in old age but active patients who had tendency of tendon weakness due to chronic tendon attrition, repeated steroid injection, diabetic tendinopathy or inflammatory arthropathy.

• Computers and Concrete
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• v.3 no.1
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• pp.43-64
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• 2006

A tendon model that can effectively be used in finite element analyses of prestressed concrete (PSC) structures with bonded tendons is proposed on the basis of the bond characteristics between a tendon and its surrounding concrete. Since tensile forces between adjacent cracks are transmitted from a tendon to concrete by bond forces, the constitutive law of a bonded tendon stiffened by grouting is different from that of a bare tendon. Accordingly, the apparent yield stress of an embedded tendon is determined from the bond-slip relationship. The definition of the multi-linear average stress-strain relationship is then obtained through a linear interpolation of the stress difference at the post-yielding stage. Unlike in the case of a bonded tendon, on the other hand, a stress increase beyond the effective prestress in an unbonded tendon is not section-dependent but member-dependent. The tendon stress unequivocally represents a uniform distribution along the length when the friction loss is excluded. Thus, using a strain reduction factor, the modified stress-strain curve of an unbonded tendon is derived by successive iterations. The validity of the proposed two tendon models is verified through correlation studies between analytical and experimental results for PSC beams and slabs.

• Archives of Plastic Surgery
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• v.32 no.4
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• pp.539-542
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• 2005

Reconstructions of soft tissue defect of the posterior ankle including Achilles the tendon should take into account not only coverage but functional outcome. Various methods of tendon transfer and tendon graft have been reported as a single-stage procedure. With advances and refinements in microsurgical techniques, several free composite flaps including tendon, fascia, or nerve have been used in single-stage reconstructions of large defects in this area minimizing further damage to the traumatized leg. However, when free flap is not feasible for some reasons, this cannot be accomplished successfully. Here we present a patient with Achilles tendon and circumferential large soft tissue defect. Because of circulatory compromise of the lower extremity, free flap reconstruction could not be applied. Instead, cross-leg composite flap of the dorsalis pedis flap including the extensor hallucis brevis musle and tendon, and tendon strips of the Second, third and fourth extensor digitorum logus were employed, Functional reconstruction of the tendon and resurfacing were obtained at the same time. The flap was detached 3 weeks postoperatively, and the transplanted flap has survived without any complications. By 3 months after surgery, full weight bearing, tip-toe standing and even walking without crutch assistance was possible. When functional reconstruction with the free flap is unattainable in the large defect of the posterior ankle including the Achilles tendon, cross-leg composite island flap of dorsalis pedis flap and tendon strips of the extensor digitorum longus tendon is a viable alternative.

• Journal of Korean Foot and Ankle Society
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• v.13 no.1
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• pp.99-102
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• 2009

Heterotopic ossification of Achilles tendon is known to be related with history of prior Achilles tendon surgery, trauma, Achilles tendon rupture. We report a case of heterotopic ossification of partially ruptured Achilles tendon and treated by surgical removal of ossification and V-Y advancement with tendon repair.