• 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 Korean Foot and Ankle Society
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• v.23 no.2
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• pp.74-77
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• 2019

Fibroma of the tendon sheath (FTS) was initially described in 1936 by Geschickter and Copeland as a benign firmed soft tissue tumor that is rare and less common than another soft tissue tumors, especially giant cell tumors (GCT) of the tendon sheath. The common distinct feature is a slow-growing least painful rare entity arising from the tendon or tendon sheath. FTS is detected mostly in the fingers, hands and wrists but less commonly in the foot. Very few cases of FTS have been described arising from a flexor tendon of the foot. This article describes a 51-year-old patient with FTS that developed in the extensor tendon of the foot, which is the only known FTS to form in this area. Heterogeneous low signal intensity in both the T1- and T2-weighted images was observed in magnetic resonance imaging. The lesion was excised completely by open surgery. Histologically, it showed randomly arranged, fibroblast-like spindle cells in dense fibrous tissue and had insufficient hemosiderin-laden macrophages that are typical for GCT.

• The Korean Journal of Pain
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• v.7 no.1
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• pp.34-38
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• 1994

The common disorder called tennis elbow exhibits typical clinical characteristics, i.e. painful condition at the lateral aspect of elbow joint on resisted wrist extension. However an exact cause for this painful condition has not yet been established. Many observers believe that the usual lesion of tennis elbow is a partial rupture of the extensor tendon at the tenoperiosteal juction on the lateral epicondyle of humerus. However the mechanism of the tendon rupture has never been explained. Conservative treatments on the tender area have been the most common therapeutic modalities for pain relief of tennis elbow. Based on my clinical experiences and anatomical studies, I discerned that tennis elbow is a periostitis of lateral epicondyle of humerus secondary to spastic contraction of muscular belly of extensor carpi radialis after over-stretched injury. Therefore, spasmolytic treatment on the extensor carpi radialis muscle provided a favorable result for permanent relief for tennis elbow pain.

• Journal of Mechanical Science and Technology
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• v.15 no.7
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• pp.1013-1021
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• 2001

A series of rabbit common extensor tendon specimens of the humeral epicondyle were subjected to tensile tests under two displacement rates (100mm/min and 10mm/min) and different elbow flexion positions 45°, 90°and 135°. Biomechanical properties of ultimate tensile strength, failure strain, energy absorption and stiffness of the bone-tendon specimen were determined. Statistically significant differences were found in ultimate tensile strength, failure strain, energy absorption and stiffness of bone-tendon specimens as a consequence of different elbow flexion angles and displacement rates. The results indicated that the bone-tendon specimens at the 45°elbow flexion had the lowest ultimate tensile strength; this flexion angle also had the highest failure strain and the lowest stiffness compared to other elbow flexion positions. In comparing the data from two displacement rates, bone-tendon specimens had lower ultimate tensile strength at all flexion angles when tested at the 10mm/min displacement rate. These results indicate that creep damage occurred during the slow displacement rate. The major failure mode of bone-tendon specimens during tensile testing changed from 100% of midsubstance failure at the 90°and 135°elbow flexion to 40% of bone-tendon origin failure at 45°. We conclude that failure mechanics of the bone-tendon unit of the lateral epicondyle are substantially affected by loading direction and displacement rate.

• Anatomy and Cell Biology
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• v.56 no.1
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• pp.137-140
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• 2023

Tibialis anterior (TA) muscle originates from the lateral surface of tibia and its tendon attaches to the medial cuneiform and base of the first metatarsal. The TA muscle is responsible for both dorsiflexion and inversion of the foot. We present a case of bilateral TA muscle variations that diverge slightly from the current classification systems of this muscle. Recognizing variations such as these may be important for anatomists, surgeons, podiatrists, and physicians. Following routine dissection, an accessory tendon of the TA muscle was found on both sides. Accessory tendons of the extensor hallucis longus and extensor hallucis brevis joined to form a common tendon on both sides. We believe that this unique case will help further the classification systems for the tendons of the TA and also be informative for clinical anatomists as well as physicians treating patients with pathology in this region.

• Archives of Plastic Surgery
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• v.50 no.2
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• pp.177-181
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• 2023

Digital extensor hypoplasia (DEH) is a rare malformation that presents with loss of active finger extension at the metacarpophalangeal (MCP) joints. Descriptions of optimal treatment and outcomes in this population are sparse. We describe successful operative treatment of a child with DEH involving the extensor digitorum communis, extensor digiti minimi, and the extensor indicis proprius tendons. The 5-year-old male patient was referred for severe limitation on bilateral finger extension since birth. He had been previously diagnosed with arthrogryposis and managed conservatively. Due to lack of improvement, magnetic resonance imaging was done evidencing hypoplasia/aplasia of the extensor tendons. The patient underwent successful tendon transfers using extensor carpi radialis longus to the common extensor tendons, and one hand required an additional tenolysis procedure. 2 years postoperatively, his MCP position and finger extension are markedly improved, and he is able to grip objects without limitation or difficulty. The patient returned to full activity without restriction.

• Journal of Biomedical Engineering Research
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• v.19 no.4
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• pp.393-401
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• 1998

Based on clinical observations, it is suspected that the bone-tendon origin is the site where piratical failure, leading to pathophysiological changes in the humeral epicondyle after repetitive loading, is initiated Mechanical properties and failure patterns of the common extensor and flexor tendons of the humeral epicondyle under static and repetitive loading have not been well documented. Our goal was to determine mechanical properties of failure strength and strain changes, to correlate strain changes and the number of cyclic repetitions, and to identify the failure pattern of bone-tendon specimens of common extensor and flexor tendons of the humeral epicondyle. Mechnaical properties of human cadaver bone-tendon specimens of the common extensor and flexor tendons of the humeral epicondyle were tested under two different loading rates. No statistically significant difference in ultimate tensile strength was found between male and female specimens or between slow (10 mm/sec) and fast elongation (100 mm/sec) rates. However, a statistically significant difference in ultimate tensile strength between the common extensor (1190.0 N/$cm^2{\pm}$388.8) and flexor 1922.0 N/$cm^2{\pm}$764.4)tendons was found (p<0.05). When loads of 25%, 33%, and 41% of the ultimate tensile strength of their contralateral sides were applied, the number of cycles required to reach 24% strain change for the common extersor and flexor tendons were approximately 8,893, 1,907, and 410, respectively. The relationship between cycles and loads was correlated ($R^2$=0.46) Histological observation showed that complete or partial failure after tensile or cyclic loadings occurred at the transitional zone, which is the uncalcified fibrocartilage zone between tendon and bone of the humeral epicondyle. Sequential histological sections revealed that failure initiated at the upper, medial aspect of the extensor carpi radialis brevis tendon origin. Biomechanical and hstological data obtained in this study indicated that the uncalcified fibrocartilage zone at the bone-tendon origin of the common extensor and flexor tendons is the weak anatomical structure of the humeral epicondyle.

• Archives of Plastic Surgery
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• v.38 no.6
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• pp.836-844
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• 2011

Purpose: Hands are the chief organs for physically manipulating the environment, using anywhere from the roughest motor skills to the finest, and since the fingertips contain some of the densest areas of nerve endings on the human body, they are continuously used organ with complex functions, and therefore, often gets injured. To prevent any functional loss, a detailed anatomical knowledge is required to have a perfect surgical treatment. Also it is necessary to have a thorough understanding of arrangements of the human extensor tendons and intertendinous connections when tenoplasty or tendon transfer is required. We performed a study of the arrangements of the human extensor tendons and the configuration of the intertendinous connections over the dorsum of the wrist and hand. Methods: A total of 58 hands from Korean cadavers were dissected. The arrangements of extensor indicis proprius, extensor digitorum communis, and extensor digiti minimi tendons and intertendinous connections were studied. Results: The most common distribution patterns of the extensor tendons of the fingers were as follows: a single extensor indicis proprius (EIP) tendon which inserted ulnar to the extensor digitorum-index (EDC-index); a single EDC-index; a single EDC-middle; a double EDC-ring; an absent EDC-little; a double extensor digiti minimi (EDM), a single EDC-index (98.3%), a single EDC-middle (62%), a double EDC-ring (50%), and an absent (65.5%) or a single (32.8%) EDC-little. A double (70.6%) EDM tendons were seen. Intertendinous connections were classified into 3 types: type 1 with thin filamentous type, type 2 with a thick filamentous type, and type 3 with a tendinous type subdivided to r shaped 3r type and y shaped 3y type. The most common patterns were type 1 in the 2nd intermetacarpal space, type 2 in the 3rd intermetacarpal space, and type 3r in the 4th intermetacarpal space. And in the present study, we observed one case of the extensor digitorum brevis manus (EDBM) on the boht side. Conclusion: A knowledge of both the usual and possible variations of the extensor tendon and the intertendinous connection is useful in the identification and repair of these structures.

• Archives of Plastic Surgery
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• v.32 no.2
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• pp.259-261
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• 2005

Ganglion is the most common soft tissue tumor of the hand, and most of them usually arise from the scapholunate ligament, scarphotrapezial ligament, radiocarpal joint or flexor tendon sheath. However, intratendinous ganglion is very rare with unknown etiology and pathogenesis that originates within tendon. We have experienced three clinical cases of intratendinous ganglion in extensor tendons of hand. The average of patients at operation was 36 years. All patients were treated by excision of the ganglion in conjunction with tenosynovectomy followed by repair of the tendon. The length of mean follow up time was 6.7 months and all of them showed no evidence of recurrence.

• Journal of Korean Foot and Ankle Society
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• v.13 no.2
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• pp.193-196
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• 2009

The first metatarsophalangeal joint injury is common in professional soldiers and athletes. But this was rarely reported. A professional soldier has varus instability in the first metatarsophalangeal joint due to hyperextension. In the MR Imaging, weavy appearance in lateral collateral ligament and high signal change in plantar plate was shown. So he has surgical treatment using reconstructive procedure. At first, $4^{th}$ extensor digitorum longus tendon was splitted longitudinally and harvested, second triangular shape reconstruction on lateral joint line was done using harvested tendon. One year later, fifteen degrees was limited compared with intact side. Reconstruction using $4^{th}$ extensor digitorum longus tendon in traumatic dynamic hallux varus was good method.