Artykuły w czasopismach na temat „Tendon”
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Belinov, Nikolay V., i Semen A. Ushakov. "Tendoplasty of the 4th finger deep flexor with the tendon of the left hand 3rd finger superficial flexor (clinical case)". Tambov Medical Journal, nr 4 (2023): 14–21. http://dx.doi.org/10.20310/2782-5019-2023-5-4-14-21.
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Damage to the tendons of the hand is a common injury among young working-age population. In most cases tendons are damaged by open wounds and accompanied by soft tissue contamination, which eliminates the imposition of primary sutures on the tendon. If the purulent-inflammatory processes of soft tissues have been developing in the area of damage, the plastic tendon is postponed indefinitely. The term depends on both subjective and objective reasons. Recovery of tendons late after injury is difficult and the longer it takes from injury, the more difficult it is to recover. The purpose of this research is to demonstrate the successful experience of treating a patient with a long-term tendon damage of the flexor fingers of the hand. Materials and methods. The clinical case of two-stage plastic of the fourth finger deep flexor tendor of the left hand is presented. As an autograft, the tendon of the 3rd finger superficial flexor, isolated from the adhesive process at the level of zones 3 and 4, was used. The effectiveness of the treatment was assessed by clinical and functional signs: the absence of rough scars on the fingers, the absence of contractures, full flexion and extension in all phalanges of the fingers in full. Results: Two-stage tendoplasty of a long-term damage to the deep tendon of the 4th finger with a superficial tendon of the 3rd finger. Complete anatomical and functional recovery of the left hand 4th finger.
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Grant, William P., Eric J. Foreman, Anne S. Wilson, Dwayne A. Jacobus i Renee M. Kukla. "Evaluation of Young’s Modulus in Achilles Tendons with Diabetic Neuroarthropathy". Journal of the American Podiatric Medical Association 95, nr 3 (1.05.2005): 242–46. http://dx.doi.org/10.7547/0950242.
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The Achilles tendon of the patient with Charcot’s foot neuroarthropathy has significantly altered physical properties compared with a normal tendon. Twenty-nine Achilles tendons from patients with Charcot’s foot (n = 20) and non-Charcot’s foot controls (n = 9) were loaded onto a biomechanical testing instrument. The biomechanical properties of the Charcot and control tendons were determined and the tendons were evaluated for differences in ultimate tensile strength and elasticity (Young’s modulus). Biomechanical test data show that there is a significant difference in ultimate tensile strength and elasticity between tendons of patients with Charcot’s foot and those of non-Charcot’s controls. The term diabetic tendo Achillis equinus is introduced as a new finding in diabetic neuroarthropathy. (J Am Podiatr Med Assoc 95(3): 242–246, 2005)
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Song, Haixin, Zi Yin, Tao Wu, Yangzheng Li, Xun Luo, Mingzhu Xu, Lihong Duan i Jianhua Li. "Enhanced Effect of Tendon Stem/Progenitor Cells Combined With Tendon-Derived Decellularized Extracellular Matrix on Tendon Regeneration". Cell Transplantation 27, nr 11 (9.10.2018): 1634–43. http://dx.doi.org/10.1177/0963689718805383.
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Decellularized extracellular matrices have been clinically used for tendon regeneration. However, only a few systematic studies have compared tendon stem/progenitor cells to mesenchymal stromal cells on the tendon-derived decellularized matrix. In the present study, we prepared extracellular matrix derived from porcine tendons and seeded with tendon stem/progenitor cells, embryonic stem cell-derived mesenchymal stromal cells or without stem cells. Then we implanted the mixture (composed of stem cells and scaffold) into the defect of a rat Achilles tendon. Next, 4 weeks post-surgery the regenerated tendon tissue was collected. Histological staining, immunohistochemistry, determination of collagen content, transmission electron microscopy, and biomechanical testing were performed to evaluate the tendon structure and biomechanical properties. Our study collectively demonstrated that decellularized extracellular matrix derived from porcine tendons significantly promoted the regeneration of injured tendons when combined with tendon stem/progenitor cells or embryonic stem cell-mesenchymal stromal cells. Compared to embryonic stem cell-mesenchymal stromal cells, tendon stem/progenitor cells combined with decellularized matrix showed more improvement in the structural and biomechanical properties of regenerated tendons in vivo. These findings suggest a promising strategy for functional tendon tissue regeneration and further studies are warranted to develop a functional tendon tissue regeneration utilizing tendon stem/progenitor cells integrated with a tendon-derived decellularized matrix.
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Havulinna, J., O. V. Leppänen, T. L. N. Järvinen i H. Göransson. "Comparison of modified Kessler tendon suture at different levels in the human flexor digitorum profundus tendon and porcine flexors and porcine extensors: an experimental biomechanical study". Journal of Hand Surgery (European Volume) 36, nr 8 (4.08.2011): 670–76. http://dx.doi.org/10.1177/1753193411415936.
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This study compared the biomechanical behaviour of repairs in the human flexor digitorum profundus tendon in zones I, II and III with repairs of different segments of the porcine flexor tendon of the second digit and the extensor digiti quarti proprius tendon, in order to assess the validity of porcine tendons as models for human flexor tendon repairs. These porcine tendons were selected after comparing their size with the human flexor digitorum profundus tendon. The tendon repairs were done in three segments of each porcine tendon and repairs in the human tendons were done in zones I,II and III. Ten tendons in each group yielded a total of 90 specimens. A modified Kessler repair was done with 3-0 coated braided polyester suture and subjected to uniaxial tensile testing. In human flexor tendons, the ultimate force was higher in zones I and II than in zone III. The porcine flexor digitorum profundus tendon from the second digit and the proximal segment of the extensor digiti quarti proprius tendon behaved similarly to the human flexor tendon in zone III and can be considered as surrogates for the human flexor tendon.
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Singh, Manjit, Hari O. Aggarwal, Sanjeev Sareen i Deepak Vashisht. "Repair of the Chronic Rupture of tendo Achilles Tendon using Peroneus Brevis Tendon". Journal of Foot and Ankle Surgery (Asia Pacific) 4, nr 1 (2017): 30–34. http://dx.doi.org/10.5005/jp-journals-10040-1066.
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ABSTRACT Aim To report 20 patients who underwent repair of chronic rupture of tendo Achilles tendon with peroneus brevis tendon. Materials and methods Records of 6 women and 14 men aged 26 to 58 (mean, 36) years who underwent repair of chronic rupture of tendo Achilles tendon with peroneus brevis tendon transfer were reviewed. Patients were evaluated at 3, 9, and 12 months using the foot and ankle outcome score (FAOS) questionnaire. Results Out of 20 patients, 4 developed superficial skin complications which healed gradually in 3 patients, and 1 patient underwent skin grafting surgery. No patient had a re-rupture of the tendo Achilles tendon. At the 1-year follow-up, all patients achieved good functional outcome in terms of the FAOS. Conclusion Repair of chronic rupture of tendo Achilles tendon with peroneus brevis tendon transfer achieved good functional outcome. How to cite this article Aggarwal HO, Singh M, Sareen S, Vashisht D. Repair of the Chronic Rupture of tendo Achilles Tendon using Peroneus Brevis Tendon. J Foot Ankle Surg (Asia-Pacific) 2017;4(1):30-34.
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Loiselle, A. E. "AGE-RELATED MECHANISMS OF ALTERED TENDON STRUCTURE AND FUNCTION". Orthopaedic Proceedings 106-B, SUPP_1 (2.01.2024): 72. http://dx.doi.org/10.1302/1358-992x.2024.1.072.
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During aging, tendons demonstrate substantial disruptions in homeostasis, leading to impairments in structure-function. Impaired tendon function contributes to substantial declines quality of life during aging. Aged tendons are more likely to undergo spontaneous rupture, and the healing response following injury is impaired in aged tendons. Thus, there is a need to develop strategies to maintain tendon homeostasis and healing capacity through the lifespan. Tendon cell density sharply declines by ∼12 months of age in mice, and this low cell density is retained in geriatric tendons. Our data suggests that this decline in cellularity initiates a degenerative cascade due to insufficient production of the extracellular matrix (ECM) components needed to maintain tendon homeostasis. Thus, preventing this decline in tendon cellularity has great potential for maintaining tendon health. Single cell RNA sequencing analysis identifies two changes in the aged tendon cell environment. First, aged tendons primarily lose tenocytes that are associated with ECM biosynthesis functions. Second, the tenocytes that remain in aged tendons have disruptions in proteostasis and an increased pro-inflammatory phenotype, with these changes collectively termed ‘programmatic skewing'. To determine which of these changes drives homeostatic disruption, we developed a model of tenocyte depletion in young animals. This model decreases tendon cellularity to that of an aged tendon, including decreased biosynthetic tenocyte function, while age-related programmatic skewing is absent. Loss of biosynthetic tenocyte function in young tendons was sufficient to induce homeostatic disruption comparable to natural aging, including deficits in ECM organization, composition, and material quality, suggesting loss biosynthetic tenocytes as an initiator of tendon degeneration. In contrast, our data suggest that programmatic skewing underpins impaired healing in aged tendons. Indeed, despite similar declines in the tenocyte environment, middle-aged and young-depleted tendons mount a physiological healing response characterized by robust ECM synthesis and remodeling, while aged tendons heal with insufficient ECM.
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Ferreira Arquez, Humberto. "Bilateral anatomical variations of the hand extensors". Bangladesh Journal of Medical Science 15, nr 2 (10.08.2016): 278–82. http://dx.doi.org/10.3329/bjms.v15i2.19481.
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Background: The purpose of this paper is to describe an anatomical variation of the hand extensor on the little finger of the right hand which receives four tendons, condition unknown, as it is the first case reported so far in the literature. The human extensor tendons of hand often display an array of variations. Awareness of the anatomy and variations of the extensor tendons on the dorsum of the hand is necessary not only for the anatomist but also for surgeons when considering tendons for hand surgery, tendon rerouting or transplants. Materials and Methods: Bilateral anatomical variation in the upper limb was found during routine dissection in a 75-year-old male cadaver in the Morphology Laboratory at the University of Pamplona. The variations were recorded and photographed. Result: In the left hand the extensor digitorum there was a single tendon to the index, double tendon to the middle, triple tendon to the ring finger, a single tendon to the little finger or digiti minimi. The extensor digiti minimi has double tendon. In the right hand the extensor digitorum there was a single tendon to the index, triple tendon to the middle finger, triple tendons to the ring finger, a double tendon to the little finger. The extensor digiti minimi has double tendon. The little finger receives four tendons, 2 of extensor digitorum and 2 of extensor digiti minimi. The dorsum of the left hand and right showed juncturae tendinum type 2, between the extensors tendons in the 3rd intermetacarpal space; type 3, between the extensors tendons in the 4th inter metacarpal space. Conclusion: The presence of multiple tendons may alter the kinematics around the site of attachment to the phalanx. Knowledge of anatomical variations and normal anatomy of the extensor tendons, may be helpful while performing graft and tendon transfer operations.Bangladesh Journal of Medical Science Vol.15(2) 2016 p.278-282
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Damiani, M. "ANALYSES OF BIOPSIED TISSUES IN AUTOLOGOUS TENOCYTE THERAPY FOR TREATMENT OF TENDINOPATHY". Orthopaedic Proceedings 105-B, SUPP_3 (luty 2023): 8. http://dx.doi.org/10.1302/1358-992x.2023.3.008.
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Autologous tendon cell injection (ATI) is a promising non-surgical treatment for tendinopathies and tendon tear that address its underlying pathology. The procedure involves harvesting autologous tendon tissue, the isolation of the tendon cells, expansion under quality assured GMP cell laboratory and the injection of the tendon cells via U/S into the degenerative tendon tissue. In clinical practice, the patella (PT) and palmaris longus (PL) tendons are common sites used for tendon tissue biopsy. The objective of this study is to compare the tendon cell quality, identity, purity, doubling time and yield of cells between PT and PL tendons for ATI.Tendon tissue biopsies were harvested from PT via U/S using a 14-gauge needle or resected surgically from the PL tendon. The biopsies were transported to a GMP cell laboratory, where tendon cells were isolated, cultured and expanded for 4 to 6 weeks, and analysed for viability, cell doubling time, cellular characteristics including cell purity, potency and identity (PPI).Tendon samples from 149 patients were analysed (63 PT). Average biopsy weight was 62mg for PT and 119mg for PI (p<0.001). Average cell doubling time (83.9 vs 82.7 hours), cellular yield (16.2 vs 15.2×106), viability (98.7 vs 99.0%) and passage number (3 vs 3) were not significantly different between tendons. Additionally, ddPCR analyses showed no differences of PPI including tendon cell markers of collagen type I, scleraxis and tenomodulin. No post-biopsy complications or contamination were reported for either group. Assessing tendon tissue from palmaris tendon is relatively easier.Tendon tissue biopsy tissue for autologous tendon cell therapy can be obtained from either the PT or PL tendons. Tendon cells isolated from PT and PL were equal in growth characteristics and PPI. There are no differences in the quality of tendon cells isolated from the PT or PL.
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JAFRI, SHAHZADA M. H., ANJUM ANWAR QADRI, KHUBAIB SHAHZAD i Mulazim Hussain Bukhari. "MORPHOLOGY OF GRAFTED TENDON". Professional Medical Journal 18, nr 01 (10.03.2011): 112–19. http://dx.doi.org/10.29309/tpmj/2011.18.01.1872.
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This is the first research done to explore the morphologic changes in two stage tendon grafting as compared to one stage tendon grafting. AIMS: To compare morphology of grafted tendons with and with out first stage silicon rubber rod implantation. STUDY DESIGN: Comparative experimental study. PERIOD: 1994-2007. MATERIAL AND METHODS: 30 patients were included in this study. They was divided into 3 groups. Group 1 underwent 2 stage tendon grafting group 3 was used as control morphological study of tendons. RESULTS: Group 1 (1-stage) tendon grafting showed degeneration and fibrous reaction as morphological changes. Group 2. (2 Stage) appeared as normal tendons morphologically. CONCLUSION: This study concludes that instead of direct tendon grafting, two stage tendon grafting is recommended.
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Chung, U. S., J. H. Kim, W. S. Seo i K. H. Lee. "Tendon transfer or tendon graft for ruptured finger extensor tendons in rheumatoid hands". Journal of Hand Surgery (European Volume) 35, nr 4 (17.08.2009): 279–82. http://dx.doi.org/10.1177/1753193409339942.
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We evaluated the clinical outcome of tendon reconstruction using tendon graft or tendon transfer and the parameters related to clinical outcome in 51 wrists of 46 patients with rheumatoid arthritis with finger extensor tendon ruptures. At a mean follow-up of 5.6 years, the mean metacarpophalangeal (MP) joint extension lag was 8° (range, 0–45) and the mean visual analogue satisfaction scale was 74 (range, 10–100). Clinical outcome did not differ significantly between tendon grafting and tendon transfer. The MP joint extension lag correlated with the patient’s satisfaction score, but the pulp-to-palm distance did not correlate with patient satisfaction. We conclude that both tendon grafting and tendon transfer are reliable reconstruction methods for ruptured finger extensor tendons in rheumatoid hands.
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Sobel, Mark, Mark J. Geppert, Jo A. Hannafin, Walther H. O. Bohne i Steven P. Arnoczky. "Microvascular Anatomy of the Peroneal Tendons". Foot & Ankle 13, nr 8 (październik 1992): 469–72. http://dx.doi.org/10.1177/107110079201300807.
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The etiology of longitudinal splitting of the peroneus brevis tendon is unclear. It has been hypothesized that compressive load applied to the tendon as it passes through the fibular groove may compromise the vascularity of the tendon with resultant inhibition of the repair response and degeneration of tendon structure. To investigate this possibility, a study of the microvascularity of the peroneal tendons was undertaken. Twelve fresh, frozen cadaveric limbs were injected with India ink. The vascularity of the peroneal tendons was examined in situ and the tendons were harvested and cleared using a modified Spalteholz technique. The vascularity of the cleared tendons was evaluated utilizing a dissecting microscope. The vascular supply of the peroneal tendons arises from two posterolateral vincula, one for the peroneus longus tendon and one for the peroneus brevis tendon. These vincula are supplied by branches of the posterior peroneal artery. A zone of hypovascularity within the peroneus brevis or peroneus longus tendon correlating with the site of peroneus brevis splits was not found. There was no relationship between increasing age of specimens and alteration in vascular supply.
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Andarawis-Puri, Nelly, Eric T. Ricchetti i Louis J. Soslowsky. "Interaction between the Supraspinatus and Infraspinatus Tendons: Effect of Anterior Supraspinatus Tendon Full-Thickness Tears on Infraspinatus Tendon Strain". American Journal of Sports Medicine 37, nr 9 (29.05.2009): 1831–39. http://dx.doi.org/10.1177/0363546509334222.
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Background Rotator cuff tears are common and not well-understood shoulder problems. Structural and mechanical inhomogeneity of the supraspinatus tendon complicates accurate prediction of risk of tear propagation and may affect appropriate clinical treatment. Hypothesis We propose that interactions between the supraspinatus and infraspinatus tendons are critical to load bearing at the glenohumeral joint and warrant investigation. Study Design Controlled laboratory study. Methods Principal strains in the infraspinatus tendon of cadaveric human shoulders were evaluated with increasing anterior full-thickness supraspinatus tendon tear sizes and loading to evaluate whether a mechanical interaction between the supraspinatus and infraspinatus tendons exists. A constant nominal load was attached to the infraspinatus throughout all experimental conditions. Results Increasing supraspinatus tendon tear width from intact and 33% to 66% and increasing supraspinatus tendon load caused an increase in maximum and a decrease in minimum principal strain in the infraspinatus tendon. Increasing the supraspinatus tendon tear size from intact to 33% of the width had no significant effect on infraspinatus tendon strain. Conclusion Supraspinatus and infraspinatus tendons mechanically interact. The observed significant increase in maximum and decrease in minimum principal strain was concurrent in both the infraspinatus and supraspinatus tendons. Clinical Relevance Changes in infraspinatus tendon strain associated with increases in supraspinatus tendon tear size and loading may shield a torn supraspinatus tendon from further injury or may have an effect on the load-bearing capacity of the infraspinatus tendon. Results also imply that the effect of a small tear that does not compromise the confluent region between the supraspinatus and infraspinatus tendon may be localized, eliminating its effect on infraspinatus tendon strain.
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Hayashi, M., C. Zhao, K. N. An i P. C. Amadio. "The effects of growth and differentiation factor 5 on bone marrow stromal cell transplants in an in vitro tendon healing model". Journal of Hand Surgery (European Volume) 36, nr 4 (maj 2011): 271–79. http://dx.doi.org/10.1177/1753193410394521.
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The effects of growth differentiation factor-5 (GDF-5) and bone marrow stromal cells (BMSCs) on tendon healing were investigated under in vitro tissue culture conditions. BMSCs and GDF-5 placed in a collagen gel were interpositioned between the cut ends of dog flexor digitorum profundus tendons. The tendons were randomly assigned into four groups: 1) repaired tendon without gel; 2) repaired tendon with BMSC-seeded gel; 3) repaired tendon with GDF-5 gel without cells; and 4) repaired tendon with GDF-5 treated BMSC-seeded gel. At 2 and 4 weeks, the maximal strength of repaired tendons with GDF-5 treated BMSCs-seeded gel was significantly higher than in tendons without gel interposition. However, neither BMSCs nor GDF-5 alone significantly increased the maximal strength of healing tendons at 2 or 4 weeks. These results suggest that the combination of BMSCs and GDF-5 accelerates tendon healing, but either BMSCs or GDF-5 alone are not effective in this model.
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O'Connor, Kathryn, Elaine Schmidt, Todd J. Hullfish, Michael W. Hast i Josh R. Baxter. "Ultrasound Stress-Imaging is a Promising Tool to Detect Achilles Tendon Damage". Foot & Ankle Orthopaedics 7, nr 1 (styczeń 2022): 2473011421S0038. http://dx.doi.org/10.1177/2473011421s00380.
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Category: Sports; Basic Sciences/Biologics Introduction/Purpose: Achilles tendon disorders are among the most common conditions observed by sports medicine physicians and among the most difficult to diagnose using current clinical tools. While qualitative imaging is a validated method to grade the severity of tendinopathy, predicting the risk of these patients progressing or suffering tendon ruptures remains a major clinical need. Therefore, the purpose of this study was to determine the efficacy of quantitative ultrasound imaging to explain in vitro fatigue-induced degradation of Achilles tendon mechanical properties. We hypothesized that decreases in mean echogenicity would be linked to in vitro tendon fatigue characterized by decreased mechanical properties. Methods: In this cadaveric tendon study, we cyclically fatigued 10 cadaveric Achilles tendons (7 donors; sex: 4M, 3F; age: 60+-15 years) and acquired b-mode ultrasound images to determine if stress-imaging biomarkers provide new insight into tendon status. We cut dog-bone shapes to concentrate tendon damage at the mid-substance where we acquired ultrasound images. In a custom- built testing bath, we cyclically applied 10-20 MPa of tendon stress at 1 Hz for 150,00 or until the specimen failed. Every 500th cycle, we applied 2 slow (0.25 Hz) tendon stresses of 10-20 MPa while acquiring ultrasound images using an 18MHz transducer. We calculated the change in tendon echogenicity caused by the applied stress to determine if this stress-imaging biomarker was associated with tendon failure. We compared these stress-imaging biomarkers from the tendons that failed (N=6) and the tendons that survived (N=4) cyclic fatigue damage using an unpaired t-test (p < 0.05). Results: Quantitative analysis of the ultrasound images indicated 2 key differences between tendons that failed during the cyclic loading protocol and those that did not (Figure 1 shows representative data of tendons with similar demographics but one tendon exhibited increased change in echogenicity before failing while the other tendon exhibited smaller changes in echogenicity and did not rupture). First, mean echogenicity decreased before failure. Second, the average change in mean echogenicity was significantly greater in tendons that failed (p = 0.031). For most tendons that did fail, mean echogenicity decreased during the third phase of fatigue life. For the tendons that did not fail, mean echogenicity plateaued along with strain during the second phase of fatigue. Conclusion: This study found detectable differences in image echogenicity during a stress test between tendons that fail during cyclic loading and those that do not. While preliminary, our findings indicate that B-mode ultrasound has potential as a clinically viable tool to predict severe tendon injuries. Our future work is focused on developing computer-based predictive tools to assess Achilles tendon fatigue in patients with tendinopathy following prolonged tendon loading to establish quantitative imaging thresholds that can serve as clinical benchmarks.
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Gaughan, E. M., R. M. DeBowes, J. P. Douglass, R. K. Frank, R. D. Klemm i L. J. Gift. "The Influence of Intratendinous Sodium Hyaluronate on Tendon Healing in Horses". Veterinary and Comparative Orthopaedics and Traumatology 05, nr 04 (1992): 151–57. http://dx.doi.org/10.1055/s-0038-1633108.
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SummaryAcute tendinitis was created bilaterally in the mid-metacarpal region of the deep digital flexor tendons of six horses with intratendinous collagenase administration. The collagenase-induced lesion in one deep digital flexor tendon of each horse was injected 48 h later with 10.0 mg of sodium hyaluronate (1.0 ml) while employing ultrasound guidance. To serve as a control, the lesion in the contralateral deep digital flexor tendon was injected with 1.0 ml of 0.9% sodium chloride. Sequential ultra-sonographic examinations revealed that the sodium hyaluronate treated deep digital flexor tendons were significantly less enlarged and the collagenase-induced tendon lesions significantly smaller than control tendons and tendon lesions. Difference could not be detected between sodium hyaluronate treated tendons and control tendons using histological and video-interactive planar morphometric evaluation six weeks after treatment.Collagenase-induced tendinitis lesions were treated with intratendinous administration of sodium hyaluronate in six horses. The size of the tendon lesions and the amount of tendon enlargement were significantly less in the sodium hyaluronate treated tendons compared to control tendons. A significant difference in the rate or quality of healing was not detected in the sodium hyaluronate treated tendons.
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Forslund, Carina, i Per Aspenberg. "Improved Healing of Transected Rabbit Achilles Tendon after a Single Injection of Cartilage-Derived Morphogenetic Protein-2". American Journal of Sports Medicine 31, nr 4 (lipiec 2003): 555–59. http://dx.doi.org/10.1177/03635465030310041301.
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Background Achilles tendon ruptures in humans might be treated more efficiently with the help of a growth factor. Cartilage-derived morphogenetic protein-2 has been shown to induce formation of tendon-like tissue. Hypothesis Cartilage-derived morphogenetic protein-2 has a positive effect on mechanical parameters for tendon healing in a rabbit model with Achilles tendon transection. Study Design Controlled laboratory study. Methods The right Achilles tendon of 40 rabbits was transected without tendon suture. Cartilage-derived morphogenetic protein-2 (10 μg) or vehicle control (acetate buffer) was injected locally 2 hours postoperatively. All tendons were tested biomechanically at 8 and 14 days, and treated tendons were histologically and radiographically evaluated at 56 days. Results At 14 days, both failure load and stiffness of treated tendons were increased by 35%. The treated tendons had significantly larger callus size at 8 and 14 days. Histologic and radiographic examination showed no signs of ossification in the treated tendons after 56 days. Conclusions A single injection of cartilage-derived morphogenetic protein-2 led to a stronger and stiffer tendon callus than that in the controls without inducing bone formation. Clinical Relevance Similar results from a larger animal model would suggest a possible future use of cartilage-derived morphogenetic protein-2 in the treatment of human Achilles tendon ruptures.
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Ozcan, Ayse Nur Sirin, Sinan Tan, Nuray Gulden Tangal, Saliha Cıracı, Savas Kudas, Suleyman Bulent Bektaser i Halil Arslan. "Real-time sonoelastography of the patellar and quadriceps tendons: pattern description in profesional athletes and healthy volunteers." Medical Ultrasonography 18, nr 3 (18.09.2016): 299. http://dx.doi.org/10.11152/mu.2013.2066.183.ays.
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Aims: The comparison of elastographic features of quadriceps and patellar tendons in a group of professional athletes and healthy volunteers and the description of elasticity characteristics of these tendons. Material and methods: Thirtynine professional athletes (22 male, 17 female; mean age 18.5 years) and 35 healthy volunteers (21 male, 14 female; mean age 19 years) were included. They were divided into two groups by gender. Quadriceps tendon, patellar side of the patellar tendon, and tibial side of the patellar tendon elasticity patterns and strain ratios were investigated with real-time ultrasound elastography. The elasticity features of the dominant leg and non-dominant leg of athletes and volunteers legs were compared. In addition quadriceps and patellar tendons were compared separately for three distinct tendon locations. Results: There was no difference between the athletes and the healthy volunteers and also between the dominant leg and non-dominant leg of athletes. At tendon comparison, the quadriceps tendon was harder than the patellar tendon at both side and patellar side of patellar tendon was found to be stiffer than the tibial side of patellar tendon. Conclusions: Although biomechanical studies showed that tendon stiffness increased after long exercise, no significant difference was found between athletes’ and healthy volunteers’ tendon elasticity. These three tendon locations exhibit different elasticity features and the knowledge of the elasticity feature will be useful in assessing tendon pathologies.
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Biehl, C., M. Rupp, S. Kern, C. Heiss, T. ElKhassawna i G. Szalay. "Extensor tendon ruptures in rheumatoid wrists". European Journal of Orthopaedic Surgery & Traumatology 30, nr 8 (3.07.2020): 1499–504. http://dx.doi.org/10.1007/s00590-020-02731-1.
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Abstract Background and aims Rheumatoid arthritis is a chronic inflammatory disease. The associated involvement of hands and tendons is over 90% and impairs overall function. In the course of the disease, the joints are often operated on. During this operation, ruptures of the extensor tendons are found by chance without the patients noticing them. The aim of this retrospective study is the prevalence of extensor tendon rupture. Which tendon is destroyed most frequently? How can the functional outcome be measured after reconstruction? Materials and methods From 1572 operations on rheumatoid wrists, 61 extensor tendon ruptures were identified in 41 patients. The average time between the first rheumatic symptoms of the hand and surgery was 6.4 years. The average duration of RA was 7.8 years. 26 patients with 27 tendon reconstructions were included in the follow-up with an average postoperative duration of 4.6 years (3 to 14.2 years). Results Extensor tendons ruptures typically occurred at mechanically stressed sites. The most frequent rupture was found in the extensor pollicis longus tendon (21 tendons), followed by the small finger extensor tendon (14 tendons). A transfer was performed on 7 tendons. Fifty-five tendon lesions were sutured at other intact tendons. Free grafts were not used. The results in Clayton and QuickDASH scores were significantly different. Functional improvement was consistent with the results of tendon reconstructions in healthy control groups. Conclusion In rheumatoid patients, a rupture of an extensor tendon must be expected at 4%. Patients tolerate and compensate this damage for a long time. The function of the hand including the tendon function is the most important factor in assessing the success of the operation. The subjective patient acceptance depends on the progress of the underlying disease, postoperative care (ergotherapy, physiotherapy, orthosis) and the patients' demands.
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Easley, Jeremiah, James Johnson, Daniel Regan, Eileen Hackett, Anthony A. Romeo, Ted Schlegel, Cecily Broomfield, Christian Puttlitz i Kirk McGilvray. "Partial Infraspinatus Tendon Transection as a Means for the Development of a Translational Ovine Chronic Rotator Cuff Disease Model". Veterinary and Comparative Orthopaedics and Traumatology 33, nr 03 (31.03.2020): 212–19. http://dx.doi.org/10.1055/s-0040-1701650.
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Abstract Objective Rotator cuff tendon tears are the most common soft tissue injuries in the shoulder joint. Various animal models have been described for this condition, but all current translational animal models have inherent weaknesses in their ability to generate chronically degenerated rotator cuff tendons. The objective of this study was to evaluate a partial infraspinatus tendon transection model as a means of creating a chronically degenerated rotator cuff tendon in an ovine model and compare the injury characteristics of this model to those observed in human patients with severe chronic rotator cuff tendon injuries. Study Design The infraspinatus tendons of six sheep were partially detached followed by capping of the detached medial section of the tendon with Gore-Tex. Human tissue samples of the supraspinatus tendon were harvested from patients undergoing primary reverse shoulder arthroplasty and served as positive controls of chronic rotator cuff tendinopathy. Results Transected sheep tendons were characterized predominantly by an acute reactive and reparative pathological process as compared with the chronic degenerative changes observed in the human tendons. In contrast, the non-transected portion of the ovine tendon showed histological changes, which were more chronic and degenerative in nature when compared with the transected tendon. Conclusion Overall, histological features of the non-transected portion of ovine tendon were more similar to those observed in the chronic degenerated human tendon.
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Watanabe, Genji, Masahito Yamamoto, Shuichirou Taniguchi, Yuki Sugiyama, Hidetomo Hirouchi, Satoshi Ishizuka, Kei Kitamura i in. "Chronological Changes in the Expression and Localization of Sox9 between Achilles Tendon Injury and Functional Recovery in Mice". International Journal of Molecular Sciences 24, nr 14 (11.07.2023): 11305. http://dx.doi.org/10.3390/ijms241411305.
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Tendons help transmit forces from the skeletal muscles and bones. However, tendons have inferior regenerative ability compared to muscles. Despite studies on the regeneration of muscles and bone tissue, only a few have focused on tendinous tissue regeneration, especially tendon regeneration. Sex-determining region Y-box transcription factor 9 (Sox9) is an SRY-related transcription factor with a DNA-binding domain and is an important control factor for cartilage formation. Sox9 is critical to the early-to-middle stages of tendon development. However, how Sox9 participates in the healing process after tendon injury is unclear. We hypothesized that Sox9 is expressed in damaged tendons and is crucially involved in restoring tendon functions. We constructed a mouse model of an Achilles tendon injury by performing a 0.3 mm wide partial excision in the Achilles tendon of mice, and chronologically evaluated the function restoration and localization of the Sox9 expressed in the damaged sites. The results reveal that Sox9 was expressed simultaneously with the formation of the pre-structure of the epitenon, an essential part of the tendinous tissue, indicating that its expression is linked to the functional restoration of tendons. Lineage tracing for Sox9 expressed during tendon restoration revealed the tendon restoration involvement of cells that switched into Sox9-expressing cells after tendon injury. The stem cells involved in tendon regeneration may begin to express Sox9 after injury.
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Hullfish, Todd J., Kenton L. Hagan, Ellen Casey i Josh R. Baxter. "Achilles tendon structure differs between competitive distance runners and nonrunners despite no clinical signs or symptoms of midsubstance tendinopathy". Journal of Applied Physiology 125, nr 2 (1.08.2018): 453–58. http://dx.doi.org/10.1152/japplphysiol.00012.2018.
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Achilles tendinopathy affects many running athletes and often leads to chronic pain and functional deficits. Although changes in tendon structure have been linked with tendinopathy, the effects of distance running on tendon structure are not well understood. Therefore, the purpose of this study was to characterize structural differences in the Achilles tendons in healthy young adults and competitive distance runners using quantitative ultrasound analyses. We hypothesized that competitive distance runners with no clinical signs or symptoms of tendinopathy would have quantitative signs of tendon damage, characterized by decreased collagen alignment and echogenicity, in addition to previous reports of thicker tendons. Longitudinal ultrasound images of the right Achilles tendon midsubstance were acquired in competitive distance runners and recreationally active adults. Collagen organization, mean echogenicity, and tendon thickness were quantified using image processing techniques. Clinical assessments confirmed that runners had no signs or symptoms of tendinopathy, and controls were only included if they had no history of Achilles tendon pain or injuries. Runner tendons were 40% less organized, 48% thicker, and 41% less echogenic compared with the control tendons ( P < 0.001). Young adults engaged in competitive distance running have structurally different tendons than recreationally active young adults. NEW & NOTEWORTHY In this study, we quantified the Achilles tendon substructure in distance runners, and a control group of young adults, to determine whether distance running elicits structural adaptations of the tendon. We found that competitive distance runners have structurally compromised Achilles tendons despite not showing any clinical signs or symptoms of tendon injury. These findings suggest that distance running may stimulate structural changes as a protective mechanism against tendon pain and dysfunction.
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Tillander, Bo, Håkan Gauffin, Johan Lyth, Anders Knutsson i Toomas Timpka. "Symptomatic Achilles Tendons are Thicker than Asymptomatic Tendons on Ultrasound Examination in Recreational Long-Distance Runners". Sports 7, nr 12 (5.12.2019): 245. http://dx.doi.org/10.3390/sports7120245.
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There is a need for clinical indicators that can be used to guide the treatment of Achilles tendon complaints in recreational runners. Diagnostic ultrasound has recently been introduced for clinical decision support in tendon pain management. The aim of this study was to determine whether tendon thickness and morphological changes in the Achilles tendon detected in ultrasound examinations are associated with local symptoms in middle-age recreational long-distance runners. Forty-two Achilles tendons (21 middle-aged runners) were investigated by ultrasound examination measuring tendon thickness and a morphology score indicating tendinosis. The Generalized Estimating Equations method was applied in multiple models of factors associated with reporting a symptomatic tendon. Eleven symptomatic and 31 asymptomatic Achilles tendons were recorded. In the multiple model that used tendon thickness measured 30 mm proximal to the distal insertion, an association was found between thickness and reporting a symptomatic tendon (p < 0.001; OR 12.9; 95% CI 3.1 to 53.2). A qualitative morphology score was not found to be significantly associated with reporting a symptomatic tendon (p = 0.10). We conclude that symptomatic Achilles tendons were thicker than asymptomatic tendons on ultrasound examination among recreational long-distance runners and that the importance of parallel morphological findings need to be further investigated in prospective studies.
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Hagan, Kenton L., Todd Hullfish, Ellen Casey i Josh R. Baxter. "Tendon structure quantified using ultrasound imaging differs based on location and training type". Journal of Applied Physiology 125, nr 6 (1.12.2018): 1743–48. http://dx.doi.org/10.1152/japplphysiol.00723.2018.
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Achilles tendinopathy is 10 times more common among running athletes compared with age-matched peers. Load-induced tendon remodeling and its progression in an at-risk population of developing symptomatic tendinopathy are not well understood. The purpose of this study was to prospectively characterize Achilles and patellar tendon structure in competitive collegiate distance runners over different competitive seasons using quantitative ultrasound imaging. Twenty-two collegiate cross-country runners and eleven controls were examined for this study. Ultrasound images of bilateral Achilles and patellar tendons were obtained near the start and end of the collegiate cross-country season and the conclusion outdoor track season. Collagen organization, mean echogenicity, tendon thickness, and neovascularity were determined using well-established image processing techniques. Achilles tendon collagen was less aligned in runners compared with controls (28% greater) but improved slightly (7% decrease) after the completion of the track season. Conversely, patellar tendons in runners were similar to control tendons throughout the cross-country season but underwent collagen alignment (17% decrease) and tendon hypertrophy (21% increase). Our findings indicate that Achilles tendon structure in trained runners differs structurally from control tendons but is stable throughout training while patellar tendon structure changes in response to the transition in training volume between cross-country and track seasons. These findings expand upon prior reports that some degree of tendon remodeling may act as a protective adaptation for sport specific loading. NEW & NOTEWORTHY In this study we prospectively examined the Achilles and patellar tendon structure of distance runners to determine if continued training through multiple seasons elicits tendon remodeling or pathology. We found that Achilles and patellar tendons respond uniquely to the changing loads required during each season. Achilles tendon collagen alignment is mostly stable throughout the competitive cycle, but the patellar tendon structurally remodels following the transition from cross-country to track season.
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DiIorio, Sarah E., Bill Young, Jennifer B. Parker, Michelle F. Griffin i Michael T. Longaker. "Understanding Tendon Fibroblast Biology and Heterogeneity". Biomedicines 12, nr 4 (12.04.2024): 859. http://dx.doi.org/10.3390/biomedicines12040859.
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Tendon regeneration has emerged as an area of interest due to the challenging healing process of avascular tendon tissue. During tendon healing after injury, the formation of a fibrous scar can limit tendon strength and lead to subsequent complications. The specific biological mechanisms that cause fibrosis across different cellular subtypes within the tendon and across different tendons in the body continue to remain unknown. Herein, we review the current understanding of tendon healing, fibrosis mechanisms, and future directions for treatments. We summarize recent research on the role of fibroblasts throughout tendon healing and describe the functional and cellular heterogeneity of fibroblasts and tendons. The review notes gaps in tendon fibrosis research, with a focus on characterizing distinct fibroblast subpopulations in the tendon. We highlight new techniques in the field that can be used to enhance our understanding of complex tendon pathologies such as fibrosis. Finally, we explore bioengineering tools for tendon regeneration and discuss future areas for innovation. Exploring the heterogeneity of tendon fibroblasts on the cellular level can inform therapeutic strategies for addressing tendon fibrosis and ultimately reduce its clinical burden.
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PRING, D. J., A. A. AMIS i R. R. H. COOMBS. "The Mechanical Properties of Human Flexor Tendons in Relation to Artificial Tendons". Journal of Hand Surgery 10, nr 3 (październik 1985): 331–36. http://dx.doi.org/10.1016/s0266-7681_85_80055-3.
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The continuation of an unacceptable failure rate with tendon repair or grafting procedures, largely due to adhesions, suggested that an artificial flexor tendon could be an attractive alternative. A literature search found no published data of the mechanical properties of fresh human finger flexor tendons, so a study of the strength and extensibility of 153 tendons was carried out. The bone insertion strength of twenty middle finger tendons was also examined. The results showed that an artificial tendon should have a strength of approximately 1500N, and that it should extend 13% at that load, an elongation of 26mm for a tendon 200mm long. The insertion strength was less than a half of the tendon strength. This data will allow an artificial flexor tendon to be designed with sufficient strength and the correct elastic properties to allow its function to integrate reliably with natural tendons in adjacent fingers.
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Ilahi, Omer A., Eugene F. Stautberg, David J. Mansfield i Ali A. Qadeer. "Relationship of Musculotendinous Junction Location to Harvested Semitendinosus and Gracilis Tendon Length". Orthopaedic Journal of Sports Medicine 5, nr 5 (1.05.2017): 232596711770463. http://dx.doi.org/10.1177/2325967117704630.
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Background: Harvested hamstring tendon length has received scant attention in published anterior cruciate ligament (ACL) reconstruction literature, yet length can limit the ability to increase graft diameter by folding the tendon over more than once. Indeed, some ultrashort tendons may be too short to yield a clinically useful graft after being folded over just once. Ultimately, the total length of a harvested hamstring tendon may depend on the length of the tendon distal to its musculotendinous (MT) junction. Purpose: To compare the lengths of harvested hamstring tendons to the location of the MT junction to help predict abnormally short tendon harvest. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Eighty-four consecutive patients undergoing primary ACL reconstruction using hamstring tendon autografts underwent intraoperative measurement of the total length of each harvested semitendinosus (ST) and gracilis (G) tendon, as well as the distance from the MT junction to that tendon’s distal end (ie, the “tendon-only” length). Results: The ratio of the tendon-only portion to total harvested tendon length averaged 0.52 (range, 0.39-0.71) for the ST and 0.52 (range, 0.43-0.71) for the G, suggesting a 95% chance of harvesting a tendon <15 cm in length for the tendon-only portion is <6.45 cm for ST or <6.75 cm for G tendons. There was moderate correlation between the lengths of harvested ST and G tendons with patient height as well as with the diameter of the combined, quadruple-stranded graft. Conclusion: The ratio of the tendon-only length to total harvested length for both the ST and G appear to range from approximately 0.4 to 0.7. Patients with abnormally distal MT junctions of either their ST or G are likely to have an abnormally short harvest of that tendon, even in the absence of technical harvesting error.
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Sun, Yulong, Chunfeng Zhao, Peter C. Amadio i Kai-Nan An. "Biomimetic modification of the gliding surface of extrasynovial tendon". Journal of Materials Research 21, nr 8 (1.08.2006): 2079–83. http://dx.doi.org/10.1557/jmr.2006.0253.
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Tendons may be classified as intrasynovial or extrasynovial based upon their anatomic location. We studied the physical properties of extrasynovial and intrasynovial tendons. Extrasynovial tendon has a rougher surface and higher friction than intrasynovial tendon. A number of carbodiimide derivatized biomaterials were developed to modify the irregular surface of an extrasynovial tendon to mimic the smooth surface of an intrasynovial tendon. We found that carbodiimide derivatized hyaluronic acid-gelatin (cd-HA-gelatin) chemically bonded to the extrasynovial tendon surface and optimally reduced gliding resistance in vitro. This biosynthetic, biomimetic modification of the extrasynovial tendon surface may prove to be a useful clinical product.
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Tis, John E., William R. Klemme, Kevin L. Kirk, Kevin P. Murphy i Bryan Cunningham. "Braided Hamstring Tendons for Reconstruction of the Anterior Cruciate Ligament: A Biomechanical Analysis". American Journal of Sports Medicine 30, nr 5 (wrzesień 2002): 684–88. http://dx.doi.org/10.1177/03635465020300050901.
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Background: In an effort to improve the strength and stiffness of anterior cruciate ligament grafts, several authors have advocated alterations of graft structure and orientation, including braiding the tendons in hamstring tendon grafts. Hypothesis: Braiding hamstring tendons does not increase graft strength and stiffness. Study Design: Controlled laboratory study. Methods: Sixteen hamstring tendon and 21 bone-patellar tendon-bone grafts were harvested from 12 cadavers and divided into three groups: 1) braided four-strand hamstring tendon, 2) unbraided four-strand hamstring tendon, and 3) bone-patellar tendon-bone. All grafts were placed under a 50-N preload on a servohydraulic testing device and were tensioned to failure. Results: The strength and stiffness of the tested specimens averaged 427 ± 36 N and 76 ± 10 N/mm, respectively, for braided specimens, 532 ± 44 N and 139 ± 18 N/mm for unbraided specimens, and 574 ± 46 N and 158 ± 15 N/mm for patellar tendon specimens. There was a 20% decrement in hamstring tendon graft tensile strength and a 45% decrease in stiffness after braiding because of the suboptimal multidirectional orientation of individual tendons within the braided grafts. Conclusions: In vitro braided hamstring tendon grafts demonstrated mechanically inferior strength and stiffness characteristics compared with unbraided hamstring tendon grafts and patellar tendon grafts. Clinical Relevance: Braiding of hamstring tendon grafts provides no mechanical advantage in anterior cruciate ligament reconstruction.
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Forthofer, BS, Michael J., Katherine M. Arnold, MS, Ramona L. Reisdorf, BS, Peter C. Amadio, MD i Chunfeng Zhao, MD. "The Effect of Gelatin Molecular Weight on Tendon Lubrication Utilizing an Extrasynovialized Turkey Flexor Tendon Model". Military Medicine 186, Supplement_1 (1.01.2021): 729–36. http://dx.doi.org/10.1093/milmed/usaa265.
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ABSTRACT Introduction Flexor tendon injuries are common hand injuries among the military population often resulting in functional impairment. Flexor tendon gliding friction has been linked to adhesion formation, especially with the use of extrasynovial grafts. Carbodiimide-derivatized hyaluronic acid with gelatin (cd-HA-gelatin) can reduce gliding friction of the tendon graft; however, the effects of gelatin molecular weight (MW) have not been studied. The turkey model has been shown to better match humans, but extrasynovial tendons are unavailable. The purpose of this study was to (1) manually roughen turkey flexor digitorum profundus (FDP) tendons to simulate extrasynovial tendons and (2) investigate the effects of gelatin MW on tendon friction. Materials and Methods The third digit of (n = 48) turkeys were dissected with the proximal pulley, and FDP tendon and the flexor superficialis tendon were preserved. Digits were randomly assigned into four groups: one saline control and three cd-HA-gelatin-treated groups of varying gelatin MW. Flexor digitorum profundus tendon friction was measured at its original condition, serving as a baseline. Tendons were roughened using a custom rig, and tendon friction was measured again. All four groups received treatment and gliding friction was measured every 100 cycles to a total of 1,000 cycles. Results Tendon friction significantly increased (P < 0.05) after roughening. Friction in the saline control group increased steadily over repeated cycles, whereas friction of all gelatin-treated tendons decreased significantly compared with the saline control group (P < 0.05), maintaining low friction to 1,000 cycles representing human tendons. There was no significant difference found between gelatin-treated groups. Conclusions We have developed a method to roughen synovial FDP tendons to create extrasynovial-like tendons for lubrication material evaluations. Cd-HA-gelatin effectively reduces tendon friction in this model. Our data suggest medium or low MW gelatin may provide a better reduction in friction compared with high MW gelatin.
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Sakaguchi, Takefumi, Bisei Ohkawara, Yasuzumi Kishimoto, Kentaro Miyamoto, Shinya Ishizuka, Hideki Hiraiwa, Naoki Ishiguro, Shiro Imagama i Kinji Ohno. "Promethazine Downregulates Wnt/β-Catenin Signaling and Increases the Biomechanical Forces of the Injured Achilles Tendon in the Early Stage of Healing". American Journal of Sports Medicine 50, nr 5 (2.03.2022): 1317–27. http://dx.doi.org/10.1177/03635465221077116.
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Background: Wnt/β-catenin signaling suppresses the differentiation of cultured tenocytes, but its roles in tendon repair remain mostly elusive. No chemical compounds are currently available to treat tendon injury. Hypothesis: We hypothesized that the inhibition of Wnt/β-catenin signaling would accelerate tendon healing. Study Design: Controlled laboratory study. Methods: Tendon-derived cells (TDCs) were isolated from rat Achilles tendons. The right Achilles tendon was injured via a dermal punch, while the left tendon was sham operated. A Wnt/β-catenin inhibitor, IWR-1, and an antihistamine agent, promethazine (PH), were locally and intramuscularly injected, respectively, for 2 weeks after surgery. The healing tendons were histologically and biomechanically evaluated. Results: The amount of β-catenin protein was increased in the injured tendons from postoperative weeks 0.5 to 2. Inhibition of Wnt/β-catenin signaling by IWR-1 in healing tendons improved the histological abnormalities and decreased β-catenin, but it compromised the biomechanical properties. As we previously reported that antihistamine agents suppressed Wnt/β-catenin signaling in human chondrosarcoma cells, we examined the effects of antihistamines on TDCs. We found that a first-generation antihistamine agent, PH, increased the expression of the tendon marker genes Mkx and Tnmd in TDCs. Intramuscular injection of PH did not improve histological abnormalities, but it decreased β-catenin in healing tendons and increased the peak force and stiffness of the healing tendons on postoperative week 2. On postoperative week 8, however, the biomechanical properties of vehicle-treated tendons became similar to those of PH-treated tendons. Conclusion: IWR-1 and PH suppressed Wnt/β-catenin signaling and improved the histological abnormalities of healing tendons. IWR-1, however, compromised the biomechanical properties of healing tendons, whereas PH improved them. Clinical Relevance: PH is a candidate repositioned drug that potentially accelerates tendon repair.
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Ruergård, Anna, Christoph Spang i Håkan Alfredson. "Results of minimally invasive Achilles tendon scraping and plantaris tendon removal in patients with chronic midportion Achilles tendinopathy: A longer-term follow-up study". SAGE Open Medicine 7 (styczeń 2019): 205031211882264. http://dx.doi.org/10.1177/2050312118822642.
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Background: Treatment with ultrasound and colour Doppler–guided minimally invasive Achilles tendon scraping and plantaris tendon removal has shown promising short-term results in patients with chronic painful midportion Achilles tendinopathy. Methods: In a follow-up study, 182 consecutive patients (241 tendons) who had undergone Achilles tendon scraping and plantaris tendon removal were contacted on telephone by an independent investigator. The patients who answered the telephone call were included, and they answered a questionnaire on telephone and then also sent their written answers. The questionnaire included information about patient satisfaction with the result of the treatment, time to return to full Achilles tendon loading activity, and a pain score (Visual Analogue Scale-VAS). Results: The follow-up period was 5.8 years (mean) (range of 2–13 years) after surgery. Altogether, 110 patients (136 Achilles tendons), 52 years (mean)(range 18-73) old at surgery could be reached and were included. In total, 81 tendons were operated with the Achilles scraping procedure alone, and for 55 Achilles operations also a plantaris tendon removal was performed. For 93% of the operated tendons, the patients were satisfied with the surgical outcome and the VAS had decreased from 74 preoperatively to 8 postoperatively. Nine male patients (9 tendons), five operated with scraping + plantaris removal, had remaining tendon pain during loading and were not satisfied. Their VAS score ranged from 22 to 91. For 21% of the operated tendons, some occasional mild discomfort not preventing from full tendon loading, was reported. There were no differences in pain reduction and satisfaction rates between men and women, and between Achilles scraping alone and scraping plus plantaris removal. Conclusion: Ultrasound and colour Doppler–guided surgical Achilles tendon scraping and plantaris tendon removal in patients with chronic painful midportion Achilles tendinopathy show remaining good clinical outcomes and high satisfaction rates in this longer-term follow-up.
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Sakuma, Yu, Kensuke Ochi, Takuji Iwamoto, Asami Saito, Koichiro Yano, Yurino Naito, Shinji Yoshida, Katsunori Ikari i Shigeki Momohara. "Number of Ruptured Tendons and Surgical Delay as Prognostic Factors for the Surgical Repair of Extensor Tendon Ruptures in the Rheumatoid Wrist". Journal of Rheumatology 41, nr 2 (15.01.2014): 265–69. http://dx.doi.org/10.3899/jrheum.130861.
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Objective.Extensor tendon ruptures in the rheumatoid wrist are usually restored by extensor tendon reconstruction surgery. However, the factors significantly correlated with the outcomes of extensor tendon reconstruction have not been defined. We examined factors showing a statistically significant correlation with postoperative active motion after tendon reconstruction.Methods.Spontaneous extensor tendon ruptures of 66 wrists in patients (mean age, 52.6 yrs) with rheumatoid arthritis (RA) were evaluated. All patients underwent tendon reconstruction surgery with wrist arthroplasty or arthrodesis. Active ranges of motion of the affected fingers were evaluated at 12 weeks postsurgery. Statistical significance was determined using multiple and single regression analyses.Results.Forty-six (69.6%) wrists had “good” results, while 13 (19.7%) and 7 (10.6%) wrists had “fair” and “poor” results, respectively. In multiple regression analysis, an increased number of ruptured tendons and the age at operation were independent variables significantly correlated with the postoperative active motion of reconstructed tendons (p = 0.009). Single regression analysis also showed a significant association between the number of ruptured tendons and surgical delay (p = 0.02).Conclusion.The number of ruptured extensor tendons was significantly correlated with the results of tendon reconstruction, and the number of ruptured tendons was significantly correlated with preoperative surgical delay. Our results indicate that, in patients presenting with possible finger extensor tendon rupture, rheumatologists should consult with hand surgeons promptly to preserve hand function.
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Pike, A. V., R. F. Ker i R. M. Alexander. "The development of fatigue quality in high- and low-stressed tendons of sheep (Ovis aries)". Journal of Experimental Biology 203, nr 14 (15.07.2000): 2187–93. http://dx.doi.org/10.1242/jeb.203.14.2187.
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The time taken to rupture in cyclic fatigue tests, to a stress of 45 MPa, was used to compare the fatigue quality of tendons from sheep of varying ages. Muscle and tendon cross-sectional areas were used to calculate the stress-in-life of each tendon. For any given age, high-stressed plantaris tendons were of a higher fatigue quality than low-stressed extensor tendons. Both fatigue quality and stress-in-life increased with age for each tendon type. High-stressed tendons are subjected to large increases in stress-in-life during growth, and fatigue quality increased significantly with this stress. This relationship was not seen, however, in low-stressed tendons, which are not subjected to a comparable range of stresses over time. It is possible that cells modify tendon fatigue quality in response to tendon loading history. Whilst Young's modulus was seen to increase with age, no difference was detected between high- and low-stressed tendons.
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Peltz, Tim Sebastian, Stuart William Hoffman, Peter James Scougall, Mark Peter Gianoutsos, Robert Savage, Rema Antoinette Oliver i William Robert Walsh. "Animal Models for Tendon Repair Experiments: A Comparison of Pig, Sheep and Human Deep Flexor Tendons in Zone II". Journal of Hand Surgery (Asian-Pacific Volume) 22, nr 03 (4.08.2017): 329–36. http://dx.doi.org/10.1142/s0218810417500381.
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Background: This laboratory study compared pig, sheep and human deep flexor tendons in regards to their biomechanical comparability. Methods: To investigate the relevant biomechanical properties for tendon repair experiments, the tendons resistance to cheese-wiring (suture drag/splitting) was assessed. Cheese-wiring of a suture through a tendon is an essential factor for repair gapping and failure in a tendon repair. Results: Biomechanical testing showed that forces required to pulling a uniform suture loop through sheep or pig tendons in Zone II were higher than in human tendons. At time point zero of testing these differences did not reach statistical significance, but differences became more pronounced when forces were measured beyond initial cheese-wiring (2 mm, 5 mm and 10 mm). The stronger resistance to cheese-wiring was more pronounced in the pig tendons. Also regarding size and histology, sheep tendons were more comparable to human tendons than pig tendons. Conclusions: Differences in tendon bio-properties should be kept in mind when comparing and interpreting the results of laboratory tendon experiments.
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Zenchenko, A. V., i Yu M. Cherniakova. "COMPARISON OF 3-WEEK CALCANEAL TENDON REGENERATES AFTER TENOTOMY AND SUTURING IN EXPERIMENT IN VIVO". Journal of the Grodno State Medical University 19, nr 1 (25.02.2021): 77–84. http://dx.doi.org/10.25298/2221-8785-2021-19-1-77-84.
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Background. Modern knowledge about tendon healing as well as possibilities of hand surgery does not solve the problem of tenogenic contractures. For the prevention of cicatricial process, the separation of the sliding surfaces of the tendon and its sheath with polymeric materials is used. However, regeneration of tendons in condition of isolation has not been proven. Aim of the research. In a laboratory animal model to perform a tenotomy and a calcaneal tendon suture, study 3-week regenerates formed in the mobilization regime and evaluate the regenerative capacity of the tendon isolated with a dissected polymer tube. Material and methods. On both paws of laboratory rats tenotomy and suturing of the calcaneal tendons were performed. The tendons on the right paws were isolated with dissected polymeric tubes. The appearance and the histological structure of the suture site were assessed after 3 weeks. Results. Tendon regenerates were distinguished by their maturity and tissue organization. Tendons without isolation healed faster, but lost their sliding surface. As a result of isolation, a sliding surface of the tendon and its sheath was formed, but the formation of the regenerate slowed down. Conclusions. Tendon healing in dissected tube is possible and occurs due to intrinsic repair. The fusion of the tendon demonstrates a well-vascularized regenerate in the suture site.
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De Micheli, Andrea J., Jacob B. Swanson, Nathaniel P. Disser, Leandro M. Martinez, Nicholas R. Walker, David J. Oliver, Benjamin D. Cosgrove i Christopher L. Mendias. "Single-cell transcriptomic analysis identifies extensive heterogeneity in the cellular composition of mouse Achilles tendons". American Journal of Physiology-Cell Physiology 319, nr 5 (1.11.2020): C885—C894. http://dx.doi.org/10.1152/ajpcell.00372.2020.
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Tendon is a dense connective tissue that stores and transmits forces between muscles and bones. Cellular heterogeneity is increasingly recognized as an important factor in the biological basis of tissue homeostasis and disease, yet little is known about the diversity of cell types that populate tendon. To address this, we determined the heterogeneity of cell populations within mouse Achilles tendons using single-cell RNA sequencing. In assembling a transcriptomic atlas of Achilles tendons, we identified 11 distinct types of cells, including three previously undescribed populations of tendon fibroblasts. Prior studies have indicated that pericytes, which are found in the vasculature of tendons, could serve as a potential source of progenitor cells for adult tendon fibroblasts. Using trajectory inference analysis, we provide additional support for the notion that pericytes are likely to be at least one of the progenitor cell populations for the fibroblasts that compose adult tendons. We also modeled cell-cell interactions and identified previously undescribed ligand-receptor signaling interactions involved in tendon homeostasis. Our novel and interactive tendon atlas highlights previously underappreciated heterogeneity between and within tendon cell populations. The atlas also serves as a resource to further the understanding of tendon extracellular matrix assembly and maintenance and in the design of therapies for tendinopathies.
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Ağır, İsmail, Mahmut Nedim Aytekin, Onur Başçı, Barış Çaypınar i Bülent Erol. "Tendon-Holding Capacities of Two Newly Designed Implants for Tendon Repair: An Experimental Study on the Flexor Digitorum Profundus Tendon of Sheep". Open Orthopaedics Journal 8, nr 1 (27.06.2014): 135–39. http://dx.doi.org/10.2174/1874325001408010135.
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Background: Two main factors determine the strength of tendon repair; the tensile strength of material and the gripping capacity of a suture configuration. Different repair techniques and suture materials were developed to increase the strength of repairs but none of techniques and suture materials seem to provide enough tensile strength with safety margins for early active mobilization. In order to overcome this problem tendon suturing implants are being developed. We designed two different suturing implants. The aim of this study was to measure tendon-holding capacities of these implants biomechanically and to compare them with frequently used suture techniques Materials and Methods: In this study we used 64 sheep flexor digitorum profundus tendons. Four study groups were formed and each group had 16 tendons. We applied model 1 and model 2 implant to the first 2 groups and Bunnell and locking-loop techniques to the 3rd and 4th groups respectively by using 5 Ticron sutures. Results: In 13 tendons in group 1 and 15 tendons in group 2 and in all tendons in group 3 and 4, implants and sutures pulled out of the tendon in longitudinal axis at the point of maximum load. The mean tensile strengths were the largest in group 1 and smallest in group 3. Conclusion: In conclusion, the new stainless steel tendon suturing implants applied from outside the tendons using steel wires enable a biomechanically stronger repair with less tendon trauma when compared to previously developed tendon repair implants and the traditional suturing techniques.
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Koivunen-Niemelä, T., i K. Parkkola. "Anatomy of the Achilles tendon (tendo calcaneus) with respect to tendon thickness measurements". Surgical and Radiologic Anatomy 17, nr 3 (wrzesień 1995): 263–68. http://dx.doi.org/10.1007/bf01795061.
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Yu, Tung-Yang, Jong-Hwei S. Pang, Li-Ping Lin, Ju-Wen Cheng, Shih-Jung Liu i Wen-Chung Tsai. "Platelet-Rich Plasma Releasate Promotes Early Healing in Tendon After Acute Injury". Orthopaedic Journal of Sports Medicine 9, nr 4 (1.04.2021): 232596712199037. http://dx.doi.org/10.1177/2325967121990377.
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Background: Acute tendon injury can limit motion and thereby inhibit tendon healing. Positive results have been found after the use of platelet-rich plasma (PRP) to treat tendon injury; however, the early effects of PRP on tendon regeneration are not known. Purpose/Hypothesis: The purpose of this study was to evaluate the effects of PRP releasate (PRPr) on the early stages of tendon healing in a rat partial tenotomy model. It was hypothesized that PRPr can promote early healing of an Achilles tendon in rats. Study Design: Controlled laboratory study. Methods: PRP was prepared by a 2-step method of manual platelet concentration from 10 rats. PRPr was isolated from the clotted preparation after activation by thrombin and was applied to an Achilles tendon on 1 side of 30 rats on the second day after partial tenotomy, with normal saline used as the control on the other side. Achilles tendon samples were harvested 5 and 10 days after tenotomy. At each time point, 15 Achilles tendon samples were obtained, of which 5 samples were evaluated by Masson trichrome staining, apoptosis, and cell proliferation, while the other 10 samples were tested for tensile strength using a material testing machine. Results: Compared with saline-treated control tendons, the PRPr-treated tendons showed increased collagen synthesis near the cut edge and fewer apoptotic cells ( P = .01). An immunohistochemical analysis revealed more Ki-67–positive cells but fewer cluster of differentiation (CD) 68+ (ED1+) macrophages in PRPr tendons compared with saline-treated tendons ( P < .01). Tendons treated with PRPr also showed higher ultimate tensile strength than those treated with saline ( P = .03). Conclusion: PRPr treatment promotes tissue recovery in the early phase of tendon healing by stimulating tendon cell proliferation and collagen production while inhibiting cell apoptosis and CD68+ (ED1+) macrophage infiltration. Clinical Relevance: These findings suggest that with PRPr treatment, higher loads can be applied to the healing tendon at an earlier time, which can help the patient resume activity earlier.
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Duci, Shkelzen, i Hasan Ahmeti. "Partially Divided Flexor Tendon Injuries: Should They Be Repaired or Not?" Surgery Journal 02, nr 03 (lipiec 2016): e89-e90. http://dx.doi.org/10.1055/s-0036-1593356.
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The correct management of partially divided flexor tendon injuries is still controversial. Opinions vary regarding whether partially divided flexor tendon injuries should be repaired. Flexor tendon injuries are common because the tendons lie close to the skin. The tendons are therefore exposed to injuries like lacerations and crush injuries, and occasionally they can rupture from where they are joined to the bone. Tendon injuries are the second most common hand injuries in orthopedic patients.
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Lieber, R. L., M. E. Leonard, C. G. Brown i C. L. Trestik. "Frog semitendinosis tendon load-strain and stress-strain properties during passive loading". American Journal of Physiology-Cell Physiology 261, nr 1 (1.07.1991): C86—C92. http://dx.doi.org/10.1152/ajpcell.1991.261.1.c86.
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The mechanical properties of the frog semitendinosis (ST) tendon, bone-tendon junction, and aponeurosis were measured during passive loading to a tension equal to maximum isometric tension (Po). Stiffness and strain in these regions continuously increased as load increased. Tendon stiffness was approximately four times the aponeurosis stiffness. Tendon Young's modulus at Po was only 188 MPa, which is approximately 10 times less than the modulus reported for most mammalian tendons. Similarly, tendon stress at Po was only approximately 3 MPa, which is also less than that predicted for many tendons. Tendon strain at Po was approximately 2% after passive loading. We conclude that different regions of the frog ST tendon have different mechanical properties and that the frog ST tendon operates physiologically in the “toe” region of the stress-strain curve with a variable stiffness that increases with load. Taken together, these results have significant implications in understanding muscle-tendon design and neuromotor control strategies.
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Zhang, Kairui, Michael W. Hast, Soutarou Izumi, Yu Usami, Snehal Shetye, Ngozi Akabudike, Nancy J. Philp i in. "Modulating Glucose Metabolism and Lactate Synthesis in Injured Mouse Tendons: Treatment With Dichloroacetate, a Lactate Synthesis Inhibitor, Improves Tendon Healing". American Journal of Sports Medicine 46, nr 9 (21.06.2018): 2222–31. http://dx.doi.org/10.1177/0363546518778789.
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Background: Tendon injuries are common problems among athletes. Complete recovery of the mechanical structure and function of ruptured tendons is challenging. It has been demonstrated that upregulation of glycolysis and lactate production occurs in wounds, inflammation sites, and cancerous tumors, and these metabolic changes also control growth and differentiation of stem and progenitor cells. Similar metabolic changes have been reported in human healing tendons. In addition, lactate production has increased in progenitors isolated from injured tendons after treatment with IL-1β. It is thought that the metabolic changes play a role in tendon healing after injury. Hypothesis: Glucose metabolism is altered during tendon injury and healing, and modulation of this altered metabolism improves tendon repair. Study Design: Controlled laboratory study. Methods: The authors used the tendon injury model involving a complete incision of the Achilles tendon in C57BL/6J female mice and studied alterations of glucose metabolism in injured tendons with [U-13C]glucose and metabolomics analysis 1 and 4 weeks after surgery. They also examined the effects of dichloroacetate (DCA; an indirect lactate synthesis inhibitor) treatment on the recovery of structure and mechanical properties of injured tendons 4 weeks after surgery in the same mouse model. Results: Significant changes in glucose metabolism in tendons after injury surgery were detected. 13C enrichment of metabolites and intermediates, flux through glycolysis, and lactate synthesis, as well as tricarboxylic acid cycle activity, were acutely increased 1 week after injury. Increased glycolysis and lactate generation were also found 4 weeks after injury. DCA-treated injured tendons showed decreased cross-sectional area and higher values of modulus, maximum stress, and maximum force when compared with vehicle-treated injured tendons. Improved alignment of the collagen fibers was also observed in the DCA group. Furthermore, DCA treatment reduced mucoid accumulation and ectopic calcification in injured tendons. Conclusion: The findings indicate that injured tendons acutely increase glycolysis and lactate synthesis after injury and that the inhibition of lactate synthesis by DCA is beneficial for tendon healing. Clinical Relevance: Changing metabolism in injured tendons may be a therapeutic target for tendon repair.
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MORRISON, W. A., i S. M. SCHLICHT. "The Plantaris Tendon as a Tendo-Osseous Graft". Journal of Hand Surgery 17, nr 4 (sierpień 1992): 471–75. http://dx.doi.org/10.1016/s0266-7681(05)80277-3.
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To minimize adhesions following tendon repair, early post-operative movement is recommended. This has proved difficult with tendon grafting because of weakness of the repair sites, particularly distally, and because of slow revascularization. A potential solution is the use of a composite tendon-bone graft in which a bone block is attached to the end of the tendon. The tendon is threaded through a hole in the distal phalanx from the dorsal to the palmar side and impacted like a cork to create an immediate strong fixation. The tendon itself is then tunnelled through the pulley system and the proximal repair is carried out with a multiple weave technique which can withstand immediate active movement. The ideal tendon-bone complex is the plantaris attached to a segment of calcaneus. A preliminary report with two case studies is presented.
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Gumucio, Jonathan P., Anthony C. Phan, David G. Ruehlmann, Andrew C. Noah i Christopher L. Mendias. "Synergist ablation induces rapid tendon growth through the synthesis of a neotendon matrix". Journal of Applied Physiology 117, nr 11 (1.12.2014): 1287–91. http://dx.doi.org/10.1152/japplphysiol.00720.2014.
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Mechanical loading can increase tendon cross-sectional area (CSA), but the mechanisms by which this occurs are largely unknown. To gain a greater understanding of the cellular mechanisms of adult tendon growth in response to mechanical loading, we used a synergist ablation model whereby a tenectomy of the Achilles tendon was performed to induce growth of the synergist plantaris tendon. We hypothesized that after synergist ablation progenitor cells in the epitenon would proliferate and increase the size of the existing tendon matrix. Adult male mice were subjected to a bilateral Achilles tenectomy, and plantaris tendons were isolated from mice at 0, 2, 7, 14, and 28 days after surgery. Tendons were sectioned stained with either fast green and hematoxylin, prepared for fluorescent microscopy, or prepared for gene expression of scleraxis and type I collagen. After overload, there was a dramatic increase in total CSA of tendons, whereas the size of the original tendon matrix was not changed. Growth primarily occurred through the formation of a neotendon matrix between the original tendon and the epitenon, and contained cells that were proliferative and scleraxis positive. Additionally, an initial expansion of fibroblast cells occurred before the synthesis of new extracellular matrix. Fibroblasts in the original tendon did not re-enter the cell cycle. The results from this study provide new insight into the mechanisms of tendon growth, indicate tendon consists mostly of postmitotic cells, and that growth of tendon primarily occurs from the most superficial layers outward.
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Li, Zhi Jie, Qian Qian Yang i You Lang Zhou. "Biological and Mechanical Factors and Epigenetic Regulation Involved in Tendon Healing". Stem Cells International 2023 (9.01.2023): 1–14. http://dx.doi.org/10.1155/2023/4387630.
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Tendons are an important part of the musculoskeletal system. Connecting muscles to bones, tendons convert force into movement. Tendon injury can be acute or chronic. Noticeably, tendon healing requires a long time span and includes inflammation, proliferation, and remodeling processes. The mismatch between endogenous and exogenous healing may lead to adhesion causing further negative effects. Management of tendon injuries and complications such as subsequent adhesion formation are still challenges for clinicians. Due to numerous factors, tendon healing is a complex process. This review introduces the role of various biological and mechanical factors and epigenetic regulation processes involved in tendon healing.
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Muller, S. "TENDON BIOENGINEERING: CHALLENGES FOR CLINICAL APPLICATION". Orthopaedic Proceedings 106-B, SUPP_2 (2.01.2024): 22. http://dx.doi.org/10.1302/1358-992x.2024.2.022.
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Tendons mainly consist of collagen in order to withstand high tensile forces. Compared to other, high turnover tissues, cellularity and vascularity in tendons are low. Thus, the natural healing process of tendons takes long and can be problematic. In case of injury to the enthesis, the special transition from tendon over cartilage to bone is replaced by a fibrous scar tissue, which remains an unsolved problem in rotator cuff repair.To improve tendon healing, many different approaches have been described using scaffolds, stem cells, cytokines, blood products, gene therapy and others. Despite promising in vitro and in vivo results, translation to patient care is challenging. In clinics however, tendon auto- or allografts remain still first choice to augment tendon healing if needed.Therefore, it is important to understand natural tendon properties and natural tendon healing first. Like in other tissues, senescence of tenocytes seems to play an important role for tendon degeneration which is interestingly not age depended. Our in vivo healing studies have shown improved and accelerated healing by adding collagen type I, which is now used in clinics, for example for augmentation of rotator cuff repair. Certain cytokines, cells and scaffolds may further improve tendon healing but are not yet used routinely, mainly due to missing clinical data, regulatory issues and costs.In conclusion, the correct diagnosis and correct first line treatment of tendon injuries are important to avoid the necessity to biologically augment tendon healing. However, strategies to improve and accelerate tendon healing are still desirable. New treatment opportunities may arise with further advances in tendon engineering in the future.
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Kwan, Ka Yu Carissa, Ka Wai Kerry Ng, Ying Rao, Chenxian Zhu, Shengcai Qi, Rocky S. Tuan, Dai Fei Elmer Ker i Dan Michelle Wang. "Effect of Aging on Tendon Biology, Biomechanics and Implications for Treatment Approaches". International Journal of Molecular Sciences 24, nr 20 (14.10.2023): 15183. http://dx.doi.org/10.3390/ijms242015183.
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Tendon aging is associated with an increasing prevalence of tendon injuries and/or chronic tendon diseases, such as tendinopathy, which affects approximately 25% of the adult population. Aged tendons are often characterized by a reduction in the number and functionality of tendon stem/progenitor cells (TSPCs), fragmented or disorganized collagen bundles, and an increased deposition of glycosaminoglycans (GAGs), leading to pain, inflammation, and impaired mobility. Although the exact pathology is unknown, overuse and microtrauma from aging are thought to be major causative factors. Due to the hypovascular and hypocellular nature of the tendon microenvironment, healing of aged tendons and related injuries is difficult using current pain/inflammation and surgical management techniques. Therefore, there is a need for novel therapies, specifically cellular therapy such as cell rejuvenation, due to the decreased regenerative capacity during aging. To augment the therapeutic strategies for treating tendon-aging-associated diseases and injuries, a comprehensive understanding of tendon aging pathology is needed. This review summarizes age-related tendon changes, including cell behaviors, extracellular matrix (ECM) composition, biomechanical properties and healing capacity. Additionally, the impact of conventional treatments (diet, exercise, and surgery) is discussed, and recent advanced strategies (cell rejuvenation) are highlighted to address aged tendon healing. This review underscores the molecular and cellular linkages between aged tendon biomechanical properties and the healing response, and provides an overview of current and novel strategies for treating aged tendons. Understanding the underlying rationale for future basic and translational studies of tendon aging is crucial to the development of advanced therapeutics for tendon regeneration.
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Yuan, Ziyang, Haomiao Yu, Huibin Long, Yike Dai, Lin Shi, Jiaming Zhao, Ai Guo, Naicheng Diao, Lifeng Ma i Heyong Yin. "Stem Cell Applications and Tenogenic Differentiation Strategies for Tendon Repair". Stem Cells International 2023 (15.03.2023): 1–15. http://dx.doi.org/10.1155/2023/3656498.
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Tendons are associated with a high injury risk because of their overuse and age-related tissue degeneration. Thus, tendon injuries pose great clinical and economic challenges to the society. Unfortunately, the natural healing capacity of tendons is far from perfect, and they respond poorly to conventional treatments when injured. Consequently, tendons require a long period of healing and recovery, and the initial strength and function of a repaired tendon cannot be completely restored as it is prone to a high rate of rerupture. Nowadays, the application of various stem cell sources, including mesenchymal stem cells (MSCs) and embryonic stem cells (ESCs), for tendon repair has shown great potential, because these cells can differentiate into a tendon lineage and promote functional tendon repair. However, the mechanism underlying tenogenic differentiation remains unclear. Moreover, no widely adopted protocol has been established for effective and reproducible tenogenic differentiation because of the lack of definitive biomarkers for identifying the tendon differentiation cascades. This work is aimed at reviewing the literature over the past decade and providing an overview of background information on the clinical relevance of tendons and the urgent need to improve tendon repair; the advantages and disadvantages of different stem cell types used for boosting tendon repair; and the unique advantages of reported strategies for tenogenic differentiation, including growth factors, gene modification, biomaterials, and mechanical stimulation.
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Bramlage, L. R., M. Bailey, A. L. Bertone, S. E. Weisbrode i R. W. Henninger. "Effects of Tendon Splitting on Experimentally-Induced Acute Equine Tendinitis". Veterinary and Comparative Orthopaedics and Traumatology 05, nr 01 (1992): 01–09. http://dx.doi.org/10.1055/s-0038-1633122.
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SummaryThe objective of this study was to compare the early phases of healing between surgically split and unsplit (control) tendons in a superficial digital flexor tendinitis model. Tendinitis was induced in both forelimbs of six horses by injection with collagenase. One tendon from each horse was randomly chosen to undergo tendon splitting. In six horses, the tendons were evaluated by ultrasonography before (week 0) and after (week 1) the onset of tendinitis and at weeks two, three, and four following tendon splitting. Three horses were euthanatized at the end of week four. Three horses were maintained for an additional month and evaluated at week eight before euthanasia. Following euthanasia, microangiographic and histologic evaluations were performed. Ultrasonographic evaluation revealed a significant (p <0.05) decrease in mean tendon lesion area in the split tendons when compared to the controls at weeks three, four, and eight. By week eight, all lesions had resolved in the split but not the control tendons. Mean lesion grade was lower in the split tendons at weeks two, three, four, and eight. Tendon area was similar (p >0.05) between groups at all periods after surgery. There was a more mature vascular pattern and greater peritendinous vascular response in the split tendons compared to control tendons. Histological examination under plain and polarized light revealed more normal collagen orientation and wave formation in the repair tissue in the split tendons at weeks four and eight. The fibroblast nuclei density was significantly (p <0.05) lower in the split tendons at week eight. These findings suggest that during the time period of this study, tendon splitting results in a more rapid decrease in lesion size and superior repair tissue organization when compared to controls.In a collagenase-induced tendinitis model, tendon splitting was shown to result in a greater reduction in tendon lesion size and superior repair tissue organization when compared to control tendons.
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Buchanan, Cindy I., i Richard L. Marsh. "Effects of long-term exercise on the biomechanical properties of the Achilles tendon of guinea fowl". Journal of Applied Physiology 90, nr 1 (1.01.2001): 164–71. http://dx.doi.org/10.1152/jappl.2001.90.1.164.
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The purpose of this study was to determine the effect of long-term exercise on tendon compliance and to ascertain whether tendons adapt differently to downhill running vs. running on a level surface. We carried out this investigation on the gastrocnemius tendon of helmeted guinea fowl ( Numida meleagris) that were trained for 8–12 wk before commencing experimental procedures. We used an in situ technique to measure tendon stiffness. The animals were deeply anesthetized with isofluorane during all in situ procedures. Our results indicate that long-term exercise increased tendon stiffness. This finding held true after normalization for the cross-sectional area of the free tendon, likely reflecting a change in the material properties of the exercised tendons. Whether training consisted of level or downhill running did not appear to influence response of the tendon to exercise. We hypothesize that the increased stiffness observed in tendons after a long-term running program may be a response to repeated stress and may function as a mechanism to resist tendon damage due to mechanical fatigue.