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Journal of Orthopaedic Research :... Jun 2018Tendon injuries are major musculoskeletal disorders. Polydeoxyribonucleotide activates the adenosine receptor subtype A2A, resulting in tissue growth and neogenesis....
Tendon injuries are major musculoskeletal disorders. Polydeoxyribonucleotide activates the adenosine receptor subtype A2A, resulting in tissue growth and neogenesis. This experimental study confirms that polydeoxyribonucleotide can improve secretion of various growth factors, promote collagen synthesis, and restore tensile strength of the Achilles tendon in a rat model with Achilles tendon injury. Thirty-six male Sprague-Dawley rats, aged 7 weeks, were divided into two groups, and the Achilles tendon was transected and repaired using the modified Kessler's method. In the experimental group (n = 18), the rats received daily intraperitoneal administration of polydeoxyribonucleotide (8 mg/kg/day for 1, 2, or 4 weeks). The control groups received the same amount of normal saline. The rats were euthanized at 1, 2, and 4 weeks, and tissues from the repair site were harvested. The cross-sectional area of the tendon was significantly increased at 2 and 4 weeks in polydeoxyribonucleotide group (p = 0.008 and p = 0.017, respectively). Moreover, tendons in the polydeoxyribonucleotide group were more resistant to mechanical stress at 2 and 4 weeks (p = 0.041 and p = 0.041, respectively). The staining levels of collagen type I in the experimental group were significantly stronger at 2 and 4 weeks (p = 0.026 and p = 0.009, respectively). Furthermore, higher expression levels of fibroblast growth factor, vascular endothelial growth factor, and transforming growth factor β1 were detected in the experimental group at 4 weeks (p = 0.041, p = 0.026, and p = 0.041, respectively). This study confirms that polydeoxyribonucleotide can improve the tensile strength of the rats' Achilles tendon following injury and repair. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1767-1776, 2018.
Topics: Achilles Tendon; Animals; Biomechanical Phenomena; Collagen Type I; Immunohistochemistry; Male; Polydeoxyribonucleotides; Rats; Rats, Sprague-Dawley; Tendon Injuries; Wound Healing
PubMed: 29094396
DOI: 10.1002/jor.23796 -
Joint Diseases and Related Surgery Apr 2024The study aimed to examine the histopathological and biomechanical effects of papaverine administered intraperitoneally and locally on Achilles tendon healing in a rat...
OBJECTIVES
The study aimed to examine the histopathological and biomechanical effects of papaverine administered intraperitoneally and locally on Achilles tendon healing in a rat model.
MATERIALS AND METHODS
Forty-eight adult male Sprague-Dawley rats (range, 300 to 400 g) were used in this study conducted between October and November 2022. The rats were divided into three groups, with each group further subdivided into two for sacrifice on either the 15 (early period) or 30 (late period) day after surgery. The first (control) group received no treatment following Achilles tendon repair, while papaverine was intraperitoneally administered every other day for 10 days in the second group and locally in the third group after surgery. On the 15 and 30 days, the rats were sacrificed, and their Achilles tendons were subjected to biomechanical testing and histopathological evaluation.
RESULTS
Histopathologically, there were no significant differences among the groups on the 15 day. However, on the 30 day, the locally applied papaverine group exhibited superior histopathological outcomes compared to the control group (p<0.05). Concerning the highest tensile strength values before rupture, the biomechanical assessment showed that the group receiving local papaverine treatment in the early period and both the group with systemic papaverine treatment and the one with local papaverine treatment in the late period displayed a statistically significant advantage compared to the control group (p<0.05).
CONCLUSION
Locally administered papaverine has positive biomechanical effects in the early period and exhibits a positive correlation both histopathologically and biomechanically in the late period. Novel therapeutic options may be provided for patients through these findings.
Topics: Animals; Achilles Tendon; Papaverine; Rats, Sprague-Dawley; Male; Tissue Adhesions; Wound Healing; Tendon Injuries; Rats; Tensile Strength; Injections, Intraperitoneal; Biomechanical Phenomena; Disease Models, Animal
PubMed: 38727117
DOI: 10.52312/jdrs.2024.1656 -
Journal of Visualized Experiments : JoVE Oct 2019Tendon disorders are common, affect people of all ages, and are often debilitating. Standard treatments, such as anti-inflammatory drugs, rehabilitation, and surgical...
Tendon disorders are common, affect people of all ages, and are often debilitating. Standard treatments, such as anti-inflammatory drugs, rehabilitation, and surgical repair, often fail. In order to define tendon function and demonstrate efficacy of new treatments, the mechanical properties of tendons from animal models must be accurately determined. Murine animal models are now widely used to study tendon disorders and evaluate novel treatments for tendinopathies; however, determining the mechanical properties of mouse tendons has been challenging. In this study, a new system was developed for tendon mechanical testing that includes 3D-printed fixtures that exactly match the anatomies of the humerus and calcaneus to mechanically test supraspinatus tendons and Achilles tendons, respectively. These fixtures were developed using 3D reconstructions of native bone anatomy, solid modeling, and additive manufacturing. The new approach eliminated artifactual gripping failures (e.g., failure at the growth plate failure rather than in the tendon), decreased overall testing time, and increased reproducibility. Furthermore, this new method is readily adaptable for testing other murine tendons and tendons from other animals.
Topics: Achilles Tendon; Animals; Biomechanical Phenomena; Female; Imaging, Three-Dimensional; Male; Mice; Mice, Inbred C57BL; Models, Animal; Printing, Three-Dimensional; Reproducibility of Results
PubMed: 31680671
DOI: 10.3791/60280 -
The Journal of International Medical... Feb 2017Objective * These authors contributed equally to this work. To explore tendon-bundle technique for treating Achilles tendon rupture with no defects. Methods Patients...
Objective * These authors contributed equally to this work. To explore tendon-bundle technique for treating Achilles tendon rupture with no defects. Methods Patients with full unilateral Achilles tendon rupture with no defects were included. The Achilles tendon medial edge surgical repair approach was used, revealing horsetail-like rupture bundles. Tendon bundles were anatomically realigned and repaired end-to-end using 5-0 sutures. Patients were followed-up for 1 year, and assessed for differences between the repaired versus healthy limb. Results Out of 24 patients (18 male, 6 female; aged 19-56 years) at 1 year following surgery, mean American Orthopaedic Foot and Ankle Society score was 92.4 ± 5.9; mean differences between the surgically repaired versus contralateral side in dorsiflexion and plantarflexion angle were 3.5 ± 2.3° and 5.6 ± 3.2°, respectively; mean difference in calf circumference between the two sides was 0.9 ± 0.5 cm; and mean increase in Achilles tendon width versus the healthy side was 0.8 ± 0.2 cm. By 1 year post-surgery, there were no significant between-side differences in dorsiflexion and plantarflexion angle, or calf circumference. Conclusions Tendon-bundle surgery resulted in good ankle function restoration and low complication rates. Tendon-bundle surgery may reduce blood supply destruction and maximally preserve Achilles tendon length, and may be effective for treating Achilles tendon rupture with no defects.
Topics: Achilles Tendon; Adult; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Orthopedic Procedures; Range of Motion, Articular; Plastic Surgery Procedures; Recovery of Function; Rupture; Suture Techniques; Sutures; Tendon Injuries; Treatment Outcome
PubMed: 28222622
DOI: 10.1177/0300060516677928 -
Annals of Biomedical Engineering Feb 2021The Achilles tendon, while the strongest and largest tendon in the body, is frequently injured. Even after surgical repair, patients risk re-rupture and long-term... (Review)
Review
The Achilles tendon, while the strongest and largest tendon in the body, is frequently injured. Even after surgical repair, patients risk re-rupture and long-term deficits in function. Poly-N-acetyl glucosamine (sNAG) polymer has been shown to increase the rate of healing of venous leg ulcers, and use of this material improved tendon-to-bone healing in a rat model of rotator cuff injury. Therefore, the purpose of this study was to investigate the healing properties of liquid sNAG polymer suspension in a rat partial Achilles tear model. We hypothesized that repeated sNAG injections throughout healing would improve Achilles tendon healing as measured by improved mechanical properties and cellular morphology compared to controls. Results demonstrate that sNAG has a positive effect on rat Achilles tendon healing at three weeks after a full thickness, partial width injury. sNAG treatment led to increased quasistatic tendon stiffness, and increased tangent and secant stiffness throughout fatigue cycling protocols. Increased dynamic modulus also suggests improved viscoelastic properties with sNAG treatment. No differences were identified in histological properties. Importantly, use of this material did not have any negative effects on any measured parameter. These results support further study of this material as a minimally invasive treatment modality for tendon healing.
Topics: Acetylglucosamine; Achilles Tendon; Animals; Biomechanical Phenomena; Disease Models, Animal; Male; Rats, Sprague-Dawley; Tendon Injuries; Rats
PubMed: 33409852
DOI: 10.1007/s10439-020-02711-w -
Journal of Orthopaedic Surgery (Hong... 2021This study aims to measure the distance between the common site of Achilles tendon rupture and calcaneal insertion through ultrasound and to compare the outcomes between...
PURPOSE
This study aims to measure the distance between the common site of Achilles tendon rupture and calcaneal insertion through ultrasound and to compare the outcomes between proximal and distal rupture groups.
METHODS
We investigated the electronic medical records of 117 patients and preoperative ultrasound describing the rupture site. Among 88 patients, we compared the patient-reported outcome and re-rupture rate of proximal and distal rupture groups.
RESULTS
The mean rupture site of the 117 included subjects was 4.5 ± 1.3 cm. The rupture site had a weak negative correlation with body mass index ( = -0.230, = 0.013). Furthermore, 77% of the patients with distal rupture reported good outcome (Achilles Tendon Rupture Score > 80) compared to 56% of the patients with proximal rupture ( = 0.041).
CONCLUSION
Patients with proximal rupture had less satisfactory postoperative outcomes than those with distal rupture.
Topics: Achilles Tendon; Adolescent; Adult; Aged; Calcaneus; Female; Follow-Up Studies; Humans; Male; Middle Aged; Patient Reported Outcome Measures; Prognosis; Plastic Surgery Procedures; Retrospective Studies; Rupture; Tendon Injuries; Treatment Outcome; Young Adult
PubMed: 33845659
DOI: 10.1177/23094990211007616 -
Journal of Biomechanics Jun 2021Inter-limb differences in Achilles tendon mechanical, material and morphological properties have previously been described in non-athletes and attributed to the...
Inter-limb differences in Achilles tendon mechanical, material and morphological properties have previously been described in non-athletes and attributed to the preferential use of a given limb. Achilles tendon overuse tendon injury generally initiate unilaterally and alters triceps surae activation and Achilles tendon properties. The investigation of inter-limb differences in muscle activation and tendon properties may provide directions for injury prevention in habitual runners. In this study triceps surae and Achilles tendon properties were investigated bilaterally in habitual runners during unilateral maximal isometric contractions. Morphological, mechanical and material Achilles tendon properties were assessed using isokinetic dynamometry, motion capture and ultrasonography while triceps surae activation strategies were assessed using electromyography. Lower limb preference was assessed for inter-limb comparisons using the Waterloo questionnaire. Zero and one-dimensional statistical analysis and Cohen's d were employed to investigate possible inter-limb differences. Inter-limb associations in Achilles tendon properties and intra-limb associations between triceps surae activations were assessed using Pearson's correlation coefficients. No differences were observed between the preferred and non-preferred limb in terms of triceps surae muscle activation amplitude and Achilles tendon properties. However, intra-limb association among triceps surae activation ratios were not identical between limbs. Runners and triathletes present similar Achilles tendons properties between limbs, and thus initial observations of unilateral changes in the Achilles tendon properties might be used as a strategy to prevent the onset of overuse tendon injury. The non-similar associations within activation ratios between limbs should be further explored since triceps surae activation strategies may alter loading of the Achilles tendon.
Topics: Achilles Tendon; Electromyography; Isometric Contraction; Leg; Muscle, Skeletal
PubMed: 34000645
DOI: 10.1016/j.jbiomech.2021.110493 -
Journal of the Mechanical Behavior of... Dec 2020Insertional Achilles tendinopathy (IAT) is a painful condition that is challenging to treat non-operatively. Although previous studies have characterized the gross...
Insertional Achilles tendinopathy (IAT) is a painful condition that is challenging to treat non-operatively. Although previous studies have characterized the gross histological features, in vivo strain patterns and transverse compressive mechanical properties of tissue affected by IAT, it is not known how IAT impacts the tensile mechanical properties of the Achilles tendon insertion along the axial/longitudinal direction (i.e., along the predominant direction of loading). To address this knowledge gap, the objectives of this study were to 1) apply ex vivo mechanical testing, nonlinear elastic analysis and quasilinear viscoelastic (QLV) analysis to compare the axial tensile mechanical properties of the Achilles tendon insertion in individuals with and without IAT; and 2) use biochemical analysis and second harmonic generation (SHG) imaging to assess structural and compositional changes induced by IAT in order to help explain IAT-associated tensile mechanical changes. Tissue from the Achilles tendon insertion was acquired from healthy donors and from patients undergoing debridement surgery for IAT. Tissue specimens were mechanically tested using a uniaxial tensile (stress relaxation) test applied in the axial direction. A subset of the donor specimens was used for SHG imaging and biochemical analysis. Linear and non-linear elastic analyses of the stress relaxation tests showed no significant tensile mechanical changes in IAT specimens compared to healthy controls. However, SHG analysis showed that fibrillar collagen was significantly more disorganized in IAT tissue as compared with healthy controls, and biochemical analysis showed that sulfated glycosaminoglycan (sGAG) content and water content were higher in IAT specimens. Collectively, these findings suggest that conservative interventions for IAT should target restoration of ultrastructural organization, reduced GAG content, and reduced resistance to transverse compressive strain.
Topics: Achilles Tendon; Humans; Tendinopathy
PubMed: 32882677
DOI: 10.1016/j.jmbbm.2020.104031 -
Journal of Orthopaedic Research :... Jan 2013To systematically review the current in-vivo evidence for the use of platelet-concentrates (PRP) in the treatment of Achilles tendinopathy and Achilles tendon ruptures... (Meta-Analysis)
Meta-Analysis Review
To systematically review the current in-vivo evidence for the use of platelet-concentrates (PRP) in the treatment of Achilles tendinopathy and Achilles tendon ruptures in animal models and human applications. A systematic search of PubMed, CINAHL, EMBASE, CCTR, and CDSR was performed for animal and human studies on the effect of platelet-concentrates in the treatment of Achilles tendinopathy and ruptures using the terms "Achilles tendon and platelet." The systematic search revealed a total of 149 papers. After excluding duplicates and cases of overlapping data, studies not focusing on in vivo evidence in terms of treatment or outcome, studies without any intervention, studies with unacceptable high attrition, one Chinese and one Swedish study, the remaining 14 manuscripts were included. The key finding of our study is evidence in support of a statistically significant effect of platelet concentrates in the treatment of Achilles tendon ruptures in vivo in animal models and human application, consistent with a medium to large sized effect. This effect is most likely attributable to fastened and enhanced scar tissue maturation. There was no evidence for a beneficial effect of platelets in Achilles tendinopathy.
Topics: Achilles Tendon; Animals; Evidence-Based Medicine; Humans; Platelet Transfusion; Platelet-Rich Plasma; Tendon Injuries
PubMed: 22886696
DOI: 10.1002/jor.22199 -
Journal of Biomechanics Feb 2022Immediately prior to inserting into bone, many healthy tendons experience impingement from nearby bony structures. However, super-physiological levels of impingement are...
Immediately prior to inserting into bone, many healthy tendons experience impingement from nearby bony structures. However, super-physiological levels of impingement are implicated in insertional tendinopathies. Unfortunately, the mechanisms underlying the connection between impingement and tendon pathology remain poorly understood, in part due to the shortage of well-characterized animal models of impingement at clinically relevant sites. As a first step towards developing a model of excessive tendon impingement, the objective of this study was to characterize the mechanical strain environment in the mouse Achilles tendon insertion under passive dorsiflexion and confirm that - like humans - mice experience impingement of the tendon insertion from the calcaneus (heel bone) in dorsiflexed ankle positions. Based on previous work in humans, we hypothesized that during dorsiflexion, the mouse Achilles tendon insertion would experience high levels of transverse compressive strain due to calcaneal impingement. A custom-built loading platform was used to apply passive dorsiflexion, while an ultrasound transducer positioned over the Achilles tendon captured radiofrequency images. A non-rigid image registration algorithm was then used to map the transverse compressive strain based on the acquired ultrasound image sequences. Our results demonstrate that during passive dorsiflexion, transverse compressive strains were produced throughout the Achilles tendon, with significantly larger strain magnitudes at the tendon insertion than at the midsubstance. Furthermore, there was increasing transverse compressive strain observed within the Achilles tendon as a function of increasing dorsiflexion angle. This study enhances our understanding of the unique mechanical loading environment of the Achilles tendon under physiologically relevant conditions.
Topics: Achilles Tendon; Animals; Ankle; Ankle Joint; Mice; Tendinopathy; Ultrasonography
PubMed: 34998182
DOI: 10.1016/j.jbiomech.2021.110920