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- Dietrich, Franciele, et al.
(författare)
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Dexamethasone Enhances Achilles Tendon Healing in an Animal Injury Model, and the Effects Are Dependent on Dose, Administration Time, and Mechanical Loading Stimulation
- 2022
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Ingår i: American Journal of Sports Medicine. - : Sage Publications Inc. - 0363-5465 .- 1552-3365. ; 50:5, s. 1306-1316
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Tidskriftsartikel (refereegranskat)abstract
- Background: Corticosteroid treatments such as dexamethasone are commonly used to treat tendinopathy but with mixed outcomes. Although this treatment can cause tendon rupture, it can also stimulate the tendon to heal. However, the mechanisms behind corticosteroid treatment during tendon healing are yet to be understood. Purpose: To comprehend when and how dexamethasone treatment can ameliorate injured tendons by using a rat model of Achilles tendon healing. Study Design: Controlled laboratory study. Methods: An overall 320 rats were used for a sequence of 6 experiments. We investigated whether the drug effect was time-, dose-, and load-dependent. Additionally, morphological data and drug administration routes were examined. Healing tendons were tested mechanically or used for histological examination 12 days after transection. Blood was collected for flow cytometry analysis in 1 experiment. Results: We found that the circadian rhythm and drug injection timing influenced the treatment outcome. Dexamethasone treatment at the right time point (days 7-11) and dose (0.1 mg/kg) significantly improved the material properties of the healing tendon, while the adverse effects were reduced. Local dexamethasone treatment did not lead to increased peak stress, but it triggered systemic granulocytosis and lymphopenia. Mechanical loading (full or moderate) is essential for the positive effects of dexamethasone, as complete unloading leads to the absence of improvements. Conclusion: We conclude that dexamethasone treatment to improve Achilles tendon healing is dose- and time-dependent, and positive effects are perceived even in a partly unloaded condition.
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| 2. |
- Rendek, Zlatica, et al.
(författare)
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Early Tensile Loading in Nonsurgically Treated Achilles Tendon Ruptures Leads to a Larger Tendon Callus and a Lower Elastic Modulus : A Randomized Controlled Trial
- 2022
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Ingår i: American Journal of Sports Medicine. - : Sage Publications Inc. - 0363-5465 .- 1552-3365. ; 50:12, s. 3286-3298
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Tidskriftsartikel (refereegranskat)abstract
- Background: Early tensile loading improves material properties of healing Achilles tendon ruptures in animal models and in surgically treated human ruptures. However, the effect of such rehabilitation in patients who are nonsurgically treated remains unknown. Hypothesis: In nonsurgically treated Achilles tendon ruptures, early tensile loading would lead to higher elastic modulus 19 weeks after the injury compared with controls. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: Between October 2015 and November 2018, a total of 40 nonsurgically treated patients with acute Achilles tendon rupture were randomized to an early tensile loading (loaded group) or control group. Tantalum bead markers were inserted percutaneously into the tendon stumps 2 weeks after the injury to allow high-precision measurements of callus deformation under mechanical testing. The loaded group used a training pedal twice daily to produce a gradual increase in tensile load during the following 5 weeks. Both groups were allowed full weightbearing in an ankle orthosis and unloaded range of motion exercises. Patients were followed clinically and via roentgen stereophotogrammetric analysis and computed tomography at 7, 19, and 52 weeks after the injury. Results: The mean +/- standard deviation elastic modulus at 19 weeks was 95.6 +/- 38.2 MPa in the loaded group and 108 +/- 45.2 MPa in controls (P = .37). The elastic modulus increased in both groups, although it was lower in the loaded group at all time points. Tendon cross-sectional area increased from 7 weeks to 19 weeks, from 231 +/- 99.5 to 388 +/- 142 mm(2) in the loaded group and from 188 +/- 65.4 to 335 +/- 87.2 mm(2) in controls (P < .001 for the effect of time). Cross-sectional area for the loaded group versus controls at 52 weeks was 302 +/- 62.4 mm(2) versus 252 +/- 49.2 mm(2), respectively (P = .03). Gap elongation was 7.35 +/- 13.9 mm in the loaded group versus 2.86 +/- 5.52 mm in controls (P = .27). Conclusion: Early tensile loading in nonsurgically treated Achilles tendon ruptures did not lead to higher elastic modulus in the healing tendon but altered the structural properties of the tendon via an increased tendon thickness. Registration: NCT0280575 (ClinicalTrials.gov identifier).
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