Restoration of strength despite low stress and abnormal imaging after Achilles injury
| Autor: | Nanthan Ramachandran, Laurent Dinh, Geoffrey P. Doherty, Guy Trudel, Yoichi Koike, Hans K. Uhthoff, Martin Lecompte |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Physical Therapy
Sports Therapy and Rehabilitation Achilles Tendon Stress Physiological medicine Animals Orthopedics and Sports Medicine Clinical imaging Ultrasonography Low stress Achilles tendon medicine.diagnostic_test business.industry Quebec Magnetic resonance imaging Anatomy musculoskeletal system Mr imaging Magnetic Resonance Imaging Tendon Biomechanical Phenomena medicine.anatomical_structure Peak load Tendinopathy Female Calcaneus Rabbits Stress Mechanical Nuclear medicine business |
| Zdroj: | Medicine and science in sports and exercise. 41(11) |
| ISSN: | 1530-0315 |
| Popis: | Purpose: To determine the usefulness of clinical imaging in predicting the mechanical properties of rabbit Achilles tendons after acute injury. Methods: We created a 2 x 7-mm full-thickness central tendon defect in one Achilles tendon of healthy rabbits. Rabbits in groups of 10 were killed immediately and 4 and 8 wk after surgery (n = 30). We then performed magnetic resonance (MR) imaging, ultrasonography (US), bone mineral densitometry (BMD), and mechanical testing to failure using a dual-cryofixation assembly on experimental and contralateral tendons. The main outcome measures included tendon dimensions, optical density (OD) of T1-weighted, proton density (PD), and T2-weighted MR sequences, US focal abnormalities, BMD of the calcaneus, and stress and peak load to failure. Results: On MR imaging and US, all dimensions of the injured tendons after 2 wk and more were greater than those of the contralateral tendons (P < 0.05). The mean T1-weighted OD was greater at 4 wk (256 +/- 53) and 8 wk (184 +/- 24) than immediately after surgery (149 +/- 15). Mechanical stress was markedly lower in the experimental than in the contralateral tendons at both 4 wk (39 +/- 9 vs 77 +/- 16 N[middle dot]mm-2) and 8 wk (58 +/- 6 vs 94 +/- 26 N[middle dot]mm-2; P < 0.05). Mean peak load to failure was significantly lower immediately after surgery (332 +/- 128 N) than at 4 and 8 wk (712 +/- 106 and 836 +/- 90 N, respectively). Both high T1-weighted OD (r = -0.73) and PD OD (r = -0.69) correlated with lower mechanical stress (P < 0.05). In the experimental tendons, higher T1-weighted OD correlated with lower peak load (r = -0.46; P < 0.05). Conclusions: Normal peak loads 4 wk after injury were withstood by an enlarged tendon of lower stress. These findings support progressive physical loading 4 wk after an Achilles tendon injury. T1-weighted OD constituted a marker of tendon mechanical recovery |
| Databáze: | OpenAIRE |
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