Skip Navigation LinksHome > November 2009 - Volume 41 - Issue 11 > Restoration of Strength Despite Low Stress and Abnormal Imag...
Medicine & Science in Sports & Exercise:
doi: 10.1249/MSS.0b013e3181a706f0
Basic Sciences

Restoration of Strength Despite Low Stress and Abnormal Imaging after Achilles Injury

TRUDEL, GUY1,2; DOHERTY, GEOFFREY P.3; KOIKE, YOICHI1,2; RAMACHANDRAN, NANTHAN1; LECOMPTE, MARTIN3; DINH, LAURENT4; UHTHOFF, HANS K.1,5

Collapse Box

Abstract

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 × 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·mm−2) and 8 wk (58 ± 6 vs 94 ± 26 N·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.

©2009The American College of Sports Medicine

Login

Article Tools

Share

Search for Similar Articles
You may search for similar articles that contain these same keywords or you may modify the keyword list to augment your search.

Connect With Us