Australian football players' Achilles tendons respond to game loads within 2 days: an ultrasound tissue characterisation (UTC) study.

BACKGROUND/AIM: The Achilles tendon is a tissue that responds to mechanical loads at a molecular and cellular level. In vitro and in vivo studies have shown that the expression of anabolic and/or catabolic proteins can change within hours of loading and return to baseline levels within 72 h. These biochemical changes have not been correlated with changes in whole tendon structure on imaging. We examined the nature and temporal sequence of changes in Achilles tendon structure in response to competitive game loads in elite Australian football players. METHODS: Elite male Australian football players with no history of Achilles tendinopathy were recruited. Achilles tendon structure was quantified using ultrasound tissue characterisation (UTC) imaging, a valid and reliable measure of intratendinous structure, the day prior to the match (day 0), and then reimaged on days 1, 2 and 4 postgame. RESULTS: Of the 18 participants eligible for this study, 12 had no history of tendinopathy (NORM) and 6 had a history of patellar or hamstring tendinopathy (TEN). Differences in baseline UTC echopattern were observed between the NORM and TEN groups, with the Achilles of the TEN group exhibiting altered UTC echopattern, consistent with a slightly disorganised tendon structure. In the NORM group, a significant reduction in echo-type I (normal tendon structure) was seen on day 2 (p=0.012) that returned to baseline on day 4. SUMMARY: There was a transient change in UTC echopattern in the Achilles tendon as a result of an Australian football game in individuals without a history of lower limb tendinopathy.

Structural integrity is decreased in both Achilles tendons in people with unilateral Achilles tendinopathy.

OBJECTIVES: A high proportion of Achilles tendinopathy patients develop bilateral symptoms with human and animal studies showing bilateral histological changes associated with overuse/pathology in one tendon. The current study examined changes in tendon structure, assessed semi-quantitatively using ultrasound tissue characterisation, in both the symptomatic and asymptomatic tendon in unilateral Achilles tendinopathy patients in comparison to individuals with no history of tendinopathy. DESIGN: Cross-sectional case-control study. METHODS: Participants with Achilles tendinopathy (n=21), with varying severity and length of clinical symptoms, and six participants with no history of tendinopathy were recruited. Tendons were scanned using ultrasound tissue characterisation, which captures contiguous transverse ultrasound images every 0.2mm and renders a 3-dimensional image. Ultrasound tissue characterisation quantifies tendon structure by measuring the stability of echopattern over contiguous transverse images. Four echo-types were discriminated and expressed as a percentage. Antero-posterior diameter of all tendons was measured. RESULTS: Significant differences were observed in the proportion of normal tendon structure between all three groups (p<0.01), with the symptomatic tendon containing the least amount of normal tendon structure (symptomatic - 79.5%, asymptomatic - 81.8%, control - 86.4%). The asymptomatic tendon contained significantly less normal tendon in comparison to the control tendon (p=0.008), suggesting the asymptomatic tendon is structurally compromised despite the absence of symptoms. CONCLUSIONS: Both Achilles tendons are structurally compromised in patients with unilateral Achilles tendinopathy. Future studies need to investigate whether these changes increase the risk of developing symptoms.