The Tendon Structure Returns to Asymptomatic Values in Nonoperatively Treated Achilles Tendinopathy but Is Not Associated With Symptoms: A Prospective Study

Background: Tendinopathy is characterized by alterations in the tendon structure, but there are conflicting results on the potential of tendon structure normalization and no large studies on the quantified, ultrasonographic tendon structure and its association with symptoms.

Purpose: To determine whether the tendon structure returns to values of asymptomatic individuals after treatment with 2 substances injected within the tendon, to assess the association between the tendon structure and symptoms, and to assess the prognostic value of the baseline tendon structure on treatment response.

Study design: Cohort study; Level of evidence, 2.

Methods: This study was part of a randomized trial on chronic midportion Achilles tendinopathy using eccentric exercises with either a platelet-rich plasma or saline injection. Symptoms were recorded using the Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire. The tendon structure was quantified with ultrasound tissue characterization (UTC); echo types I + II (as a percentage of total tendon types I-IV) are structure related. Follow-up was at 6, 12, 24, and 52 weeks. A control group of asymptomatic subjects (similar age) was selected to compare the tendon structure. Patient symptoms were correlated with the tendon structure using a linear model.

Results: Fifty-four patients were included in the symptomatic group. The mean (± SD) echo types I + II in the symptomatic group increased significantly from 74.6% ± 10.8% at baseline to 85.6% ± 6.0% at 24-week follow-up. The result for echo types I + II at 24 weeks was not significantly different (P = .198) from that of the asymptomatic control group (87.5% ± 6.0%). In 54 repeated measurements at 5 time points, the adjusted percentage of echo types I + II was not associated with the VISA-A score (main effect: β = .12; 95% CI, -0.12 to 0.35; P = .338). The adjusted baseline echo types I + II were not associated with a change in the VISA-A score from baseline to 52 weeks (β = -.15; 95% CI, -0.67 to 0.36; P = .555).

Conclusion: In symptomatic, tendinopathic Achilles tendons, the ultrasonographic tendon structure improved during nonoperative treatment and normalized after 24 weeks to values of matched asymptomatic controls. There was no association between the tendon structure and symptoms. The percentage of echo types I + II before treatment was not associated with change in symptoms over time. This study demonstrates that restoration of the tendon structure is not required for an improvement of symptoms.