Tendon structure's lack of relation to clinical outcome after eccentric exercises in chronic midportion Achilles tendinopathy

Abstract

Context: Chronic midportion Achilles tendinopathy is a common and hard-to-treat disorder characterized by degenerative changes of the tendon matrix. Ultrasonographic tissue characterization (UTC) was successfully used to quantify structural human Achilles tendon changes. This novel and reliable technique could be used in follow-up studies to relate tendon structure to symptoms.

Objective: To quantify structural tendon changes and assess clinical change in patients with tendinopathy.

Design: Prospective observational study.

Setting: Orthopedic department in a university medical center.

Patients: 23 patients with chronic midportion Achilles tendinopathy.

Intervention: The patients performed a 16-wk home-based eccentric exercise program. An experienced researcher performed the ultrasonographic data collection with the UTC procedure. These data were assessed by a blinded observer. The severity of symptoms was established with the validated Victorian Institute of Sport Assessment-Achilles (VISA-A) questionnaire.

Main outcome measures: UTC was performed to quantify tendon structure through measuring the proportion of 4 echo types. Echo types I and II represent more or less organized tendon bundles, and echo types III and IV represent disintegrated tendon structure. On the VISA-A, the total possible score is divided by 100 for a percentage score, with a perfect score of 100. Follow-up was at 2, 8, 16, and 24 wk.

Results: The mean percentage of echo types I and II changed by 0.3% after 24 wk (P = .92, 95% CI -5.8 to 5.3). The mean VISA-A score increased slightly but significantly by 11.3 points after 24 wk (P = .01, 95% CI 2.6-20.0). An increased VISA-A score was not correlated with an increased percentage of echo types I and II (P = .94, r = -.02), and the baseline percentage of echo types I and II did not correlate with an increased VISA-A score (P = .74, r = .07).

Conclusions: There is no short-term increase in organized tendon structure after eccentric exercises. Tendon structure is not related to symptom severity and cannot be used as a predictor of clinical outcome.