Factors associated with outcome following exercise interventions for Achilles tendinopathy: A systematic review

Objective: This systematic review aimed to synthesize current evidence on contributing factors influencing outcome following exercise management for Achilles tendinopathy (AT). Data Sources: Databases (PubMed, Embase, and Cochrane Library) were searched from inception to February 2020. Study Selection: Studies investigating factors (e.g., age, BMI) associated with outcome (e.g., pain and function questionnaires) following exercise interventions for AT were included. Data Extraction: Data were extracted into a standardized form, including patient demographics, population sample, study type, factors associated with outcome, and outcome measures. Data Synthesis: Meta-analysis was planned to be performed, where appropriate. Where data could not be pooled, we summarized the findings descriptively. Results: Six studies investigating 11 different factors were included; overall the quality of evidence was poor. There was conflicting evidence that imaging measures had an association with a change in VISA-A outcome. These included signal intensity and tendon size determined by MRI, and Ultrasound Tissue Characterization echopattern. Three studies found that duration of symptoms was not associated with a change in VISA-A. Also, three studies found that age, and one study found that prior sporting activity level, were not associated with outcome. Baseline pain with activity, baseline VISA-A, sex, and BMI were inconsistently associated with specific outcomes. Conclusion: Due to the poor quality of evidence overall, no firm conclusions can be drawn. At best, there was inconsistent evidence that imaging factors, baseline pain and function, BMI, and sex showed some associations with outcomes, but these findings need to be confirmed in more extensive studies.