Favorable Outcomes Following Extra-Corporeal Shockwave Therapy for Chronic Non-Insertional Achilles Tendinopathy Compared to Chronic Insertional Achilles Tendinopathy: A Retrospective Review

Abstract

Category: Ankle; Basic Sciences/Biologics Introduction/Purpose: Extracorporeal shockwave therapy (ESWT) is a non-invasive treatment modality that is utilized in the treatment of chronic Achilles tendinopathy (AT). The purpose of this study was to retrospectively assess outcomes following ESWT for both NAT and IAT at greater than 1-year follow-up, and to identify potential predictors of outcomes. Methods: Chart review was conducted to identify patients who underwent ESWT for AT with a minimum of 1-year follow-up. Data collected and assessed included: patient demographics, pathological characteristics, treatment characteristics, Victorian Institute of Sports Assessment-Achilles (VISA-A) and visual analog scale (VAS) scores and failures. Linear regression was performed to identify potential predictors of outcomes. Survival analysis was conducted using Kaplan Meier curves. Fifty-two cases of IAT and 34 cases of NAT were included. The mean follow-up in the NAT cohort was 22.3±10.2 months and the mean follow-up time in the IAT cohort was 26.8±15.8 months. Results: Improvements in VISA-A and VAS scores were observed in the NAT cohort at 6 months follow-up and at final follow-up (p < 0.01). Improvements in VISA-A scores and VAS scores were recorded in the IAT cohort at 6 months follow-up which subsequently deteriorated at final follow-up. In the NAT cohort, the failure rate at 6 months follow-up was 11.8% which increased to 29.4% at final follow-up. In the IAT cohort, the failure rate at 6 months follow-up was 32.7% which increased to 59.6% at final follow-up. Predictors of poor outcomes in the NAT cohort included pre-ESWT subjective clinical score, male, presence of cardiovascular risk factor, and increasing MRI severity. Predictors of poor outcomes in the IAT cohort included pre-ESWT subjective clinical score and increasing MRI severity. Conclusion: This study found that superior subjective clinical outcomes together with a lower failure rate maintained over 1 year in the NAT cohort compared to the IAT cohort. This may implicate ESWT as a temporising treatment in IAT and a longer term solution in patients with NAT.