Paper 68: Outcomes following Extracorporeal Shockwave Therapy for chronic Achilles tendinopathy at short to mid-term follow-up

OBJECTIVES: The purpose of this retrospective clinical study was to evaluate outcomes following extracorporeal shockwave therapy (ESWT) for the treatment of Achilles tendinopathy. Subgroup analysis was conducted to identify predictors of poor outcomes. METHODS: This retrospective cohort study included existing clinical data from 74 patients from a single academic institution. Patients greater than 16 years of old who underwent ESWT for Achilles tendinopathy in the office setting between 3/3/2017 to 8/2/2022 were included. Data collected included: patient demographics, co-morbidities, treatment characteristics, Victorian institute of sports assessment – Achilles (VISA-A) scoring tool, visual analog scale (VAS), magnetic resonance imaging data, return to play (RTP) data and failures were recorded. Failure was defined as no improvement in VISA-A nor VAS scores or surgical intervention. For these data, mean and standard deviation were calculated, and paired samples T-tests and Welch’s T-tests were performed on clinical outcome scores. RESULTS: In total, 74 patients (91 heels) with a mean age of 54.1 ± 14.0 years and BMI of 27.3 ± 4.5 kg/m(2) underwent ESWT for Achilles tendinopathy at a mean follow-up of 25.7 ± 15.0 months. Eighteen patients were in the non-insertional Achilles tendinopathy (NAT) cohort and 56 patients were in the insertional Achilles tendinopathy (IAT) cohort. Both NAT and IAT cohorts had a similar improvement in VISA-A score (p=0.365) and VAS scores (p=0.65). A shorter return to play time was found in the NAT cohort (1.1 ± 0.9 months) compared to the IAT cohort (2.6 ± 5.7 months) but this was not statistically significant (p=0.34). There was a higher failure rate in the the IAT cohort (50.0%) than the NAT cohort (38.9%). Patients who received platelet-rich plasma (PRP) had a higher failure rate (61.2%) than those who did not receive PRP (39.6%). In the NAT cohort, the failure rate in females was 0.0%. In the IAT cohort, the failure rate in females was 61.9%. Linear regression analysis found that elevated BMI and MRI severity were associated with worse post-ESWT outcomes. CONCLUSIONS: This retrospective study demonstrated a high failure rate at short-term follow-up in patients who underwent ESWT for Achilles tendinopathy. Higher failure rates were found in patients with IAT and those who received intratendinous PRP. Predictors of poor outcomes included elevated BMI and MRI severity. Further studies with larger patient cohorts and a longer follow-up are necessary to determine the role of ESWT in the treatment of Achilles tendinopathy.