research here at NYU in the foot and ankle department and today I'll be presenting our paper which is a retrospective analysis of outcomes following shockwave therapy for chronic Achilles tendinopathy. So there's no disclosures relevant for this talk. So chronic Achilles tendinopathy is a very disabling overuse injuries and is seen in approximately 20% of runners. It can be broadly sub classified into insertional Achilles tendinopathy which occurs within two centimeters at a calcaneal insertion and non-insertional Achilles tendinopathy which occurs approximately two to six centimeters to the calcaneal insertion. So first-line treatment initially involves physical therapy with an emphasis on eccentric calf loading and other functional exercises. However this typically is not most fruitful in about 10 to 20% of patients who often historically would have required surgical intervention. But there's been a growing interest in the use of shockwave therapy for a chronic Achilles tendinopathy as a second line treatment. So this involves the use of longitudinal sound waves which leads to a production of growth factors via mechanotransduction and reduction in pain via a reduction in substance P. So there's been good evidence showing superior outcomes in shockwave therapy versus control in many studies but these are often limited by small patient cohorts and follow-up times of between three to six months. So the purpose of our study was to evaluate clinical outcomes following shockwave therapy at a minimum of 12-month follow-up for patients with chronic Achilles tendinopathy. We wanted to subdivide our patients into insertional and non-insertional chronic Achilles tendinopathy and compare outcomes between the two cohorts and then also identify any potential predictors of clinical outcomes. So we did a retrospective chart review of all of our patients who underwent three sessions of extracorporeal shockwave therapy over a period of three weeks in conjunction with physical therapy. We collected and analyzed the patient's demographic details, their MRI data, their outcomes and any complications or failures that are observed. We did both a linear and logistic regression analysis to identify any potential predictors of outcomes and we conducted survival analysis via Kaplan-Meier curves. So in total in the non-insertional cohort there were 34 patients who had a mean follow-up time of 22 months. In the insertional cohort there were 52 patients who had a mean follow-up time of 26 months. The patients were well matched with regards to mean age and mean BMI. In regards to severity in the non-insertional cohort most patients had grade 1 severity based on MRI findings and in the insertional cohort most patients had grade 3 severity based on MRI findings. In addition in the insertional cohort about 40% of the patients had a Hagman's deformity and a further 20% had retrocranial bursitis. So in total there was superior clinical outcomes in the non-insertional cohort compared to the insertional cohort. We found that in the non-insertional cohort there was an increase in the visa A scores at six months and this was sustained at two-year follow-up and this was also seen in the VAS scores. At six months there was an 11% failure rate which then further increased to 30% a final follow-up. In the insertional cohort there was initial increase in visa A scores but this subsequently deteriorated at two-year follow-up and this was also seen with the VAS scores. At six-month follow-up there was a 30% failure rate and a final follow-up this increased to a 60% failure rate. So in the non-insertional cohort we looked at various different parameters to identify any different potential predictors of outcomes. So in regards to the post visa A scores we found that your pre visa A score, male sex, the presence of a cardiovascular risk factor and increased severity on MRI were associated with worse clinical outcomes. For the post shockwave VAS score we found that your pre shockwave VAS score, cardiovascular risk factor and increased severity on MRI were associated with worse clinical outcomes. The only predictor of failure in this cohort was male sex. For the insertional cohort the predictors of post shockwave visa A scores included the pre shockwave visa A score and increased severity on MRI and this is also seen with the post shockwave VAS score which was associated with pre shockwave VAS scores and increased severity on MRI. The only predictor of failure in this cohort was increased severity of MRI. In regards to survivorship the log-rank tests show there is a statistically significant difference in Kaplan-Meier survival curves between the non-insertional cohort and the insertional cohort. The mean time to failure in the non-insertional cohort was five months and the mean time to failure in the insertional cohort is 3.6 months. So there are numerous limitations in this study primarily being that there was no control group of physical therapy only patients. There was a relatively short follow-up and this is a retrospective study. So in summary we found that shockwave therapy produced good clinical outcomes in patients with chronic Achilles tendinopathy and that there were superior outcomes for the non-insertional cohort compared to the insertional cohort. This study has numerous limitations and therefore further research with a longer follow-up and an adequate control group is warranted to identify the precise role of shockwave for chronic Achilles tendinopathy.

retrospective analysis

shockwave therapy

chronic Achilles tendinopathy

clinical outcomes

predictors of outcomes