Pain relief after extracorporeal shock wave therapy for patellar tendinopathy: An ultrasound evaluation of morphology and blood flow

We aimed to investigate the changes caused by focused extracorporeal shock wave pain therapy (f-ESWT) in patients with patellar tendinopathy by means of ultrasound imaging. We included 18 knees from 11 college athletes with patellar tendinopathy. We assessed the tendon thickness and blood flow of the patellar tendon using ultrasound imaging, rest pain using NRS and tenderness using a pressure pain gauge. We recorded four measurements: Immediately before f-ESWT (PRE①) and after f-ESWT (POST①) and two weeks after the first irradiation before f-ESWT (PRE②) and after f-ESWT (POST②). Only the resting pain in both the first and second irradiations showed a significant difference immediately before and after the treatment. In terms of pain changes after two weeks later, we observed significant differences in the resting pain between PRE① and PRE② and also in the resting pain, tenderness and blood flow area between PRE① and POST②. No significant difference was seen in the tendon thickness. We concluded that pain in the patellar tendon at rest decreased before and after irradiation, suggesting that f-ESWT may have influenced the nociceptive structures and had an analgesic effect.