We describe an arthroscopic technique for the treatment of chronic patellar tendinopathy (jumper’s knee). Preoperatively, tendon necrosis or rupture is excluded by sonography. Diagnostic arthroscopy is performed and hypertrophic synovitis around the inferior patellar pole is removed with a bipolar cautery system. Two outside-in cannulas mark the clinically symptomatic region, mainly found between the tendon insertion site and the lateral aspects of the patellar tendon. The bipolar cautery is used for a release of the paratenon and a bone denervation at the inferior patellar pole including the tendon insertion site within the marked area. No tendon or bone material is removed or excised throughout the procedure. We treated 15 athletes with stage 3 and 4 chronic patellar tendinopathies on a modified version of the Blazina score (0-5). Patients’ mean age was 29 years and the mean follow-up period was 41 months. In 13 cases, clinical symptoms subsided completely within 3 months after surgery. The mean preoperative Blazina score was 3.7 (SD, 0.5) and the mean postoperative Blazina score was 0.4 (SD, 1.0; paired 2-tailed t test, P < .01). Ultrasound showed a reduction of tendon edema within 3 weeks and no signs of edema within a mean period of 5 weeks after surgery. The minimal surgical impact to the tendon allows early and functional rehabilitation. The technique is effective, easy to perform, and safe to apply.