The purpose of this study is to determine in the athletes a sonographic grading of the patellar tendinopathy correlated to prognosis and therapy. The 298 patellar overuse tendinopathies were divided in four grades according to the extension of the injured area of the tendon in the axial sonograms. Grades 1, 2, and 3 were managed with medical and physical therapy. A surgical treatment was performed in grade 4 and in grades 1, 2, and 3 tendinopathies not responding to our conservative therapy. There were 21.8% injuries in grade 1 (100% responding; prognosis 20 days), 61.2% injuries in grade 2 (94.5% responding; prognosis 40 days), 16.4% injuries in grade 3 (85.7% responding; prognosis 90 days), and 0.6% injuries in grade 4. The sonographic study is fundamental to characterize adequately the patellar tendinopathy. The conservative therapy is the first option for grades 1, 2, and 3 as it determines a complete healing in most of cases.