Patellar tendinitis can be considered as an overload lesion in athletes. Anatomical pathology reveals focal degeneration and microtearing at predisposed areas near the insertion of the quadriceps or patellar tendon. Thie prognosis and treatment are dependent on the stage of the affection. A program of conservative treatment is effective in the early stages of the disease but it fails in a high proportion (16/38) of cases in the later stages. Surgery directed towards the tendon, rather than a bony procedure, yielded favourable results in 27 out of 29 patients.