Clinical signs and anatomical correlation of patellar tendinitis

Background: Patellar tendinitis is one of the several differential diagnosis of anterior knee pain. The clinical diagnosis of patellar tendinitis is based on tenderness to palpation at the inferior pole of the patella. The tenderness has been noted to be maximal when the knee is extended and the quadriceps relaxed, but a definite clinical sign for diagnosis is lacking. The accuracy of two clinical signs was assesed by a two-stage study which included physical examination, MRI and a cadaveric study.