Anterior Knee Impingement in a High-Level Football Punter: A Case Report and Description of the Active-Passive Knee Extension Test

A 22-year-old football punter complained of anterior knee pain deep to his patellar tendon that occurred every time the knee of his kicking leg reached full extension during a punt. Arthroscopy confirmed anterior impingement between a fibrous tissue eminence directly anterior to his anterior cruciate ligament (ACL) and the intercondylar roof in full extension. With the eminence removed, full extension no longer caused impingement as demonstrated arthroscopically. He resumed punting at maximal effort 6 weeks postoperatively without pain. We report the active-passive knee extension test, a physical examination maneuver designed to identify patients with anterior knee impingement between tissue anterior to the ACL and the intercondylar roof. This test is a helpful part of the clinical examination in detecting these lesions.