Chronic Infrapatellar Fat Pad Fibrosis: Hoffa's Disease, a Commonly Unrecognized Source of Anterior Knee Pain - A Report of Two Cases.

Fibrosis of the infrapatellar fat pad (Hoffa's disease) is a frequently missed cause of anterior knee pain in young, active individuals. A diagnostic test that involves injection of the infrapatellar fat pad with local anesthetic and subsequent stress with treadmill running, is a simple in office strategy to effectively diagnose pathology of the fat pad. Selective arthroscopic debridement of the fat pad using superolateral viewing portal aids in adequate visualization not otherwise feasible using standard anterior viewing portals alone. The purpose of this case report is to describe two cases of anterior knee pain arising from fibrosis of the infrapatellar fat pad as identified on imaging and arthroscopy. Both patients were found to suffer from pain arising from a fibrotic infrapatellar fat pad and responded well to surgical intervention. Level of Evidence: 5.