Infrapatellar Fat Pad Bursa

bursa infrapatellaris — regio corporis adiposi Hoffae

The infrapatellar fat pad (Hoffa's fat pad) contains small bursae within its substance between the patellar tendon and the underlying tibial surface. The fat pad itself acts as a pressure buffer and can become impinged and inflamed (Hoffa's disease) by mechanical compression between the patellar tendon and the femoral condyle during terminal extension. Inflammatory or fibrotic change within the fat pad bursae contributes to anterior knee pain.

Region: Knee

Clinical Relevance

Clinical Notes

Hoffa's fat pad impingement (Hoffa's disease) produces bilateral inferior patellar pain at the fat pad margins, worsened by terminal knee extension and Stork standing. MRI demonstrates fat pad oedema, fibrosis, or signal change within the fat pad tissue. Post-surgical or post-traumatic fat pad fibrosis from scarring (often from previous Osgood-Schlatter surgery or tibial tubercle osteotomy) restricts the fat pad, limiting knee extension. Arthroscopic fat pad debridement and decompression relieves the impingement in resistant cases.

Pathology

Common Injuries & Conditions

Hoffa's Fat Pad Impingement Causing Anterior Knee Pain

Repetitive terminal knee extension compresses the enlarged or fibrotic infrapatellar fat pad between the distal patellar tendon and the femoral condyle, producing bilateral inferior patellar pain reproduced by the Hoffa test (bimanual thumb compression of the fat pad); MRI demonstrates fat pad signal abnormality and arthroscopic fat pad debridement is reserved for conservative treatment failure.