• The infrapatellar fat pad (IFP), also known as Hoffa’s fat pad, fills the anterior knee compartment behind the infrapatellar tendon.
• Hoffa fat pad is highly vascular with anastomosis from the Superior and Inferior Genicular arteries and it is richly innervated from branches from the Femoral, Common Peroneal and Saphenous nerves.
• IFP is made up of fat lobules separated by thin fibrous cords
• The Ligamentum Mucosa is the infrapatellar plica that runs from the intercondylar femur notch anteriorly through the fat pad and represents an embryological synovial membrane remnant.
• The IFP main function is to reduce friction between the patellar, patellar tendon and deep skeletal structures and prevents pinching of the synovial membrane. IFP impingement is characterised by fat pad oedema as demonstrable on MRI scan.

Everted knee cap

MRI demonstrate fat pad oedema

Non-operative management:
Local injection with local anaesthetic and corticosteroid

Injection of IFP

Arthroscopic partial debridement of fat pad