infrapatellar

Infrapatellar is a directional term used in anatomy to describe structures located below the patella (kneecap). A key infrapatellar structure is the infrapatellar fat pad, also known as Hoffa’s fat pad. This is an intracapsular but extrasynovial fat-filled structure situated in the anterior knee, inferior to the patella and posterior to the patellar tendon, with its superior border near the inferior pole of the patella and its inferior aspect toward the proximal tibia. It is enclosed by the synovial membrane and is richly vascularized and innervated.

The infrapatellar fat pad serves as a cushion within the knee joint and assists in the smooth glide of the patellar tendon during knee flexion and extension. Its location allows it to fill the space between the patellar tendon, femur, and tibia, helping to distribute load and reduce impingement during movement. The pad’s properties can adapt with movement, but it is susceptible to irritation or inflammation.

Clinical relevance includes Hoffa’s disease or infrapatellar fat pad syndrome, where inflammation or edema of the fat pad causes anterior knee pain, swelling, and mechanical symptoms. Causes can include trauma, repetitive kneeling, degenerative changes, or postoperative scarring. Diagnosis typically relies on clinical assessment and imaging, especially MRI. Management ranges from conservative measures—rest, physical therapy, anti-inflammatory medications—to injections or, in persistent cases, surgical resection of the affected portion of the fat pad.

Nervous and vascular supply to the infrapatellar region is primarily from branches of the saphenous nerve and genicular arteries, providing sensory innervation and blood flow to support function and healing.