Hoffa's Fat pad knee pain
What is Hoffa's Infrapatellar Fat Pad?
The infrapatellar fat pad (often known as Hoffa's pad) is a soft tissue that lies underneath the patella (kneecap) separating it from the end of the thigh bone (or femoral condyle). It helps to protect the knee like a shock absorber and also helps to lubricate the joint so it can move smoothly.
Long term knee pain is often caused by a build-up of gritty tissue after a fall on the fat pad.
The fat pad is attached to ligaments from the thigh bone to the knee cap. When we straighten our leg, the fat is pulled out of the joint.
Even injuring the ligaments of the knee - something as simple as playing sport- can damage this mechanism, so that the fat pad is not pulled out of the way, but is impinged between the femur and tibia when the leg is extended.
When you get a hard blow to the kneecap, the fat pad can become impinged (trapped) between the femoral condyle and the patella. As the fat pad has a lot of nerve cells, this injury is extremely painful. This condition is normally long-standing as it is made worse by extension (straightening) of the knee joint. The fat pad becomes irritated and may become significantly swollen.
It occurs in around 25% of patients with a knee injury and can happen to anyone at any age.
Symptoms of Hoffa's Fat Pad Trapping
Tenderness and swelling around the bottom and under the kneecap
In some cases the bottom of the kneecap may be distorted due to swelling underneath
A cracking sound can sometimes be heard when standing up which feels like the lump of fat popping out of the joint. Over time this can become hard and gristly because it is being squeezed.
In many cases, the lump is so hard you hear a crack each time you straighten your leg as the gristle pops out of the joint.
Tests for Hoffa's Knee pain
Hoffa's test with the patient in lying with their knee bent, the Osteopath presses both thumbs along either side of the knee patella tendon, just below the knee cap. The patient is then asked to straighten their leg. Pain and fear of performing the movement is considered a positive sign for fat pad trapping.
Treatment of Hoffa's fat pad impingement.
Your Osteopath would treat this condition by conservative methods which include:
Your osteopath will look for other "maintaining factors" that ay be preventing you from achieving full recovery.
Strapping the patella is known to be highly effective in fat pad impingement.
If left untreated, it can eventually lead to osteo-arthritis, but if the condition is caught early, an Osteopath can treat it by strapping the kneecap for around six weeks so the pad of fat is pulled away from the joint and it no longer catches.
If conservative treatment does not work then surgery may be advised which may involve the complete or partial removal of the fat pad itself.