Fat Pad Impingement – Anterior Knee Pain

What is fat pad impingement?

Do you get knee pain when going up or down stairs? Did you fall onto your knee one day and it’s still sore? What you may be experiencing is fat pad impingement, also referred to as Hoffa’s fat pad. Your fat pad is a pocket of soft tissue that sits underneath your knee cap at the front of your knee. It acts as a cushion between your knee cap (patella) and your shin bone (tibia). Sometimes this fat pad can be compressed causing what we call fat pad impingement. If the fat pad becomes inflamed, this can cause scar tissue to form. This scar tissue can lead to less room around the soft tissue of the knees causing further impingement when you try and straighten your knee. 

How can you injure your fat pad?

Injuries to your fat pad can be caused by a variety of injuries:

• Tight quadriceps (thigh muscles)
• Fall onto the front of the knee or a direct hit to the front of the knee
• Overloading of the knee e.g. frequent going up/down stairs
• An injury where the knee is pushed into hyper-extension 

Why does it hurt so much?

If you are wondering why your knee hurts so much – it very well could be the fat pad. The fat pad is a highly innervated and vascularized structure which means it has lots of nerve endings and blood vessels that supply it. This causes increased pain levels as there are lots of nerves in the area. 

Who may suffer from fat pad injuries?

• Higher level sports where a blow to the knee may occur e.g. rugby, martial arts 
• People who have experienced past injuries e.g. ACL tear
• People who have weakness around the hip or knee
• People who have a history of hyper-extension in the knee  
• More common in young women
• Those that partake in jumping sports 

Symptoms

• Pain when straightening the knee especially towards the end of the movement 
• Pain with being on your feet for hours
• Difficulty doing up/down stairs 
• Inflammation and swelling under the knee cap
• Burning or tingling under the knee cap 
• Stiffness in the knee and reduced mobility
• May have difficulty walking or moving the knee if irritable 

Management

• Ice 
• Avoid aggravating activities – this may require a short break from sports
• Braces for the knee 
• Hands on therapy
• Exercise for stretching and strengthening 
• Taping 

Exercises to try at home

• Quads stretching
• Knee extension holds against a wall or with a resistance band if irritable. Aim to hold this position for 30 seconds. You may feel some discomfort during this exercise but it should not make your knee worse afterwards. 
• Heel slides to increase bending and straightening movement – don’t push the knee into extension if it is sore