The infrapatellar (Hoffa’s) fat pad explained

There are various fat pads, but the one at the knee that causes a lot of problems is the infrapatellar fat pad, also known as Hoffa’s fat pad after the man who first described it.

The fat pad has been shown to be very pain sensitive. It is rich with nerve endings that can fire off messages of pain to the brain, and it is therefore of no surprise that people with fat pad problems are often in a lot of pain.

The fat pad is often overlooked, with clinicians concentrating on joint surfaces, cartilage, ligaments and tendons, and dismissing the patient if these structures appear normal on imaging.

So what can go wrong in this funny pad of fat? There are two very different scenarios. The first is mechanical. The fat pad gets a trauma to it. Now this may be an obvious one off blow to the knee, or where the patient straightens their knee at speed and feels an immediate very sharp pain in the fat pad. Or, as is seen more commonly the fat pad may get nipped between the patella and the tibia, and microtrauma leads to a macro problem. In either of these situations it is common to see an inflammatory response. This is a problem as inflammation leads to swelling, and leads to the scenario where the fat pad gets pinched and caught even more. This feeds into a vicious cycle that many patients get completely stuck in. Furthermore, once the fat pad becomes big it alters the way the kneecap moves, and this in turn can lead to high pressure under the patella, which is also often painful.

Can anything be done? Yes! The first is to try and break the vicious cycle of inflammation and swelling. I often recommend ice massage to oiled skin, right on to the fat pad, (the ice-it-away  is really effective for this), and will often tape the kneecap off the fat pad. Wearing a slight heel can help stop the patella knocking onto the fat pad, and most definitely avoiding standing with the knee locked back.

A treating clinician should also be assessing if there are other factors contributing to squashing the fat pad. These may, for example be quadriceps tightness, or poor movement patterns, particularly in people who are hypermobile.

There are also non-mechanical sources of problem in the fat pad, and these should be referred to as metabolic. This is seen with obesity and osteoarthritis of the knee.

Let’s take obesity. When someone is carrying excess fat they will have systemic inflammation. This is one of the reasons for raised cardiovascular risk, but the fat pad becomes inflamed and can hurt. The good news is that weight loss not only reduces load to the knee but also with immediate effect has been shown to reduce the inflammatory state of the knee.

In osteoarthritis it appears that the fat pad changes its state to produce unhelpful pro-inflammatory cells. As the fat pad is housed within the capsule of the knee the fat pad drives further joint breakdown that clearly is undesirable. The good news here is that any efforts to reduce the inflammatory state of the fat pad will have a positive effect on the inflammatory state of the whole knee.

To conclude, as weird as it is, this little pad of fat under the kneecap can be a very painful and persistent source of problem. Make sure you seek the right help to treat the problem, and help you get back to the things you love doing.

If you want to understand this in more depth why not look at my webinar on the fat pad https://t.co/juxILqftIm


kevin 05-01-2016


Claire 09-01-2016

I would always recommend that you have a detailed assessment to see if there is also any biomechanical reason why you are still nipping the fat pad. they are very tricky to treat, but not impossible! Let me know if I can help further.. Good Luck! Caire

Aly 28-01-2016

Can I cure fad pad inflammation with PRP?

Claire 01-02-2016

There is no decent research to suggest you can. In addition, any interventions aimed at treating the fat pad need to consider why the problem came on in the first place. Faulty biomechanics/training/movement patterns etc need to be addressed otherwise the fat pad problem can return. Hope that helps? Claire

wheelchairindia 22-06-2016

Hey, very nice site. I came across this on Google, and I am stoked that I did. I will definitely be coming back here more often. Wish I could add to the conversation and bring a bit more to the table, but am just taking in as much info as I can at the moment. Thanks for sharing. Kneecap Keep Posting:)

Claire 22-06-2016

Thank you for your kind comments! I will keep posting, don't worry! Best wishes Claire

Katie 04-09-2016

Well written and relevant article! Thank you for sharing. Why do you suggest icing over oiled skin? What is the importance of the oil?

Claire 05-09-2016

Hi Katie, It simply helps to protect the skin from an ice burn. Thanks Claire

Frank 10-09-2016

Hi there! This blog post couldn't be written any better! Reading through this post reminds me of my previous roommate! He continually kept talking about this. I am going to send this post to him. Fairly certain he will have a good read. Many thanks for sharing! http://bing.org

Claire 10-09-2016

Thanks Frank! I'm glad you could relate to it and hope your friend finds it useful too.

Eleanor 22-02-2018

Thank you for writing this! I've been struggling with fat pad impingement for about five months now (but it was misdiagnosed for two of those months), and nothing was really working, although taping provided some temporary and imperfect relief. I had an injection of cortisone a couple of weeks ago which was initially extremely painful but has since improved slightly. I've been icing the area, but I will definitely adopt your ice massage recommendation in future. I was just wondering what your opinion is on using ultrasound therapy for fat pad impingement?

Claire 22-02-2018

Hi Eleanor, I'm sure there will be some advocates of US for fat ads, but personally I haven't found it that helpful. Good luck!! best wishes Claire

MJ 27-04-2018

Dear Clair, I am 6 months out from arthroscopic meniscus trim of the lateral compartment but awoke from anesthesia to learn the surgeon decided to “clean up around my synoviumand fat pad”. My symptoms fit all descriptions of medial plica and patellar fat pad irritation. Biggest concern is may have fibrotic changes to medial plica that could damage articular cartilage of my tibia and femur. Do you think infra-articulate cortisone shot is indicated now? Other posts here don’t sound like Cortisone shot was that helpful. Thanks, MJ

Claire 04-05-2018

Hi Sorry to hear you are having a difficult time. I wouldn't proceed to a steroid injection until you have had a go at settling it with physiotherapy. However, if the knee is very swollen the steroid may help accelerate your progress. I hope that helps. best wishes Claire

Christine 20-06-2018

Hi- great site! 9/1/17 I was doing a wall squat, fell severe pain along w cracking sound in knees. Dr said both knees were sprained. Went to Europe for 18 day tour, (no refunds so I was stuck going)... took Aleeve for 3 weeks. 5 mos later- after lots of PT & ice daily still no progress so had MRI which was normal; went to new Dr & PT group who said I have PFS. I am def a little better, but still have pain under medial sides of patella & on sides of patellar tendon. In Feb I could only do 5 min of exercise, now I’m at 35. Stairs & ROM havent beenna prob. Using Voltaren when needed. Will this ever get better? I’m worried that I have permanent damage from my injury...any thoughts?

Karla 10-07-2018

Dear Claire, I used to be a competitive swimmer and have struggeled with chronic fat pad inpingement in both knees for the past 4 years, I am only 16. I have so far had 6 cortisone injections, 1 arthoscope, many physiotherpy rehab programs, acupuncture, medication, orthotics and rest from all activites. I am very hypermobile and this issue started as I was hyperextending my legs whilst kicking in swim training, but has now started to be too painful to straigten my leg in any setting. Out of frustration I had an arthoscope last year, but done by a poor surgeon who did not look properly into the fat pad and did not trim anything. I had to quit swimming around 4 months ago but despite, the pain has stayed the same. I am now considering getting a bilateral fat pad trim, so that I can start to do more intense strengthening programs, as all I can do now is floor bridging. I was wondering what your opinion is on fat pad trim at such a young age and how the sucess and recovery is like? Thank you so much for your help.

Susan nixon 23-07-2018

Hi I recently had arthroscopic surgery, my issue. ifraptellar fat pad odema indicating maltracking with a thickened medial plica , this was shaved down. My question is after this is it normal to have so much popping and cracking in the knee which I never had before , is this a sign of recovery? Thanks

Claire 26-07-2018

Hi Susan It is common to have noises and as long as they are not associated with sharp catches of pain they usually settle down. The most important thing now is to regain your strength but ideally guided by a physiotherapist to max out on strength gains without over stressing your knee as it recovers from surgery. I hope that helps and good luck! BW Claire

Claire 26-07-2018

Sorry you are having such a tough time. I would be very cautious as it is certainly not a quick fix. Have you tried off loading taping of the fat pad, and also lots of control strength work around zero to stop you hyperextending too readily? Have you tried ice massage religiously ie min x1 every day. Good luck with it. BW Claire

Claire 26-07-2018

Hi Christine, Although not pain free you are so much further forwards than you were! This is a great sign.keep going-it can take many months of building up but just keep the upward trend but in really small increments. If the damage was severe it would be less likely to improve like this so I would say stay positive. Good luck! BW Claire

Leave a comment

Your email address will not be published. Required fields are marked *


four × 2 =