Knee fat pad syndrome: causes, symptoms and treatment

Written by Dr Sean Leo, a consultant orthopaedic surgeon whose clinical focus is the knee, sports injuries and the lower limb.

Last updated: 9 October 2026.

Knee fat pad syndrome is one cause of pain at the front of the knee ^[1]. It is a condition in which the fat pad below the kneecap becomes inflamed and pinched ^[1]. It is described as a relatively underdiagnosed cause of front-of-knee pain ^[3].

This page explains what it is, what it can feel like, how it is assessed and how it is treated.

What is knee fat pad syndrome?

It is a condition in which the fat pad below the kneecap becomes inflamed and pinched ^[1]. The infrapatellar fat pad, also called Hoffa’s fat pad, is a structure of fatty tissue that occupies most of the front compartment of the knee ^[1]. Inflammation of this fat pad can lead to impingement, known as Hoffa pad impingement syndrome ^[1].

• The fat pad sits behind the patellar tendon (the tendon just below the kneecap) ^[1].
• It is richly vascularized and innervated, meaning it has a rich blood supply and nerve supply ^[1]. Because it is richly innervated, it is a source of front-of-knee pain ^[2].
• The condition is named after Hoffa, who described it in 1904 ^[3].

What’s covered on this webpage

• What is knee fat pad syndrome?
• What does knee fat pad syndrome feel like?
• What causes knee fat pad syndrome?
• How is knee fat pad syndrome diagnosed?
• How is knee fat pad syndrome treated?
• When is urgent help needed?
• What should I do next?

What does knee fat pad syndrome feel like?

Typically it is a sharp or burning pain at the front of the knee, below and beside the patellar tendon near its lower attachment ^[3].

• Symptoms are often made worse by fully straightening the knee, climbing stairs, or keeping the knee bent ^[3].
• One imaging review describes pain that is aggravated by physical activity and slowly disappears with rest ^[2].
• A swollen knee joint (fluid in the joint) is only rarely detected ^[2].
• Front-of-knee pain has many causes, and fat pad impingement is one of them ^[1].

More on where the pain sits

In the type of impingement described in that imaging review, the pain was lateral parapatellar, meaning at the outer side of the kneecap ^[2]. For another cause of pain below the kneecap, see patellar tendonitis.

What causes knee fat pad syndrome?

In one imaging review, impingement most commonly occurred after repetitive local microtraumas (repeated small injuries) ^[2].

• A single injury or repeated injury can lead to local bleeding and inflammation, which are the most frequent causes of fat-pad-related pain ^[2].
• Inflammation and scarring (fibrosis) within the fat pad, caused by trauma and/or surgery, can lead to a variety of arthrofibrotic lesions (scar-like changes), including Hoffa’s disease ^[4].
• Impingement means the inflamed fat pad is caught at the joint between the thigh bone and the shin bone, or at the outer side of the joint between the kneecap and the thigh bone ^[1].
• A higher-riding kneecap (patella alta) is also associated with impingement of the fat pad ^[2].

More on what a systematic review found

In a 2023 systematic review of 21 articles and 3603 knees, patella alta was found to predispose the development of the condition, and age and body mass index (BMI) were not associated with it ^[5]. In a separate cross-sectional study, patella alta was more frequent in people with fat pad impingement (31.1% versus 5.7% on one X-ray measurement), and the authors state that these associations do not establish causation ^[6].

How is knee fat pad syndrome diagnosed?

In one long-term surgical study, diagnosis was based on a physical examination (Hoffa’s test, described below), MRI findings and response to a lidocaine (local anaesthetic) injection ^[3].

• Hoffa’s test: the examiner first bends the knee, then presses on one side of the patellar tendon. While keeping up that pressure, the examiner straightens the knee passively ^[3].
• This squeezes the fat pad into the joint between the kneecap and thigh bone, and it may provoke pain ^[3].
• In that study the test was counted as positive if the person felt pain or discomfort in the last 10 degrees of straightening ^[3].
• A sagittal (side-view) MRI is the most common imaging technique used to assess fat pad problems ^[4].

More on why scans need an examination alongside

Fat pad abnormalities on imaging do not always cause pain. Careful correlation with clinical findings is required to avoid unnecessary treatment in people without symptoms ^[2].

Owner clinical review required · not a release asset

How is knee fat pad syndrome treated?

Conservative (non-surgical) management is the initial approach, although some people need surgery ^[3].

• For isolated fat pad lesions, conservative treatment with local physiotherapy and non-steroidal anti-inflammatory drugs (NSAIDs, a group of pain-relief medicines) is preferred ^[2]. Check with your doctor or pharmacist before taking any medicine.
• One review describes the condition as often managed with physical therapy ^[4].
• That physical therapy can include passive taping to unload or shorten an inflamed fat pad, quadriceps (front thigh) exercises, gluteus medius (hip muscle) training and stretching the front of the hip ^[4].
• Gait training and avoiding hyperextension (the knee pushed back past straight) can also be used for long-term management ^[4].
• A 2012 review reports that injections of local anaesthetic plus corticosteroids (a steroid medicine) into the fat pad have been explored as treatments for fat pad pain ^[4].
• If the condition does not respond to physical therapy, operative treatment is an option. Arthroscopic partial resection (keyhole surgery to remove part of the fat pad) has shown favourable results ^[4].
• In one long-term series of 18 people treated with keyhole surgery, scores improved, but 5 of 18 (27.8%) still had persistent symptoms at long-term follow-up ^[3].

More on the surgical series

The series was a retrospective case series of 18 patients with a mean follow-up of 148.7 months. Surgery was undertaken in those patients who had consistent symptoms despite more than 3 months of conservative treatment. The pain score (VAS, a visual analogue scale) fell from 7.25 to 2.43 at 2 years and was 3.66 at the final follow-up ^[3].

When is urgent help needed?

The list below applies to any knee problem.

What should I do next?

For anyone with pain at the front of the knee, an assessment is a sensible next step. It brings together the patient’s story, an examination and any tests that help, so that the patient and clinician can decide what to do next. An appointment supports an informed decision. It is not a commitment to surgery.

• Read about knee arthroscopy and about injury prevention.
• Read about knee plica syndrome and about patella alta and patella baja.
• Arrange a knee assessment when you are ready.
• Browse the Knee Hub for other knee problems, or more articles.
• Read more about Dr Sean Leo, who is named as the author of this page.

References

1. DuBose M, Taqi M. Hoffa Pad Impingement Syndrome. StatPearls. 2023 Jan. Bookshelf ID NBK589637. PMID:36943955. https://pubmed.ncbi.nlm.nih.gov/36943955/
2. Draghi F, Ferrozzi G, et al. Hoffa’s fat pad abnormalities, knee pain and magnetic resonance imaging in daily practice. Insights Imaging. 2016;7:373. doi:10.1007/s13244-016-0483-8. PMID:27000624.
3. Park, Kim, et al. Arthroscopic Resection of Infrapatellar Fat Pad Impingement Syndrome: Long-Term Clinical Results at a Minimum of 10 Years. Medicina (Kaunas). 2025;61(6):997. doi:10.3390/medicina61060997. PMID:40572684.
4. Dragoo JL, et al. Evaluation and treatment of disorders of the infrapatellar fat pad. Sports Med. 2012;42(1):51-67. doi:10.2165/11595680-000000000-00000. PMID:22149697.
5. Abelleyra Lastoria DA, Benny CK, Hing CB. Predisposing factors for Hoffa’s fat pad syndrome: a systematic review. Knee Surg Relat Res. 2023;35(1):17. doi:10.1186/s43019-023-00192-4. PMID:37296488.
6. Almohideb, Felemban, et al. Patella Alta on X-Ray and MRI. Diagnostics. 2026;16(15):2444. doi:10.3390/diagnostics16152444. PMID:42587681.