The Fat Pad, Hoffa’s Fat Pad, Infrapatellar Fat Pad… All these terms are synonyms for a normal anatomical structure in the front of the knee that can cause problems amongst athletes of all ages. As always, understanding what you are dealing with is the first step to getting better.
What is the Fat Pad?
The main fat pad in the knee sits behind the tendon that connects the knee cap to the shin bone. It lies between the tendon and the front of the thigh bone. It allows the tendon to move smoothly across the front of the thigh bone as the knee is flexed and extended.
When you operate on the knee, the fat pad resembles an oyster: it is extremely soft and slippery and about the same size. Importantly, the fat pad has a very dense nerve and blood supply, meaning it can be painful and scar quickly when injured.
How is the Fat Pad injured?
The fat pad can become inflamed, scarred and therefore painful due to a number of causes. The most common is an acute injury, such as a sports injury or a knee cap dislocation that causes bleeding, pain and inflammation in the fat pad.
Secondly, the fat pad can be injured by repetitive microtrauma, such as an increase in running or exercise on a knee where the biomechanics of the lower limb isn’t right. We commonly see this in endurance athletes, weight lifters, or those returning to sport after some time off.
Finally, the fat pad can be damaged at the time of surgery, particularly key-hole surgery.
Symptoms of an injured Fat Pad
Symptoms are varied but include pain under and below the knee cap, reduced range of movement, pain on fully extending the knee particularly when there is weight on the knee, tenderness and swelling on the knee.
The symptoms tend to be worse on activity and relieved with rest. Patients have often tried and failed to return to sports on a number of occasions.
Diagnosing a Fat Pad injury
The first step is to have a thorough clinical examination by one of our experts. Following this the imaging technique of choice is an MRI.
Treating a Fat Pad injury
Surgery for fat pad problems is always a last resort. Initially, physiotherapy from an experienced musculoskeletal physiotherapist is essential to correct imbalances around the knee. Our specialists can help you find a physiotherapist to help you.
Taping can help to offload the knee cap and take pressure off the fat pad. In some cases, depending on examination and imaging findings, targeted injections using ultrasound scan can help break the pain cycle and allow you to rehabilitate more effectively.
It is rare to operate on the fat pad, however key-hole surgery or even open surgery can be used once all non-operative measures have been exhausted.
If you have any questions about a Fad Pad injury or associated symptoms, please contact our team to arrange an initial consultation.