What are fat pad injuries?
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.
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 microtraumas, 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.
What are the symptoms of fat pad injuries?
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.
How are fat pad injuries diagnosed?
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.
What are my options for treatment?
Surgery for fat pad problems is always a last resort. Initially, physical therapy 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 scans 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.