Plica Syndrome and Fat Pad Impingement

The plica is a fold of joint lining (synovium) that may become thickened and swollen. This is known as plica syndrome.

The fat pad is fatty tissue below the knee cap (patella) between the end of the thigh bone (femur) and the shin bone (tibia). The fat pad can become swollen and pinched between the bones with knee movement. This is known as fat pad impingement.

Pain in the front of the knee, usually on the inner side. Pain typically occurs with bending of the knee such as running, kneeling, squatting, and sitting for long periods of time, getting up from a seated position, and going up and down stairs. The knee can click, lock, or pop. Swelling is occasionally seen.

It can be caused by direct injury such as a fall onto the knee or a direct blow. It may occur after repeated injury to the fat pad or plica during activities or sports that involve repetitive bending and straightening of the knee. The injury causes swelling and thickening of the fat pad and plica, which can be painful.

Initial treatment includes medications and ice to relieve pain and reduce swelling, stretching and mild strengthening exercises, and modification of activities that cause the symptoms.

Two types of medication may be used. In most cases, a combination of these methods will be chosen:

• Nonsteroidal anti-inflammatories (NSAIDs): medications such as Advil (ibuprofen), Aleve (naproxen), or Mobic (meloxicam) are often recommended. Ask your child’s care provider about how much to take and how often to take them. For the best results, have your child take them consistently.

Steroid injections: Your child’s care provider may recommend an injection in the office. This medicine reduces swelling of the plica and fat pad.

Your child’s care provider may give your child exercises to be done at home. Your child may be referred to a physical therapist or athletic trainer if needed.

Your child’s care provider may recommend an outpatient, minimally invasive procedure called an arthroscopy. During surgery, your child’s care provider will remove the plica and part of the fat pad to eliminate painful popping and pinching that occurs with knee movement.

Full recovery will depend on how the problem was treated. Most patients treated without surgery fully recover in 6 to 12 weeks.

If your child is treated with an arthroscopy, they may need crutches for 1 to 2 weeks after surgery. Following a dedicated physical therapy program after surgery, most patients return to athletic activities in 8 to 12 weeks.