Plica syndrome

Many of the joints of the body are held stable by soft tissue known as ligaments and soft tissue capsules which surround the joints. Lining the inner surface of the joint capsule is a further tissue known as the synovial membrane.

The synovial membrane has several roles including the production of joint fluid (synovial fluid) to lubricate the joint and reduce joint forces during movement.

Plica, found within the knee is the name given to thickened areas of the synovial membrane. Researchers have not found an obvious need for plica and it is thought they are simply remnants from embryonic development when the knee joint and synovial membrane was split into three compartments.

There are three plica folds of the synovial membrane of the knee and plica syndrome from any of these structures is very rare. However, when plica syndrome does occur, it normally involves a plica fold which runs to the inside of the knee cap (medial plica).

Some cases of plica syndrome begin with a blunt trauma to the area of the knee where a plica runs. This leads to inflammation, scarring and subsequent thickening of the plica. Sometimes these same processes to the plica occur with no obvious trauma. Once inflamed and thickened the plica is more likely to become frictioned over the knee joint and knee cap during certain movements which can lead to longer term problems.

Ongoing symptoms of plica syndrome include a well localised pain over the area of ythe affected plica. The pain is normally to the immediate inside of the knee cap but may be the outside or below the knee cap depending on the exact synovial plica fold affected.

As well as pain, there is often a catching sensation or locking feeling to the knee when performing certain movements which friction the plica against parts of the knee joint.

Sometimes there can be a palpable thickening which can be felt clunking back and forth. Movements most likely to cause symptoms include deep squatting movements or rotating movements with the knee flexed.

Plica syndrome will not show on x-rays and may not show on other forms of imaging such as MRI ultrasound scans. An initial diagnosis should be made by an experienced orthopaedic knee consultant surgeon. Depending on the exact history and findings a consultant may request scans in the form of an MRI or ultrasound and in some cases may offer an investigative keyhole operation which is able to examine the knee with a camera placed inside the joint.

Circle Health is able to offer short-notice appointments with orthopaedic knee consultants as well as immediate booking for any diagnostic imaging required.

Individuals who are undergoing initial plica symptoms should rest the knee from aggravating activities and undertake a course or anti-inflammatory medication for 6 weeks or until the symptoms have resolved. Icing the knee may also help to reduce inflammation.

A gradual return to sports should be attempted after this, being careful not to stress the knee too early in deep squatting movements.

Physiotherapy plays a limited role in managing this condition as plica syndrome does not seem to be related to any definite biomechanical problem that needs to be fixed. A physiotherapy supervised program of strengthening exercises if the condition has calmed down may be of benefit.

In cases of plica syndrome which have occured after trauma or for patients who have suffered their first set of symptoms after a specific period of exercise, surgery may not be offered as the first line of invasive treatment.

To help settle remaining plica inflammation and pain our consultants may offer a corticosteroid injection which they will discuss the risks versus benefits of if needed at your consultation.

Plica syndrome is a condition caused by trauma or through an unidentified mechanism and as symptoms become more persistent so may the scarring and thickening to the synovial plica tissue. Due to this, many patients suffering with this condition are offered a keyhole operation to remove the thickened plica.

Prior to making any incision, the exact location of symptoms will be identified. A small keyhole incision will be made and the source of symptoms will be identified with a camera on the end of a tool known as an arthroscope. The inflamed portion of synovial plica tissue will be removed and the small incision closed.

Although this form of keyhole surgery is a very safe procedure with very small incisions being needed, there is still a small risk of infection. Any patients undergoing surgical treatment for plica syndrome will be closely monitored by their consultant knee surgeon post operatively.

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