Almost everyone has synovial folds, or plicae, in their knees. The most common location is along the inner knee. Occasionally, a fold may be present above the kneecap. Ordinarily, the synovium lines the joint cavities of the knee, but sometimes an overgrowth of normal tissue occurs. These plicae usually dissolve; however, sometimes they partition and a remnant remains. If a patient performs an activity repetitively or suffers an injury to this area, the plica may become irritated. Once it becomes irritated, it gets larger. When it gets larger, it then can cause more mechanical problems, and a vicious cycle ensues.
A thickening of a synovial fold (plica) in the knee can become irritated by use and then worsen with more use.
The most common complaint is an aching on the inner side of the knee. If this plica is above the kneecap, some of the aching may be on the top of the knee. Usually patients complain of a feeling of tightness, and occasionally patients describe throbbing. The examiner may feel a plica popping across the femoral cartilage or bone as the knee extends or bends. This symptom is most commonly seen in patients who participate in sports in which running is integral. This condition should not be confused with chondromalacia, or roughening underneath the kneecap, or a medial cartilage tear. In an adolescent, the pain is usually a plica or possibly kneecap pain as opposed to frank wearing or chondromalacia of the kneecap. Only relatively few people have a plica requiring treatment.
Treatment essentially consists of rest, anti-inflammatory medicines, and ice when the knee is acutely irritated. The condition requires giving attention to alignment of the knee and ankle, and the patient may have to modify activity for a short time. Oral anti-inflammatory drugs are usually helpful, and occasionally a cortisone shot into the plica area is necessary. A neoprene brace can be of benefit. When all conservative measures have failed and diagnostic imaging by X-ray and magnetic resonance imaging does not show any kneecap problem or meniscal problem, the patient may be a candidate for arthroscopic surgery. This operation is very successful if indeed the patient has a pathologic plica.
This is a section from Dr. Jack E, Jensen′s book The One Stop Knee Shop. Read the next section Loose Bone or Cartilage within the Knee.