Synovitis or an inflammation of the synovium occurs about four to six percent of the time. The synovium is a lining inside the joint with fluid that lubricates the joint. The inflammatory response is common when the body sees the sutures as a foreign invader. As the suture starts to break down, this reaction is triggered.

Synovitis occurs most often when sutures or tacks are placed inside the joint (as opposed to on the outside of the articular surface). The reaction occurs about two to four months after the operation. This is about the time the suture material starts to disintegrate.

Studies show that some materials are more likely to cause synovitis than others. The reason for this is unknown. It may be the design, type of material used, or amount of surface exposed. Given how popular these devices have become, we may expect to see this problem occur more often in the future.