An articular cartilage injury, or chondral injury, may occur as a result of a pivot or twist on a bent knee, a direct blow to the knee, or wear and tear as a patient gets older.

In some cases, chondral injuries may accompany an injury to a ligament such as the anterior cruciate ligament (ACL).

Small pieces of the articular cartilage can break off and float around in the knee as loose bodies, causing locking, catching and/or swelling.

This type of injury can result from a series of minor injuries that have occurred over time.