A chondral defect refers to a specific, localized area of damage to the articular cartilage that lines the ends of the bones (like a tile missing in the floor). Articular cartilage is the coating of the bones and allows for smooth motion between the ends of the bones. It is a common injury affecting 5-10% of people over age 40, but it can also affect young patients that experience traumatic injuries. Damage to knee cartilage can lead to osteoarthritis of the knee over time.
Focal chondral defects are graded by severity. Grade I is the mildest and grade IV is the most severe describing full thickness injury of the cartilage.
Damage is typically caused by an acute traumatic injury such a sudden pivot or twist with a bent knee, or a fall or direct blow to the knee. When the underlying bone beneath the cartilage is also damaged it is called an osteochondral injury.
The purpose of articular cartilage is to provide smooth movement between the bones that make up the joint. A focal injury to the cartilage can cause pain, joint stiffness, intermittent swelling, and catching or locking of the knee joint when there is a loose fragment of cartilage.
Doctor will review the patient’s health history and ask about the circumstances surrounding the injury, activities that cause pain, and identify the patient’s future activity goals.
The physical examination will test joint laxity, joint line pain, misalignment, and assess range of motion, stability, and gait. However, physical exam alone may not reveal the damage. X-rays will rule out arthritis, bony defects, and misalignment. Other imaging may also be ordered such as MRI. MRI is a sensitive technique to diagnose chondral injuries. However, the most reliable diagnosis is made with knee arthroscopy using a small camera inserted into the joint where the lesion can also be treated, measured, or biopsied if further treatment is needed down the line.
The choice of treatment will depend on the size of the defect, its location, and the patient’s goals. Chondral defects are difficult to treat and can sometimes require surgical repair if all conservative measures have failed.
