An osteochondral lesion (“OCL”) is the name given to an area of damaged cartilage inside the knee, arising during an injury or occasionally “spontanteously”, when it is termed “osteochondritis dissecans”. OCLs can occur in other joints, for example the ankle.

The knee may fail to recover as expected after an injury, with persistent pain and swelling on activity. Alternatively, symptoms such as locking (inability to fully straighten the knee) or giving way may indicate that an area of cartilage or bone has detached fully and become a “loose body”. If this is the case, then usually a keyhole operation, or arthroscopy, is required to remove the loose body.

Whether or not a loose body is present, the cartilage crater or defect may require surgery. The first line of treatment is an arthroscopic treatment to stimulate “fibrocartilage” to fill the defect, and there are several techniques. OCLs can co-exist with other injuries, for example ACL rupture, and if so it will be necessary deal with these injuries at the same time. The success rate of surgery is 70–80%.

If first line treatment fails, other techniques are available and may be appropriate, including Mosaicplasty and Autologous Chondrocyte Implantation (ACI). Your surgeon can discuss these with you in detail.