This usually occurs after a sports injury, where an area of articular cartilage (the solid lubricant inside the joint lining the bones) is damaged. The injury is not necessarily related to trauma, but can be developed over long periods in sports that require heavy lifing.  The injury can present as knee pain, knee locking and/or the knee giving way.

This usually requires a MRI or knee arthroscopy (looking inside the joint with a camera) to accurately diagnose

It can be treated with a procedure called autologous chondrocyte implantation (ACI), where the patient’s own cartilage cells are harvested, grown in the lab, then implanted back in to the patient to fill the defect.

While not always completely successful in removing pain, it has excellent results worldwide.

If the defect is present on a weight-bearing area of the knee, you will be allowed to bend the knee almost normally but not take weight on the leg for around six weeks.

If the defect is on the patella (knee cap), you will be allowed to take weight on the leg, but will have to keep it straight in a brace for 2-3 weeks, with a graduated return to normal motion over the next three weeks.