A cartilage defect is difficult to diagnose based on the history and physical examination alone. Sometimes this diagnosis is mistakenly made as being a meniscus lesion and then MRI or arthroscopy shows a cartilage defect that can explain the clinical complaints.
An X-ray can help the doctor rule out other causes of knee pain, such as a fracture or arthritis. Cartilage does not show up on a standard X-ray. Sometimes bone changes under the cartilage defect can raise the suspicion of cartilage damage.
To properly visualize the cartilage, an MRI scan can be used and is frequently indicated in the younger patient. For older patients it is thought to be wise to be careful with ordering MRI investigations because they will show many more degenerative lesions that have no clinical implications and can worry and confuse some patients.