It can be difficult to diagnose an articular cartilage injury. Physical
examination may show a swollen knee, but frequently the exam is
normal.
Imaging may help the doctor make a diagnosis in some, but not all,
cases. X-rays may be normal in most cases because only bone damage
is visible on X-ray. One indication of advanced cartilage loss
is a decrease in space between two bone surfaces. A loose bone
fragment may be detected in a condition called osteochondritis
dissecans(OCD), in which a portion of bone detaches
with the articular cartilage.
An MRI (Magnetic Resonance Image) may reveal softened cartilage
in many cases. This softening can be difficult to detect, however,
and the diagnosis may require the most sensitive and highest quality
MRI images, which may show changes in the underlying bone. Cartilage
thinning or loss is also usually visible on MRI.
Articular cartilage damage is most
reliably diagnosed with an arthroscopic examination of the
joint. In this procedure, a tiny fiberoptic scope is inserted into
the joint. The doctor uses this scope to visually assess the damage.
