How Are Knee Problems Diagnosed?

How Are Knee Problems Diagnosed?

Doctors diagnose knee problems based on the findings of
the medical history, physical exam, and diagnostic tests.
Medical history
During the medical history, the doctor asks how long symptoms
have been present and what problems you are having
using your knee. In addition, the doctor will ask about any
injury, condition, or health problem that might be causing
the problem.
Physical examination
The doctor bends, straightens, rotates (turns), or presses
on the knee to feel for injury, and determine how well the
knee moves and where the pain is located. The doctor
may ask you to stand, walk, or squat to help assess the
knee’s function.
Diagnostic tests
Depending on the findings of the medical history and physical
exam, the doctor may use one or more tests to determine
the nature of a knee problem. Some of the more commonly
used tests include:
• X ray (radiography) – a procedure in which an x ray
beam is passed through the knee to produce a twodimensional
picture of the bones.
• Computerized axial tomography (CAT) scan – a
painless procedure in which x rays are passed through
the knee at different angles, detected by a scanner,
and analyzed by a computer. CAT scan images show
soft tissues such as ligaments or muscles more clearly
than conventional x rays. The computer can combine
individual images to give a three-dimensional view
of the knee.
• Bone scan (radionuclide scanning) – a technique
for creating images of bones on a computer screen or
on film. Prior to the procedure, a harmless radioactive
material is injected into your bloodstream. The material
collects in the bones, particularly in abnormal
areas of the bones, and is detected by a scanner.
• Magnetic resonance imaging (MRI) – a procedure
that uses a powerful magnet linked to a computer to
create pictures of areas inside the knee. During the
procedure, your leg is placed in a cylindrical chamber
where energy from a powerful magnet (rather than
x rays) is passed through the knee. An MRI is particularly
useful for detecting soft tissue damage.
• Arthroscopy – a surgical technique in which the doctor
manipulates a small, lighted optic tube (arthroscope)
that has been inserted into the joint through a
small incision in the knee. Images of the inside of the
knee joint are projected onto a television screen.
• Joint aspiration – a procedure that uses a syringe to
remove fluid buildup in a joint, and can reduce
swelling and relieve pressure. A laboratory analysis
of the fluid can determine the presence of a fracture,
an infection, or an inflammatory response.
• Biopsy – the examination of a piece of tissue under
the microscope.