Knee joint

Fractures
The Ottawa knee rule, a clinical prediction rule, can guide need for an x-ray:
 * 1) age 55 years or older
 * 2) "isolated tenderness of patella (no bone tenderness of knee other than patella)"
 * 3) "tenderness at head of fibula"
 * 4) "inability to flex 90 degrees"
 * 5) "inability to bear weight both immediately and in the emergency department for 4 steps (unable to transfer weight twice onto each lower limb regardless of limping) "

Torn meniscus or ligament
Many tests have been proposed to improve the physical examination. Examples are: Meniscal injuries: Cruciate ligaments injuries:
 * Apley compression, McMurray's, and medial-lateral grind tests
 * Anterior drawer, posterior drawer, lateral pivot shift, and Lachman tests

Injuries to the cruciate ligaments can be accuractly diagnosed with physical examination by orthopedic physicians; meniscal injuries are more difficult to detect. No sign on the physical examination (McMurray's, Apley's, and joint line tenderness) is more than 70% sensitive for meniscal injuries.

The presence of a hemarthrosis indicates likely injury to a meniscus or ligament, usually of the anterior cruciate ligament with high specificity.