The KT-1000 arthrometer is a small device that's strapped to the leg during knee examination. It's used when the doctor thinks there may be a tear in the anterior cruciate ligament (ACL).

The examiner pulls on the uninjured knee and the gauge on the KT 1000 shows how many millimeters of motion occur between the lower leg bone (tibia) and the upper leg (femur). This motion is called a drawer sign. The reading is compared between the injured knee and the normal knee.

If there's more than three millimeters difference between the knees, the ACL is torn. It's considered more accurate than an MRI.

If you'd like to see a photo of this tool go to: http://www.medmetric.com/kt1.htm or http://www.ismoc.net/procedures/kt1000.html.