The KT-1000 is used to get an objective measurement of the a-p
displacement of the knee. A significant tear is diagnosed when there
is 5 mm side to side difference in the measurement.My right knee measures 11mm of movement while my left measures 17mm. While the difference isnt extreme, 6mm, the value for each leg is rather high.
The pivot shift test must be negative to be a partial tear. If the
test is positive, this is a clinically unstable knee and should be
regarded as anterior cruciate deficient. This is the most important
assessment of the partial tear. Both of my knees have been described
as "textbook" pivots. Very few doctors resist the urge to have an
intern or student play with the shift it is so pronounced.
The MRI can image the tear of the anterior cruciate, but is unable to distinquish the degree of tear. The following image shows a tear and how difficult it is to see one in an MRI image. Note: this is not an MRI from my knees.