Background: Cruciate ligament tears are clinically diagnosed by detection of anterior or posterior tibial translation on physical examination; however, this manual method of assessment is imprecise, subjective, and not reproducible. Recently a new instrument, a stress radiographic device and knee stability test (DYNEELAX), were produced to objectively measure these displacements.

Objective: To assess new diagnostic methods, in the measurement of anterior/posterior tibial translation in cruciate ligament-deficient knee compared to the healthy knee.

Material and method: The MRI, stress radiographic device and knee stability test was applied to cruciate ligament-tear knees that were diagnosed by physical examination as having partial or complete cruciate ligament tears. Each knee was tested under a force 120 Newtons in a posterior to anterior direction to create anterior tibial translation at 20 degrees knee flexion. Side-to-side difference of anterior/posterior tibial translation (mm) was measured from radiographs. Measurement of rotation and translation by DYNEELAX was also recorded.

Inclusion Criteria: Patients are diagnoed as ACL/PCL injury or suspect ligament sprain at Kaohsiung veteran general hospital.

Exclusion Criteria: Unable receing MRI exam, any op history of knee or fracture history on the impaired knee.

Over 20 years old, suspected ligament damage caused by knee contusion