Can a ligament tear be noticed in an x-ray, or is an MRI scan necessary?

MRI much much better. Radiographs can sometimes show subtle abnormalities, or the presence of a chronic care which is calcified. However, MRI is outstanding in imaging soft tissue including the tendons and ligaments and is by far the preferred method for imaging soft tissue injuries and joints.
Although . There are subtle xray findings that would demonstrate a ligament tear, MRI is the study of choice to accurately evaluate this.

Related Questions

Is it still possible to have a meniscus tear and ligament tear even when the MRI scans show nothing?

For sure. This is a great question and a touchy subject. 1st of all, MRI cannot make the diagnosis 100% of the time even in the best of hands (with the top rad in the world). There are many technical limitations that come into play, the tear may be small or partial, and different magnets have varying quality. Tears can be present and missed. Consider getting another opinion from an orthopedic radiologist. Read more...
Meniscus. Mri is most sensitive test available. If negative pain from other source. Read more...