A PT is assessing the knee.  The patient is positioned prone…

A PT is assessing the knee.  The patient is positioned prone with the knee flexed to 90 degrees.  The PT compresses the tibia on the femur and then rotates it.  The patient complains of severe pain.  The PT then distracts and rotates the tibia on the femur, and the patient complains of severe pain again.   What conclusion might the PT draw from this assessment?