The vastus medialis trigger points refer a toothache-like pain deep in the knee joint that may disappear after a few weeks, only to be replaced by a sudden weakness in the knee (a condition called “buckling knee”) that causes a person to unexpectedly fall while walking.
Dr. Travell called this muscle the “two-joint puzzler” because of its ability to cause trouble at both the hip joint and the knee joint. The trigger point in the rectus femoris causes a deep aching pain in the front of the knee, even though the trigger point itself is located up near the hip joint.
The vastus lateralis trigger points refer pain to the outside of the thigh, knee, and upper lower leg. They may also cause the “stuck patella” or “locked knee cap” conditions in which the knee cap fails to track up and down naturally during movements of the knee.