Question: Can a low back injury cause knee pain?

Answer: Yes

Question: Can a hip joint injury cause knee pain?

Answer: Yes

Question: Does a knee injury usually cause referred pain down the front of the lower leg?

Answer: No

The mechanism of referred pain - pain felt at a place other than its source - is prevalent in cases of low-back injury. The low back can refer pain anywhere in the lower limb. Referred pain from the low back often is felt in the thigh, knee, calf, shin or foot. Sometimes, a generalized pain felt at the knee is referred from the low back. Injury to the hip joint also can refer pain to the medial thigh and the medial aspect of the knee.

The knee itself does not refer pain to other parts of the body. When the knee is injured, it generally hurts at the knee and nowhere else. Pain in the lower leg can indicate referred pain from a low-back injury, or an injury to the shin or calf muscles.

There also can be a vague pain at the knee. In this case, the person knows the problem is in the knee, but can't say precisely where in the knee the pain exists. The person says it hurts somewhere "deep inside the knee" or it hurts "all over the knee," or that the pain site keeps changing. What this generally means is that the injury is deep inside the knee; there is knee swelling; or the person has multiple injuries.

For example, if a cruciate ligament or meniscus tears in the center of the knee joint, the body reacts by producing pain felt deep inside the knee. If there is knee swelling, which can be caused by many different injuries, the person experiences a deep pain or ache in the knee, and often a feeling of stiffness.

This is because the swelling limits the range of motion and makes it more difficult to flex and extend the knee. It is nature's way of telling the body, "Be careful; don't move me too far, or I will hurt you to remind you I am injured." Finally, if the person has several injuries in different places in the knee, the person can perceive pain all over the knee.