A knee contusion usually results from a blow to or fall on the knee. The knee is particularly vulnerable to contusions. In addition to the contusion, a knee injury may result in abrasions or skin tears, which are frequent in knee injuries, according to HealthCareClinic.org. Recovery from a knee contusion may take a few days or several weeks, depending on the severity of the injury and how it is managed.
A contusion occurs when the skin of the knee and the underlying tissues suffer a direct blow. Small blood vessels called capillaries break open, spilling blood into the tissues, muscles and tendons of the knee. The bleeding can cause swelling and bruising as well as pain in the knee. If the swelling is serious, the tissues may feel tight when pressed with a finger. Bleeding may gravitate down the leg, so the shin or calf may also be bruised. In addition to the tissue injury, the bone of the knee may be bruised, which increases the severity of the injury.
The basic treatment for a knee contusion is known by the acronym R.I.C.E., or rest, ice, compression and elevation. R.I.C.E. should be started as soon as the injury occurs. Rest the knee; avoid sports or work activities that will put stress on the injured area, such as climbing stairs or running. The University of Iowa recommends a cloth-covered ice pack for 20 minutes four to eight times a day. An elastic bandage will provide compression to help decrease swelling and provide support. Elevate the knee above the level of the heart as much as possible to help diminish swelling and drain excess fluid from the knee.
Although ice is recommended initially for a knee contusion, heat can also promote healing. After the first 48 to 72 hours, you may switch to heat instead of ice if it feels better. Heat increases circulation in the injured knee and may help reduce swelling. You may also massage the knee or apply heating liniments to increase circulation in the injured area. HealthCareClinic.org also recommends you eat extra protein during recovery to promote healing.
The severity of the injury will determine how long it takes for your knee to heal. A simple bruise may disappear within a week, especially if your pain is minor and you are able to perform gentle exercise to keep the knee limber. Severe bruising and swelling may take several weeks to subside, according to the American Academy of Orthopaedic Surgeons. The AAOS warns that if you stress the knee by trying to do too much, you may delay healing.