Impact or blunt trauma to the knee can produce a bruise, technically known as a knee contusion. Although it may sound like a minor injury, some types of bruises cause long-lasting pain and discoloration. Bruises to the bone are the most severe and usually the slowest to heal. Although less severe than a fracture, the inner, or medullary, portion of the bone is damaged in a bone contusion and requires weeks to months to heal. When the impact of the injury crushes muscle fibers deep in the tissue, it is known as a muscle bruise. Mild bruises may affect only the outer tissue and skin. Hematomas occur when a pool of blood forms below the surface of the skin, creating a swollen lump.
Diagnosis
Step 1
If you are unable to walk or if you experience severe pain, swelling and bleeding as a result of a knee injury, you should seek medical attention. Extensive bleeding and inflammation below the skin can cause shock or loss of consciousness. Seek assistance in obtaining transportation to a medical facility.
Step 2
A blunt-force injury to the knee should be evaluated by a doctor. A bone contusion may be difficult to distinguish from a bone fracture and your doctor may order a diagnostic scan to assist in visualization. Magnetic resonance imaging, or MRI, is often successful at imaging a knee contusion; computerized tomography, or CT scanning, X-ray or ultrasound may also be used.
Step 3
Many bone contusions are accompanied by other soft tissue injuries, such as damage to the anterior cruciate ligament, or ACL. These are particularly common in sports-related knee injuries and can often be detected by magnetic resonance imaging. Ask your doctor whether ligaments, muscles and tendons have also been affected.
Implement Treatment
Step 1
Do not ignore the pain of a knee injury but immediately rest and protect the injured site. If necessary, use crutches or other assistance until you can obtain medical attention.
Step 2
Ice your knee using crushed ice or a package of frozen peas or corn wrapped in a clean towel. Do not apply ice directly to the skin. Ice the area for 15 to 20 minutes at a time and repeat this every hour as needed for 24 to 48 hours after the injury. This reduces swelling and inflammation.
Step 3
Apply gentle compression to the area by wrapping your knee in an Ace bandage or other soft wrap. Do not apply extensive pressure to the injured area.
Step 4
If possible, lie down and elevate your leg so that your knee is raised above the level of your heart. This will prevent blood from pooling in the area.
Step 5
Acetaminophen can help you manage the pain associated with a bruised knee. Discuss other options for pain relief with your doctor; prescription-strength medications may be needed in some cases. Avoid massaging the affected area.
Watch for Complications
Step 1
Call your doctor if you experience pale skin, weakness, severe pain, numbness or tingling in the affected area. These are possible signs of compartment syndrome. An acute injury to the leg can cause this rare but serious complication. Compartments are areas consisting of muscle, nerves and blood vessels and are delineated by a thick membranous tissue called fascia. The fascia hold the softer tissues in place. When there is extensive swelling or bleeding inside a compartment, the fascia may not be able to stretch to accommodate the extra volume. Pressure builds up inside the compartment, reducing blood flow to the muscles and nerves. In the absence of oxygen and nutrients, these tissues may become permanently damaged. This condition is potentially life-threatening and requires immediate medical attention. Surgical intervention can save the affected limb from amputation and spare the patient's life.
Step 2
Call your doctor if your pain worsens and if you are unable to resume normal, low-impact movement. You may have an additional injury to the soft tissues surrounding the knee or an undiagnosed fracture. These may require additional treatment or therapy to restore motion.
Step 3
Consult your doctor about exercises you can do to maintain your overall fitness while your injured knee heals. Your doctor or a rehabilitation therapist can help you design activities to gradually increase your activity level. In the first phases, this may consist of gentle stretching to aid in restoring flexibility to the injured region. Weight-bearing exercises should be added slowly over time to prevent additional injury.
Step 4
Be aware that a rapid return to high activity can cause a complication called myositis ossificans. This means that a bruised muscle begins to grow bone cells, rather than new muscle cells, to repair the damaged area. The condition is more common in young athletes and is marked by persistent pain and swelling.
Tips and Warnings
- During the healing process, the color of the affected knee may change from red and purple to yellow or green. Although discoloration of skin is temporary, it may take weeks or even month for it to fade, depending on the severity of the bruise.
Things You'll Need
- Ice
- Towels
- Ace bandage
- Acetaminophen
