A bruised knee (contusion) occurs when blunt force trauma damages small blood vessels beneath the skin. This causes blood to leak and pool in the soft tissues, resulting in characteristic discoloration and tenderness. While painful and limiting mobility, these common injuries usually resolve completely with appropriate self-care at home. Applying immediate, targeted care can significantly influence the speed and comfort of recovery.
Immediate Steps for Reducing Swelling
The immediate treatment for a knee contusion focuses on minimizing internal bleeding and controlling swelling during the first 24 to 48 hours. This acute management involves the four-part strategy of Rest, Ice, Compression, and Elevation (RICE). Rest requires ceasing any activity that caused the injury or causes pain, preventing further damage.
Applying cold constricts blood vessels, limiting blood leakage, reducing swelling, and numbing pain. Ice should be applied for 15 to 20 minutes at a time, using a thin towel barrier to prevent frostbite or tissue damage. Reapply the cold pack every two to three hours during the initial 48 hours.
Compression involves wrapping the knee with an elastic bandage (Ace wrap) to provide gentle pressure and control swelling. The wrap must be snug but never so tight that it causes numbness, tingling, increased pain, or color changes below the knee, which indicates restricted blood flow.
Elevation uses gravity to encourage fluid drainage away from the injury site. Position the injured knee above the level of the heart as often as possible, especially when resting, by propping the leg up with pillows. This promotes the return of excess fluid to the circulatory system, helping to decrease internal pressure and discomfort.
Managing Discomfort and Mobility
After the initial swelling phase (typically 48 hours), focus shifts to managing discomfort and restoring function. Over-the-counter (OTC) pain relievers effectively manage the soreness associated with a bruise. Acetaminophen reduces pain perception without addressing inflammation.
Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or naproxen, relieve pain and reduce inflammation. Although some professionals suggest avoiding NSAIDs immediately after a contusion due to bleeding risk, studies show no significant difference in pain relief compared to acetaminophen for acute soft tissue injuries. Follow dosage instructions on the product label and consult a healthcare provider if you have pre-existing conditions.
As pain subsides, gentle movement prevents joint stiffness and aids healing, transitioning away from complete rest. Begin with passive and active range-of-motion exercises, such as slowly bending and straightening the knee to its comfortable limit. Movement must be slow and controlled, stopping immediately if sharp pain occurs.
Gentle movement encourages blood flow, assisting the body in clearing pooled blood and cellular debris. Avoiding prolonged immobilization is key to swift recovery. Do not attempt strenuous activities until full, pain-free range of motion has returned.
When to Consult a Healthcare Provider
While most bruised knees heal with home care, certain signs suggest a severe underlying issue, such as a fracture or ligament damage, requiring professional medical evaluation. A more serious injury is likely if you experience an inability to bear any weight on the injured leg, if the knee feels unstable, or if there is a visible deformity or a popping sound heard at the time of injury.
Persistent or worsening pain and swelling after 48 hours of home treatment should not be ignored. Other concerning symptoms include numbness or tingling in the leg or foot below the knee, which may indicate nerve involvement. Signs of infection, such as fever, red streaking, or increasing warmth, also warrant an immediate consultation.
If the bruise is extremely large or continues to grow after the first day, it could signal a hematoma that may need draining. Seeking professional guidance ensures accurate diagnosis and prevents potential long-term complications.
Recovery Timeline and Return to Activity
Recovery for a simple knee contusion typically takes two to four weeks, depending on the severity and depth of the bruise. As healing progresses, the bruise undergoes a predictable color transformation as the body breaks down hemoglobin. Initially, it appears red, then turns purplish-blue or black within a day or two as the blood loses oxygen.
After five to ten days, the bruise transitions to shades of green and yellow before fading to a yellowish-brown color. This color change is a visible indicator that the injury is resolving. Note that bone bruises, which are deeper injuries, can take significantly longer, sometimes months, to heal fully.
Returning to normal activity should be a gradual process guided by the absence of pain. Begin with low-impact movements, such as walking or cycling, avoiding activities that cause sharp discomfort. Full participation in sports or higher-impact activities must be delayed until the knee has regained full, pain-free strength and range of motion. Listening to the body ensures a complete recovery and prevents re-injury.