Elevation of an injured or swollen knee is a simple, effective practice often recommended as part of the initial RICE (Rest, Ice, Compression, Elevation) recovery protocol. This technique involves raising the limb to a specific height to assist the body in managing fluid accumulation. Understanding the correct positioning allows a person to effectively reduce discomfort and promote the initial stages of healing.
Why Knee Elevation is Necessary
Elevation works by directly opposing the effects of gravity on fluid movement. When the knee is injured, the body initiates inflammation, increasing blood flow and causing fluid (edema) to leak from blood vessels into the surrounding tissue. This fluid accumulation causes swelling, increases pressure, and leads to pain.
Raising the leg utilizes gravity to reduce the hydrostatic pressure inside the capillaries of the lower limb. This reduction in pressure minimizes fluid leaking out of the vessels. The elevated position also helps improve venous return, assisting veins in carrying blood and excess fluid back toward the heart. This promotion of lymphatic drainage and improved blood outflow helps lessen the total volume of fluid at the injury site.
Achieving the Correct Elevation Technique
The effectiveness of elevation depends on achieving the correct height and ensuring stable support for the entire leg. To maximize fluid drainage, the knee must be positioned above the level of the heart. For most people, this means propping the leg up while lying down so the foot is approximately 12 inches higher than the heart.
Use soft materials, such as pillows, blankets, or foam wedges, to support the leg along its entire length. The goal is to create a gentle, stable slope for the limb. The foot should be higher than the knee, and the knee should be higher than the heart, often resulting in an angle of about 30 degrees.
Avoid placing support directly behind the knee, which can cause the joint to rest in a bent position. Resting the knee in a flexed position can increase stiffness and interfere with the ability to fully straighten the knee later. Instead, stack pillows or a wedge under the calf and ankle to keep the knee straight and fully supported, preventing strain and promoting proper alignment.
When to Elevate and When to Seek Medical Help
For acute swelling, elevation is recommended in short, frequent intervals rather than continuously. Elevating the knee for 15 to 20 minutes at a time, several times a day, is more beneficial than one long session. This frequency helps manage swelling without the discomfort associated with prolonged elevation. Consistency in this practice, especially within the first 24 to 48 hours, is important for the best results.
While elevation is a helpful initial step, certain symptoms indicate a need for immediate professional medical attention. Seek care if you experience severe, unrelenting pain that does not improve with rest, or if you are completely unable to bear weight on the affected leg. Other red flag symptoms include a visible deformity of the joint, numbness or tingling in the leg or foot, or swelling accompanied by fever or chills, which could suggest an infection. A rapid increase in swelling, severe discoloration, or a feeling of instability in the knee also warrants a prompt medical evaluation.