A strained knee occurs when a muscle or tendon is injured due to over-stretching, or by absorbing an impact it is not prepared to handle. The tiny fibers that make up the muscle or tendon begin to tear, causing pain and sometimes inflammation. A strained knee is different than a sprained knee, which occurs when ligaments within the joint are damaged. Treating a strained knee involves using the RICE treatment: rest, ice, compression, and elevation. In more serious cases, the muscle or tendon may tear completely; this is known as a rupture and surgery is likely to be needed for the repair.
The RICE treatment will help swelling and bleeding to a minimum; these can both cause pain, so using the RICE treatment both promotes healing and relieves pain. Minor knee injuries generally do not swell as much as more serious injuries, but any swelling can cause pain or discomfort and prolong recovery time. The most important step in treating a strained knee is rest; allowing the muscle fibers to heal on their own will promote the most healing, and it is important to stay off the knee until little or no pain is felt.
Once the swelling is down and the pain is gone or mostly gone, rehabilitation will be necessary to restore the knee to its former strength. This phase of treatment will include physical therapy and regular stretching. The muscles must be strengthened again, and mobility will need to be restored, so it is important to build strength and mobility in the knee. A doctor may recommend you see a professional physical therapist who can guide you safely through the process. If pain recurs or worsens, physical therapy should be stopped. Starting physical therapy too early can re-injure the muscles and cause even more pain.
After the knee injury has had sufficient time to heal, a doctor or professional may recommend that you wear a knee brace. This provides compression to the injured area to keep swelling down, and it adds support to the knee joint during the physical therapy process. Knee braces are more useful in treating a sprained knee, in which the ligaments have been damaged, but they can also provide support and comfort for muscle and tendon injuries as well. If swelling or inflammation occurs at any point during the recovery period, a doctor may prescribe anti-inflammatory medications or painkillers as well.