Symptoms of a sprained knee generally depend on the ligament involved. In most cases, however, a sprain to a knee ligament will be painful and cause swelling. There are three grades of sprain, and the severity of the symptoms will vary depending on the grade. An athlete or physically active person may sometimes feel unstable on the joint and may find that the knee buckles sideways. Other symptoms include tenderness, bruising, and stiffness.
The symptoms of a sprained knee can vary between patients because the injury can affect one of several ligaments. If the anterior cruciate ligament is sprained, for example, this is often much more serious than a medical collateral ligament injury. For this reason, the symptoms of a knee sprain can range from minor discomfort and swelling to severe pain and instability that requires surgical intervention. In most cases, a sprained knee refers to a minor injury, although it’s important to get an accurate diagnosis from a doctor.
There are three grades of sprained knee. Grade One sprains involve the least severe symptoms, as the ligament fibers are not torn. Grade Two sprains involve a tear to some ligament fibers but not all, and Grade Three sprains involve a complete ligament tear. Symptoms become more severe as the number of torn fibers increases.
A knee sprain will often be accompanied by pain. For minor sprains, the pain may only become apparent when a person stops exercising. Severe sprains will prevent any further athletic activity and are much more painful. Pain is often felt when the knee is put under stress, such as going up or down stairs, although it may also be painful to merely walk after the initial injury. Along with pain, the patient may also notice some swelling around the knee joint which can restrict movement.
Knee sprains commonly occur during a sporting activity; they are often the result of sharp turns which put a lot of stress through the joint. If the knee sprain results in a major tear to the ligament, the athlete may feel unstable while walking. Depending on which ligament is torn, the knee may also buckle sideways. In some cases, an audible pop is heard when the ligament is damaged.
There are a number of other potential symptoms of a sprained knee. Tenderness around the knee joint is often present; this usually persists until the swelling has gone down. This may be accompanied by a visible bruise. The knee may also appear stiff to bend, and a person can sometimes have difficulty walking.