Some of the most common symptoms of a torn knee ligament include pain, swelling and, in some cases, an audible snap. The severity of these symptoms depends on which knee ligament has been torn. Most people with a torn knee ligament will also suffer from knee instability, which can result in the knee giving way. Instability in the joint may be masked by large amounts of swelling.

The symptoms of an injury to a knee ligament depend on the severity. A Grade One sprain is the least severe and often only results in minor pain and instability. Grade Two tears are more serious and cause a greater amount of pain and instability. A Grade Three sprain, also referred to as a completely torn knee ligament, is the most severe. The symptoms of a torn knee ligament also partly depend on which ligament is involved.

A torn knee ligament is often the result of a twisting movement. When a tear occurs, there may be a popping noise, although this depends on which ligament is involved. An anterior cruciate ligament (ACL) tear is most likely to result in an audible snap. If the injury happens during an athletic activity, this noise is often loud enough for surrounding participants to hear.

Pain is common to all types of torn knee ligament, but is most severe if the ACL is affected. A tear to the medial ligament is often painful, but is not thought to be as excruciating. After the injury, the joint will swell in order to protect itself. This can happen immediately after the injury or there may be a short delay. Swelling is important in the initial stages because it helps to prevent further injury, but it needs to be managed carefully.

Instability is a common symptom of a torn knee ligament. The main function of knee ligaments is to provide stability in the joint; if one becomes torn, it affects the joint’s balance. If the ACL is torn, for example, then there will be significant instability immediately after the injury. Once the joint begins to swell, however, then this instability may not be so obvious.

Proper treatment for a torn knee ligament is essential for a full recovery. A physiotherapist may provide a conservative treatment plan or a set or exercises to perform in the lead up to surgery. If rehabilitation is ignored by the athlete, it can result in additional problems and may prevent a full return to competitive sports.