Knee sprains symptoms vary considerably depending upon grade (I, II, or III). While all grades of knee sprains are likely to result in swelling and limited mobility, more severe sprains may cause audible popping noises at the time of the injury, buckling sensations, severe bruising, and more.
Common symptoms of knee sprains include:
- Pain. Athletes who have sustained knee sprains will experience varying degrees of pain depending on the severity of their injury. Knee pain will be dull and throbbing for mild sprains and sharp and constant in the case of severe sprains. Typically, pain subsides when the knee is at rest and returns with movement.
- Knee swelling. A knee sprain is usually accompanied by swelling. The amount of swelling present will vary based upon exactly how severe the sprain is, as well as how long it has been since the injury was sustained.
- Limited mobility. Following a sprain, weakness in the affected ligament(s) and localized swelling may limit an athlete’s mobility.
- A popping sound. An athlete may hear an audible popping or snapping sound at the moment that the sprain occurs. This sound may indicate that one of the four major knee ligaments was torn at the moment of injury, suggesting a more serious (Grade III) sprain.
- Inability to hold weight. The injury to the ligament and the accompanying knee inflammation and tenderness may make it difficult or impossible for the knee joint to bear weight.
- Buckling of the knee. If a person can put weight on the affected leg, a buckling sensation may be felt in the knee when trying to stand, walk, or run. The direction in which the knee buckles may help indicate which ligament has been injured. For example, an LCL injury may cause the knee to buckle slightly towards the inside of the leg.
- Bruising. Though possible with sprains of any of the four major ligaments in the knee, bruising is most likely to occur following an ACL sprain. Discoloration will appear on and around the front of the kneecap.
A knee sprain, particularly a lower grade knee sprain, may not fully present symptoms until after a few hours or a day of rest.
Knee sprains symptoms can be similar to the symptoms of many other knee injuries. For example, a lateral collateral ligament sprain, a lateral meniscal tear, and iliotibial band tendonitis all produce pain at the outside of the knee. In addition, knee sprains can occur in combination with other knee injuries. If a sprained knee or other injury is suspected, it is advisable to stop participating in sports or any activity that causes knee pain until after a medical evaluation.