The knee is one of the most important joints. It enables you to walk, squat, and climb steps. A knee sprain can seriously affect your quality of life by making these everyday movements difficult and painful. This common injury occurs when the connective tissues in your knee stretch or tear.
Athletes are especially prone to knee sprains, but this injury can happen to anyone. Fortunately, a knee sprain is treatable, and most people recover.
Discover the causes, symptoms, and treatment for this disorder.
What Is a Knee Sprain?
The human knee is a complex joint that contains three bones: the femur, patella, and tibia. Ligaments are rope-like pieces of tissue that attach these three bones and stabilize your knee. Your knee has four main ligaments belonging to two different categories, each with different functions.
Collateral ligaments. These connecting tissues support the sides of your knee and allow the joint to move from side to side. These ligaments include the:
- Medial collateral ligament (MCL). This ligament attaches the femur to the tibia along the inside of your knee.
- Lateral collateral ligament (LCL). This tissue runs along the outside of your knee. It links your femur to the fibula, a small bone in your leg.
Cruciate ligaments. These two ligaments cross inside your knee joint in an “X” shape. They allow your knee to move forward and backward without moving too far sideways. The two cruciate ligaments are the:
- Anterior cruciate ligament (ACL). This tissue stretches diagonally across the middle of your knee and attaches the femur to the tibia. The ACL is your knee’s weakest and most commonly injured cruciate ligament.
- Posterior cruciate ligament (PCL). This fiber lies behind the ACL and stabilizes your shinbone. The PCL is less prone to injury than the ACL.
An injury to any of these ligaments can cause a knee sprain.
What Causes a Knee Sprain?
A knee sprain can be caused by any movement or trauma that stretches your ligament too far, causing it to tear. Common knee sprain causes include:
- A hard blow to the knee (for instance, while playing sports)
- A car crash
- Changing direction rapidly while moving
- Landing awkwardly after a fall or jump
- Putting too much pressure on the knee
- Twisting the knee
Most knee sprains only affect one ligament. However, multiple ligaments may be injured during a traumatic event like a car accident or a long fall.
What Are the Symptoms of a Knee Sprain?
If you sprain your knee, you will probably notice the injury immediately. Knee sprain symptoms include:
- An altered gait
- Difficulty bending your knee
- Instability in your knee
- Pain or discomfort
You may also feel a “snapping” sensation inside your knee when your ligament tears.
If you experience severe pain or if your symptoms persist even after treating your knee at home, you should see contact at Apex Center for Regenerative Medicine is dedicated to keeping our athletic & active community healthy and active. We work with patients of all ages and performance levels, from students involved in competitive school and club sports; to avid amateurs who participate for fun and fitness, to professionals whose livelihood depends on their physical health.