Soccer is a tough sport on the knees. It requires you to run, kick, stop and start in all directions, including sideways. If your knee hurts when side kicking the soccer ball, you may have a condition that ranges from an overuse syndrome to a serious injury. See your doctor as soon as possible to prevent further injury.
You have two vital cushions in your knee called the menisci, one on each side of your joint. Each meniscus is cartilage that cushions the ends of the femur in your thigh and tibia in your shin and keeps them from grinding together. Too much force or twisting of your knee during a side kick can tear a meniscus. A small tear will enable you to go about your day and will hurt mostly if you squat or side kick. Treatment usually involves rest and icing and the injury will heal itself. A large tear will make it difficult and painful to walk and will require surgery to remove the torn section of meniscus or repair it if possible.
Collateral Ligament Tear or Sprain
Your knee is held together by connective tissue called ligaments. You have two ligaments on the inside of your knee. You also have collateral ligaments, one ligament on either side of your knee. The collateral ligaments can be injured when they are hit by a force on the opposite side. For example, using your right leg to side kick the ball to the left may cause pain on the outside of your right knee from damage to the ligament on that side. A small tear or stretch of the ligament is a sprain, which will cause pain when you side kick the soccer ball. Treat this by resting and icing your knee. You may also need a brace until it feels better. A more serious tear or rupture will require surgery.
Iliotibial Band Syndrome
Overuse of the knee may also cause your knee to hurt when you side kick a soccer ball. One common injury is iliotibial band syndrome, when the iliotibial band becomes irritated. The iliotibial band is a tendon that stretches from your hip to your knee along the outside of your leg. Repetitive flexing of your knee may cause the iliotibial band to become inflamed as it constantly slides back and forth over the end of your femur. The pain that results will feel like it's going across your knee and will be worse when you flex your knee, such as when you side kick. Treatment involves resting, icing and physical therapy to stretch the iliotibial band and strengthen the muscles that support it in your thigh and buttocks.
Patellofemoral Pain Syndrome
Another common overuse injury is patellofemoral pain syndrome. It results from frequent knee flexing, causing the kneecap to become misaligned on the groove it slides along on the femur. Pain when you side kick will feel like it is coming from behind your knee. Treatment for this condition involves icing and resting your knee, then physical therapy to strengthen the muscles that stabilize the knee cap, mainly the quadriceps and hamstrings. Surgery is rarely required but may be necessary if the condition advances to cause damage to the underside of the knee cap, in which case you may need a surgeon to smooth the under surface of the knee.