Sprains and strains are two common types of traumatic injuries that can occur in teenagers. Sprains and strains of the knee joint commonly occur as sports injuries in young athletes. Both types of injuries can cause severe swelling and pain, but sprains are generally more severe injuries that may require more medical intervention for proper healing of the knee joint.
A sprain is overstretching or tearing of a ligament, a strong band of connective tissue that connects bones to other bones to stabilize a joint. The knee joint, which is particularly prone to injuries because it is a weight-bearing joint, has four different ligaments that can be sprained. These ligaments are called the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL) and lateral collateral ligament (LCL). These ligaments can all be sprained playing sports, but the ACL is the most commonly sprained knee ligament. A knee sprain can vary in severity from very small tears that cause some swelling and pain to a complete tear of the ligament, which may require surgery to repair the function of the knee joint. If a ligament in the knee is completely torn, the knee joint may have decreased stability and a person may not be able to put weight on the injured joint.
A strain is overstretching or tearing of muscle fibers or the tendons that connect muscles to bones. It may be difficult to tell the difference between a knee sprain and a knee strain until a doctor performs a clinical examination of the knee injury because both types of injuries will cause pain and some swelling of the knee joint. Strains can range from a mild injury of a muscle that heals on its own after a period of rest to a complete tear of a muscle tendon.
If a knee sprain or strain occurs in a teenaged athlete, it is important for the injured individual to seek medical attention and not resume playing sports until the injury has fully healed. Re-injuring the same knee only adds on more healing time, so it is better to let the injury fully heal before attempting to resume activity. Properly stretching and warming up before playing sports can also improve flexibility and reduce the risk of knee sprains and strains while playing sports.