Muscle injuries They are called sprains, but knee sprains are caused by injuries to the ligaments. The ligaments support the joints in your body and connect your bones to each other. The ligaments are formed of fibrous tissue and stretch like a rubber elastic. Most sprains occur in the ankle, knee or wrist and are the result of sports activities. Knee sprains can be particularly painful.
A knee sprain is often caused by a traumatic event, such as twisting your knee to an abnormal position, falling or stopping your movement too quickly. As the ligaments in your knee extend beyond their limits, the ligament fibers begin to fail sequentially. Failure in the fibers eventually causes a complete tear of the ligament. There are four main ligaments that provide stability to the knee and can suffer a sprain: the tibial collateral ligament, inside the knee; the lateral lateral ligament, on the outside of the knee; and the anterior and posterior cruciate ligaments, both deep in the knee joint.
When a sprain happens, you may have a broken or cracked sensation at the time of your injury. It is often followed by pain, swelling and difficulty in supporting the weight on the knee. Stiffness and contusion usually develop 24 to 48 hours after the injury. The most common collateral tibial ligament injuries are caused by a lateral impact to the outside of the knee, forcing it to bend forcefully inward, such as in a collision. It is more common for anterior cruciate ligament tears to occur through a non-contact twisting mechanism, such as sudden braking and turning during an evasion maneuver.
Seek medical attention, especially if your knee is swollen. To determine the stability of your knee and the degree of the injury, the doctor will examine the area to detect inflammation, sensitivity and bruising. If your injury is deep inside the knee joint, the symptoms may not be evident. It is advisable to compare the injured knee with the healthy knee. Examining the injury can be difficult because your joint can be extremely painful. Some ligament injuries require special clinical examination techniques to determine the degree of injury and instability. Stress tests in valgus or varus are used to diagnose sprains in the tibial collateral ligament or external lateral ligament. During this test, the examiner will place one hand on the thigh, bend the knee to 30 degrees of flexion and force the lower leg either inward (varus) or outward (valgus).Pain in the inside of the leg with a valgus strain indicates a sprain in the tibial collateral ligament, while pain on the outside indicates a sprain in the lateral lateral ligament. A chronic or untreated sprain can cause instability in the joint, and persistent joint instability can accelerate knee deterioration.