Related Document: Therapy Specialists Inc's Guide to Osteoarthritis of the Knee Diagnosis Also important in the decision about treatment is the growing realization by orthopedic surgeons that long-term instability leads to early arthritis of the knee. The symptom of instability and the inability to trust the knee for support are what require treatment. The pain and swelling from the initial injury will usually be gone after two to four weeks, but the knee may still feel unstable.
And you may have trouble coming to a quick stop. Walking downhill or on ice is especially difficult. There may be activity-related pain and/or swelling. The knee may feel like it wants to slip backwards. The instability caused by the torn ligament leads to a feeling of insecurity and giving way of the knee, especially when trying to change direction on the knee. This is due to bleeding into the knee joint from torn blood vessels in the damaged ligament. Usually, the knee joint swells within a short time following the injury. Some patients report hearing and/or feeling a pop. The symptoms following a tear of the ACL can vary. Taken together, these factors may explain why female athletes have a higher risk of ACL tears. Other studies suggest that women's ACLs may be weakend by the effects of the female hormone estrogen. Women's sluggish hamstring response may allow the tibia to slip forward, straining the ACL. The hamstring muscles normally protect the tibia from sliding too far forward.
Meanwhile, women's hamstring muscles (on the back of the thigh) respond more slowly than in men. This pulls the tibia forward, placing the ACL at risk for a tear. Women's quadriceps muscles (on the front of the thigh) work extra hard during knee-bending activities. Also, tests show that women's quadriceps and hamstring muscles work differently than men's. This means women don't get their knees to hold as steady, which may give them less knee protection during heavy physical activity. Women athletes seem less able to tighten their thigh muscles to the same degree as men. Recent research has shown several factors that contribute to women's higher risk of ACL tears. But studies have shown that female athletes are two to four times more likely to suffer ACL tears than male athletes in the same sports. This is due in part to the rise in women's athletics. The number of women suffering ACL tears has dramatically increased. Many patients recall hearing a loud pop when the ligament is torn, and they feel the knee give way. An ACL injury usually occurs when the knee is forcefully twisted or hyperextended while the foot remains in contact with the ground. These boots move the impact of a fall to the knee rather than the ankle or lower leg. Downhill skiing is another frequent source of injury, especially since the introduction of ski boots that come higher up the calf. Football combines the activity of planting the foot and rapidly changing direction and the threat of bodily contact. For example, a blow to the outside of the knee when the foot is planted is the most likely contact-related injury.įootball is also frequently the source of an ACL tear. However, contact-related injuries can result in ACL tears. In this way, most ACL injuries are considered noncontact. Those sports requiring the foot to be planted and the body to change direction rapidly (such as basketball) carry a high incidence of injury. The types of sports that have been associated with ACL tears are numerous. Sports-related injuries are the most common. The mechanism of injury for many ACL ruptures is a sudden deceleration (slowing down or stop), hyperextension, or pivoting in place. Related Document: Therapy Specialists Inc's Guide to Knee Anatomy It is not uncommon to also see a tear of the medial collateral ligament (MCL) on the inside edge of the knee, and the lateral meniscus, which is the U-shaped cushion between the outer half of the tibia and femur bones. Other parts of the knee may be injured when the knee is twisted violently, as in a clipping injury in football. If the knee is forced past this point, or hyperextended, the ACL can also be torn. The ACL is also the first ligament that becomes tight when the knee is straightened. If the tibia moves too far, the ACL can rupture. This is called anterior translation of the tibia. The ACL is the main controller of how far forward the tibia moves under the femur. The ACL runs through a special notch in the femur called the intercondylar notch and attaches to a special area of the tibia called the tibial spine. The ACL is located in the center of the knee joint where it runs from the backside of the femur (thighbone) to connect to the front of the tibia (shinbone). Ligaments are tough bands of tissue that connect the ends of bones together.