Ligaments are strong, leather-like fibers of connective tissue that enclose a joint. They can be stretched (sprained), or partially or completely torn.
A patient can tear one or more ligaments, or ligaments and menisci simultaneously. The degree of damage depends on the direction and magnitude of the injuring force.
The most common combination is injury to the medial collateral and the anterior cruciate ligaments, often seen in football after a player is hit from the side. The high incidence of knee injuries from this mechanism led to the abolition of the "crack-back" block in American football.
Most ligament tears are caused by severe forces, but the anterior cruciate ligament (ACL) may be damaged by moderate forces such as landing from a jump. An isolated tear of the anterior cruciate ligament is the most common ligament injury.
If the force to the side of the knee is more severe, or if you are rotating your knee when you are hit, then the ACL may be stretched or torn. The most severe ruptures are caused not by trauma but usually by a heavy athlete, such as a football lineman, running and then planting his foot and turning 90 degrees to go upfield. This twisting can cause a complete ACL rupture.
If the ACL ruptures, a loud pop may be heard. A person will feel pain and instability in the knee. The knee will swell up rapidly because the ACL bleeds quickly when injured. Any ACL injury causes symptoms profound enough for one to seek professional help.
A ligament tear causes a hemorrhage, producing a swollen, painful joint that will not bear weight. A chronic tear causes symptoms only during vigorous activities such as sports, usually in the form of giving way. Over a period of time, this can damage the menisci and cartilage, leading eventually to degenerative wear and tear osteoarthritis.
Within two weeks of the injury, a simple sprain or partial tear are treated in a plaster cast (groin to toes) for four to six weeks. This is followed by approximately six weeks of physiotherapy and a return to sports in three to six months.
Non-surgical treatment of a chronic tear depends on the patient's age and needs. The low demand or unathletic person may be content to decrease activities so that the knee never gives way. More athletic individuals may be able to cope by wearing a brace to stabilize the knee during sports.
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