The Anterior Cruciate ligament is one of the most important stabilising ligaments of the knee.
|The ligament is shown here in red color. The cruciate ligaments are so called because the anterior and posterior cruciate ligaments cross over in like the two limbs of a cross.
The anterior cruciate ligament can be torn by significant injuries like skiing accidents, rugby tackle or high energy sports injuries. Such an injury leads to immediate swelling of the knee due to bleeding inside the joint. There is a lot of pain and the thighs muscles go weak very quickly.
After a few weeks, the pain and swelling subside, but the knee can be unstable and keep on giving way. Sporting activities may be difficult.
Anterior cruciate ligament rupture can be confirmed by a careful history of the mode of injury, a physical examination and by a MRI scan. Quite often the physical signs are confirmatory and a scan may not be needed . Further treatment needs to be tailored to individual patient’s circumstances and the age, the anticipated level of physical activity, return to sports all need to be considered.
Anterior cruciate rupture can lead to repeated giving way of the knee, which in turn can cause damage to the semilunar cartilages and consequently lead to premature arthritis. In young patients, therefore, if the knee is unstable and does not respond to a course of muscle building exercise, then reconstruction of the ligament will be an appropriate option, whereas, in a middle aged person whose knee does not give way, surgery is not needed.
Reconstruction of the ligament can be done by the open or the arthroscopic method.In the arthroscopic method, a small telescope is used to visualise the inside of the knee and to help in the reconstruction of the ligament. As the torn ligament is like shredded wheat, a repair is not possible and another tissue of the body is used to fashion a new ligament. Generally, the middle of the patellar tendon or the hamstring tendons are used for this purpose.
The two tendons generally used to fashion the cruciate ligament are the Gracilis and Semitendinosus tendons which are located on the inner side of the thigh and the knee as shown in the diagram on the left. The tendons can be stripped out through a small cut just below the knee with the help of a special tendon stripper.
A double loop of both the tendons is then fashioned to provide a four stranded graft.
This graft is then inserted through the knee in the path of the original anterior cruciate ligament with the help of special arthroscopic instruments as shown in the next page.