Ligament Injuries


The volleyball match has been going

on for over an hour. Both teams have been trading

points and side-outs. The ball is set high outside so

that the big outside hitter can put the ball away.

She comes in hard, plants, leaps into the air and

smashes the ball down the line in a twisting motion.

As she lands on her right leg, a POP is heard and

down she goes. What has just happened is

occurring more and more often in athletics, the

athlete has just torn the anterior cruciate ligament

(ACL). In this paper I will describe ACL, how it

is injured and diagnosed, how it be repaired and

what is being done to prevent ACL injuries. The

Anterior Cruciate Ligament (ACL) is one of the

two cruciate ligaments of the knee, the other being

the Posterior Cruciate Ligament (PCL). These

ligaments are the stabilizers of the knee. The ACL

is a strip of fibery tissue, which is located deep

inside the knee joint. It runs from the posterior

side of the femur (thigh bone) to the anterior side

of the tibia (shin bone) deep inside of the knee.

The ligament is a broad, thick cord the size of a

person's index finger. It has long collagen strands

woven together in a fashion that permits forces of

up to 500 pounds to be exerted. The function of

the ACL is to prevent the tibia from moving in

front of the knee and femur. The ACL also

prevents hyperextension (or extreme stretching of

the knee backward) and helps to prevent rotation

of the tibia. The amount of knee ligament injuries

have been on the rise in recent years. Over the last

15 years, ankle sprains have decreased by 86%

and tibia fractures by 88%, but knee ligament

injuries have increased by 172%. The injury

usually occurs in either a slow twisting fall, a

sudden hyperextension, or a sudden hyperflexion

as when landing from jumping. When the injury

occurs the athlete usually hears a "pop" and they

will have immediate swelling of the knee. When

the person tries to put weight on the leg it will feel

like the knee isn't underneath the athlete. With

most injuries the type of movement will help to

determine the injury: "I twisted to the right." etc.

When ACL injuries occur there is a "popping"

sound at the time of injury and swelling within six

hours. An experienced clinician can diagnose an

ACL tear with relative accuracy by a manual

examination. X-ray examination and Magnetic

Resonance Imaging (MRI) is also used in

diagnosing ACL injuries. The knee joint will be

instable and the athlete will have joint pain on the

inner (medial) side of the knee. Doctors or trainers

can use three different types of physical

examinations: Lachman's test, Anterior drawer test

and Pivot shift test of MacIntosh. Lachman's test

is performed by having the athlete lie on his/her

back, then passively flexing the knee of the athlete

to between 20 degrees and 30 degrees. Make

sure that the hamstring is relaxed or it can produce

a false test result. Holding the lower part of the

athlete's thigh in one hand and the upper part of

the athlete's calf in the other, slowly pull the tibia

forward. Increased looseness in the knee joint is

indicative of an ACL injury. During the Anterior

drawer test the athlete lies on his/her back with the

knee bent to 90 degrees and the foot resting on

the table. Stabilizing the foot either by sitting on it

or having someone else hold it down, the doctor

will place his/her hands around the upper part of

the calf with thumbs on the end of the thigh bone

(tibal condyles), slowly appling pressure on the

posterior side of the proximal tibia. Any looseness

in the joint could indicate ACL injury. The Pivot

shift test of MacIntosh is done by having the

athlete lay on his/her back. The foot of the injured

side is lifted with the leg straight and the foot

turned inward. Pressure is applied to the outside

of the knee while the knee joint is slowly bent. An

ACL injury is detected if the tibia moves out of

joint at 30-40 degrees or if a clunk is felt. One

should note that this test can be very painful for the

athlete. When an athlete has injured his/her ACL

the initial treatment involves splinting the knee, ice

treatment to help reduce swelling, elevation of the

joint (just above the heart) and administration of

anti-inflammatory drugs. The athlete also needs to

limit physical activity. A non-athletic person can

live with the injury using rehabilitation and bracing.

When the ACL is injured the guide wire of the

knee is gone, creating instability. Without the

stabilizing actions of the ligament, there is

increased wear