Knee pain - anterior cruciate ligament

The anterior cruciate ligament (ACL) is the most commonly injured ligament of the knee, and it is most frequently injured during an athletic activity. Sports are becoming an increasingly important part of day-to-day life in the United Kingdom, increasing the number of ACL injuries. This injury has received a great deal of attention from orthopaedic surgeons over the past 15 years, and very successful operations have been developed to reconstruct the torn anterior cruciate ligament.

anatomy

The ACL controls how far forward the tibia (shin bone) moves in relation to the femur (thigh bone). If the tibia moves too far, the ACL can rupture. The ACL is also the first ligament that becomes tight when the knee is straight. If the knee is forced past this point, or hyperextended, the ACL can also be torn.

This tearing of the ligament results in a loud pop and a feeling of instability in the knee. The ACL may not be the only ligament injured when the knee is twisted violently, such as in a clipping injury in football. It is not uncommon to see both the medial collateral ligament (MCL) and the ACL injured.

causes and symptoms

The major cause of injury to the ACL is sports related. Numerous types of sports-related activities have been associated with ACL tears. Those sports requiring the foot to be planted and the body to change direction rapidly (such as basketball) carry a high incidence of injury. Football is frequently the source of an ACL tear because it combines the activity of planting the foot and rapidly changing direction with the threat of bodily contact. Downhill skiing is another frequent source of injury, especially since the introduction of ski boots that extend higher up the calf. These boots move the forces caused by a fall to the knee rather than the ankle or lower leg. The ACL injury usually occurs when the knee is forcefully twisted or hyperextended. Many patients recall hearing a loud pop when the ligament tears and feeling the knee give out.

There has been a dramatic increase in the number of females who suffer ACL tears. This is in part due to the rise in women's athletics, but studies have shown that female athletes are more likely to suffer this injury then their male counterparts. It is uncertain why this is the case. Initially, it was thought that females were at higher risk because of differences in training intensity. But more evidence suggests that there may be a difference in the anatomy of the female knee, or the female ligament may not be as strong due to the effects of the female hormone oestrogen. These factors may lead to a higher risk of ACL injury for the female athlete.

The symptoms following a tear of the ACL vary in different people. Usually, swelling of the knee occurs within a short time following the injury. This is due to bleeding into the knee joint from torn blood vessels in the damaged ligament.

The instability caused by the torn ligament leads to a feeling of insecurity and weakness of the knee, especially when trying to change direction on the knee. The knee may feel like it wants to bend too far backwards.

The pain and swelling from the initial injury will usually be gone after two to four weeks, but the instability remains. The symptom of instability and the inability for the patient to trust the knee for support is what requires treatment.

treatment in the acute phase

If traumatic injury of the knee occurs immediate medical attention should be sought.

P - R - I - C - E

Protection - Your knee may be splinted, taped or braced to prevent further injury.

Rest - You should rest from all activities that cause pain or limping. Use crutches/cane until you can walk without pain or limping.

Ice - Place a plastic bag with ice on the knee for 15-20 minutes, 3-5 times a day for the first 24-72 hours. Leave the ice off at least 1 1/2 hours between applications.

Compression - Wrap an elastic bandage from the toes to mid calf, using even pressure. Wear this until swelling decreases. Loosen the wrap if your toes start to turn blue or feel cold.

Elevate - Make sure to elevate the knee above heart level

to restore normal function

Exercises should not hurt, if they do stop!

Here are some exercises to help your knee pain. After you do all the exercises as shown in the drawings, reverse your position, and do the exercises with your other leg, so both knees get the benefit of stretching

stretching exercises

Technique:	Hold each exercise 30seconds at a gentle stretch. Do not bounce!
Frequency:	6-10 repetitions/exercise, 5-7 days per week

Iliotibial band and buttock stretch (right side shown)

Position yourself as shown above. Twist your trunk to the right and use your left arm to "push" your right leg. You should feel the stretch in your right buttock and the outer part of your right thigh. Hold the stretch for 30 seconds. Repeat on the other side.

Technique:	Hold each exercise 20 seconds at a gentle stretch. Do not bounce!
Frequency:	6-10 repetitions/exercise, 5-7 days per week

Iliotibial band stretch (left side shown).

Position yourself as shown above, with your right leg crossed in front of your left leg. Hold your hands together and move them toward the floor. You should feel a stretch in the outer part of your left thigh. Hold the stretch for 30 seconds. Relax then repeat on the other side

Technique:	Hold each exercise 20seconds at a gentle stretch. Do not bounce!
Frequency:	6-10 repetitions/exercise, 5-7 days per week

Hamstring stretch

Rest the leg to be stretched on a supporting surface while keeping the knee from bending. Lean forward toward your toes by bending at the waist and keeping your back straight. You should feel the stretch but it should not hurt.

Technique:	Hold each exercise 30 econds at a gentle stretch. Do not bounce!
Frequency:	6-10 repetitions/exercise, 5-7 days per week

Calf stretch

Foot alignment should be shoulder width apart, you can confirm this by standing either side of a straight line on the floor. When you take your rear foot back, it should not cross or move away from the midline, your foot should be pointing forward with your heel either flat on the floor, or raised if aiming to develop the stretch.

Your front leg should bend so that when you look down over your knee, you can see the tip of your toes. Lean forward aiming to keep a straight line with your heel, hip and head.

For best results, push against a wall.

strengthening exercises

Technique:	Hold each exercise 30 seconds at a gentle stretch.
Frequency:	2-3 repetitions/exercise, 5-7 days per week

Quadriceps strengthening: straight leg

Position yourself as shown above. Hold your right leg straight for 30 seconds and then relax.

Technique:	Hold each exercise 5-10 seconds at a gentle stretch.
Frequency:	6-10 repetitions/exercise, 5-7 days per week

Quadriceps strengthening: straight leg lift.

Position yourself as shown above. Raise your right leg several inches, and hold it up for 5 to 10 seconds. Then lower your leg to the floor slowly over a few seconds. Then repeat the exercise

Technique:	Hold each exercise 5-10 seconds.
Frequency:	5-10 repetitions/exercise, 5-7 days per week

Hip adductor strengthening.

While sitting, squeeze a rubber ball between your knees. Hold the squeeze for 5 to 10 seconds. (If you don't have a ball, put your hands or fists between your knees and then squeeze.)

Technique:	Hold each exercise for 5-10 seconds
Frequency:	10 repetitions/exercise, 5-7 days per week

Hip abductor strengthening (left side shown, front and side views)

Position yourself as shown above, standing on your left leg with the knee slightly bent. Slowly raise your right foot about 30 degrees, hold for a few seconds, and then slowly lower the foot and straighten both legs. Don't let your pelvis tilt (be crooked), and don't let your knees turn inward during bending.

Repeat the exercises below several times with each leg on a daily basis. Over several weeks, increase the resistance by adding ankle weights or by looping purse straps or the handle of a weighted pail over your ankle. Start with one or two pounds, adding one-half pound at a time as you build strength.

Bent-Leg Raises

This strengthens the inner thigh muscle to balance the pull on the knee joint from the outer thigh, which is often stronger.

Sit on a chair and straighten one leg.
Hold for one minute.
Bend your knee to lower that leg about halfway to the floor (a 45-degree angle).
Hold for 30 seconds.
Return to starting position and rest for one minute.
Repeat.
Work up to four repetitions for each leg.

Straight-Leg Raises

This strengthens the thigh muscles to help support the knee joint.

Sit in a chair with one leg extended, resting your foot on a chair.
Lift that foot a few inches while keeping your leg straight.
Hold for 10 seconds.
Return to resting position for 10 seconds.
Repeat.
Work up to three minutes of lifting for each leg.

to help prevent injury

Remember, many patello-femoral problems occur at contact phase of gait (when the foot hits the ground) due to increased biomechanical stress at this point. It is therefore vital to improve your biomechanics with orthotics designed for you chosen sport.

Golden rule- Don't ignore the problem, it won't go away!

The way we function biomechanically is predominantly controlled by genetics, its hereditary (runs in the family). The way you function is set and cannot be cured.

What you can do however is control lower limb biomechanics by altering foot position during the contact phase of gait. This can only be done by wearing a good shoe (see our shoe guide) and with orthotics (foot beds). This is the cheapest and most cost effective way for any athlete to reduce the risks of injury from occurring and from helping to prevent re-injury. Overall costs for the average athlete will run into pennies per mile/hour of sport.

Orthotics are designed to alter the biomechanics during the time the foot is on the ground. They are also used to provide increased shock absorbency working in harmony with the sport shoe worn.

Consider purchasing a knee brace . This device provides extra stability to the knee when playing sports. The material also causes localised vaso-dilation (opening of the blood vessels) increasing circulation to the area. This is vital as all ligaments have a notoriously poor blood supply. Increasing circulation to the ligaments can reduce the chance of injury. Have a look at the knee brace information page in our online store.

Wobble boards- Designed to improve proprioception these devices used as per the manufacturers instructions will improve the connection between the brain and the nerve fibres in the leg. Have a look at the wobble board information page in our online store.

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Check your running shoes, are they worn, how long have you had them? Trainers used for running are designed to last at most about 750 miles. If you think you have done more mileage then replace them with a new pair. Read the running shoe page to get practical advice on running shoes.

returning to sporting activity

The goal of rehabilitation is to return you to your sport or activity as soon as is safely possible. If you return too soon you may worsen your injury, which could lead to permanent damage. Everyone recovers from injury at a different rate. Return to your activity is determined by how soon your knee recovers, not by how many days or weeks it has been since your injury occurred.

You may safely return to your sport or activity when, starting from the top of the list and progressing to the end, each of the following is true:

You have full range of motion in the injured leg compared to the uninjured leg.

You have full strength of the injured leg compared to the uninjured leg.

You can jog straight ahead without pain or limping.

You can sprint straight ahead without pain or limping.

You can do 45-degree cuts, first at half-speed, then at full-speed.

You can do 20-yard figures-of-eight, first at half-speed, then at full-speed.

You can do 90-degree cuts, first at half-speed, then at full-speed.

You can do 10-yard figures-of-eight, first at half-speed, then at full-speed.

You can jump on both legs without pain and you can jump on the injured leg without pain.

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